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PLOS ONE logoLink to PLOS ONE
. 2023 Apr 27;18(4):e0284908. doi: 10.1371/journal.pone.0284908

Improved cookstoves to reduce household air pollution exposure in sub-Saharan Africa: A scoping review of intervention studies

Eunice Phillip 1,*, Jessica Langevin 1, Megan Davis 1, Nitya Kumar 2, Aisling Walsh 1, Vincent Jumbe 3, Mike Clifford 4, Ronan Conroy 1, Debbi Stanistreet 1
Editor: Srijan Lal Shrestha5
PMCID: PMC10138283  PMID: 37104469

Abstract

Household air pollution (HAP), primarily from biomass fuels used for cooking, is associated with adverse health outcomes and premature mortality. It affects almost half of the world’s population, especially in low-income and low-resourced communities. However, many of the ’improved’ biomass cookstoves (ICS) aimed at reducing HAP lack empirical evidence of pollutant reduction and reliability in the field. A scoping review guided by the Joanna Briggs Institute framework was systematically conducted to explore and analyse the characteristics of cookstoves to assess the ICS available to meet the socio-economic and health needs of households in sub-Sahara Africa (sSA). The review searched Scopus, PubMed, Web of Science, EMBASE, Global Health Database on OVID, BASE, and conducted a grey literature search from 2014 to 2022 for all field-based ICS studies. In addition, user perspectives were explored for cookstoves analysed as available, affordable, and effective in reducing harmful biomass emissions. The search returned 1984 records. Thirty-three references containing 23 ICS brands were included. The cookstoves were analysed into seven categories: (1) efficiency in HAP reduction, (2) availability, (3) affordability, (4) sustainability, (5) safety, (6) health outcomes, and (7) user experience. Most (86.9%) of the improved cookstoves showed a reduction in harmful emission levels compared to the traditional three-stone fire. However, the levels were higher than the WHO-recommended safe levels. Only nine were priced below 40 USD. Users placed emphasis on cookstoves’ suitability for cooking, fuel and time savings, safety, and price. Equality in cooking-related gender roles and psychosocial benefits were also reported. The review demonstrated limited field testing, a lack of evidence of ICS emissions in real-life settings in sSA, heterogeneity in emission measurements, and incomplete descriptions of ICS and kitchen features. Gender differences in exposure and psychosocial benefits were also reported. The review recommends improved cookstove promotion alongside additional measures to reduce HAP at a cost affordable to low-resource households. Future research should focus on detailed reporting of study parameters to facilitate effective comparison of ICS performance in different social settings with different local foods and fuel types. Finally, a more community-based approach is needed to assess and ensure user voices are represented in HAP intervention studies, including designing the cookstoves.

Introduction

The incomplete combustion of biomass fuel and kerosene in traditional cookstoves (TCS) and with three-stone fires (TSF) used in low-income communities emits pollutants such as fine particulate matter (PM2.5) and toxic gases, including carbon monoxide (CO), contributing to household air pollution (HAP) and ambient air pollution [1, 2]. These pollutants are linked to environmental damage through deforestation [3], climate depleting compounds such as black carbon (BC) [4]. They are also directly associated with poor health outcomes, including pregnancy-related complications [5, 6], cardiovascular and respiratory illnesses [79].

The World Health Organization (WHO) described HAP as one of the most significant environmental health risks, accounting for 7.7% of global mortality in 2016 [10]. This includes 25% of chronic obstructive pulmonary disease, 12% of strokes, 17% of lung cancers, 45% of pneumonia-related deaths in children under five years old (CU5) [4], and a higher risk of burn injuries [4, 11]. While this is of global concern, the burden is highest in low- and middle-income countries (LMICs) [8] among the poorest rural communities that rely on biomass fuel due to lack of access (availability and affordability) to cleaner energy sources and technologies [4, 10]. Women and children in these communities bear the highest burden, accounting for 60% of all HAP-related deaths [11, 12], with seven times the levels of PM2.5 and CO in women and adolescent girls compared to men and boys [13]. In addition, time lost to women and girls due to fuel collection further exacerbates the gender inequality gap and cycle of poverty [14].

While these health and social issues could be addressed with cleaner energy sources (e.g., liquid petroleum gas (LPG) and electricity) and advanced cookstove technologies (e.g., solar-powered and biogas cookstoves), these technologies remain unavailable, inaccessible, and unaffordable. In addition, the barriers to uptake and adoption of interim HAP-reducing practices (e.g., ventilation and behavioural practices such as reducing time spent in proximity to the open fire and improved cookstoves) also remain a challenge. Similarly, the adoption of the widely promoted improved cookstoves has been hindered by its inability to meet users’ cooking needs compared with the traditional three-stone fire (TSF) [15, 16], as well as other factors affecting financial and market development [15, 17, 18], regulation, standards, and quality of ICS [18, 19].

Our initial review of the literature demonstrated a wealth of studies measuring improved cookstove emissions [2022] and health outcomes [2325], including systematic reviews [7, 9, 15, 16, 18, 2628]. In addition, the effectiveness of these promoted cookstoves has mainly been tested in laboratory conditions [17, 19]. However, there remains limited research on ICS effectiveness in reducing HAP in real-life settings. This makes it difficult to benchmark their emission performance with the 2014 WHO indoor air quality (WHO-IAQ) guidelines [29] in real-life field situations as these values neither reflect how ICS perform in actual settings [30] nor their performance across different cultures and cooking practices.

Further, where available, studies tend to focus primarily on emission levels, and they often lack information on the cookstoves’ affordability, availability, sustainability, and ability to meet user cooking needs. Therefore, this review seeks to address this gap and build on the recommendation of Stanistreet et al. [30] to bring together all relevant information on improved cookstoves and review field-tested ICS evidence in sub-Saharan Africa (sSA), given that this region will account for 90% of the world’s population without electricity by 2030. This review thus aims to identify which improved cookstoves would be the most suitable to promote among poor communities in sub-Saharan Africa.

Materials and methods

This scoping review (ScR) examines evidence of improved cookstoves’ effectiveness, efficiency, and benefit to the poorest populations in sSA. Scoping reviews provide overviews of a topic, synthesise and map existing evidence, and identify gaps in a subject area [31, 32]. The protocol for this study was developed using the Joanna Briggs Institute’s (JBI) six-step framework for ScR. Originally developed by Arksey and O’Malley [32], the framework was modified by Levac and colleagues [33] and enhanced by Peters et al. [34]. The protocol was registered prospectively on ‘The Open Science Framework’, available at https://osf.io/pkzgh/. Our reporting structure was guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analysis extension for Scoping Reviews (PRISMA-ScR) [35] (S1 Table). All the review stages were iterative to ensure full exploration and understanding of the literature’s content.

The six-step framework

1. Identifying and developing the review questions

The research questions, inclusion and exclusion criteria were guided by JBI’s Participants/Population, Concepts, Context (PCC) search framework (Table 1) [34]. In consultation with social scientist experts, the review questions were developed to explore the state of current ICS evidence (Concept) that could be promoted among the poorest populations in sSA (Population) to reduce HAP and improve health outcomes (Context) (Table 1).

Table 1. Review questions and domains developed with JBI’s PCC and experts’ consultation.
Review questions Domains
1. What are the ICS characteristics? • Type or design • Affordability • Availability
• Safety • Sustainability
2. What is known about the ICS effectiveness? • Black carbon • CO • PM2.5 emissions
• Health outcomes compared to the TSF
3. What other measures support the implementation of the ICS? • Education • Awareness campaigns
• Incentives • Support
4. What are the users’ perceptions of the ICS identified from questions 1 and 2 above? • Health • Family • Timesaving • Cooking and cultural practices • Fuel saving

2. Identifying relevant studies and eligibility criteria

Six electronic databases were initially searched with the collaboration of an experienced librarian in June 2020. EP and DS screened the first 100 records for titles and abstracts to refine the terms used in the subsequent search of Scopus, PubMed, Web of Science, Embase, the Global Health Database on OVID, and BASE. EP and JL manually searched relevant websites (S1B Fig) and individual records within systematic reviews, and carried out backward snowballing of studies eligible for full-text screening. The search was updated in July 2021 and September 2022 (S1A Fig).

ICS were considered as an intervention if described as having the potential to reduce pollutants and improve health outcomes compared to the TSF (pot placed on three stone over an open fire) [36] or traditional cookstove (locally made from mud or metal and slightly more fuel-efficient than the three-stone fire) [37]. Studies eligibility criteria are as follows;

  • Time frame: From August 2014 to September 2022 to include all ICS designs studied after the 2014 publication of WHO Indoor Air Quality Guidelines and interim PM2.5 target for HAP.

  • Study type and publication: Empirical qualitative, quantitative, or mixed-methods studies published in peer-reviewed journals and/or on relevant organisation websites.

  • Type of Intervention and outcome: ICS intervention studies with personal and/or household measurements of HAP (CO, PM2.5, Black Carbon) and/or reported health outcomes and/or user perspectives

  • Population: Households in sSA.

  • Language: Published or auto-translated into English language due to limited translation resources.

We excluded sources if

  • Studies were laboratory-based

  • Interventions were LPG and electricity (target populations are unlikely to have access in the next 10–20 years)

  • Interventions were based on solar or biogas

  • There was no name or description of the improved cookstove

3. Selection of evidence

Search duplicates were removed from ENDNOTE® X9 reference manager software before exporting to Rayyan®, a platform that allows multiple collaborators to simultaneously screen and code the studies [38]. Four reviewers (EP, JL, MD, NK) conducted a three-stage blinded screening process using the established inclusion and exclusion criteria. The title and abstract screening preceded the full-text retrieval and screening. To ensure consistency, each reviewer double-screened a 20% random selection of each other’s work. Consensus was achieved through group consultations and discussions [33]. The final data screening occurred during the data charting process.

4. Data charting

Seven reviewers (EP, JL, MD, NK, DS, AW, VJ) independently extracted data from included studies. Non-sSA sites and non-biomass cookstoves’ data in our included studies were excluded at the data charting stage. In one instance, there were two papers reporting on the same study. We therefore only included the paper with the more comprehensive analysis. This paper reported the same data but included potential confounders in the analysis including fuel used for lighting, number of cooking episodes, and average number of people cooked for. We deemed this a more robust picture of reported pollutant levels in real-life settings.

We utilised a Microsoft Excel© spreadsheet to chart domains specified by the review questions. These domains included study design, location, duration of the intervention, population, ICS characteristics (design, fuel, combustion type), comparator (three-stone fire or traditional cookstove), ICS features (sustainability, safety, cost), supporting interventions (incentives and awareness), outcome measures (PM2.5, CO, black carbon, health outcomes), and user perceptions (S2 and S3 Figs). In addition, where required, missing information, such as ICS name, description, cost, market availability, and tier ratings, was sought from corresponding authors, Clean Cooking Alliance Catalogue [36], and marketing websites.

4.1. Quality appraisal. Although an optional process in a scoping review [34], a quality appraisal was deemed appropriate to assess the quality of available ICS studies. The studies were appraised using the Liverpool Quality Assessment Tool (LQAT) [16] for quantitative studies, the adapted version of Harden et al.’s [15] appraisal tool for qualitative studies, and the global rating scale [39]. Mixed-method studies were appraised with both appraisal tools. Assessment entailed rating the studies based on study context, methodology, baseline and outcome assessments, analysis/confounding, and impact of the findings to the review. Each element was assigned a rating of strong, moderate, or weak. The studies were rated as strong if there was no weak element, or moderate if one weak, and all other cases were rated as weak. if there was no weak. We provided an example, each of qualitative and quantitative study appraisal in S4A and S4B Fig.

5. Summary synthesis and reporting results

Validated conversion metrics for PM2.5 [27] and CO emissions [40] were used to standardise emission units to facilitate comparison. The conversion was not done for g/kg of fuel weight as conversion could not be justified without parameters such as fuel water content. The resulting data were categorised by ICS type, draft system, fuel type, HAP, and health outcome measures. In addition, fuel type, chimney, draft, and type of combustion chamber were mapped with HAP emissions, health outcomes and, subsequently, against the ICS classification. We labelled kitchen and household HAP measurements as ‘household’ measurements due to the studies’ limited descriptions of the term ‘kitchen’. Furthermore, in this review, we labelled the comparators, i.e., traditional cookstoves and three-stone fire, as TCS/TSF.

5.1 Post-synthesis screening of ICS to be promoted. Following the synthesis of emission levels and health outcomes, the ICS were evaluated to identify which cookstoves should be promoted to poorer communities in sSA. Cookstoves were excluded if (1) there was no reduction in emission level or health improvement, (2) they were no longer available on the market irrespective of HAP reduction levels, (3) priced ≥ $40 (mid-range of prices), (4) manufactured outside Africa (added shipping and import fees and difficulties in accessing customised parts reduce sustainability), (5) uses only pellets as fuel (the high price increases overall household cooking expenditure, and (6) uses charcoal fuel (ineffective use emits high PM, carbon monoxide, nitrogen oxides, sulphate oxides and other volatile compounds. These compounds have severe implications for health outcomes, e.g., cancer, low birth weight, and exposure associated with equivalent to smoking two packs of cigarettes/day [41]).

The user perspectives of included ICS were subsequently explored to inform their suitability to meet user needs. All findings are summarised in textual descriptions, data tables, and figures.

5.2 Exploring the user perceptions. We conducted the user perspective literature search in two phases. First, relevant studies were extracted from the initial search result. Second, a brand-specific search of ICS was executed in February 2021 and updated in July 2021 and September 2022 on PubMed, Global Health, Google Scholar, and relevant organisations’ websites, including United Nations High Commission for Refugees. In addition, studies were included if conducted in sSA, published after 2014, and explored the experiences and user perceptions of the ICS that met review questions 1, 2, and 3. The findings are presented in descriptive and diagram format using relevant themes from existing literature [15, 42, 43].

6. Consultation with experts

We engaged with experienced researchers, social scientists, and an engineer, all with extensive experience in HAP, cookstove research and behavioural change approaches in LMICs to develop review questions, themes, methodology, and data extraction processes.

Results

Overall, the review included a total of 33 studies, including 27 for review questions 1,2 and 3, and 10 that explored the ICS’s user perspectives. All were peer-reviewed articles, except for two non-peer-reviewed publications [44, 45] which reported the user views of the Save80 cookstove. Reviewed studies were conducted in only 10 of the 48 SSA countries [46] (Fig 1), spanning 35 study sites, 27 of which were in rural areas. Where sites were peri-urban and urban, studies [5, 4749] described them as socio-economically disadvantaged areas.

Fig 1. Representation of the 33 reported studies across the sub-Saharan African countries.

Fig 1

The review included six clustered- and five randomised controlled trials (cRCT) and (RCT), respectively. Other designs included pre-post (n = 5), case-control (n = 2), comparative (n = 2), uncontrolled infield test (n = 3), controlled cooking (n = 2), quasi (n = 2), cross-sectional (n = 1), qualitative structured interview (n = 1), and two mixed-method studies. The ICS were comparable to the three-stone fire in all the studies. Only 10 of the 33 studies reported additional techniques to support the ICS interventions. These included awareness/education/training (n = 7), behavioural change (n = 1), participatory methods (n = 2), and subsidised repairs and maintenance (n = 3). However, none reported the impact of the measures on study outcomes. Our quality assessment of included studies scored 12 as strong, 17 as moderate, and four studies as weak quality.

The study characteristics of included studies are displayed in Table 2 below.

Table 2. Characteristics of included studies.

Section A: Sources examining emission levels and health related outcomes of cookstoves
# Source Country Study design Population studied Study Sample size N (I; C) Intervention Control/ Comparator Types of measurement Follow-up time Quality appraisal score
Personal Household
1 Adane et al., 2021 [50] Ethiopia rural C-RCT 2031 low-income HH from North-west Ethiopia 1977 HH Mirt Traditional cookstove Not measured Baseline & follow-up indoor PM2.5 (1hr) 12 months Moderate
2 Adane et al., 2021 [51] Ethiopia rural C-RCT <4year old children from low-income HH in North-West Ethiopia 5508 children Mirt Traditional cookstove Incidence of childhood acute lower respiratory infection (ALRI) Not measured 12 months Moderate
3 Alexander et al., 2017 [5] Nigeria urban RCT, Women who are HH primary cooks, <18 weeks pregnant and use wood/ or kerosene as primary cooking fuel. 324 (162;162) pregnant women Cleancook Chulika
Smoke awareness campaign
Traditional cookstove/ kerosene or firewood 3 consecutive blood pressure (SBP & DBP) measurements at 16,20,26,30, 34, & 38 wk. gestation Not measured 4.9 months Moderate
4 Bensch and Peters 2015 [23] Senegal rural C-RCT Women responsible for cooking in 253 HH in 12 villages 253 (98;155) HH Firewood Jambar Three-stone stoves & traditional metal woodstove Self-reported respiratory and eye problems Not measured 12 months Strong
5 Champion & Grieshop 2019 [47] Rwanda urban /peri-urban Case-control HHs in Gisenyi low-resourced communities using biomass and locally manufactured charcoal as fuel 22HH (14 Mimi Moto; 4 TSF & 4 Charcoal stoves) MimiMoto
Educational program
Three stone fire and charcoal stoves Not measured Fuel-based in-use emission PM2.5, CO, Black carbon organic and elemental carbon 36 months (yearly interval. 2015–2017) Moderate
6 Coffey et al., 2017 [20] Ghana rural In-field Uncontrolled test A subset of the intervention arm (N not stated) from the 200 HH in the main study (RCT) from the Kessana-Nankana districts Intervention arm
(i) 2 stoves (Gyapa/ Gyapa) in 50HH
(ii) 2 stoves (Philips/Philips) in 50HH
(iii) 2 stoves (Gyapa/ Philips) in 50HH
Gyapa woodstove
Philips HD4012
Three stone fire
Coal pot
Not measured Real-time cooking emission. CO, CO2, PM organic carbon, elemental carbon 1.5 months Strong
7 Cundale et al., 2017 [25] Malawi rural Qualitative: Semi-structured interviews 10 HH from 10 village clusters in Chilumba. Mostly rural fishing and farming communities. HHs were participants in the CAPs 2015 trial 100HH (50I, 50C)
100 semi-structured interviews
Philips HD4012LS
User training & maintenance support
Traditional three-stone fire Health and non-health benefits HH time usage
Fuel consumption
36 months Moderate
8 Dutta et al., 2021 [52] Nigeria peri-urban RCT Women in the early second trimester of pregnancy 324 CleanCook (Sweden AB) Firewood/ Kerosene Mother: 72hr Personal PM2.5*
Fetus: growth trajectories using biparietal diameter, head & abdominal circumference femur length, and ultrasound-estimate fetal weight
Not measured 5.2 months (average follow-up) Moderate
9 Garland et al., 2017 [48] Uganda peri-urban Comparative study 16 HH in community outside of Kampala 16 HHs Referred to as TEG rocket Traditional three-stone fire and Charcoal stoves Not measured Real cooking time uncontrolled black carbon emission < 1 month Weak
Kenya, urban 22HH Urban community, Kwangware, Nairobi 22 participants Kenyan Ceramic Jiko Traditional cookstove
10 Gebreegzrabher et al., 2018 [53] Ethiopia, rural Controlled cooking test 108 HH from 81 villages in the forestry region 108 HH from 360 HH that received the ICS Mirt Traditional three-tripod stove Respiratory discomfort Not measured 5–6 months Moderate
11 Gitau et al., 2019 [54] Kenya rural Quasi HHs in Waa ward, Matunga constituency, Kwale 25HH for ICS; 5HH for TSF (different cooking test dates) Gastov Three stone fire Not measured Real-time PM2.5, CO, CO2 2 months Strong
12 Hankey et al., 2015 [55] Uganda
rural
Pre-post design 54 HH in 6 rural Ugandan villages surrounding Kyetume 28 HH for PM2.5 and 34 HH for CO. Ugastove Three stove fire Not measured 48 hr PM2.5 24 hr CO 1 month Moderate
13 Jagger et al., 2019 [49] Rwanda urban Cross-sectional (impact evaluation study) 144 HH decision-makers (>15years) and primary cooks in 22 communities in Bugoyi and Kivumu of Gisenyi district who had never used an ICS. 91 primary cooks at midline who were present at baseline. Mimi Moto
Marketing strategy
Door-to-door visits
Cooking demonstration
Traditional and charcoal stove Blood pressure, Shortness of breath
Cooking time
Not measured 8 months Moderate
14 Jagoe et al., 2020 [56] Kenya rural Pre-post design (exploratory sequential) Mixed study Participants who do most of the cooking in HHs from 3 rural agricultural communities (Githembe, Kambaa, and Bathi) 55HH Kuniokoa Three stone fires Not measured Real-time cooking measurement using SUM 3.5 months Moderate
15 Jary et al., 2014 [24] Malawi, rural RCT (feasibility study) Non-smoking women in the Ntcheu district who cooked on traditional open wood fires and wished to purchase a chitetezo stove 51 (25;26) women Chitetezo stove Traditional open fire Exhaled CO, shortness of breath, wheezing, eye problems, back pain, using questionnaire 24 hr Ambient CO 0.2 months Moderate
16 Kirby et al., 2019 [57] Rwanda, rural C-RCT Primary cook and children under 5 years in poor region of Ududehe region 1582 HH (789, 793) HH Eco Zoom Dura
community and HH education, e.g., radio songs
behavioural change messaging
Traditional biomass stoves Acute respiratory infection in CU5 48 hours PM2.5 None 12 months Strong
17 LaFave et al., 2021 [58] Ethiopia, rural RCT- post-intervention 480 HH in 36 communities All children and adult cook Mirt Stove
Training and ICS awareness
Traditional cookstove Child growth, respiratory conditions, activities of living 72 hours PM2.5 40 months Strong
18 Mortimer et al. 2017 [59] Malawi, rural C-RCT 8470 HH in 150 communities with at least one child aged below 5 years 10750 (5400;5350) children Philips HD4012LS
Philips SA
Traditional open fire Pneumonia, severe pneumonia/death in CU5 Not measured 26 months Moderate
19 Njenga et al., 2016 [60] Kenya, rural Quasi Women in selected HHs in rural Kibungu, Embu County 5HH from 57 baseline(trial) participants Gastov
Hifadhi ICS
Participatory approach
Three-stone fire & Improved Hifadhi stove Not measured PM2.5, CO Cooking time, fuel savings Not explicit Strong
20 Ochieng et al., (2017) [61] Kenya, rural Uncontrolled pre-post comparison HH in siaya country with primary cook having a child under 5, and exclusively using biomass 48HH Rocket mud stove Pre-intervention use of three-stone fire 8 hours personal CO exposure 48 hours kitchen CO levels, PM2.5 10 months Moderate
21 Onyeneke et al., 2018 [22] Nigeria, rural Pre-post design (cross-sectional) HH in 9 rural communities in Kaduna where most HH depend on fuelwood for cooking 280HH (70 adopters;210 non-adopters) Save80
Mass media exposure
Three stone fire Exhaled CO
Sore eyes
Cold
Real-time cooking CO measurement
Fuel use
Time savings
>6 months Moderate
22 Pilishvili et al., 2016 [21] Kenya, rural Uncontrolled pre-post comparison (Cross-over design) HH in 2 villages in Nyanza province with women (15–49 years old) and with one or more children under five. 45HH Ecochula
EcoZoom
Envirofit
Philips
Prakti
Rocket (TECA)
Traditional three-stone fire 48-hour personal CO exposure 48 hours CO and PM2.5 0.5 months
-2 wks. use with 1 wk. interval
Strong
23 Quinn et al., 2017 [62] Ghana, rural RCT Pregnant women in HH in Kimtapo north & south districts enrolled in the GRAPHs study. 44 Women Biolite
LPG2
Traditional cookstoves 24-hour ambulatory Home BP2 monitoring and Personal CO Not measured Not explicit Strong
24 Rosa et al. 2014 [63] Rwanda, rural C-RCT Head of HH (>18years) in 566 HH in 3 villages, Nyarutovu and Kabuga and Rubona, 126 (63;63) HH EcoZoom Dura stove
Program support/ periodical HH visit.
One-to-one training & maintenance
Community participation
Three stone fire Not measured 24- hour average PM2.5 exposure in the main cooking area (both indoors & outdoors) 5 months Strong
25 Saleh et al 2022 [64] Malawi, rural Mixed: quantitative before-after intervention study and qualitative observations /discussions Residents of rural HH of the study location n = 300 households 18 individuals Chitetezo mbaula
Community engagement
Not applicable Personal 48hr PM2.5 exposure Not measured 3 months Moderate
26 Vaccari, Vitali & Tudor 2017 [65] Cameroon/Chad, rural Comparative study Logone Valley, the border of Cameroon and Chad. 3HH CentraAfricain
Ceramic ICS2
Rice-husk burner2
LPG2
Solar Cooker2
Traditional three-stone fire Not measured 8- hour exposure to indoor CO Not stated Weak
27 Wathore, Mortimer & Grieshop, 2017 [66] Malawi rural Uncontrolled pre-post design Not described 22 HH with 45 HH cooking sessions. Cooking time (49 mins 15–223 min) median ACE 1
Philips HD4012LS
Chitetezo Mbaula
Traditional three-stone or simple mud stoves Not measured Indoor emissions of CO and particulate light scattering (proxy for PM2.5) 2 months Strong

Table 2 reference key

1 = GRAPHs: Ghana randomised air pollution and health study; CRCT = clustered randomised controlled trial; RCT = Randomised controlled trials; HH = households; SUM: Stove use monitors; N = total number of samples; I- Intervention group number; C- Control/Comparator group where applicable; SBP- systolic blood pressure; DBP- diastolic blood pressure. This review defines the kitchen as any area or room where stoves are used in the household. 2 = Excluded from synthesis. LPG and solar (exclusion criteria), Ceramic ICS and rice husk burner were reported using apposite laboratory values (exclusion criteria); Home BP was measured with the use of LPG. * Although measured in the study, the values were not reported cleary to report their impact on the reported health outcomes.

We divided our result sections to reflect the different review questions. Section A reports on review questions 1, 2, and 3 findings; and section B on question 4, the exploration of user perspectives of improved cookstoves.

Section A: Characteristics of improved cookstoves, household air pollution and health outcomes

Selection and characteristics of studies

Of the 1905 records retrieved from electronic databases, relevant websites, and grey literature searches, we found 27 field studies with HAP emission measurements and health outcomes (Fig 2). While most (20) reported kitchen/household PM2.5 levels, only one and two studies had data on black carbon and personal PM2.5 data, respectively. Although Duttal et al. [52] reported higher levels of PM2.5 in the control group, the actual data was not reported and thus was excluded from personal PM2.5 synthesis. Measured and self-reported health outcomes were available in 13 studies and included blood pressure (n = 2), burns (n = 5), eye problems (n = 4), fetal growth/weight (1), musculoskeletal issues (n = 2), pneumonia (n = 3), respiratory issues (n = 6), sneezing, cold and cough (n = 4). Fuel savings and cooking time were reported in 15 and nine studies, respectively. Only seven studies reported on cookstoves’ durability. The follow-up period in these studies ranged from 0.2 [24] to 40 months [58], modal ≥ 6 months.

Fig 2. PRISMA flow diagram of selection of studies included in HAP and health outcomes.

Fig 2

Characteristics of improved cookstoves

We identified 23 ICS brands from the 39 tested cookstoves. The ICS were classified as improved/ energy-efficient cookstoves (rocket style n = 13), advanced cookstoves (gasifier n = 3; semi-gasifier n = 1), and unclassified stove types (n = 6). The presence of a chimney (a feature that directs smoke away from the cooking area) was described only in EcoZoom Dura [57, 63], Mirt [53, 58], Prakti Leo [21], and RTI-TECA [21] studies. Other ICS either had no chimney (1/39) or was not reported (19/39) in the studies. The draft system (airflow system which impacts fuel burning rate, thermal efficiency, and completeness of combustion) [71] was described in only 11 cookstoves. Mostly (28/39), firewood was reported as the primary fuel. Other fuels included charcoal, pellet, and crop residues. Twenty-two cookstoves were locally made in sSA, with eight being produced industrially and four semi-industrial. For comparison, we defined ‘locally made’ as produced using local materials in sSA, ‘industrially made’ as imported as a whole unit, and semi-industrial as parts imported but cookstoves assembled locally.

HAP outcome measures: Black carbon, PM2.5, and CO levels compared to TCS/TSF

The household and personal HAP emission levels are summarised and presented with the cookstoves’ characteristics and study design in Table 3 below.

Table 3. Summary of findings of HAP measurements by ICS design, draft system, and brand.
Stove design Stove draft system Stove brand Study design Combustion chamber/ Fuel type *Chimney features *Place manufacturedi *Personal levels
^ = Statistical test (study#)
*Household levels
^ = Statistical test (study#)
Monitoring time* (hour) *Fuel % reduction/kg *Cooking time reduction min/day Cost of cookstoves (USD$)
PM2.5 mean; (% reduction); p-value; (n) CO (mean); % reduction (95%CI); p-value; (n) PM2.5 (mean); % reduction (95%CI); p-value; (n) CO (mean); % reduction (95%CI); p-value; (n) Compared to TCS/TSF
Rocket Forced draft TEG2ii [48] Comparative Stainless steel/ Wood U NO NM NM Black Carbon: Mean 0.69 g/kg 38% (95%CI 0.23; 0.25,1.60); p = 0.10 (n = 11) U -51.0% NM NO
Rocket Natural draft Chitetezo Mbaula [66] Pre-post Unspecified /Wood N Locally made NM NM 6.8g/kg;
-12.82% p = 0.347 (n = 16)
106g/kg;
8.16%↓ p = 0.51(n = 16)
≥24 -26.0% NM $ 1-2iii
Chitetezo [24] RCT Unspecified/ wood N Locally made NM 0.5 PPMiv
-33.3% p = 0.04 (n = 50)
NM NM <24 NM NM $2iii
Chitetezo Mbaula [64] Pre-post Clay/ Maize cobs, Firewood, Charcoal N Locally made 0.0019 mg/m3
(-16%)
p = 0.71
NM NM NM >24 NM NM $ 1–2.5 v
EcoZoom Duravi [63] CRCT Unspecified/ Wood Y Industrial NM NM 0.485mg/m3, (0.04,2.28);
-46.4% p = 0.005 (n = 60)
NM ≥24 NM NM $30-40v
EcoZoom Dura [57] CRCT Unspecified/Wood Y Industrial 0.218 mg/m3
-55.1%
p = 0.49 (n = 183)vii
NM NM NM ≥24 NM NM $30-40v
0.224 mg/m3
-3.0%;
p = 0.13 (n = 84)vii
Mirt Stove [58] RCT follow up Unspecified/Firewood Y Locally made NM NM 0.135 mg/m3–10.4%
p = 0.5 (n = 202)
NM ≥24 NM NM $10viii
Mirt Stove [50] CRCT Concrete & volcanic ash/ Briquettes, wood, crop residue, dung N Semi industrial NM NM 0.340 mg/m3
-58% from baseline
p = 0.0001
NM <24 NM NM $2.9 - $6.1v
Rocket Unspeci
fied
Gyapa [20] RCT Ceramic/ Wood U Locally made NM NM 2.6g/kg;
-18%
(-47,27) p = 0.36 (n = 18)
58g/kg; -21% (-41,7) p = 0.12 (n = 18) ≥24 -10.0% -5 $7iii
Envirofit [21] Pre-post Metal alloy/ Wood U Industrial NM 1.3 PPM
-54%
(-2.0 to -0.6); p<0.01 (n = 30)
0.277mg/m3, -35.6% (25.7,44.2) p<0.001 (n = 35) 3.4PPM;
-27.6% (16.6,37.2) p = 0.02 (n = 34)
≥24 -22.5% -14 $99.95v
EcoZoom [21] Pre-post Ceramic/ Wood U Industrial NM 0.7 PPM
-32%
(-1.1 to -0.3); p<0.01 (n = 31)
0.109mg/m3;
-19.7% (7.6,30.2) p = 0.12 (n = 37)
0.2PPM; 1.9%
(-12.6,14.6)
p = 0.89 (n = 36)
≥24 -29.2% -12 $30-40v
Prakti-Leo [21] Pre-post Steel alloy/Wood Y Industrial NM 0.9 PPM
-45%
(-1.4 to -0.4); p<0.01 (n = 32)
0.118mg/m3;
-38.6% (29.5,46.5) p < .0.001 (n = 39)
0.7PPM;
-32.3% (22.3,41.0) p<0.01(n = 37)
≥24 -20.8% 2 39ix
RTI-TECAx [21] Pre-post Brick and clay/ Wood Y Locally made NM 0.8 PPM
-35%
(-1.5 to -0.1); p = 0.03 (n = 31)
0.215mg/m3; -31.9% (21.1,41.3) p<0.01 (n = 35) 2.5PPM;
-25.1% (13.2,35.3) p = 0.05 (n = 34)
≥24 -31.7% -2 $130v
Uga-stove [55] Pre-post (observational) Unspecified/ wood U Semi-industrial NM NM 0.68mg/m3;
-37%
(0.2, -1.2);
p<0.01 (n = 28)
1.4PPM
-8%
(-5.2, -7.9) p = 0.68 (n = 34)
≥24 NM NM $17xi
Rocket Mud-stove [61] Pre-post (longitudinal) Unspecified/ wood N Locally made NM 0.9 PPM 11.6%
(-4.3 to 2.6); (n = 23)
0.345;
-13.1%
(SD 0.273mg/m3); (n = 33)
3.1 PPM
-28.1%
(-8.1 to 1.8); (n = 23)
≥24 -20% -60 $2-4xii
Save80 [22] Pre-post (Case control) Unspecified /Wood N Semi-industrial NM 9.8 PPM xiii
96.4%
(SD 46.97); p <0.001 (n = 70)
NM NM <24 -46.5% -91 $17-37v
Gasifier Forced draft EcoChula [21] Pre-post Ceramic U Industrial NM 1.7 PPM -68%
(-2.6 to -0.8); p<0.01 (n = 31)
0.116mg/m3; -18.0%
(5.1,29.2)
p = 0.18 (n = 36)
1.7PPM; -21.5% (9.1,32.2)
p = 0.10 (n = 34)
≥24 -37.5% -16 $29-33v
Philips [21] Pre-post Ceramic U Industrial NM 0.6 PPM -29%
(-1.0 to -0.2); p<0.01 (n = 29)
0.357mg/m3; -45.2% (36.6,52.6) p<0.001 (n = 35) 2.7PPM; -38.5% (28.9,46.7);
p <0.01 (n = 35)
≥24 -55.8% -21 $89v
Philips HD
4012LS [20]
RCT Ceramic/ Wood U Industrial NM NM 2.5g/kg;
-13% (0,28) p = 0.04 (n = 11)
45g/kg; -46%
(-65, -18) p<0.01 (n = 11)
≥24 -50% -22 $89v
Philips HD
4012LS [20]
RCT Ceramic/ Charcoal U Industrial NM NM 1.6g/kg;
-58% (−90, 81) p = 0.04 (n = 13)
92g/kg; -77% (−92, −34)
p< 0.01 (n = 13)
<24 -30.0% -5 $89v
Philips
HD
4012LS [66]
Pre-post Unspecified /Wood U Industrial NM NM 4.1g/kg ± 0.6SD -47%
p < .005 (n = 8)
52g/kg; -45%; p< 0.005 (n = 8) ≥24 -51% NM $90iii
Forced draft ACE-1 [66] Pre-post Unspecified /Wood U Not Specified NM NM 6.8 ± g/kg p = 0.158 (n = 8) 60g/kg (30,75) -40% ≥24 -27.0% NO $90 iii
Gasifier Natural Draft/TLUDxiv Gastov [60] Quasi Galvanised steel/ Grevillea pruning N Industrial NM NM 0.3mg/m3;
-89% p<0.05
18PPM (±6); -45% (n = 25) observation from 5HH) <24 -27%xiv -9xv $35 iii
Gastov [54] Quasi Galvanised steel/ wood N Industrial NM NM 0.187 ± 75 mg/m3–41% (n = 5HH) 6 (± 3PPM)
-57%
<24 -18% 17xvi $35 iii
Semi-gasifier Forced draft Mimi Moto [47] Case-control Unspecified /Pellets U Industrial NM NM 0.4g/kg p<0.05 14 g/kgxvii
-97% p<0.05
<24 NM NM $40-65v
Unclas-sified Unspecified Centra Africain [65] Comparative Unspecified /Wood N Locally made NM NM Not measured 11.96 PPM;
-25.14%
≥24 -52.2% -12 $7 iii
Kenya ceramic Jiko [48] Comparative study Stainless steel/Charcoal N Not specified NM NM Black Carbon: 0.28 g/kg
-36.6% (95%CI = 0.049; 0.07,0.63); p = 0.081 (n = 32)
<24 -45.0% NM $35-40v
BioLite [62] RCT Unspecified U Industrial NM 1.45 PPM; 1.4% (n = 4) NM NM ≥24 NM NM $40-70v
Clean-Cook Sweden AB) [52] Pre-post Metal / Ethanol N Industrial 0.023 mg/m3
12.3%
NM NM NM >24 NM NM NO
Hifadhi Stove [60] Quasi Galvanised steel/ Grevillea pruning N Locally made NM NM 4.25mg/m3 40PPM
11.11%
≥24 NM 5 NO

Table 3 reference key

*: U = unspecified in the study; NM = not measured; Y = yes; N = no; NM = not measured in the study; NO = not obtainable; n = sample size; PPM = parts per million- the mass of a chemical or contaminate per unit volume of water.

^ = Unpaired student t-test (48); Two-sample test (66); Mann Whitney U-test (24, 52); Wilcoxon signed-rank test (64); Wilcoxon rank sum (63, 47); Two-sided test (57, 58); Wald CI test (50); Paired t-test (21, 55, 61, 54); Non- parametric Kruskale Wallis test (60); Multi-level regression models (20, 22, 62); not explicit in the study (65).

i: Semi-industrial described as domestically manufactured, or parts imported but assembled locally to enhance skill; locally made = made by local artisans in sSA, Industrial = manufactured and imported. ii: TEG = Thermo-Electric Generator cookstove. iii: Price obtained from the article. iv: Carbon monoxide was measured during participants’ exhalation. v: Price obtained from the clean cooking catalogue. http://catalog.cleancookstoves.org/stoves. Accessed & updated October 5th, 2020 & February 3rd, 2022, respectively. vi: Two additional components, a ‘‘stick support” onto which fuel wood is placed to promote airflow and a ‘‘pot skirt” which increases fuel efficiency, were added to the stove in this study. vii: Outcome in primary cook (n = 183); Outcome in children under 5 years (n = 84). viii: Obtained from energypedia.info https://energypedia.info/images/a/a0/GIZ_HERA_2012_Mirt_stove.pdf Accessed October 21st,2021. ix: Price obtained from Engineering for change https://www.engineeringforchange.org/solutions/product/prakti-single-burner-wood-stove/ Accessed February 3rd, 2022: x: Built-in rocket stove with Thermoelectric-Enhanced Cookstove Add-on (TECA). xi: Price obtained from the article and www.ugastove.net. (subsidised for $7 for the study). xii: Single pot design. Price obtained from https://energypedia.info/images/1/11/GIZ_HERA_2011_Shielded-fire-stove-with-bypass-air-inlet_Uganda.pdf Accessed October 5th, 2021 & updated Feb 3rd 2022. xiii: Endline mean value was not provided in the study. We calculated from baseline (187.9PPM), and estimated difference value (178.1PPM) described in the study as the average change in total household carbon monoxide exposure brought about by the adoption of Save80 cook-stove pgs 1331 &1333. xiv: TLUD: Top Lit Up Draft: 27% reduction in fuel reports is without the use of charcoal produced from the gasifier. The study reported the reduction increasing to 40% when charcoal is used. xv: The difference in time taken to cook ugali and Sukuma meal using grevillea pruning in both the gasifier and TSF. xvi: The study reported the increase as the result of time to load, reload and time to light the fuel load needed for the gasifier. Cooking time is only lower by 1 min in the gasifier. Increase of 32% fuel saving if the char produced is used. xvii = Values obtained from the plot chart provided in the study. Data table or sources not available in the study.

Except for the increase in percentage reduction in household CO with EcoZoom [21] (1.96% n = 36), Hifaldhi and personal CO (1.45% n = 4) with Biolite [62], all reviewed ICS reduced HAP emissions compared to TCS/TSF although the amount varied across the different studies and between same brand cookstoves such as Gastov and Philips HD4012LS+ (Table 3).

The outcome of the percentage reductions in household-level PM2.5 and CO and personal-level CO compared to TCS/TSF are displayed in Fig 3A–3C.

Fig 3. Percentage reduction change in household and personal emission levels by ICS brand and chimney features.

Fig 3

(A) Bar chart shows percentage reduction in household PM2.5 with ICS brand compare to TCS/TSF (B) Percentage reduction in household CO measurements with ICS compared to TCS/TSF, variance in changes within same ICS brands, and % increase in EcoZoom and Hifadhi ICS (C) Personal CO and PM2.5 percentage reduction with ICS compared to TCS/TSF and a 1.5% and 12.3% increases in the Biolite and Cleancook respectively.

Surprisingly, ICS without chimneys showed the highest percentage reductions across the household and personal PM2.5 and CO levels. However, the EcoZoom dura [63] with a chimney demonstrated a higher percentage reduction (-46%) in household PM2.5 levels compared to EcoZoom [21] without a chimney (-20%) (Fig 3A).

All the ICS tested failed to reduce household PM2.5 to a level close to the WHO 24-hour average of 0.025mg/m3 for safe indoor air quality in LMICs [29]. The lowest level of 0.11mg/m3 reported with the rocket-design EcoZoom [21] cookstove was over four times the WHO- IAQ-safe level. Measured in PPM, 75% of the 12 household CO levels measured were within WHO recommendations of 6.11PPM [29], with the lowest mean of 0.2PPM in the EcoZoom cookstove [21]. The available data on black carbon shows a mean level of 0.69 g/kg (n = 11) with the forced draft thermoelectric generator (TEG) [48] and 0.28g/kg (n = 32) with the Kenyan Ceramic Jiko cookstoves. Respectively, this represents a 38% increase and a 37% decrease compared to TSF and TCS. While the study [60] recorded this difference in terms of surface oxidation of the charcoal cookstove (a process where PM formation is less likely), the sample size of only 11 cookstoves with the TEG compared to 32 with the charcoal cookstove may be a factor in the precision of the TEG measurement. Also, the mean CO level was higher in the TEG (0.50g/kg) than the charcoal cookstove (0.44g/kg).

In addition, we found a large variation in the units used to report pollution levels. For example, household PM2.5 and CO levels are reported in units of g/kg, mg/m3 and g/kg, PPM, respectively, which creates difficulties in comparing HAP levels between studies. Also, some studies measure household CO (n = 19) and PM2.5 (n = 21), whereas others measure personal CO (n = 9) and PM2.5 (n = 3) and only reported two black carbon measurements. Table 4 shows the different units of reporting used in the reviewed studies by cookstove design and draft systems.

Table 4. A snapshot of heterogeneous characteristics, units of measurement and range of HAP emission by ICS.
Draft system ICS classification Black Carbon (n) Personal PM2.5 range (n) Personal CO range (n) Household PM2.5 range (n) Household CO range (n)
g/kg mg/m3 PPM g/kg mg/m3 g/kg PPM
Forced Rocket 0.69 (1) X X X X X X
Gasifier X X 0.60–1.70 (2) 1.60–6.80 (4) 0.12–0.36 (2) 45–92 (4) 1.70–2.70 (2)
Semi-gasifier X X X 0.40 (1) X 14 (1) X
Natural Rocket X 0.002–0.22 (2) 0.50 (1) 6.80 (1) 0.14–0.49 (2) 106 (1) X
Gasifier X X X X 0.19–0.30 (2) X 6.00–18.00 (2)
Unspecified Rocket X X 0.70–9.8 (6) 2.60 (1) 0.11–0.68 (6) 58 (1) 0.20–3.40 (6)
Unclassified 0.28 (1) X 1.45 (1) X 4.25 (1) X 11.96–40.00 (2)

Health-related outcomes

A summary of health outcomes from the 13 studies where they were reported is presented in Table 5. The results were self-reported except for blood pressure [5, 49], fetal biometric parameters [52], and childhood pneumonia and incidence of ALRI [51, 57, 59].

Table 5. Description of health outcomes by author, ICS design and brand.
First author, date/ study design 1Name; Design;
Combustion chamber;
Fuel; Chimney
Description of participants Health-related outcome change
^ = Statistical test (study #)
Burns/Safety Stove stacking Fuel collection time min/wk reduction Cooking time minutes (%reduction) Fuel savings Sustain ability Cost (USD)
Adane, 2021 [51]
RCT
Mirta;
Rocket;
Natural draft; wood
No chimney
Low-income rural community of the Mecha Health and Demographic Surveillance System site. 5333 (I,2659; C, 2674) children <4 years No evidence of reduced risk of childhood ALRI with intervention (OR 0.95 (95% CI:0.89–1.02). No statistically significant difference between the I and C group. 20% reduced risk in children × × × × × $2.90–6.102
Alexander 2017 [5]/
RCT
Cleancook Chulikaa;
Rocket;
Unspecified;
Wood & ethanol
No Chimney
101 of the 324 pregnant women. (I: (Firewood to ethanol cookstove)3 n = 50; C: firewood) n = 51. Pre (16wks gestation), Post (38wks gestation) SBP: -0.60mm/Hg (mean difference)
DBP: -1.5mm/Hg (mean difference)
× Not reported in the group randomized to firewood. × × × × $55−802
Dutta et al 2021 [52]
RCT
Cleancooka
Rocket;
Unspecified;
Wood & ethanol;
Unspecified
306 women in the second pregnancy trimester (C: (Firewood n = 152; I: ethanol cookstove)3 (n = 15) in Ibadan, Nigeria, using PM2.5 levels and fetal ultrasound measurement No significant difference in growth trajectories between I & C group
No sig association between PM2.5 levels and fetal biometric parameters and intrauterine growth
x x x x x x $55−802
Bensch 2015 [23]/RCT Firewood Jambaara;
Unclassified;
Unspecified;
Clay/Wood;
No Chimney
Women responsible for cooking in 253 HH in 12 villages in rural Senegal. (I): n = 778; ©: n = 1199 Eye problems (Mean)
Prim cook (I): 2.9% & (C) 9.8%. % reduction = -70.4% n = 778 p = 0.01
Respiratory Problems (Mean)
Prim cook: (I) 4.7% & (C) 11.8%. % reduction = -60.2% n = 778 obs.
Male: 4.5 (-62%) p = 0.01
× × 153 min/wk. (mean diff)
-15.49%
84 min/day
20% reduction in cooking time
27.7 mean difference = $ 2.03$ per month savings 49% in use after 3.5 years $104
Cundale 2017 [25]/ Semi-structured interviews Philips HD4012 LSc;
Gasifier;
Forced draft;
Firewood;
No chimney
10 HHs from 10 village clusters in the Chilumba district. Primarily rural fishing and farming communities. HHs were participants in the CAPs 2015 trial. Cough: (I): 1/50
Less smoke: (I): 10/50 (associated with reduced illness by respondent
Less eye pain: 5/50
Reduced Pneumonia 4/50 (I); 6/50 (C)
Reduced sneezing (C)
1 in 5 found no health benefits
× × 168min/week (mean diff)
-37.1%
110 min/day (mean diff)
-50.2%
(I): 43/50; (C): 21/50 I: 3/50. The solar panel was not durable. $892
Gebreegzrabher 2018 [53]/ RCT Mirta; Rocket;
Natural draft;
Firewood/dung;
Chimney
360 treatment HHs Self- Reported
Less smoke
Less respiratory discomfort
x 88% stove-stacked with 3SF x 75% reported cooking time savings -22% to -31% reduction compared to 3SF x $3.5- $7.35
Jagger 2019 [49]/ RCT MimiMotoc;
Semi-gasifier; TLUD forced draft; wood pellets; No chimney
91 primary cooks at midline (adopters) who were present at baseline from the 144 HH. (HH fixed effect) SBP: -3.32mmHg (5.21) p <0.1
DBP: -2.37 mmHg (2.24) p = not significant
SOB: -1.80 (0.86) p <0.01 48.8 (I) 41.06 (C): n = 182
-1.64 (0.96)
p <0.1 (self-reported)
Increased mostly during large cooking events x Mean reduction 0.7 ICS adopter’s vs 1.9 non-adopters No statistical significance between adoption of ICS and TSF fuel expenditure x $40−652
Jagoe 2020 [56]/ Pre-post exploratory sequential Kuniokoab; Rocket;
Unspecified; wood;
No chimney
55 HH with participants who do most of the HH cooking in 3 rural agricultural communities Self- Reported:
Decrease smoke inhalation.
Decrease intense heat.
Less back strain from bending to blow on fire.
≈ 8hrs/wk of increase sleep time
Reduced risk of burns & intense heat.
Fewer safety concerns
Increased by 75% (n = 41) from n = 5 baseline. ICS use 93 vs 267 min/day TSF Reduced 414 min/wk. (mean diff) @14 wks.
-58.48%
69 min/day (mean diff)
-19.49%
x x $386
Jary 2014 [24] RCT- feasibility Chitetezoa
Rocket;
natural draft
Wood
No Chimney
51 non-smoking women in rural Malawi who cook primarily on a TSF and wants to purchase chitetezo n: I = 25; C26. Cough:28.57
Back pain 60%
SOB 100%
Eyes burning: 66.67%
Sneezing & running nose: 150 increase cases
Increase cases in both groups. × × × × × $22
Kirby 2019 [57]
cRCT
EcoZoom durac
Rocket;
Natural draft;
Wood; Chimney
793 HH- control & 789 HH- intervention of ARI in CU5 in poor region of Ubudehe Current pneumonia: 41/2574 compared to 55/2829 control group p>0.05 1.8 vs 3.6 (rate)cases in control. P<0.001 × × × × × $30−402
LaFave 2021 [58] RCT- post intervention Mirt Stovea
Rocket; Natural draft; Unspecified;
Chimney
All children and adult cooks from 480 HH in 36 communities in rural Ethiopia Child growth: 0.06 SD taller than in control (not significant)
Respiratory- Adult: No significant difference
Respiratory- Child: Reduced in children ≤5yrs (p = 0.14) but not in older children
Activities of daily living- Primary cook: minimal difference, not significant
× × × × × 60% of ICS in use at 40 months post-intervention $104
Mortimer 2017 [59] cRCT Philips HD4012LSc;
Philips SAC
Gasifier;
Forced draft;
Unspecified;
No chimney
8470 HH in 150 communities with at least 1 child under 5 in rural Malawi- CAPs. I: n = 1255, C: 1251 Childhood Pneumonia: IRR (95% CI) p.
IMCI7 1.05 (0.93–1.18)0.44
All pneumonia cases 1.02 (0.91–1.13)0.75
no evidence of association
10% reduction in serious cooking-related burns & 42% in non-serious burns Reported as a possibility with a high rate of solar panel and cookstove breakdowns × × × High rate of breakdown of solar charging panel cookstove $892
Onyeneke 2018 [22] Pre-post Save80b
Rockets;
Unspecified; Wood;
No chimney
280HH (70 adopters; 210 non-adopters) in 9 rural communities in Kaduna with high reliance on firewood for cooking Cough 3.38 (17.77%) reduction in cases
Sore eyes 3.72 (- 45.26% reduction
× × 614 min/wk. (mean diff) -46.51% 91 min/day (mean diff) -38.32%v 5.671kg/wk adopters’ vs 0.002 kg/week (non-adopters) 80.58% × $20−552

Table 5 reference key

Abbreviations: TLUD: Top Lit Up Draft. I = Intervention Group; C = Control Group; n = number of observations; HH = households; ALRI = acute lower respiratory infections; SOB = Shortness of Breath; CAPs = Cooking and Pneumonia Study;; SBP = Systolic Blood Pressure; DBP = Diastolic Blood Pressure; IRR = Incidence Rate Ratio; OR = ODD ratio; SD = Standard Deviation; Prim cook = Primary cook in the sampled house.

^ = Two-sided test (51, 23, 57, 58); Fisher’s exact test (5); Breusch-Pagan and Hausman tests (49); Paired t-test (56); Cox regression (59); Multi-level regression models (22).

1. a = Locally made; b = Semi-Industrial; c: Industrial; Semi-industrial is described as domestically manufactured, or parts imported but assembled locally to enhance skill acquisition, and locally made as produced locally using local materials in this study. Unclassified = Unclassified stove design in the study and no information on the web. Unspecified = Unspecified draft or chimney system or fuel used in the study; 2. Price obtained from clean cooking catalogue. http://catalog.cleancookstoves.org/stoves. Accessed & updated October 8th, 2020 & February 3rd, 2022, respectively; 3. We reported only outcomes from the participant group that compared ethanol cookstoves to firewood, i.e., excluded comparison to kerosene users, as this is not part of this review’s objectives; 4 Price obtained from the article; 5. Obtained from energypedia.info https://energypedia.info/images/a/a0/GIZ_HERA_2012_Mirt_stove.pdf; 6 Price obtained from https://www.burndesignlab.org/projects/kuniokoa# Accessed February 3rd, 2022; 7 IMCI = WHO Integrated Management of Childhood Illness, -defined pneumonia episodes in children under 5 years (CU5) of age diagnosed by physicians, medical officers, or other appropriately trained staff at local health-care facilities routinely accessed by trial participants, unaware of intervention allocation [54]

Blood pressure (BP). Post-intervention BP levels showed a reduction in the two studies that measured BP. Respectively, the use of Cleancook Chulika [5] and MimiMoto [49] cookstoves reduced systolic blood pressure (SBP) by 0.60mmHg, and 3.32mmHg and diastolic blood pressure by 1.5mmHg and 2.37mmHg.

Pneumonia. The association between pneumonia and HAP was examined in three clustered randomised trials (cRCT) [51, 57, 59] and one semi-structured interview study [25]. There was no significant difference between the intervention and control group in the diagnosis of childhood pneumonia (incidence rate ratio [IRR]1.05, 95%CI 0.93–1.18, p = 0.44, n = 10471) and severe pneumonia (1.30, 0.99–1.71,p = 0.06) with Philips HD4012LS and Philips SA [59], prevalence ratio (PR) 0.87, 95% CI 0.58–1.30, p = 0.491, n = 5403 and severe pneumonia (PR = 0.75, 0.45–1.24, p = 0.256, n = 5403) with EcoZoom Dura [57], and odds ratio (OR) 0.95 (95% CI: 0.89–1.02, n = 5333) with the Mirt [51] cookstoves. The number of pneumonia cases was slightly higher in the intervention (n = 1255) than the control (n = 1251) group with the Philips brand [59] but slightly lower in the intervention group (41/2574) compared to the control (55/2829) with EcoZoom Dura [57]. The non-significant effects from the large sample could suggest that there weren’t any meaningful changes in the groups over the short follow-up times involved. The qualitative study [25], which explored the views of 50 participants in the intervention arm (Philips HD4012LS) of the above cRCT study [59], found only four of the 50 participants self-reported reduced pneumonia incidence as an advantage and health benefit of the ICS.

Eye symptoms. All four studies measuring eye symptoms reported reduced eye discomfort, including eye pain, discomfort, and burning. Compared with pre-intervention data, self-reported reduction in eye-related symptoms was 70.4% (n = 778,p = 0.01) with Firewood Jambar [23], 66.7% (n = 25) with Chitetezo [24], 45.3% (n = 70) with Save80 [22], and 20% (n = 50) with Philips ICS.

Respiratory symptoms. Five of the six studies that measured respiratory symptoms (defined in this review as the presence of cough, sneezing, wheezing, and difficulty breathing) reported a reduction in symptoms. Reductions were reported with the Firewood Jambar [23], MimiMoto [49], Mirt [53], Philips HD4012 [25], Save80 [22], and the Chitetezo [24] cookstoves. In addition, a decrease in complaints of shortness of breath was statistically significant among adopters of MimiMoto [49] (p = 0.01, n = 182). While all participants (n = 25) with the Chitetezo reported reduced shortness of breath, increased sneezing or running nose was mentioned in 20.8% at follow-up compared to baseline (8.3%) [24].

Burns- a proxy for safety. Of the 13 studies on ICS-related health outcomes, data on burns were reported in only six, with 78% reporting a reduction in cases with the ICS intervention. Reduction in prevalence of burns between intervention and control groups was significant with EcoZoom Dura [57] (PR 0.51, 95% CI 0.36–0.74, p < 0.001), Philips HD4012 [59] (IRR 0·58 [95% CI 0.51–0·65]; p<0·0001). In self-reported cases, severe burns (including death) were reduced by 10% (n = 19) and in non-severe burns by 42% (n = 1505) with Philips HD4012. In addition, participants reported fewer safety concerns and reduced risks of burns with MimiMoto [49] and Kuniokoa cookstove [56]. In the locally made stoves, 41 cooking-related burns with Mirt compared to 51 cases in the control group [51]. However, burns incidence did increase in the intervention and control groups of the Chitetezo [24].

Gender-specific health outcomes. Associated HAP disease incidence and gender roles were highlighted only in the Bensch et al. study [23]. Though there was a substantial decrease in respiratory diseases and eye problems in users of Firewood Jambar compared to the control group, the incidence of respiratory disease was 1.2 times higher in women who cook than in men within the same households despite the intervention.

Other health-related outcomes. Six of the studies reported other noteworthy health-related outcomes, including a self-reported reduction in back pain and strain in 60% (n = 25) of Chitetezo users [24], reduced back pain, increased sleep time of up to eight hours/week with the Kuniokoa [56], and reduced level of smoke with users of the Kuniokoa [56], Mirt [53], and Philips HD4012 [25] cookstoves. The study on perinatal health using the Cleancook ethanol stove showed no significant association between exposure to PM2.5 and fetal biometric parameters and similar fetal growth trajectories in the intervention and control groups [52].

Availability of cookstoves

We obtained information on market availability for 17 out of the 23 cookstove brands, including locally made (n = 6/23), semi-industrial (n = 3/23), imported (n = 7/23), and the Philips stove, which is no longer manufactured (n = 1/24) ICS. The six cookstoves (CentrAfricain, Gastov, Rocket-Mudstove, RTI-TECA, TEG, and Ugastove) with missing information were classified as unavailable in this review. We compiled and presented the descriptions of the available cookstoves in the S2 Table.

Affordability of cookstoves

The market price was available for 21 of the 23 cookstoves brands. The available prices ranged from $1–2 for the locally made Chitetezo [24, 66] to $130 [21] for the industrially made RTI-TECA. Fig 4 below shows that only 25% of stoves cost ≤$10, half ≤$35, and three-quarters ≤$55. A cost beyond the budget of most households in poor communities in sSA. An average price was calculated when stove prices varied with the same brand.

Fig 4. The cummulative distribution chart of the stepped rises in the number of cookstoves (n = 21) available at or below the given cost.

Fig 4

Sustainability

Information on the cookstoves’ sustainability (defined as evidence of stove breakdown and repair needed) was available in only four of the 27 studies. The Mirt [58] and the EcoZoom Dura [63] studies report 60% (n = 480HH) continuing functionality at 40 months and 5% (n = 60) required repairs at five months follow-up, respectively. Similarly, almost half of the 253 HH users of the Firewood Jambar [23] still used the ICS at 3.5 years post-intervention, with technical problems reported as rare. In contrast, the Philips [59] and the Gastov [60] users reported a high number of stove breakdowns with limited availability of repair parts. Participants ranked the durability of the CentrAfricain ICS as similar to the TSF [65].

Stove stacking

Evidence of stove stacking (concurrent use of multiple cookstoves) was reported in seven of the 27 HAP and/or health outcome studies with varying justification for use and comprehensiveness of reporting. Stove stacking was reported as being due to ICS ‘not being suitable for households with greater cooking needs’ with MimiMoto [49] and being ‘unsuitable for baking local dishes’ with the Mirt [58] cookstoves. Overall PM2.5 reduction was unsurprisingly greater in households without stove stacking’ [21]. Although Jagoe et al. [56] distributed multiple Kuniokoa cookstoves to households, the study observed stove stacking with TSF, although no information was provided on users’ justification by the study.

Fuel savings

Compared to inefficient cookstoves, the reduction in the fuel used with the ICS varied among the 15 studies that measured fuel savings. The reduction in firewood use ranged from 10% with the locally made Gyapa [20] to 80.6% with the semi-industrial Save80 [22]. When reported in terms of cost, savings of $2.03 per month was recorded with the Firewood Jambar [23] cookstove (Tables 3 and 5).

Time poverty (Cooking and fuel collection time savings)

Reduction in cooking times was reported in 14 of the 20 studies that evaluated the time efficiency of ICS. The savings compared to the TCS/TSF ranged from 2min/day (RTI-TECA) [21] to 110 min/day (PhilipsHD4021LS) [25]. With fuel type, time savings was higher (22min/day) with firewood than with charcoal (5min/day) with the Philips ICS within the same study [20]. Although an increase of 17min/day was associated with increased loading, reloading, and lighting time of firewood with the Gastov [60], there was a 9min/day savings with the same ICS with crop residues [54]. Savings in fuel-gathering times were highlighted in all five self-reported accounts [2, 22, 23, 25, 56] with the highest reduction of 58.5% (414 min/week) and 46.5% (614 min/week) with Kuniokoa [49, 56] and Save80 [22] ICS, respectively. Increase were reported of 2min/day, 5min/day, 17min/day, and 60 min/day with Prakti-Leo [21], Hifadhi [60], Gastov [60], and RocketMud [61] cookstoves, respectively.

Supporting measures used in addition to the ICS Intervention

Twelve studies mentioned instituting additional measures alongside the ICS intervention, which varied in type and description. Of the eight studies that mentioned community awareness or educational approaches, only one study [5] described the educational content (dangers of exposure to smoke). While the study [47] reported encouraging and supporting participants with behavioural and environmental modifications, these targeted lighting and fuelling the ICS. Other additional measures included a support system (implementation team’s contact details and posters with instructions) [63], follow-up visits aimed at troubleshooting the ICS [49, 54], repairs and replacement of cookstoves and repair parts [25, 59]), and community participation [56, 59, 60]. Despite the description of these additional measures, only one paper reported on the impact of the measure in relation to improved adoption of the Gastov ICS [54].

Result section B: User perspective of cookstoves

This section describes the views of the end users of the improved cookstoves.

Selection of cookstove brand and studies

Of the 23 cookstove brands reported in section A, only six met the requirements for our review questions 1 and 2, i.e. (availability, affordability, reduction of pollutants and/or improvement in health outcomes). In Fig 5, we describe our systematic selection of these cookstoves. Cookstoves were excluded if there was no reduction in HAP, no health benefit, not available, and not affordable. The ten articles selected to inform the user perspectives of the six cookstoves (Chitetezo Mbaula [64, 69, 70], Mirt [53, 68], Firewood Jambar [23], Gyapa [67], Kuniokoa [56], Save80 [44, 45]) is presented in the PRISMA diagram (Fig 6).

Fig 5. Systematic selection of ICS for effectiveness in HAP reduction, market availability, and affordability.

Fig 5

Fig 6. PRISMA flow diagram showing the selection of sources for User perspectives.

Fig 6

User perspectives

Overall, users liked the ICS and found several advantages to their use compared to the TCS/TSF. For example, in all the studies, participants reported significant time-saving benefits with the ICS from cooking and fuel collection [64, 69], with food cooking faster [64, 67], and less time required to supervise the stove [23, 44, 45, 64]. This allowed participants to multi-task [23, 56] and resulted in more time for leisure and social activities [56].

Cooking pots were described as ‘cleaner’ with the Gyapa [67], offering timesaving from cleaning off black soot associated with TSF. Interestingly, and related to timesaving, users of the Kuniokoa cookstove highlighted a more equitable distribution of cooking duties with "male partners helping with cooking tasks" [56].

Some participants described ’family togetherness’, that "the change has been positive to me and my family because they like the Kuniokoa and this has made us feel that we belong to a developed family" [56], suggesting a subtle link between wellbeing and ICS use. Users also reported reduced back pain [70] from less bending and fuel collection [56] and less eye irritation [67]. Other reported advantages of the ICS included reduced fuel use [69, 70], suitability of use for various cooking tasks [69, 70], stoves being lightweight, portable and durable [67, 69], affordability [69, 70], and better shielding from wind and dust [23, 64] compared to baseline TCS/TSF.

Burns injury used as a proxy for safety in our review was viewed as a highly significant advantage of the improved cookstoves in the ‘willingness to adopt’ study [69], where over 95% (n = 121) of participants reported reduced incidence of burns and accidents. However, while the covering chamber for the flame was reported as a good design and safety measure [70], users also commented on excessive heat from the chamber and a lengthy cooling period, "making it unsafe for children" [70]. Other ICS disadvantages include reduced durability [67], unsuitability of the burner size for large cooking pots used in large-size households [23], resulting in stove stacking to meet the cooking needs, and back pain was associated with the low-height design of Chitetezo Mbaula [69]. In addition, compared to readily available firewood used with TSF, the fuel cost was higher with ICS [69], with igniting taking longer [70]. A thematic description of the user perspective is presented in Fig 7

Fig 7. Thematic presentation of user perspectives of available, affordable, and efficient improved cookstove.

Fig 7

Benchmarking the International Workshop Agreement (IWA) tier of cookstove performance with available field data

The International Organization for Standardization (ISO) IWA uses four indicators (efficiency, total emissions, indoor emissions, and safety) to evaluate cookstove performance across five tiers (0–4), with Tier 4 as the highest and Tier 0 as the lowest-performing cookstoves [36]. These indicators are based on performance under laboratory conditions. Table 6 presents an overview of the current IWA tier rating alongside the collated field data from this review. The field values examined in this review are subject to factors such as the cooking area’s ventilation level and the fuel’s water content which generally were not described within the studies reviewed. Therefore, we recommend caution in the use and interpretation of the scorecard.

Table 6. Available cookstoves by IWA tier and field emissions score card.

Cookstove Cost (USD) Stove description IWA Tier Field-based results from this review (% reduction) Field-base health outcome from this review
Indoor emission Efficiency Safety Sustain ability Kitchen Personal
PM2.5 PM2.5% CO %
Tier four
Mimi moto 40 to 65 Portable, Gasifier (TLUD), Fan, Solar Panel, pellets, wood 4 4 - 10 years - -97 - Reduced systolic and diastolic BP
Reduced shortness of breath
Reduced burns
Tier three
Ace 1 90 Gasifier, Fan (TLUD), dung, pellets, crop residue, portable 3 3 4 12 years - -40 - -
Kuniokoa 30 to 41 Rocket, Portable, Side-feed 3 2 3 3 years - - - Decrease smoke inhalation.
Decrease intense heat.
Less back strain from bending to blow on fire.
At least 8hrs/wk. increase in sleep time
Reduced burns
Tier Two
Biolite 40 to 70 Fan, TEG, Portable, crop residue, dung, wood 2 2 - 5 years - - 1.5 -
Tier One
Envirofit 100 Rocket, Portable, wood fuel 1 2 3 - -36 -27 -54 -
Tier Zero
Gyapa woodstove 7 Rocket, Batch load, Portable, wood 0 2 - 3 years -18 -21 - Reduced pneumonia cases
Unrated
Chitetezo- Mbaula 2–4 Rocket, Side-feed, wood Crop residue, Portable, - 2 3 4 years -13 -8.2 -33 Reduced cough, SOB
Reduced backpain
Reduced eye burning
Increase sneezing and running nose
Increase cases of burns
EcoZoom Dura 30–40 Rocket, side-feed, chimney, - - - 5 years -46 - - Reduced burns
EcoZoom 30–40 Rocket, side-feed, no chimney - - - - -20 2 -32 -
Mirt Stove 3.5 to 7 Rocket, portable, chimney, dung, briquettes, wood - - - 5 years -10 - Reduced smoke
Less respiratory discomfort
Reduced respiratory illness in children under age 5 years.
Save80 20 to 55 Portable, Pot skirt, Sunken pot, Crop residue, Dung, wood - - - 15 years - - -96.4 Reduced cough
Reduced sore eyes
Eco Chula 29 to 33 Gasifier (TLUD), Portable, Wood - - - - -18 -21.5 -68 -
Firewood Jambar 10 Ceramic-lined, wood - - - 2 years - - - Reduced eye problems
Reduced respiratory problems
Hifadhi - Crop residue, wood - - - 5 years - 11.1 - -
Prakti Leo 23.62 Chimney, Multiple burners, Rocket, wood - - - 5 years -39 -32.3 -45 -

Discussion

This systematic scoping review identified and examined 39 field-tested ICS from 31 intervention studies and two non-peered review reports published between 2014 to 2022 in sSA. The aim was to identify available, affordable, safe, and efficient ICS, effective in reducing harmful emissions compared to TCS/TSF in real-life settings and able to meet user cooking needs.

Identifying only 33 intervention studies across nine of the 42 sSA countries reflects the paucity of available field evidence. It highlights the need for more field-testing of ICS in sSA, the region with the highest reliance on biomass and, therefore, exposure to household pollutants [10, 72]. The review also demonstrates the wide heterogeneity in the descriptions of ICS characteristics, designs, supporting interventions, and metric units (PPM, mg/m3, μg/m3, g/kg) used in intervention studies. The heterogeneity prevented effective comparison of HAP emission levels across the different ICS and was further compounded by the scant reporting of HAP-associated factors such as fuel water content for units measured in g/Kg, cookstove features (unspecified chimney and draft systems), and household structure (e.g., ventilation, chimney, open or enclosed roof) in the studies.

Emission levels, health, and safety-related outcomes

Our main finding shows a general trend of ICS in reducing PM2.5 compared to baseline TCS/TSF. However, no ICS was effective in reducing levels close to the WHO-IAQ safe level, with the lowest reduction of 0.11mg/m3 over four times the WHO 24-hour average of 0.025mg/m3 for safe indoor air quality. In contrast, CO levels were substantially reduced (lowest value of 0.2PPM) below the WHO recommendations of 6.11PPM. These findings are reported in previous reviews [7, 27, 28], which also found that ICS interventions did not reduce PM2.5 close to the WHO interim guideline levels.

In line with emission reduction, the forced-draft cookstoves consistently show the highest reduction levels of personal and household PM2.5 and CO. This accords with Memon et al.’s systematic review [73] findings on the effectiveness of forced-draft cookstoves in reducing incomplete fuel combustion, thereby reducing exposure to harmful emissions [36, 74]. Kumar et al.’s [7] meta-analysis also reported the lowest reduction in kitchen-level CO with advanced combustion cookstoves. Regarding ICS chimney features, our findings of a higher reduction in kitchen PM2.5 levels with the chimney cookstove EcoZoom Dura [59] compared to the same brand non-chimney EcoZoom ICS [21] concurs with earlier systematic reviews evidence [7, 27] that chimneys play a role in reducing HAP emission. However, when compared across ICS brands, we found this association inconclusive, with some ICS brands without chimneys reporting higher emission reductions than chimney cookstoves. A possible explanation for this might be related to the chimney’s primary function of directing smoke away from the cooking areas, usually into the ambient environment [75] and the chimney heights, which were not described in any of the included studies. Some chimneys, for example, direct smoke away from the cookstove but do not remove it from the kitchen, which could result in a higher concentration of pollutants, especially in kitchen areas with minimal or no ventilation.

Further, the practice of measuring personal CO and personal PM2.5 levels compared to household-level measurements (function of cookstoves and fuel used) will produce differing results. Dickinson et al. [76] describe how the ‘function of activity’ measured by personal exposure does not capture accurate data such as duration of cooking and type of dishes prepared. These activities are dependent to some extent on user behaviour, such as the actual time spent in the kitchen or how closely the cooks stand to the cookstove while cooking and may not reflect the function of the cookstove. This can also be deduced from the users’ account of spending less time supervising the fire, suggesting reduced exposure time to pollutants. While personal level measurement may not capture accurate data on ICS effectiveness, it could inform data on the users’ behaviour of spending less time in the fire’s proximity if examined together with kitchen-level emissions in the same setting.

In addition to emission levels, health-related outcomes provide another measure of the effectiveness of the ICS in reducing health risks and improving user experience. Measured (BP), self-reported eye and respiratory symptoms, and user accounts of back pain, burns, and smoke, reported a reduction in health-related symptoms irrespective of levels of PM2.5, CO, and black carbon in the reviewed studies. Previous systematic reviews have demonstrated reductions in respiratory and non-respiratory health [28] and burn injuries [18]. There are also similarities between the effect of ICS on blood pressure expressed in studies reviewed and those described by Onakomaiya et al. [26] and in Kumar et al.’s metanalysis review [7] of statistically significant BP reductions despite pollution reduction not being at safe levels.

Affordability and availability

The use of less harmful cookstoves can only be realised in practice if the cookstoves are available and affordable to the end user. Some studies alluded to high costs contributing to low ICS adoption rates, especially in more disadvantaged communities [16, 18, 77]. Notably, within this review, only a few ICS with reduced emission levels were priced at less than $40, a cost subject to inflation with additional shipping and importation fees [37, 78]. While we adopted a <$40 price cap in this review due to the focus on the poor communities in sSA, we acknowledge that even a price of $40 would require subsidisation, with almost 40% of 1.08 billion people in sSA living below 1.90 per day [79]. Even with the subsidisation, the purchasing power parity, e.g., $1≈312.3 of Malawi Kwacha [80] of most sSA currencies, could compound the affordability issue, resulting in very limited affordable ICS options for the poorer households and creating a practical barrier to ICS accessibility and adoption [15]. However, the study, which subsidised the ICS price to enhance adoption, found that the approach failed to address the long-term affordability of ICS for poor households [22]. Similarly, in Rosenbaum and colleagues’ ‘willingness to pay’ study [17], of the 105 participants, only one opted to buy the ICS at market price ($19-$54) and most reported a preference to keep the ICS if it were free or available at a nominal price. Additional to the price of the ICS, reductions in the fuel used (where purchased) and in timesaving (where gathered) could be translated into an economic benefit. This is mentioned in several studies [15, 22, 65, 81], where fuel reduction, if measured in time saved, would result in enhanced productivity to invest in other income-generating activities. It also accords to the report from systematic reviews [15, 70], where participants ranked the importance of fuel savings higher than smoke emissions reduction.

Although we did not examine fuel unit prices in this review, their significance is not to be underestimated in determining the feasibility and effectiveness of ICS in poor communities. Poor households, for instance, are unable to obtain wood pellets due to high prices and limited availability, although there is evidence that they produce more heat, reduce emissions, and improve health outcomes [49]. Therefore, wood pellet availability and cost reduction would be required to increase ICS options for most poor rural communities.

Cookstove durability

Only four of the 33 studies in this review described the cookstoves’ durability/ sustainability. A high incidence of cookstove breakdowns will discourage communities from using ICS. Moreover, for households unable to afford a replacement, this could facilitate the reverting to inefficient cookstoves to meet their cooking needs. Therefore, field studies exploring the uptake and sustainability of ICS should also consider stove reliability in addition to its cost and ease of stove repair where required.

Gender equality

Few studies in this review linked findings of time spent on fuel collection and cooking with gender, with only one study suggesting a direct association between ICS use and observed improvement in the health of women who are primary cooks [23]. This disproportionate gender impact of HAP from inefficient cookstoves is referred to as ’an obstacle to women’s human rights, health and sustainable development by Hyde and colleagues [82] and requires urgent and greater attention. Furthermore, the continued promotion and use of inefficient cookstoves further perpetuates the cycle of gender-related ill-health and poverty associated with HAP [83] from long and unpaid hours (≈14 hours/day) of women and girls in developing countries [2] undertaking household chores such as fuel gathering and meal preparation [2, 14].

User perspectives

Finally, our exploration of user perspectives highlights the importance of user experience in promoting the scale-up of cleaner cookstoves. Users suggest that they value less time required for supervision, less time cleaning soot off pots, multitasking opportunities, and more time for families to socialise. User accounts focus on the health-related benefits of ICS more widely than specific symptoms reported in many studies to improve feelings of well-being. Also, while most cookstove designs are centred around reducing emission levels and fuel use, users suggest that other factors, such as ICS height for postural comfort and the convenience of moving the cookstoves to different locations, are important. The ICS portability would particularly be valued in households with a shared cooking and living space due to higher accumulation and increased exposure to pollutants in shared spaces [11]. In addition, cultural cooking practices also play a significant part in stove satisfaction, with ’suitability for cooking a traditional meal’ seen by users as an important benefit of an ICS. These practices are also reflected in the preference for ‘burners to fit large or multiple cooking pots’ for large family sizes and/or communal cooking in most local communities in sSA. The users also called attention to the safety of four of the six ICS explored for user perspectives. In addition to fewer burns, the combustion chamber’s importance in enclosing the flame made it safer for children. However, a more prolonged cooling-off period and inability to cool with water were reported as unsafe by some users of the Chitetezo Mbaula.

In summary, good stove design, fuel and time savings, health benefits, and meeting traditional cooking needs have been identified as critical to cookstove uptake [15]. It is essential in this review to highlight that most of the themes described by the users centred around the cookstoves’ design, indicating the value of including the end-user voice at the design stage, which could address some of the root causes of stove-stacking identified in several other studies [15, 16, 43]. For example, a brick plinth against the wall could raise the height of Mbaula, direct the smoke nearer to the ceiling vents (ventilation), reduce back pain, and raise it above child level, thereby reducing the risk of burns.

Strengths and limitations

Collating relevant recent evidence on all ICS that have reduced harmful emissions in the field, alongside information on availability and affordability, whilst also considering user cooking needs, is an important step forward in ICS assessment. To our knowledge, this is the first field evidence collated together in this way. Our approach to the review’s questions, aims, search strategy and reporting was systematic and guided by an established scoping review framework [34]. The validity of the search outcome was also enhanced by hand searches of reference lists and studies reported within identified systematic reviews. Our quality appraisal process (not mandatory in scoping reviews) allowed evaluation of the quality of evidence available for ICS field studies. All reviewed studies had pre-intervention exposure to TSF or traditional cookstoves for comparison across studies. In addition, we reported on measures such as awareness and support alongside ICS promotion, albeit limited studies described these measures. Finally, the additional exploration of the user voice gives a deeper understanding of ICS features that are important to the communities most likely to benefit from these stoves. While it reflects the importance of the voice of the end-user, it highlights the gap in evidence available based on the user voice in HAP interventions.

Conclusion

While ICS have increased in popularity in recent decades as an alternative to the three-stone fire or traditional stove, their characteristics and effectiveness in reducing HAP differ considerably. However, given their importance as an interim solution until global access to clean energy sources and cleaner cooking technologies is achieved, the scale-up of ICS needs to be underpinned by evidence of substantive reductions in HAP compared to many currently being used. Based on the findings of this review, the following recommendations are suggested to inform research, policy, and current practices in the design and promotion of ICS in SSA (Table 7)

Table 7. Recommendation for research, practice, and policy.

Recommendations Target
• Given that evidence suggests that ICS reduce HAP but not close to safe levels, additional interventions should be promoted alongside cleaner stoves as standard practice. Future research should identify any additional benefits of community engagement practices, cleaner lighting sources, adequate storage for drying of wood, and improved ventilation alongside ICS. Research and Policy
• A detailed standardised description of all relevant study information should be considered the gold standard for the field cookstove evaluation study. This should include cookstove design, chimney height, variation in kitchen design (type of ventilation), availability and cost to the local user, sustainability and durability, ease of repair, incidence of burns, user perspectives, season, i.e., wet or dry, and detailed description of type fuel including water content. Research and practice
• The use of available local resources, such as knowledge, skills, and raw materials, should be considered when developing an ICS to reduce purchasing costs and enhance the community’s skills and capacity to maintain the ICS with less reliance on the importation of repair parts, thereby increasing the lifespan of the intervention. Research and practice
• ICS engineers and researchers should ensure that the user perspective informs all stages of ICS development. The user voice will ensure that ICS meets household socio-economic, cultural, gender, and structural needs. Policy, Research and Practice
• Policy and funding bodies should place more emphasis on the assessment of cookstove efficiency and net health benefits before promoting them to poor communities. Policy

Supporting information

S1 Table. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist.

(DOCX)

S2 Table. Available descriptions of ICS examined in this review.

(DOCX)

S1 Fig

A. Sample of database search terms with results from EMBASE June 2020, July 2021, September 2022. B. Sample of relevant organisation searches and outcomes.

(ZIP)

S2 Fig. Study’s data extraction tool- Excel®.

(TIF)

S3 Fig. Data extraction tool for users’ perspective.

(TIF)

S4 Fig

A. Sample of quality appraisal of included quantitative study using LQAT and the global rating tool. B. Sample of quality appraisal of included qualitative study using adapted Hayden et al.’s and the global rating tools.

(ZIP)

Acknowledgments

We acknowledge and appreciate the support, time, and expertise of Paul Murphy, the information specialist at the Royal College of Surgeons in Ireland library, with the literature searches. pjmurphy@rcsi.ie, ORCID 0000-0001-5056-1971.

Data Availability

All data and processes files are available from the Open Science Framework repository (https://doi.org/10.17605/OSF.IO/PKZGH).

Funding Statement

This review is part of The Smokeless Village Project, funded by the Irish Research Council, project number: COALESCE/2020/13 awarded to author DS. The funder had no role in the study design, collection, analysis, interpretation of data, and in the decision to submit the article for publication.

References

  • 1.World Health Organization. Air Pollution: Overview: WHO; 2022. Available from: https://www.who.int/health-topics/air-pollution#tab=tab_1. [Google Scholar]
  • 2.Critchley K, Teather K, Hughes H, MacDonald A, Gibson M. Air quality, respiratory health and wood use for women converting from low-to high-efficiency stoves in rural Kenya. WIT Trans Ecol. 2015;198:205–16. [Google Scholar]
  • 3.van der Plas RJ, Abdel-Hamid MA. Can the woodfuel supply in sub-Saharan Africa be sustainable? The case of N’Djaména, Chad. Energy Policy. 2005;33(3):297–306. [Google Scholar]
  • 4.World Health Organization. Household air pollution and health: WHO; 2022. [cited 2022 20th, August]. Fact Sheet N292]. Available from: http://www.who.int/news-room/fact-sheets/detail/household-air-pollution-and-health [Google Scholar]
  • 5.Alexander D, Northcross A, Pandya R, Adu D, Ibigbami T, et al. Randomized controlled study of bioethanol stove intervention on blood pressure changes during pregnancy in Nigerian Women. Am J Respir Crit Care Med. 2017;195(12):1629–39. Epub 2017. [DOI] [PubMed] [Google Scholar]
  • 6.Amegah AK, Quansah R, Jaakkola JJ. Household air pollution from solid fuel use and risk of adverse pregnancy outcomes: a systematic review and meta-analysis of the empirical evidence. PLoS One. 2014;9(12):e113920. Epub 2014/12/02. doi: 10.1371/journal.pone.0113920 ; PubMed Central PMCID: PMC4252082. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 7.Kumar N, Phillip E, Cooper H, Davis M, Langevin J, et al. Do improved biomass cookstove interventions improve indoor air quality and blood pressure? A systematic review and meta-analysis. Environ Pollut. 2021;290(2). doi: 10.1016/j.envpol.2021.117997 [DOI] [PubMed] [Google Scholar]
  • 8.Stanaway JD, Afshin A, Gakidou E, Lim SS, Abate D, et al. Global, regional, and national comparative risk assessment of 84 behavioural, environmental and occupational, and metabolic risks or clusters of risks for 195 countries and territories, 1990–2017: a systematic analysis for the Global Burden of Disease Study 2017. The Lancet. 2018;392(10159):1923–94. doi: 10.1016/S0140-6736(18)32225-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 9.Thakur M, Nuyts PA, Boudewijns EA, Kim JF, Faber T, et al. Impact of improved cookstoves on women’s and child health in low and middle income countries: a systematic review and meta-analysis. Thorax. 2018;73(11):1026–40. doi: 10.1136/thoraxjnl-2017-210952 [DOI] [PubMed] [Google Scholar]
  • 10.World Health Organization. Global Health Observatory. Household air pollution: situation and trends: WHO; 2021. Available from: https://www.who.int/data/gho/data/themes/topics/topic-details/GHO/household-air-pollution. [Google Scholar]
  • 11.Kiser MM, Samuel JC, Mclean SE, Muyco AP, Cairns BA, Charles AG. Epidemiology of pediatric injury in Malawi: burden of disease and implications for prevention. Int J Surg. 2012;10(10):611–7. doi: 10.1016/j.ijsu.2012.10.004 [DOI] [PubMed] [Google Scholar]
  • 12.World Health Organization. Household air pollution is a gender issue 2021. Available from: https://www.who.int/life-course/news/household-air-pollution/en/#:~:text=In%20a%20world%20where%20women,issue%20that%20demands%20global%20attention.&text=More%20than%2060%25%20of%20all,were%20among%20women%20and%20children. [Google Scholar]
  • 13.Okello G, Devereux G, Semple S. Women and girls in resource poor countries experience much greater exposure to household air pollutants than men: Results from Uganda and Ethiopia. Environ Int. 2018;119:429–37. doi: 10.1016/j.envint.2018.07.002 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 14.Oxfam International. Not all gaps are created equal: the true value of care work: Oxfam; 2021. Available from: https://www.oxfam.org/en/not-all-gaps-are-created-equal-true-value-care-work.
  • 15.Stanistreet D, Puzzolo E, Bruce N, Pope D, Rehfuess E. Factors influencing household uptake of improved solid fuel stoves in low- and middle-income countries: a qualitative systematic review. Int J Environ Res Public Health. 2014;11(8):8228–50. doi: 10.3390/ijerph110808228 . [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 16.Puzzolo E, Pope D, Stanistreet D, Rehfuess EA, Bruce NG. Clean fuels for resource-poor settings: A systematic review of barriers and enablers to adoption and sustained use. Environ Res. 2016;146:218–34. doi: 10.1016/j.envres.2016.01.002 [DOI] [PubMed] [Google Scholar]
  • 17.Rosenbaum J, Derby E, Dutta K. Understanding consumer preference and willingness to pay for improved cookstoves in Bangladesh. J Health Commun. 2015;20(sup1):20–7. doi: 10.1080/10810730.2014.989345 [DOI] [PubMed] [Google Scholar]
  • 18.Rehfuess EA, Puzzolo E, Stanistreet D, Pope D, Bruce NG. Enablers and barriers to large-scale uptake of improved solid fuel stoves: a systematic review. Environ Health Perspect. 2014;122(2):120–30. doi: 10.1289/ehp.1306639 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 19.Adane MM, Alene GD, Mereta ST, Wanyonyi KL. Facilitators and barriers to improved cookstove adoption: a community-based cross-sectional study in Northwest Ethiopia. Environ Health Prev Med. 2020;25:1–12. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 20.Coffey ER, Muvandimwe D, Hagar Y, Wiedinmyer C, Kanyomse E, et al. New emission factors and efficiencies from in-field measurements of traditional and improved cookstoves and their potential implications. Environ Sci Technol. 2017;51(21):12508–17. doi: 10.1021/acs.est.7b02436 [DOI] [PubMed] [Google Scholar]
  • 21.Pilishvili T, Loo JD, Schrag S, Stanistreet D, Christensen B, et al. Effectiveness of six improved cookstoves in reducing household air pollution and their acceptability in rural Western Kenya. PLoS One. 2016;11(11):e0165529. doi: 10.1371/journal.pone.0165529 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 22.Onyeneke RU, Nwajiuba CU, Mmagu CJ, Aligbe JO, Uwadoka CO, et al. Impact of adoption of improved cook-stove on different components of household welfare in rural communities in Nigeria: The case of Save80 cook-stove in Kaduna. Environ Prog Sust Energy. 2018;37(4):1327–38. doi: 10.1002/ep.12815 [DOI] [Google Scholar]
  • 23.Bensch G, Peters J. The intensive margin of technology adoption—Experimental evidence on improved cooking stoves in rural Senegal. J Health Econ. 2015;42:44–63. doi: 10.1016/j.jhealeco.2015.03.006 [DOI] [PubMed] [Google Scholar]
  • 24.Jary H, Kachidiku J, Banda H, Kapanga M, Doyle J, et al. Feasibility of conducting a randomised controlled trial of a cookstove intervention in rural Malawi. Int J Tuberc Lung Dis. 2014;18(2):240–7. doi: 10.5588/ijtld.13.0485 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 25.Cundale K, Thomas R, Malava JK, Havens D, Mortimer K, Conteh L. A health intervention or a kitchen appliance? Household costs and benefits of a cleaner burning biomass-fuelled cookstove in Malawi. Soc Sci Med. 2017;183:1–10. Epub 2017/04/26. doi: 10.1016/j.socscimed.2017.04.017 ; PubMed Central PMCID: PMC5446311. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 26.Onakomaiya D, Gyamfi J, Iwelunmor J, Opeyemi J, Oluwasanmi M, et al. Implementation of clean cookstove interventions and its effects on blood pressure in low-income and middle-income countries: systematic review. BMJ open. 2019;9(5):e026517. doi: 10.1136/bmjopen-2018-026517 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 27.Pope D, Bruce N, Dherani M, Jagoe K, Rehfuess E. Real-life effectiveness of ‘improved’stoves and clean fuels in reducing PM2. 5 and CO: systematic review and meta-analysis. Environ Int. 2017;101:7–18. doi: 10.1016/j.envint.2017.01.012 [DOI] [PubMed] [Google Scholar]
  • 28.Quansah R, Semple S, Ochieng CA, Juvekar S, Armah FA, et al. Effectiveness of interventions to reduce household air pollution and/or improve health in homes using solid fuel in low-and-middle income countries: A systematic review and meta-analysis. Environ Int. 2017;103:73–90. doi: 10.1016/j.envint.2017.03.010 [DOI] [PubMed] [Google Scholar]
  • 29.World Health Organization. WHO guidelines for indoor air quality: household fuel combustion. Geneva: WHO; 2014. [cited 2021 18th, December]. Available from: https://www.who.int/airpollution/guidelines/household-fuel-combustion/IAQ_HHFC_guidelines.pdf. [PubMed] [Google Scholar]
  • 30.Stanistreet D, Phillip E, Kumar N, Anderson De Cuevas R, Davis M, et al. Which Biomass Stove(s) Capable of Reducing Household Air Pollution Are Available to the Poorest Communities Globally? Int J Environ Res Public Health. 2021;18(17):9226. doi: 10.3390/ijerph18179226 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 31.Sucharew H, Macaluso M. Methods for research evidence synthesis: the scoping review approach. J Hosp Med. 2019;14(7):416–8. [DOI] [PubMed] [Google Scholar]
  • 32.Arksey H, O’Malley L. Scoping studies: towards a methodological framework. Int J Soc Res Methodol. 2005;8(1):19–32. [Google Scholar]
  • 33.Levac D, Colquhoun H, O’Brien KK. Scoping studies: advancing the methodology. Implement Sci. 2010;5(1):69. doi: 10.1186/1748-5908-5-69 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 34.Peters MD, Marnie C, Tricco AC, Pollock D, Munn Z, et al. Updated methodological guidance for the conduct of scoping reviews. JBI Evidence Synthesis. 2020;18(10):2119–26. doi: 10.11124/JBIES-20-00167 [DOI] [PubMed] [Google Scholar]
  • 35.Tricco AC, Lillie E, Zarin W, O’Brien KK, Colquhoun H, et al. PRISMA extension for scoping reviews (PRISMA-ScR): checklist and explanation. Ann Intern Med. 2018;169(7):467–73. doi: 10.7326/M18-0850 [DOI] [PubMed] [Google Scholar]
  • 36.Clean Cooking Alliance. The clean cooking catalog: product and performance data for the clean cooking sector: Clean Cooking Alliance; 2021. Available from: http://catalog.cleancookstoves.org/, http://catalog.cleancookstoves.org/glossary#stove-characteristics, http://catalog.cleancookstoves.org/glossary. [Google Scholar]
  • 37.Ekouevi K, Freeman KK, Soni R. Understanding the differences between cookstoves: World Bank Group,; 2014. Available from: https://openknowledge.worldbank.org/bitstream/handle/10986/18411/880580BRI0REPL00Box385214B00PUBLIC0.pdf?sequence=6&isAllowed=y. [Google Scholar]
  • 38.Ouzzani M, Hammady H, Fedorowicz Z, Elmagarmid A. Rayyan—a web and mobile app for systematic reviews. Syst Rev. 2016;5(1):1–10. doi: 10.1186/s13643-016-0384-4 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 39.Picot J, Hartwell D, Harris P, Mendes D, Clegg A, Takeda A. The effectiveness of interventions to treat severe acute malnutrition in young children: a systematic review. Appendix 4, Quality assessment. Health Technol Assess. 2012;16(19):1. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 40.World Health Organization. WHO guidelines for indoor air quality: selected pollutants: World Health Organization, Regional Office for Europe: Copenhagen, Denmark; 2010. [cited 2021 15th, December]. Available from: https://apps.who.int/iris/handle/10665/260127. [Google Scholar]
  • 41.Wang M, Aaron CP, Madrigano J, Hoffman EA, Angelini E, et al. Association Between Long-term Exposure to Ambient Air Pollution and Change in Quantitatively Assessed Emphysema and Lung Function. JAMA. 2019;322(6):546. doi: 10.1001/jama.2019.10255 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 42.Hooper LG, Dieye Y, Ndiaye A, Diallo A, Sack CS, et al. Traditional cooking practices and preferences for stove features among women in rural Senegal: Informing improved cookstove design and interventions. PLoS One. 2018;13(11):e0206822. doi: 10.1371/journal.pone.0206822 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 43.Loo JD, Hyseni L, Ouda R, Koske S, Nyagol R, et al. User perspectives of characteristics of improved cookstoves from a field evaluation in Western Kenya. Int J Environ Res Public Health. 2016;13(2). doi: 10.3390/ijerph13020167 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 44.Innovation Beck L., A congolose mother sings the praises of wonder stove: UNHCR- The UN Refugee Agency, Ireland; 2015. Available from: https://www.unhcr.org/en-ie/news/latest/2015/3/550991ef9/innovation-congolese-mother-sings-praises-wonder-stove.html. [Google Scholar]
  • 45.Ndunda N. Innovation: Smart Clean Cook Stove Transforming Lives in Kakuma: UNHCR- The UN Refugee Agency; 2017. Available from: https://www.unhcr.org/ke/10699-innovation-smart-clean-cook-stove-transforming-lives-kakuma.html. [Google Scholar]
  • 46.The African Union Commission. Member States Addid Ababa, Ethiopia: The African Union Commission; ND [cited 2023 3rd, March]. Available from: https://au.int/en/member_states/countryprofiles2#:~:text=The%20AU%20is%20made%20up,countries%20on%20the%20African%20continent.
  • 47.Champion WM, Grieshop AP. Pellet-Fed Gasifier Stoves Approach Gas-Stove Like Performance during in-Home Use in Rwanda. Environ Sci Technol. 2019;53(11):6570–9. doi: 10.1021/acs.est.9b00009 [DOI] [PubMed] [Google Scholar]
  • 48.Garland C, Delapena S, Prasad R, L’Orange C, Alexander D, Johnson M. Black carbon cookstove emissions: A field assessment of 19 stove/fuel combinations. Atmos Environ. 2017;169:140–9. [Google Scholar]
  • 49.Jagger P, Das I, Handa S, Nylander-French LA, Yeatts KB. Early Adoption of an Improved Household Energy System in Urban Rwanda. Ecohealth. 2019;16(1):7–20. Epub 2019/01/09. doi: 10.1007/s10393-018-1391-9 ; PubMed Central PMCID: PMC6592015. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 50.Adane MM, Alene GD, Mereta ST. Biomass-fuelled improved cookstove intervention to prevent household air pollution in Northwest Ethiopia: a cluster randomized controlled trial. Environ Health Prev Med. 2021;26(1):1–15. doi: 10.1186/s12199-020-00923-z [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 51.Adane MM, Alene GD, Mereta ST, Wanyonyi KL. Effect of improved cookstove intervention on childhood acute lower respiratory infection in Northwest Ethiopia: a cluster-randomized controlled trial. BMC Pediatr. 2021;21(1):1–13. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 52.Dutta A, Alexander D, Karrison T, Morhasson-Bello O, Wilson N, et al. Household air pollution, ultrasound measurement, fetal biometric parameters and intrauterine growth restriction. Environmental Health. 2021;20(1):1–9. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 53.Gebreegziabher Z, Beyene AD, Bluffstone R, Martinsson P, Mekonnen A, Toman MA. Fuel savings, cooking time and user satisfaction with improved biomass cookstoves: Evidence from controlled cooking tests in Ethiopia. Resour Energy Econ. 2018;52:173–85. [Google Scholar]
  • 54.Gitau JK, Sundberg C, Mendum R, Mutune J, Njenga M. Use of Biochar-Producing Gasifier Cookstove Improves Energy Use Efficiency and Indoor Air Quality in Rural Households. Energies. 2019;12(22):4285. [Google Scholar]
  • 55.Hankey S, Sullivan K, Kinnick A, Koskey A, Grande K, et al. Using objective measures of stove use and indoor air quality to evaluate a cookstove intervention in rural Uganda. Energy Sustain Dev. 2015;25:67–74. doi: 10.1016/j.esd.2014.12.007 WOS:000352119800009. [DOI] [Google Scholar]
  • 56.Jagoe K, Rossanese M, Charron D, Rouse J, Waweru F, et al. Sharing the burden: Shifts in family time use, agency and gender dynamics after introduction of new cookstoves in rural Kenya. Energy Res Soc Sci. 2020;64. doi: 10.1016/j.erss.2019.101413 WOS:000532669700011. [DOI] [Google Scholar]
  • 57.Kirby MA, Nagel CL, Rosa G, Zambrano LD, Musafiri S, et al. Effects of a large-scale distribution of water filters and natural draft rocket-style cookstoves on diarrhea and acute respiratory infection: A cluster-randomized controlled trial in Western Province, Rwanda. PLoS Med. 2019;16(6):e1002812. doi: 10.1371/journal.pmed.1002812 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 58.LaFave D, Beyene AD, Bluffstone R, Dissanayake ST, Gebreegziabher Z, et al. Impacts of improved biomass cookstoves on child and adult health: Experimental evidence from rural Ethiopia. World Dev. 2021;140:105332. [Google Scholar]
  • 59.Mortimer K, Ndamala CB, Naunje AW, Malava J, Katundu C, et al. A cleaner burning biomass-fuelled cookstove intervention to prevent pneumonia in children under 5 years old in rural Malawi (the Cooking and Pneumonia Study): a cluster randomised controlled trial. Lancet. 2017;389(10065):167–75. doi: 10.1016/S0140-6736(16)32507-7 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 60.Njenga M, Iiyama M, Jamnadass R, Helander H, Larsson L, et al. Gasifier as a cleaner cooking system in rural Kenya. J Clean Prod. 2016;121:208–17. [Google Scholar]
  • 61.Ochieng C, Vardoulakis S, Tonne C. Household air pollution following replacement of traditional open fire with an improved rocket type cookstove. Sci Total Environ. 2017;580:440–7. doi: 10.1016/j.scitotenv.2016.10.233 [DOI] [PubMed] [Google Scholar]
  • 62.Quinn AK, Ayuurebobi K, Kinney PL, Kaali S, Wylie BJ, et al. Ambulatory monitoring demonstrates an acute association between cookstove-related carbon monoxide and blood pressure in a Ghanaian cohort. Environ Health. 2017;16(1):1–14. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 63.Rosa G, Majorin F, Boisson S, Barstow C, Johnson M, et al. Assessing the impact of water filters and improved cook stoves on drinking water quality and household air pollution: a randomised controlled trial in Rwanda. PLoS One. 2014;9(3):e91011. Epub 2014/03/13. doi: 10.1371/journal.pone.0091011 . [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 64.Saleh S, Sambakunsi H, Makina D, Kumwenda M, Rylance J, et al. “We threw away the stones”: a mixed method evaluation of a simple cookstove intervention in Malawi. Wellcome Open Research. 2022;7. doi: 10.12688/wellcomeopenres.17544.3 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 65.Vaccari M, Vitali F, Tudor T. Multi-criteria assessment of the appropriateness of a cooking technology: A case study of the Logone Valley. Energy Policy. 2017;109:66–75. doi: 10.1016/j.enpol.2017.06.052 [DOI] [Google Scholar]
  • 66.Wathore R, Mortimer K, Grieshop AP. In-use emissions and estimated impacts of traditional, natural-and forced-draft cookstoves in rural Malawi. Environ Sci Technol. 2017;51(3):1929–38. doi: 10.1021/acs.est.6b05557 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 67.Dickinson KL, Piedrahita R, Coffey ER, Kanyomse E, Alirigia R, et al. Adoption of improved biomass stoves and stove/fuel stacking in the REACCTING intervention study in Northern Ghana. Energy Policy. 2019;130:361–74. doi: 10.1016/j.enpol.2018.12.007 WOS:000471083700032. [DOI] [Google Scholar]
  • 68.Dresen E, Devries B, Herold M, Verchot L, Müller R. Fuelwood Savings and Carbon Emission Reductions by the Use of Improved Cooking Stoves in an Afromontane Forest, Ethiopia. Land. 2014;3(3):1137–57. doi: 10.3390/land3031137 [DOI] [Google Scholar]
  • 69.Jagger P, Jumbe C. Stoves or sugar? Willingness to adopt improved cookstoves in Malawi. Energy Policy. 2016;92:409–19. doi: 10.1016/j.enpol.2016.02.034 WOS:000373863600038. [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 70.Pailman W, de Groot J, Clifford M, Jewitt S, Ray C. Experiences with improved cookstoves in Southern Africa. J Energy South Africa 2018;29(4):13–26. doi: 10.17159/2413-3051/2018/v29i4a5072 WOS:000456121000002. [DOI] [Google Scholar]
  • 71.Energypedia. Improved Cookstoves and Energy Saving Cooking Equipment: GIZ HERA; 2021. Available from: https://energypedia.info/wiki/Improved_Cookstoves_and_Energy_Saving_Cooking_Equipment.
  • 72.International Energy Agency. SDG7: Data and projections. Access to affordable, reliable, sustainable and modern energy for all Paris: IEA; 2020. Available from: https://www.iea.org/reports/sdg7-data-and-projections.
  • 73.Memon SA, Jaiswal MS, Jain Y, Acharya V, Upadhyay DS. A comprehensive review and a systematic approach to enhance the performance of improved cookstove (ICS). J Therm Anal Calorim. 2020;141(6):2253–63. [Google Scholar]
  • 74.Global Alliance for Clean Cooking. Handbook for Biomass Cookstove Research, Design, and Development: A PRACTICAL GUIDE TO IMPLEMENTING RECENT ADVANCES. NY. p. 1–56.
  • 75.Mortimer K. Chimney stove intervention–ready for scale up? CON. BMJ Publishing Group Ltd; 2016. doi: 10.1136/thoraxjnl-2016-208318 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 76.Dickinson KL, Kanyomse E, Piedrahita R, Coffey E, Rivera IJ, et al. Research on Emissions, Air quality, Climate, and Cooking Technologies in Northern Ghana (REACCTING): study rationale and protocol. BMC Public Health. 2015;15(1):1–20. doi: 10.1186/s12889-015-1414-1 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 77.Jeuland M, Bhojvaid V, Kar A, Lewis J, Patange O, et al. Preferences for improved cook stoves: Evidence from rural villages in north India. Energy Econ. 2015;52:287–98. [Google Scholar]
  • 78.Putti VR, Tsan M, Mehta S, Kammila S. The state of the global clean and improved cooking sector. ESMAP Technical Paper. Washington, DC: World Bank; 2015. Available from: https://openknowledge.worldbank.org/handle/10986/21878. [Google Scholar]
  • 79.Schoch M, Lakner C. World Bank Blogs [Internet]: Worldbank.org. 2020. [19th, February 2022]. Available from: https://blogs.worldbank.org/opendata/number-poor-people-continues-rise-sub-saharan-africa-despite-slow-decline-poverty-rate#:~:text=The%20latest%20estimates%20show%20that,the%20global%20extreme%20poor%20population. [Google Scholar]
  • 80.The world Bank Group. PPP conversion factor, private consumption (LCU per international $) 2022 [cited 2022 August 1st,]. Available from: https://data.worldbank.org/indicator/PA.NUS.PRVT.PP?locations=MW/.
  • 81.Person B, Loo JD, Owuor M, Ogange L, Jefferds MED, Cohen AL. “It is good for my family’s health and cooks food in a way that my heart loves”: Qualitative findings and implications for scaling up an improved cookstove project in rural Kenya. Int J Environ Res Public Health. 2012;9(5):1566–80. doi: 10.3390/ijerph9051566 [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 82.Hyde E, Greene ME, Darmstadt GL. Time poverty: Obstacle to women’s human rights, health and sustainable development. J Glob Health. 2020;10(2). [DOI] [PMC free article] [PubMed] [Google Scholar]
  • 83.Rehfuess E. Fuel for life: household energy and health. France: World Health Organization; 2006. [cited 2021 15th, December]. Available from: https://www.who.int/publications/i/item/9789241563161. [Google Scholar]

Decision Letter 0

Srijan Lal Shrestha

6 Mar 2023

PONE-D-22-35350Improved cookstoves to reduce household air pollution exposure in sub-Saharan Africa: a scoping review of intervention studies.PLOS ONE

Dear Dr. Phillip,

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Reviewer #1: Yes

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2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: N/A

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Reviewer #1: Yes

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Reviewer #1: Yes

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Reviewer #1: The paper based on systematic review is well written, and is attempted to identify which improved cookstoves would be the most suitable to promote among poor communities in Sub-Sahara Africa (sSA).The manuscript is technically sound, systematic review is done following the standard protocol, quality assessment of the included studies are also assessed by using standard tools. The conclusions are supported by the data. Data curation is done rigorously. However there are still some comments to improve the manuscript, which are as follows.

1. In Line 171 under 'Data Charting', it is mentioned that only the most comprehensive study data were included where multiple publications reported on the same data. What is the basis used for considering them the most comprehensive? It is suggested to explain point wise clearly.

2. In Line 225, it is reported that the total number of sSA countries is 46. Again in contrary with this, the total sSA countries is reported 42(in Line 507). Actually the total number of sSA countries is more than 46. Please make your reporting consistent, and report exact number of sSA countries what exactly is in existence.

3. Add percentage along with numbers in Figure 1 related to sparsity of reported relevant studies in Sub-Saharan Africa. It will help readers to understand quickly.

4. If possible, present the major review report according to some geographic distribution of Sub-Saharan Countries such as West Africa, East Africa, Central Africa, and Southern Africa which suits for the analysis based on the studies incorporated. There may be considerable variations with respect to population distribution, socio-economic indicators and others. The analysis based on some appropriate geographical domain may be helpful for future policy point of view.

5. Figure numbers are not matching in text and in the provided figures, and they are not in sequential order. Some figures indicated in the text such as (S2 & S3 Figs) not found in the provided figure lists. It is strongly suggested to check all figure numbers indicated in the text and keep accordingly.

6. In each table, please add serial number creating a first column (if possible) so that it would be easy for the readers to go through it.

7. In Table 2, only 'Section B' is mentioned without mentioning 'Section A'. Please add Section A in appropriate place of the table.

8. Check all the symbols used in Table3, and match with Reference Key. There is mismatch in the notations such as 'NM= Not measured', 'NM=Not measured in the study'. What is the difference between them? In Table 5 also, A study namely LaFave 2021[57] RCT- 10th column, what is the meaning of "?". If it is symbol, please change by another one. I suggest you to go through them one by one.

9. Please add statistical method/statistical test/statistical model whichever was applied in each study incorporated in this review report in Table 3 and Table 5 where estimates and p-values are reported. In the manuscript, it is only reported different estimates, p-values, and confidence interval, etc. which are not comprehensive.

10. Figure 7 seems to be prepared through some step function using time to event data (having censored data) because in some costing points, there is constant probability and then increases. Generally such type of curves can be observed in hazard function. It is better to explain the curve for making it comprehensive.

11. Add the definition of quality assessment criteria ('strong', 'moderate', & 'weak)' in the text for clarity though it is indicated in the submitted supplementary document.

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Reviewer #1: No

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PLoS One. 2023 Apr 27;18(4):e0284908. doi: 10.1371/journal.pone.0284908.r002

Author response to Decision Letter 0


7 Apr 2023

Editor's comment 1. Please ensure that your manuscript meets PLOS ONE's style requirements, including those for file naming.

Authors: Thank you. We have followed the provided guidelines throughout the manuscript, including formatting styles, authors’ names, addresses and tags.

Editor's comment 2. We note you have included a table to which you do not refer in the text of your manuscript. Please ensure that you refer to Table 7 in your text; if accepted, production will need this reference to link the reader to the Table.

Authors: Thank you for pointing this out. We have referenced the table in the manuscript text. Page 46.

Editor's comment 3. We note that this manuscript is a systematic review or meta-analysis; our author guidelines, therefore, require that you use PRISMA guidance to help improve reporting quality of this type of study. Please upload copies of the completed PRISMA checklist as Supporting Information with the file name “PRISMA checklist”.

Authors: We submitted Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) Checklist as part of the supplementary information with the prior submission. We have updated the form to correspond to the changes made in the manuscript. S1 Table…. We submitted Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews (PRISMA-ScR) Checklist as part of the supplementary information with the prior submission (S1 Table). We have updated the supplementary information file to correspond to the changes made in the manuscript. We’ve submitted tracked and clean versions of the SI file.

Editor's comment 4 Please review your reference list to ensure that it is complete and correct. If you have cited papers that have been retracted, please include the rationale for doing so in the manuscript text or remove these references and replace them with relevant current references. Any changes to the reference list should be mentioned in the rebuttal letter that accompanies your revised manuscript. If you need to cite a retracted article, indicate the article’s retracted status in the References list and include a citation and full reference for the retraction notice.

Authors: We have reviewed and formatted the reference list to match the journal’s criteria. We changed the reference (United Nations Development Program. About Sub-Saharan Africa: United Nations; 2021) to The African Union Commission—member states to accurately address reviewer’s comment 2 below.

Reviewer’s comments

1. In Line 171 under 'Data Charting', it is mentioned that only the most comprehensive study data were included where multiple publications reported on the same data. What is the basis used for considering them the most comprehensive? It is suggested to explain point-wise clearly.

Authors: Thank you for the comment. We compared (1) the population studied to see if they were the same. (2) If not, we included both studies. If yes, we looked at what was measured, analysed, and reported. In the one study that we excluded, the same population was sampled for kitchen PM2.5 & CO, and a mother and one child’s personal CO over 48 hours using six cookstove interventions. This was the same as the authors' previous publication except that the study included in our review analysed and reported the same result but included confounders in the analysis such as fuel used for lighting, number of cooking episodes, and average number of people cooked for. We have rephrased and included a succinct description of this step in the manuscript (Page 7)

2. In Line 225, it is reported that the total number of sSA countries is 46. Again in contrary with this, the total sSA countries is reported 42 (in Line 507). Actually the total number of sSA countries is more than 46. Please make your reporting consistent, and report exact number of sSA countries what exactly is in existence.

Authors: We thank you for your observation. We have updated this with the number of SSA countries (48) reported by the African Union and updated the reference source to reflect this.

3. Add percentage along with numbers in Figure 1 related to sparsity of reported relevant studies in Sub-Sahara Africa. It will help readers to understand quickly.

Authors: Thank you for this comment. We have changed Figure 1 to show the high number of countries without relevant studies and the percentage of studies in the countries with relevant studies.

4. If possible, present the major review report according to some geographic distribution of Sub-Saharan Countries such as West Africa, East Africa, Central Africa, and Southern Africa which suits for the analysis based on the studies incorporated. There may be considerable variations with respect to population distribution, socio-economic indicators and others. The analysis based on some appropriate geographical domain may be helpful for future policy point of view.

Authors: Thank you for your comment. We agree that collating the evidence based on the geographical distribution would be relevant to policy and enhance the manuscript. However, the sparsity of description of information like socioeconomic factors, food cooked and exposure levels in almost all the studies makes synthesising the data using the SSA geographical distribution. In addition, there are too few studies in each SSA geographical distribution, and the diverse population studied would not allow comparison. This type of analysis would be best suited for systematic review, focusing on specific parameters across the 4 regions in SSA.

5. Figure numbers are not matching in text and in the provided figures, and they are not in sequential order. Some figures indicated in the text such as (S2 & S3 Figs) not found in the provided figure lists. It is strongly suggested to check all figure numbers indicated in the text and keep accordingly.

Authors: Thank you for your comment. The indicated S2 and S3 (data extraction tools) you highlighted were included in our previous supplementary information (SI)file submission. We have ensured that the listed SI list at the end of the manuscript matches the named tables and figures. We have collated all the SI figs and tables sequentially.

Authors: Thank you for your comment. The indicated S2 and S3 (data extraction tools) you highlighted were included in our previous supplementary information (SI)file submission. We have ensured that the listed SI list at the end of the manuscript matches the named tables and figures. We have collated all the SI figs and tables sequentially.

6. In each table, please add serial number creating a first column (if possible) so that it would be easy for the readers to go through it.

Authors: We see the rationale in your comment. However, it was only possible to add an extra column to Table 2. We could not achieve this with Table 3 without it being out of margin. We have added the associated reference to the ICS names to make it easier for readers.

7. In Table 2, only 'Section B' is mentioned without mentioning 'Section A'. Please add Section A in appropriate place of the table.

Authors: Thank you. We have included section A and its label in Table 2. (page 11)

8. Check all the symbols used in Table3, and match with Reference Key. There is mismatch in the notations such as 'NM= Not measured', 'NM=Not measured in the study'. What is the difference between them? In Table 5 also, A study namely LaFave 2021[57] RCT- 10th column, what is the meaning of "?". If it is symbol, please change by another one. I suggest you to go through them one by one.

Authors: Many thanks for this observation. We have corrected and updated the key used in all the tables to reflect their intended meanings. NM now corresponds to ‘Not measured in the referenced study’. The "?" in Table 5, 10th column was an error. This has now been corrected, and the sentence, adjusted for clarification. All the symbols have been updated.

9. Please add statistical method/statistical test/statistical model whichever was applied in each study incorporated in this review report in Table 3 and Table 5 where estimates and p-values are reported. In the manuscript, it is only reported different estimates, p-values, and confidence interval, etc. which are not comprehensive.

Authors: Thank you for your suggestion. We have included this information in Tables 3 and 5 under their respective sections. We denoted this with ^ = Statistical test (study #) in the ‘KEY’ sessions. We did not report in the tables as suggested due to table size challenges/limitations.

10. Figure 7 seems to be prepared through some step function using time to event data (having censored data) because in some costing points, there is constant probability and then increases. Generally, such type of curves can be observed in hazard function. It is better to explain the curve for making it comprehensive.

Authors: Thank you for your comment. We have assumed that the figure in question is Fig 4 (per cent of available cookstove price). The figure is simply the cumulative distribution function. To avoid readers puzzling over this term, we have captioned it "Stoves costing this much or less". The reason why the graph looks like a hazard function is that this, too, is a cumulative distribution but, of event probabilities, not stove prices. The graph is stepped rather than continuous as the price rises because the number of stoves only rises when a further stove becomes available for that amount of money. The revised submission has minor improvements in the manuscript and captioning, as noted above.

11. Add the definition of quality assessment criteria ('strong', 'moderate', & 'weak)' in the text for clarity though it is indicated in the submitted supplementary document.

Authors: Thank you for your comment. We have included the description of our rating under the method section under quality appraisal for clarity.

Attachment

Submitted filename: Response to Reviewers.docx

Decision Letter 1

Srijan Lal Shrestha

12 Apr 2023

Improved cookstoves to reduce household air pollution exposure in sub-Saharan Africa: A scoping review of intervention studies.

PONE-D-22-35350R1

Dear Dr. Phillip

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

Within one week, you’ll receive an e-mail detailing the required amendments. When these have been addressed, you’ll receive a formal acceptance letter and your manuscript will be scheduled for publication.

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Kind regards,

Srijan Lal Shrestha, Ph.D.

Academic Editor

PLOS ONE

Additional Editor Comments (optional):

Reviewers' comments:

Acceptance letter

Srijan Lal Shrestha

17 Apr 2023

PONE-D-22-35350R1

Improved cookstoves to reduce household air pollution exposure in sub-Saharan Africa: A scoping review of intervention studies.

Dear Dr. Phillip:

I'm pleased to inform you that your manuscript has been deemed suitable for publication in PLOS ONE. Congratulations! Your manuscript is now with our production department.

If your institution or institutions have a press office, please let them know about your upcoming paper now to help maximize its impact. If they'll be preparing press materials, please inform our press team within the next 48 hours. Your manuscript will remain under strict press embargo until 2 pm Eastern Time on the date of publication. For more information please contact onepress@plos.org.

If we can help with anything else, please email us at plosone@plos.org.

Thank you for submitting your work to PLOS ONE and supporting open access.

Kind regards,

PLOS ONE Editorial Office Staff

on behalf of

Dr. Srijan Lal Shrestha

Academic Editor

PLOS ONE

Associated Data

    This section collects any data citations, data availability statements, or supplementary materials included in this article.

    Supplementary Materials

    S1 Table. Preferred Reporting Items for Systematic reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) checklist.

    (DOCX)

    S2 Table. Available descriptions of ICS examined in this review.

    (DOCX)

    S1 Fig

    A. Sample of database search terms with results from EMBASE June 2020, July 2021, September 2022. B. Sample of relevant organisation searches and outcomes.

    (ZIP)

    S2 Fig. Study’s data extraction tool- Excel®.

    (TIF)

    S3 Fig. Data extraction tool for users’ perspective.

    (TIF)

    S4 Fig

    A. Sample of quality appraisal of included quantitative study using LQAT and the global rating tool. B. Sample of quality appraisal of included qualitative study using adapted Hayden et al.’s and the global rating tools.

    (ZIP)

    Attachment

    Submitted filename: Response to Reviewers.docx

    Data Availability Statement

    All data and processes files are available from the Open Science Framework repository (https://doi.org/10.17605/OSF.IO/PKZGH).


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