Table 2.

Summary of key characteristics of international research centers by country based on sampling, government information, or published studies.

Country	India	Guatemala	Peru	Rwanda
State/province(s) District(s)	Tamil Nadu, selected blocks: Kalrayan Hills (Villupuram District); Kezhvelur, Keelayur, Vedaranyam, and Thalaignayiru (Nagapattinam District)	Jalapa municipality: Regions: Santa Maria Xalapan, Ladinos Pardos	Department of Puno: Provinces of Puno, San Roman, Azángaro, Huancané, El Collao, and Chicuito	Eastern Province: Kayonza District: Selected sectors: Kabare, Kabarondo, Murama
Altitude (m above sea level)	10–165	871–2,677	3,825	1,300–1,700
Population density (${\text{per}\mathrm{km}}^2$)	892–1,098	233	17.6	274
Cooking practices (stoves, fuel, location)	Traditional plastered clay/mud stoves fueled with biomass, with 90% cooking indoors. Use of chimneys is negligible.	Chimney stoves and open fires; 97% wood use; cooking mainly indoors	Rural households use traditional biomass (typically dung)-burning stoves daily for cooking	Traditional three-stone fires (62.6%) or Rondereza (34.6%) fueled with wood (89.9%) or charcoal (8.1%), cooking indoors (71.9%)
Baseline 24-h ${\mathrm{PM}}_{2.5}$ concentration (${\mathrm{\mu }\mathrm{g}/\mathrm{m}}^3$)	Mean: Kitchen area: 210 Personal: 155	Median (Q1–Q3): Personal: 115 (80–265) Kitchen: 349 (244–524) Bedroom: 25 (17–120) Patio: 30 (16–50)	Median indoor: 130	Mean 24 h: Personal: 329 Kitchen: 437 Outdoor: 44
Other sources of air pollution	Incense, mosquito coils, etc. (55% of households), trash burning (38% of households)	Trash burning and seasonal burning crop residue (February–April)	Low ambient air pollution	Minimal unless near road or in more urban/dense area.
Prevalence of smoking in the home	Women rarely smoke. Other smokers reported in 24% of households but smoking inside house reported in less than 1% of households.	Women rarely smoke ($<1\%$ ever smoked). Secondhand smoke in 20% of homes, but limited to 1–2 cigarettes/day	Self-reported daily smoking is 0.2%.	Province level: Never: 76.4% Daily: 21.9%

Note: Data are from Guatemala: Fujisada H et al. 2012; Government of the Republic of Guatemala 2019; Johnson M et al. 2018. Peru: Pollard SL et al. 2014; Jaganath D et al. 2015; Hollada J et al. 2017. India: Balakrishnan et al. 2013, 2018. Rwanda: National Institute of Statistics of Rwanda, 2010, 2012; unpublished data from Kirby et al. 2016; HAPIN formative research results (unpublished). ${\mathrm{PM}}_{2.5}$, fine particulate matter with aerodynamic diameter $\le 2.5$.