Table 2.
Summary of the reviewed articles.
| Factor Ranking | Factor | Category | % of Factor Appearance | Respiratory Diseases (RD) | Pollutant/Effect | Selected Sources |
|---|---|---|---|---|---|---|
| 1 | Living close to city areas, main roads, highways or industrial areas | Outdoor environment | 34% | Acute and chronic respiratory diseases (Asthma, COPD, pneumonia, tuberculosis) | PM, CO, NOx, SO2, O3, VOC | Morgenstern et al. [39], Ji and Zhao [40] |
| 2 | Exposure to solid fuel | Indoor air pollution | 17% | Asthma, COPD, pneumonia, ARI, URD (both acute and chronic respiratory infection) | PM2.5, PM10, CO, NO2, SO2 | Da Silva et al. [41], Murray et al. [42], Ranathunga et al. [43] |
| 3 | Meteorological factors | Outdoor environment | 11% | Asthma, pneumonia, RSV | Extreme temperature and humidity, rainfall and high atmospheric pressure related to an increase in the rate of RDs | Han et al. [44], Fernandez-Raga et al. [45], Son et al. [46] |
| 4 | Exposure to ETS | Indoor air pollution | 9% | Asthma, ARI, lung cancer, COPD, URD | PM10, PM2.5, CO, methane | Walker et al. [47], Håberg et al. [48] |
| 5 | Moisture or mould damage | Structural related | 7% | Asthma, pneumonia, URD | Allergens, bacteria | Park et al. [49], Karvonen et al. [50] |
| 6 | Exposure to radon | Indoor air pollution | 4% | Lung cancer | Radioactive gas | Bräuner et al. [51], Dempsey et al. [52] |
| 7 | Exposure to indoor asbestos fibers | Indoor air pollution | 3% | Malignant mesothelioma, lung cancer, lower lung fibrosis | Asbestos fibers | Reid et al. [53], Visonà et al. [54] |
| 8 | Carpet floors and HDM | Non-structural related | 2% | ARI | Dust, PM | Dales et al. [55], Shendell et al. [56] |
| 9 | Presence of pets | Non-structural | 2% | Asthma and wheeze | Allergens | Fernandes et al. [57], Dong et al. [58] |
| 10 | Exposure to wildland fire | Outdoor environment | 2% | Asthma, COPD | PM10, PM2.5 | Liu et al. [59], Shaposhnikov et al. [60] |
| 11 | Exposure to VOCs | Indoor air pollution | 2% | Asthma, pneumonia | VOCs | Cipolla et al. [61], Jiang et al. [62] |
| 12 | Crowding | Non-structural | 1% | ARI | Inadequate ventilation | Taksande and Yeole [5], Murray et al. [63] |
| 13 | Exposure to dust storms | Outdoor environment | 1% | Asthma, ARI | Dust | Trianti et al. [64], Thalib and Al-Taiar [65] |
| 14 | Pollen | Outdoor environment | 1% | Asthma, eczema, allergic rhinitis |
Allergens | Linares et al. [66], Li et al. [67] |
| 15 | Use of ozone emitting air cleaners | Indoor air pollution | 1% | Asthma, wheeze, dry cough | Ozone | Liu et al. [68], Nguyen et al. [69] |
| 16 | Daily cleaning activities (ammonia or chlorine-based cleaners) | Non-structural | 0.5% | Asthma | Ammonia | Wang, Su, Hsu, Wang and Wu [4], Medina et al. [70] |
| 17 | Drying clothes inside | Non-structural | 0.5% | ARI, URD | Facilitate the growth of mould spores and HDM | Mengersen et al. [71], Turunen et al. [72] |
| 18 | Living close to mines | Outdoor environment | 0.5% | Asthma, lung cancer | Dust | Herrera et al. [73], Pun et al. [74] |
| 19 | Exposure to Portland cement dust and volcanic ash | Outdoor environment | 0.5% | Lung cancer | Dust | Eom et al. [75], Higuchi et al. [76] |
Note: COPD = Chronic obstructive pulmonary disease; ARI = Acute respiratory infection; URD = Upper respiratory disease; RSV = Respiratory syncytial virus; EMR = Eastern Mediterranean region; ETS = Environmental tobacco smoking; HDM = House dust mites; VOC = Volatile organic compounds; PM = Particulate matter; CO = Carbon monoxide; NOx = Nitrogen dioxide; SO2 = Sulfur dioxide; O3 = Ozone.