Table 4.
Proportion of people with elevated COex level by exposure to various sources of indoor air pollution among 317 549 never smokers in urban and rural areas
| Types of exposure | Urban |
Rural |
|||||||
|---|---|---|---|---|---|---|---|---|---|
| No. | COex ≥7 ppm |
P-value | No. | COex ≥7 ppm |
P-value | ||||
| No. | (%a) | No. | (%a) | ||||||
| Current daily exposure to passive smoking | |||||||||
| No | 25 269 | 2339 | (9.4) | 38 555 | 7551 | (22.2) | |||
| Yes | 43 624 | 4938 | (11.2) | <0.0001 | 69 079 | 16 575 | (22.5) | 0.15 | |
| Hours of exposure per week | |||||||||
| 1–10 | 21 470 | 2218 | (10.1) | 38 310 | 6322 | (21.2) | |||
| 11–20 | 8625 | 989 | (10.9) | 10 324 | 2306 | (23.6) | |||
| ≥21 | 13 529 | 1731 | (13.5) | <0.0001 | 20 445 | 7947 | (29.3) | <0.0001 | |
| Having chimney in kitchen | |||||||||
| Yes/no cooking facility | 128 859 | 15 194 | (11.0) | 114 538 | 13 925 | (21.4) | |||
| No | 16787 | 1045 | (12.6) | <0.0001 | 57 365 | 24 593 | (24.4) | <0.0001 | |
| Cooking on the day of surveyb | |||||||||
| Cooking fuel | |||||||||
| Electricity/gas | 45 849 | 5639 | (11.7) | 9001 | 559 | (20.4) | |||
| Wood | 5732 | 157 | (7.7) | 34 909 | 2556 | (17.0) | |||
| Coal | 831 | 199 | (20.6) | <0.0001 | 58 609 | 23 462 | (32.1) | <0.0001 | |
| Duration of cooking (minutes) | |||||||||
| 1–60 | 51 596 | 5825 | (11.3) | 94991 | 22 081 | (25.3) | |||
| ≥61 | 816 | 170 | (17.5) | <0.0001 | 7528 | 4496 | (33.4) | <0.0001 | |
| Type of coal used when indoor stove burning all day longb,c | |||||||||
| Smokeless coal | 1699 | 99 | (6.7) | 47 667 | 6536 | (24.6) | |||
| Smoky coal | 1611 | 217 | (8.6) | 7189 | 931 | (30.4) | |||
| Coal brick/coalite | 3287 | 247 | (9.5) | 0.005 | 50 271 | 24 997 | (36.9) | <0.0001 | |
| Season when surveyed | |||||||||
| Spring | 44 185 | 5582 | (12.9) | 52 601 | 12 969 | (23.3) | |||
| Summer | 36 779 | 4055 | (10.8) | 41 634 | 6130 | (11.4) | |||
| Autumn | 37 565 | 3763 | (9.5) | 43 843 | 7324 | (17.9) | |||
| Winter | 27 117 | 2839 | (11.1) | <0.0001 | 33 825 | 12 095 | (40.4) | <0.0001 | |
| Type of fuel used for winter heatingb,d | |||||||||
| Electricity/gas/central heating | 10 148 | 1695 | (12.9) | 1796 | 405 | (45.6) | |||
| Wood | 436 | 87 | (19.7) | 6658 | 2214 | (47.7) | |||
| Coal | 2419 | 342 | (30.0) | <0.0001 | 12 704 | 7923 | (51.6) | 0.09 | |
| Current house ‘coal-smoky’ (among those surveyed in winter) | |||||||||
| No | 24 831 | 2551 | (10.6) | 11 294 | 976 | (32.7) | |||
| Yes | 2286 | 288 | (9.1) | 0.15 | 22 531 | 11 119 | (37.3) | 0.0007 | |
P-values are for heterogeneity or trend test, as appropriate.
aAdjusted for age at survey, sex, area, time of day, season, educational level, fuel used for heating in winter, chimney availability, cooking on the survey day, stove used inside the house and ‘coal-smoky’ in winter.
bRestricted to participants who reported specified type of fuel used for cooking, stove or heating.
cRestricted to participants who kept a stove burning slowly all day long inside house.
dRestricted to participants who were surveyed in winter and heated their houses in winter.