Table 2. Average daily indoor and outdoor air pollution concentrations (μg m-3) in rural Sichuan, by fuelstove category and season.
| Measurement type | Number of householddays | Arithmetic mean PM2.5 (95% CI, μg m-3) | Geometric mean PM2.5 (95% CI μg m-3) | % householddays <35 μg m-3* | % household-days <35 μg m-3 *, outdoor PM2.5 subtracted |
|---|---|---|---|---|---|
| Summer | |||||
| Kitchen | |||||
| Wood chimney | 94 | 114 (108,120) | 72 (59, 87) | 16 | 39 |
| Semi-gasifier | 13 | 119 (44,194) | 46 (20, 101) | 38 | 77 |
| LPG or electric | 19 | 48 (42,54) | 38 (26, 56) | 32 | 89 |
| Mixed stove-use | 41 | 111 (102,120) | 84 (65, 107) | 15 | 24 |
| All stoves | 172 | 105 (102,108) | 62 (53, 73) | 20 | 45 |
| Outdoor | 172 | 36 (34,38) | 16 (5, 51) | - | - |
| Winter | |||||
| Kitchen | |||||
| Wood chimney | 80 | 238 (226,250) | 155 (125, 192) | 5 | 18 |
| Semi-gasifier** | 2 | 102 | 92 | 0 | 0 |
| LPG or electric | 11 | 85 (73,97) | 79 (62, 100) | 0 | 55 |
| Mixed stove-use | 20 | 321 (243,399) | 177 (110, 285) | 5 | 15 |
| All stoves | 114 | 237 (228,246) | 140 (117, 167) | 4 | 22 |
| Outdoor | 106 | 41 (39,43) | 38 (27, 54) | - | - |
CI = confidence interval; LPG = liquefied petroleum gas; PM2.5 = particulate matter <2.5 gm in diameter
*
Percent of household-days at or below the WHO interim 24-h target for household (household or indoor- only) air pollution based on arithmetic 24-h means of household PM2.5.
**
Our estimates for exclusive semi-gasifier stove use in winter were limited to just two measurement days and should therefore be treated with caution.