Table 4. Estimates and 95% confidence intervals (CIs) for change in peak expiratory flow (PEF) per 10-µg/m3 or 10-ppb increase of each pollutant during the study period.
| Single-pollutant model* | Two-pollutant model† | |||||||
| Change ‡ | 95% CI | P value | Change ‡ | 95% CI | P value | |||
| PEF in the morning | ||||||||
| Indoor PM2.5(LD) | ||||||||
| 24-h mean | -2.86 | -4.12 | -1.61 | <0.001 | -2.92 | -4.23 | -1.61 | <0.001 |
| 12-h mean | -2.11 | -3.02 | -1.21 | <0.001 | -2.12 | -3.04 | -1.20 | <0.001 |
| 1-h maximum in the preceding 12 h | -1.42 | -2.03 | -0.82 | <0.001 | -1.42 | -2.03 | -0.82 | <0.001 |
| Outdoor PM2.5(LD) | ||||||||
| 24-h mean | -1.34 | -2.99 | 0.32 | 0.113 | -1.96 | -3.84 | -0.09 | 0.040 |
| 12-h mean | -1.65 | -3.18 | -0.12 | 0.034 | -2.04 | -3.64 | -0.44 | 0.013 |
| 1-h maximum in the preceding 12 h | -1.51 | -2.59 | -0.43 | 0.006 | -1.88 | -3.06 | -0.69 | 0.002 |
| Stationary-site PM2.5 | ||||||||
| 24-h mean | -0.35 | -1.89 | 1.20 | 0.662 | 0.01 | -1.61 | 1.63 | 0.991 |
| 12-h mean | -0.54 | -2.99 | 1.92 | 0.667 | -0.55 | -3.20 | 2.10 | 0.685 |
| 1-h maximum in the preceding 12 h | -1.03 | -2.24 | 0.19 | 0.098 | -1.34 | -2.80 | 0.13 | 0.074 |
| Stationary-site NO2 | ||||||||
| 24-h mean | -0.68 | -2.65 | 1.29 | 0.498 | - | |||
| 12-h mean | -0.26 | -1.96 | 1.44 | 0.761 | - | |||
| 1-h maximum in the preceding 12 h | 0.03 | -1.21 | 1.26 | 0.968 | - | |||
| PEF in the evening | ||||||||
| Indoor PM2.5(LD) | ||||||||
| 24-h mean | -3.59 | -4.99 | -2.20 | <0.001 | -3.59 | -4.98 | -2.20 | <0.001 |
| 12-h mean | -4.92 | -7.00 | -2.85 | <0.001 | -4.96 | -7.04 | -2.89 | <0.001 |
| 1-h maximum in the preceding 12 h | -2.22 | -3.09 | -1.36 | <0.001 | -2.23 | -3.10 | -1.37 | <0.001 |
| Outdoor PM2.5(LD) | ||||||||
| 24-h mean | -3.40 | -6.47 | -0.33 | 0.030 | -4.00 | -7.51 | -0.49 | 0.025 |
| 12-h mean | -1.87 | -3.85 | 0.11 | 0.064 | -2.39 | -4.75 | -0.02 | 0.048 |
| 1-h maximum in the preceding 12 h | -0.65 | -1.69 | 0.38 | 0.217 | -0.48 | -1.35 | 0.39 | 0.283 |
| Stationary-site PM2.5 | ||||||||
| 24-h mean | -1.38 | -3.84 | 1.08 | 0.271 | -0.28 | -2.63 | 2.06 | 0.812 |
| 12-h mean | -0.72 | -2.43 | 0.98 | 0.406 | -0.80 | -2.60 | 1.01 | 0.388 |
| 1-h maximum in the preceding 12 h | -0.73 | -1.85 | 0.39 | 0.202 | -0.45 | -1.48 | 0.58 | 0.393 |
| Stationary-site NO2 | ||||||||
| 24-h mean | -1.69 | -4.18 | 0.81 | 0.186 | - | |||
| 12-h mean | -0.34 | -2.66 | 1.98 | 0.774 | - | |||
| 1-h maximum in the preceding 12 h | -1.27 | -2.91 | 0.38 | 0.131 | - | |||
PM2.5, particulate matter less than 2.5 µm in diameter; PM2.5(LD), PM2.5 measured using the dust monitor with a laser diode; NO2, nitrogen dioxide.
* : The association between PEF and each pollutant was analyzed and adjusted for sex, age, height, temperature, relative humidity, and growth of the children.
† : The association between PEF and each pollutant was analyzed and adjusted for NO2 concentration, sex, age, height, temperature, relative humidity, and growth of the children.
‡ : Mean changes in PEF (L/min) associated with a 10 µg/m3 or 10 ppb increase of each pollutant.