Descriptive statistics of the study variables during November 1996–April 97
| days | Min | 25% | Median | 75% | Max | |
| Morning PEF deviation L·min−1 | 181 | −12.6 | −3.3 | 0.4 | 3.3 | 10.2 |
| Afternoon PEF deviation L·min−1 | 181 | −13.2 | −2.2 | −0.1 | 2.4 | 9.6 |
| Evening PEF deviation L·min−1 | 181 | −12.6 | −2.7 | −0.7 | 3.0 | 12.1 |
| Cough prevalence % | 181 | 17.5 | 25.0 | 29.4 | 34.7 | 48.0 |
| Asthma symptom prevalence % | 181 | 14.9 | 27.1 | 31.9 | 35.7 | 52.5 |
| Bronchodilator use doses·person−1day−1 | 181 | 3.3 | 4.3 | 4.6 | 4.8 | 5.8 |
| PM10 μg·m−3 | 169 | 3.8 | 10.2 | 13.5 | 19.5 | 73.7 |
| PM2.5–10 μg·m−3 | 164 | 0.8 | 2.8 | 4.7 | 8.9 | 49.3 |
| PM2.5 μg·m−3 | 169 | 2.4 | 5.5 | 8.4 | 12.1 | 38.3 |
| PM1 μg·m−3 | 170 | 1.0 | 3.4 | 5.6 | 7.5 | 22.9 |
| PNC 1000·cm−3 | 151 | 3.8 | 11.2 | 15.6 | 18.5 | 48.9 |
| NC0.01–0.1 1000·cm−3 | 151 | 3.7 | 10.4 | 14.5 | 17.7 | 46.5 |
| NC0.1–1 1000·cm−3 | 151 | 0.1 | 0.6 | 0.8 | 1.2 | 2.8 |
| CO mg·m−3 | 177 | 0.1 | 0.3 | 0.4 | 0.5 | 1.1 |
| NO μg·m−3 | 180 | 3.7 | 10.8 | 15.7 | 22.5 | 146.1 |
| NO2 μg·m−3 | 180 | 8.5 | 20.4 | 25.3 | 31.9 | 67.6 |
| Temperature °C | 178 | −20.3 | −3.4 | 0.3 | 2.8 | 8.8 |
| Relative huimidity % | 168 | 40.1 | 76.6 | 87.5 | 93.5 | 99.2 |
PM1: particle mass concentration <1 μm
PM2.5: particle mass concentration <2.5 μm
PM10: particle mass concentration <10 μm
PM2.5–10: coarse particle mass (PM10−PM2.5)
PNC: daily mean particle number concentration
NC0.01–0.1: number concentration in sizerange 0.01 μm–0.1 μm
NC0.1–1: number concentration in sizerange 0.1 μm–1 μm
CO: carbon monoxide
NO: nitric oxide
NO2: nitrogen dioxide
Min: minimum value
Max: maximum value.