Exposure levels among cases and controls for carbon monoxide (CO), nitrogen dioxide (NO2), nitrogen monoxide (NO), ozone (O3), sulphur dioxide (SO2), particulate matter (PM10, PM2.5) and black carbon (BC) derived using inverse-distance weighted (IDW) and/or land use regression (LUR) models
| Pollutant_metric | Pre-school | School age |
| CO_IDW µg·m−3 | ||
| Cases | 628.7±119.6 (165.0) | 628.2±120.6 (160.4) |
| Controls | 626.7±119.7 (163.9) | 636.7±121.9 (165.7) |
| NO2_IDW# µg·m−3 | ||
| Cases | 33.7±6.8 (9.7) | 33.4±6.8 (9.4) |
| Controls | 33.3±7.0 (10.0) | 33.7±7.0 (10.1) |
| NO_IDW µg·m−3 | ||
| Cases | 23.0±10.9 (15.6) | 22.5±11.0 (15.1) |
| Controls | 22.7±10.9 (15.4) | 23.0±11.1 (16.0) |
| O3_IDW# µg·m−3 | ||
| Cases | 27.7±5.8 (8.6) | 27.9±6.0 (8.7) |
| Controls | 27.9±5.8 (8.5) | 28.3±5.9 (8.6) |
| SO2_IDW µg·m−3 | ||
| Cases | 5.67±2.4 (3.2) | 5.5±2.4 (2.8) |
| Controls | 5.63±2.4 (3.1) | 5.7±2.5 (3.3) |
| PM10_IDW µg·m−3 | ||
| Cases | 12.5±1.0 (1.3) | 12.5±1.1 (1.4) |
| Controls | 12.5±1.0 (1.3) | 12.5±1.1 (1.3) |
| PM2.5_LUR µg·m−3 | ||
| Cases | 4.09±1.6 (1.4) | 4.1±1.6 (1.4) |
| Controls | 4.06±1.7 (1.5) | 4.0±1.7 (1.5) |
| NO2_LUR µg·m−3 | ||
| Cases | 33.6±8.8 (9.35) | 33.2±8.6 (9.1) |
| Controls | 33.6±9.1 (9.50) | 33.5±8.9 (9.5) |
| NO_LUR µg·m−3 | ||
| Cases | 31.3±13.4 (14.5) | 31.4±13.2 (13.7) |
| Controls | 31.3±13.8 (14.6) | 31.4±13.6 (14.2) |
| BC_LUR 10−5·m−1 | ||
| Cases | 1.6±1.2 (1.2) | 1.6±1.2 (1.1) |
| Controls | 1.6±1.2 (1.1) | 1.6±1.2 (1.1) |
Data represent mean±sd (interquartile range). #: significant paired t-test comparison (p<0.05).