Model | NO2 or PM2.5 (μg/m3) | n | Two pollutants model—NO2 + PM2.5 | |
---|---|---|---|---|
HR (95% CI) | p value | |||
Model a | Per 10 μg/m3 increment | |||
NO2 | 10,759 | 0.978 (0.950, 1.008) | 0.148 | |
PM2.5 | 10,759 | 1.252 (1.227, 1.279) | < 0.001 | |
Model b | NO2 (μg/m3) | |||
[ 1.22, 10.00) | 2704 | 1.111 (0.965, 1.278) | 0.143 | |
[ 10.00, 20.00) | 4564 | 0.980 (0.861, 1.114) | 0.753 | |
[ 20.00, 30.00) | 2216 | 1.101 (0.970, 1.250) | 0.136 | |
[ 30.00, 40.00) | 786 | 1.019 (0.884, 1.174) | 0.795 | |
[ 40.00,109.04] | 489 | Reference | / | |
PM2.5 (μg/m3) | ||||
[ 14.8, 25.0) | 218 | 0.171 (0.134, 0.218) | < 0.001 | |
[ 25.0, 35.0) | 1149 | 0.209 (0.183, 0.237) | < 0.001 | |
[ 35.0, 50.0) | 3834 | 0.516 (0.473, 0.563) | < 0.001 | |
[ 50.0, 70.0) | 4226 | 0.728 (0.677, 0.783) | < 0.001 | |
[ 70.0,133.1] | 1332 | Reference | / | |
Model c | Combination of NO2 and PM2.5 (median cut-off) | |||
NO2 < 16 & PM2.5 < 51 | 3701 | Reference | / | |
NO2 ≥ 16 & PM2.5 < 51 | 1765 | 1.295 (1.197, 1.401) | < 0.001 | |
NO2 < 16 & PM2.5 ≥ 51 | 1889 | 1.641 (1.521, 1.770) | < 0.001 | |
NO2 ≥ 16 & PM2.5 ≥ 51 | 3404 | 1.843 (1.715, 1.981) | < 0.001 | |
Model d | Combination of NO2 and PM2.5 (guideline cut-off) | |||
NO2 < 20 & PM2.5 < 35 | 1221 | Reference | / | |
NO2 ≥ 20 & PM2.5 < 35 | 146 | 1.797 (1.380, 2.338) | < 0.001 | |
NO2 < 20 & PM2.5 ≥ 35 | 6047 | 2.756 (2.501, 3.038) | < 0.001 | |
NO2 ≥ 20 & PM2.5 ≥ 35 | 3345 | 3.241 (2.909, 3.610) | < 0.001 |