Baseline air pollution concentrations descriptive statistics
| Mean (SD) | Min | Max | IQR | n | Pearson correlation coefficients (95% CI) | |||
| PM2.5 | NO2 | Black carbon | ||||||
| PM2.5 (µg/m3) | 14.8 (1.02) | 9.35 | 21.8 | 1.30 | 135 226 | 1.000 | 0.565 (0.561 to 0.568) | 0.480 (0.476 to 0.484) |
| NO2 (µg/m3) | 21.5 (4.99) | 9.07 | 65.4 | 6.92 | 135 226 | 1.000 | 0.889 (0.888 to 0.890) | |
| Black carbon (10−5 m−1) | 1.22 (0.23) | 0.65 | 3.15 | 0.29 | 135 226 | 1.000 | ||
For participants with complete data for chronic bronchitis, sex, age, educational attainment, BMI, smoking status, pack-years smoking, environmental tobacco smoke at home.
BMI, body mass index; NO2, nitrogen dioxide; PM2.5, particulate matter with a diameter of less than 2.5 µm.