Summary of NOx, PM2.5 (road traffic sources only), traffic volume, major road distance and night noise (n=211 016)
| Correlations | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Traffic exposure | Level | N | NOx (mean ±SD) | PM2.5 due to traffic (mean ±SD) | Lnight (mean ±SD) | Age at baseline (mean ±SD) | Current smokers (%) | Most deprived IMD 5th (%) | ICC* | NOx | PM2.5 traffic | Km driven | Distance to major road |
| NOx (μg/m3) | 0–55 | 68 644 | 48.2±4.4 | 1.0±0.1 | 50.9±2.9 | 56.4±11.2 | 21.7 | 6.4 | 0.80 | – | 0.96 | 0.47 | −0.41 |
| 55–75 | 101 287 | 63.3±5.4 | 1.4±0.2 | 51.8±4.1 | 55.4±11.0 | 20.6 | 12.7 | ||||||
| 75+ | 41 085 | 86.8±11.8 | 2.3±0.5 | 55.0±6.6 | 53.9±10.8 | 23.3 | 23.3 | ||||||
| PM2.5 from traffic sources (μg/m3) | 0–1 | 32 322 | 44.8±3.5 | 0.9±0.1 | 50.1±1.8 | 56.4±11.2 | 22.2 | 6.1 | 0.67 | 0.96 | – | 0.58 | −0.43 |
| 1–2 | 152 042 | 62.0±9.1 | 1.4±0.3 | 51.6±3.8 | 55.5±11.1 | 20.8 | 11.2 | ||||||
| 2+ | 26 652 | 90.5±12.8 | 2.5±0.5 | 57.5±6.9 | 54.0±10.8 | 24.1 | 31.5 | ||||||
| Vehicle km driven† | None | 119 984 | 58.8±11.6 | 1.3±0.3 | 49.9±1.2 | 55.5±11.0 | 20.8 | 11.1 | 0.07 | 0.47 | 0.58 | – | −0.32 |
| Low volume | 63 455 | 64.5±14.8 | 1.5±0.5 | 54.4±5.1 | 55.5±11.2 | 21.8 | 13.4 | ||||||
| High volume | 27 677 | 77.2±19.6 | 2.1±0.8 | 56.2±6.8 | 55.1±11.1 | 23.4 | 22.9 | ||||||
| Distance(m) to major road | >250 m | 95 481 | 57.5±12.0 | 1.2±0.4 | 50.9±3.3 | 55.6±11.1 | 21.1 | 10.7 | 0.28 | −0.41 | −0.43 | −0.32 | – |
| 100–250 m | 71 328 | 64.0±12.9 | 1.5±0.4 | 51.2±3.2 | 55.2±11.0 | 21.0 | 14.1 | ||||||
| 0–100 m | 44 207 | 73.1±18.5 | 1.9±0.7 | 56.2±6.3 | 55.4±11.1 | 22.8 | 22.8 | ||||||
| Lnight (dB) | 0–55 | 172 940 | 60.8±13.2 | 1.4±0.4 | 50.1±1.2 | 55.4±11.1 | 21.3 | 13.1 | 0.05 | 0.40 | 0.52 | 0.59 | −0.27 |
| 55–60 | 16 467 | 64.8±15.6 | 1.6±0.5 | 57.5±1.5 | 55.9±11.1 | 21.1 | 11.3 | ||||||
| 60+ | 21 609 | 78.3±19.3 | 2.2±0.7 | 63.7±2.8 | 55.2±11.1 | 22.7 | 17.1 | ||||||
*Intraclass correlation by practice cluster.
†Within 100 m radius of postcode address centroid only, with >100 000 km driven annually defined as high volume.
ICC, intraclass correlation coefficient; IMD, Index of Multiple Deprivation; NOx, nitrogen oxide; PM2.5, particulate matter with a median aerodynamic diameter <2.5 μm.