Table 1 Prevalence of smoking in cars by site, time, and weather conditions.
| Key characteristics | Total cars observed | Any smoking in the car | Rate ratio for smoking in cars versus no smoking (95% CI) | Driver smoking in cars with smoking | Other occupant present in cars with smoking | Window open in cars with smoking | ||||
|---|---|---|---|---|---|---|---|---|---|---|
| n | % | n | %* | n | %* | n | %* | |||
| Sites | ||||||||||
| High deprivation area site (Wainuiomata) | 5055 | 325 | 6.4 | 3.18 (2.55 to 3.97) | 316 | 97.2 | 69 | 21.2 | 264 | 81.2 |
| Central business district (3 sites†) | 6000 | 233 | 3.9 | 1.92 (1.53 to 2.42) | 216 | 92.7 | 62 | 26.6 | 195 | 83.7 |
| Low deprivation area site (Karori) | 5000 | 101 | 2.0 | 1.0 (reference) | 96 | 95.1 | 25 | 24.8 | 81 | 80.2 |
| Total (95% CI for per cents) | 16055 | 659 | 4.1 (3.8 to 4.4) | 628 | 95.3 (93.4 to 95.8) | 156 | 23.7 (20.5 to 27.1) | 540 | 81.9 (78.8 to 84.8) | |
| Time of day | ||||||||||
| Morning (8–10 am) | 8055 | 372 | 4.6 | 1.29 (1.11 to 1.50) | 354 | 95.2 | 81 | 21.8 | 314 | 84.4 |
| Afternoon (4–6 pm) | 8000 | 287 | 3.6 | 1.0 (reference) | 274 | 95.5 | 75 | 26.1 | 226 | 78.8 |
| Weather | ||||||||||
| Overcast/rain | 8939 | 400 | 4.5 | 1.23 (1.05 to 1.43) | 379 | 94.8 | 85 | 21.3 | 335 | 83.8 |
| Sunny | 7116 | 259 | 3.6 | 1.0 (reference) | 249 | 96.1 | 71 | 27.4 | 205 | 79.2 |
*Calculated as a proportion of the number of cars with any smoking occurring (by driver or a passenger).
†The corners of: Kent Terrace/Vivian St; Jervois Quay/Cable St; and Taranaki St/Vivian St (n = 2000 cars each).