Descriptive statistics of the mean and maximum PM2.5 concentrations found during smoking and non-smoking car journeys
| Journeys | N | AM (SD) (μg/m3) | GM (GSD) (μg/m3) | Range (μg/m3) | p Value |
| TWA | |||||
| Smoking | 49 | 85 (67) | 67 (2) | 16–331 | <0.001 |
| Non-smoking | 34 | 7 (7) | 5 (3) | 0.4–29 | |
| Peak levels | |||||
| Smoking | 49 | 385 (216) | 321 (7) | 55–885 | <0.001 |
| Non-smoking | 34 | 13 (10) | 9 (2) | 2.6–43 | |
p Value is for the difference in PM2.5 measured in smoking and non-smoking journeys.
AM, arithmetic mean; GM, geometric mean; GSD, geometric standard deviation; TWA, time-weighted average.