Levels of PM2.5 in smoking rooms, adjacent to smoking rooms and non-smoking areas of the four airports
| Location | Mean PM2.5 (µg/m3) | 95% CI | p Value* |
|---|---|---|---|
| Airport A (18 measurements) | |||
| Smoking rooms | 348.5 | 199.2 to 497.8 | 0.000 |
| Adjacent to smoking rooms | 17.2 | 12.4 to 22.0 | |
| Non-smoking areas | 9.6 | 7.7 to 11.6 | |
| Airport B (19 measurements) | |||
| Smoking rooms | 1793.9 | 1476.2 to 2111.4 | 0.000 |
| Adjacent to smoking rooms | 155.9 | 90.3 to 221.7 | |
| Non-smoking areas | 13.2 | 9.7 to 16.8 | |
| Airport C (24 measurements) | |||
| Smoking rooms | 799.4 | 508.9 to 1090.0 | 0.000 |
| Adjacent to smoking rooms | 33.2 | 28.6 to 37.9 | |
| Non-smoking areas | 23.4 | 18.7 to 28.1 | |
| Airport D (43 measurements) | |||
| Smoking rooms | 151.9 | 106.4 to 197.4 | 0.000 |
| Adjacent to smoking rooms | 12.0 | 11.1 to 12.8 | |
| Non-smoking areas | 8.9 | 7.1 to 10.8 | |
| Overall (104 measurements) | |||
| Overall mean for smoking rooms | 532.5 | 354.0 to 710.9 | 0.000 |
| Overall mean for adjacent to smoking rooms | 50.1 | 25.6 to 74.6 | |
| Overall mean for non-smoking areas | 13.8 | 11.2 to 16.5 | |
Airport A: largest in northern Thailand, serves 2 million yearly; airport B: largest seaside airport for tourists, serves 3 million yearly; airport C: second largest metropolitan airport in Thailand, serves 18 million yearly; airport D: main hub international airport of Thailand, serves 48 million yearly.
*p Value for analysis of variance test with log transformation of data.
PM2.5, particulate matter ≤2.5 μm.