Mixed effects model analysis of PM2.5, using natural log-transformed data based on 10 s average raw data, Toronto Doorway Study, May to June 2008
| Adjusted analysis | ||||
| Outdoor† | Indoor* ‡ | |||
| Coefficient (95% CI) | p Value | Coefficient (95% CI) | p Value | |
| Model 1 | ||||
| Background | ¶ | ¶ | ||
| Outdoor or indoor | ¶ | ¶ | ||
| Model 2 | ||||
| 0 lit cigarettes | Reference | Reference | ||
| 1 or more lit cigarettes | 0.54 (0.38 to 0.71) | <0.0001 | 0.06 (−0.03 to 0.15) | 0.2072 |
| Model 3 | ||||
| 0 lit cigarettes | Reference | Reference | ||
| 1–4 lit cigarettes | 0.49 (0.33 to 0.66) | <0.0001 | 0.06 (−0.03 to 0.15) | 0.2181 |
| 5 or more lit cigarettes | 0.85 (0.61 to 1.10) | <0.0001 | 0.07 (−0.07 to 0.22) | 0.3287 |
| Model 4 | ||||
| Linear trend of lit cigarettes§ | 0.10 (0.07 to 0.14) | <0.0001 | 0.0002 (−0.02 to 0.02) | 0.9853 |
| Model 5 | ||||
| Indoor PM2.5 by outdoor PM2.5 | 0.04 (0.01 to 0.07) | 0.0046 | ||
↵* Lit cigarettes for indoor measures meant smoking outside the entrance while measuring PM2.5 inside the entrance.
↵† Outdoor measures adjusted for: wind strength and direction, distance to nearest lit cigarette from the monitor.
↵‡ Indoor measures adjusted for: distance from nearest lit cigarette to entrance, distance from indoor monitor to entrance, number of door openings, as well as outdoor wind direction and strength.
↵§ Actual number of lit cigarettes was entered into the mixed model so that the coefficient indicated the log PM2.5 level increased by each 1 lit cigarette increase.
↵¶ No wind measures and distance to nearest lit cigarette from the monitor were taken for background measures.
PM2.5, air pollutant particles with a diameter of 2.5 μm or less.