TABLE 3.
Outdoor vs Indoor PM2.5 Comparison
| Sampling days |
Outdoor–indoor PM2.5 difference (μg/ m3) Mean (sd) min, median, max |
Outdoor/indoor PM2.5 ratio |
Infiltration efficiency (95% CI) |
|
|---|---|---|---|---|
| All facilities | 1226 | 5.1 (8.4)–1.5, 2.7, 102.4 | 2.5 | 0.55 (0.52, 0.58) |
| Wildfire season | 474 | 7.5 (12.1)–0.5, 3.2, 102.4 | 2.0 | 0.58 (0.54, 0.63) |
| Non-wildfire season | 752 | 3.6 (3.9)–1.5, 2.4, 29.3 | 8.9 | 0.20 (0.19, 0.20) |
| Wildfire day | 88 | 25.3 (19.2) 5.0, 19.9, 102.4 | 1.8 | 0.59 (0.49, 0.71) |
| Non-wildfire day | 1138 | 3.5 (3.6)–1.5, 2.5, 29.3 | 3.7 | 0.29 (0.28, 0.30) |
| Non-wildfire day during wildfire season | 386 | 3.5 (3.0)–0.5, 2.6, 16.7 | 2.5 | 0.43 (0.41, 0.46) |
| Facility 1 | 321 | 6.5 (8.8)–0.2, 3.5, 52.7 | 3.3 | 0.38 (0.35, 0.41) |
| Facility 2 | 321 | 2.3 (3.7)–1.4, 1.0, 29.1 | 1.5 | 0.76 (0.72, 0.79) |
| Facility 3 | 311 | 5.5 (7.9)–1.5, 3.2, 76.3 | 6.3 | 0.22 (0.21, 0.23) |
| Facility 4 | 273 | 6.2 (11.2)–0.1, 3.5, 102.4 | 2.1 | 0.61 (0.57, 0.64) |
Note: Only sampling days with >12 h of hourly data for both indoor and outdoor PM2.5 are included in the table.
Abbreviations: PM2.5, fine particulate matter; sd, standard deviation; CI, confidence interval; Wildfire Season, July through October; Wildfire Day, day with mean 24 h PM2.5 > 21 μg/m3 during wildfire season.