Table 2.
Comparison of indoor and outdoor air quality data.
| Sampling Days | Outdoor–Indoor PM2.5 Difference (µg/m3) | Indoor/ Outdoor PM2.5 Ratio |
Infiltration Efficiency (95% CI) |
Outdoor-Generated Indoor PM2.5 (µg/m3) | Percent (%) Indoor PM2.5 Generated Outdoors | |
|---|---|---|---|---|---|---|
| Mean (sd) Min, Median, Max |
Mean (sd) Min, Median, Max |
Mean (sd) Min, Median, Max |
||||
| All Study Days | ||||||
| Indoor location | 28 | 17.3 (16.8) 1.6, 11.4, 64.8 |
0.34 | 0.30 (0.21, 0.43) |
7.7 (7.0) 1.9, 5.4, 27.8 |
80 (17) 37, 82, 100 |
| HEPA cage location | 28 | 23.1 (23.5) 3.2, 14.9, 89.7 |
0.12 | NA* | NA* | NA* |
| Wildfire Day | ||||||
| Indoor location | 12 | 31.1 (17.6) 14.0, 24.0, 64.8 |
0.31 | 0.30 (0.17, 0.50) |
13.1 (7.9) 6.8, 9.6, 27.8 |
94 (8) 74, 100, 100 |
| HEPA cage location | 12 | 42.0 (25.5) 20.1, 29.7, 89.7 |
0.07 | NA* | NA* | NA* |
| Non-Wildfire Day | ||||||
| Indoor location | 16 | 6.9 (3.4) 1.6, 6.8, 12.8 |
0.43 | 0.40 (0.29, 0.54) |
3.6 (1.3) 1.9, 3.4, 5.8 |
70 (14) 37, 72, 88 |
| HEPA cage location | 16 | 9.0 (4.3) 3.2, 8.0, 16.2 |
026 | NA* | NA* | NA* |
PM2.5 = fine particulate matter; sd = standard deviation; CI = confidence interval; HEPA = high efficiency purified air; min = minimum; max = maximum. Wildfire Day = day with mean 24-h outdoor PM2.5 > 21 µg/m3 during wildfire season. Only sampling days with >12 h of hourly data for both indoor and outdoor PM2.5 are included in table. NA* = model estimates were equal to 0, meaning infiltration efficiency was equal to 0 and confidence intervals could not be calculated.