Table 2.
Concentrations (mean ± SD) of measured pollutants
| Environmental measurements | Unfiltered rides | HEPA-filtered rides | ||||
|---|---|---|---|---|---|---|
| Mean | SD | Median | Mean | SD | Median | |
| Air inside vehicle cabin | ||||||
| Particle Number (cm−3) | 41,350 | 12,678 | 40,806 | 44,411 | 16,115 | 40,063 |
| PM2.5 (μg/m3) | 11.7 | 6.3 | 10.7 | 12.2 | 6.2 | 10.3 |
| BC (μg/m3) | 6.1 | 3.6 | 5.5 | 6.2 | 2.5 | 6.2 |
| CO (ppm) | 1.1 | 0.4 | 1.1 | 1.3 | 0.4 | 1.2 |
| NO2 (ppb) | 26 | 9 | 26 | 26 | 11 | 24 |
| Temp °C | 24.5 | 2.9 | 24.2 | 23.6 | 2.4 | 23.8 |
| RH% | 25 | 10 | 28 | 27 | 10 | 28 |
| Air inside respirator facepiece | ||||||
| Particle number (cm−3) | 37,999 | 9,545 | 37,928 | 3.5 | 4.1 | 2.2 |
| PM2.5 (μg/m3) | 9.1 | 4.8 | 8.2 | 1.4 | 0.6 | 1.3 |
Abbreviations: HEPA High-Efficiency Particulate Air.
Pollutant measurements were made in the vehicle cabin air and inside the facepiece of the respirator (particle number and PM2.5 only) during all rides under both unfiltered and filtered conditions.