Randomized Cross-Over Study of In-Vehicle Cabin Air Filtration, Air Pollution Exposure, and Acute Changes to Heart Rate Variability, Saliva Cortisol, and Cognitive Function

摘要

To determine how traffic-related air pollution (TRAP) exposures affect commuter health, and whether cabin air filtration (CAF) can mitigate exposures, we conducted a cross-over study of 48 adults exposed to TRAP during two commutes with and without CAF. Measurements included particulate air pollutants (PM_(2.5), black carbon BC, ultrafine particles UFPs), volatile organic compounds, and nitrogen dioxide. We measured participants' heart rate variability (HRV), saliva Cortisol, and cognitive function. On average, CAF reduced concentrations of UFPs by 26,232 (9596CI: 11,734, 40,730) n/cm~3, PM_(2.5) by 6 (9596CI: 5, 8) μg/m~3, and BC by 1348 (9596CI: 1042, 1654) ng/m~3, or 28, 30, and 32, respectively. Each IQR increase in PM_(2.5)was associated with a 28 (95CI: 2, 60) increase in high-frequency power HRV at the end of the commute and a 22 (9596CI: 7, 39) increase 45 min afterward. IQR increases in UFPs were associated with increased saliva Cortisol in women during the commute (18 95CI: 0, 40). IQR increases in UFPs were associated with strong switching costs (19 95CI: 2, 39), indicating a reduced capacity for multitasking, and PM_(2.5) was associated with increased reaction latency, indicating slower responses (5 95CI: 1, 10). CAF can reduce particulate exposures by almost a third.