In-vehicle microenvironments can contribute significantly to human daily exposure to traffic-related air pollutants, which have been associated with adverse respiratory, cardiovascular and reproductive health outcomes. Despite recent advances in commuters exposure research, variations in exposure between different routes and transport modes present a challenge for health effects studies.Methods
Commuters exposure to traffic-related air pollution was studied for two public transportation routes with different length and various car intensities in Kyiv city, Ukraine. Concentrations of PM10, PM2.5, PM1, CO and CO2 were measured between July and October on 42 weekdays during traffic peak hours while commuting by bus and by light vehicle. Light car microenvironment was tested for 2 cabin ventilation modes: windows opened without air conditioning system (A/C) working and windows closed with A/C turned on. Additionally, background measurements were conducted at an urban background location.Results
It was revealed that pollutants concentrations in all transport modes for both routes were higher than respective background values. The highest median PM10 exposures were registered in public buses (66 µg/m3 for PM10, 33 µg/m3 for PM2.5 and 0.25 µg/m3 for PM1) following the longest route and lowest in cars with closed windows and working A/C (14 µg/m3 for PM10, 11 µg/m3 for PM2.5 and 17 µg/m3 for PM1). Median CO exposure was highest in the car when windows opened without A/C (3.1 ppm), while median CO2 concentrations were the highest in the car with A/C turned on and closed windows (1841 ppm). It was observed that turning car cabin air conditioning system on could reduce PM exposure by 50%–60% depending on size as well as to further improve ventilation rate and filtration efficiency.Conclusion
The results revealed that observed variability of commuting-related pollution levels is predefined by commuting route, vehicle type and cabin ventilation mode. Findings of this research proved that exposure to air pollutants in vehicle microenvironments should be accounted in studies of impacts of daily air pollution exposures on human health.