Using Transit Vehicles as Probes to Monitor Community Air Quality and Exposure

Project DescriptionThis project evaluated the feasibility of using transit vehicles traveling on fixed routes for near-road exposure assessment. Continuous onroad measurements of four pollutants (PM2.5, PM10, NO2, and O3) were recorded in conjunction with GPS locations. The data can be used to quantify exposure experiences by pedestrians, passengers, bus users, and near-road residents. Concurrent near-road measurements were used to verify and provide associations with the on-road data. The study tested two hypotheses: 1) community exposures to transportation pollutants that can be represented by short-term spatio-temporal measurements using onroad air monitors; and 2) near-road receptors that are not affected by the traffic emissions from surface street emissions and that can be represented by on-road air monitors. The objectives of this study were to 1) provide reliable exposure concentration estimates for a community using transit vehicles equipped with mobile air monitors, and 2) evaluate associations of short-term transportation related air pollutant (TRAP) concentrations with hourly exposure concentrations for near-road communities. Mobile monitoring was conducted along two designated routes around the UTEP campus shown in Figure 1, with UTEP researchers driving at a speed of less than 30 miles per hour. In both routes, a detour was made on Schuster Avenue to take the mobile monitoring station (Figure 2) closer to the CAMS 12 site, which was located approximately 50 feet off Rim Road, so that a comparison could be made between the air pollutant data collected by the mobile monitoring station’s instruments and CAMS 12 FRM data. In addition, a fixed site with the same air quality monitoring instruments was installed on Sun Bowl Drive to provide another location for data comparison. Each trip lasted about 12-15 minutes, including stop-andgo at all traffic intersections. The air monitoring campaign made a total of 282 trips (170 outer loops and 112 inner loops) and collected PM2.5, PM10, NO2, O3, and GPS data every second. Data were analyzed in conjunction with the fixed station data.U.S. Department of Transportation 69A355174711