AAAR 35th Annual Conference October 17 - October 21, 2016 Oregon Convention Center Portland, Oregon, USA
Abstract View
Effects of Various Mitigation Measures in Reducing Fine and Ultrafine Particle Concentrations inside Taxi Vehicles
NU YU, Shi Shu, Yan Lin, Yifang Zhu, University of California Los Angeles
Abstract Number: 151 Working Group: Control and Mitigation Technology
Abstract More than 4000 taxi drivers working in Los Angeles are likely exposed to high levels of traffic related air pollutants (TRAP) such as fine (PM$_(2.5)) and ultrafine particles (UFPs). However, their TRAP exposures were poorly understood and mitigation strategies were rarely explored. In this study, 22 Los Angeles taxi drivers were recruited and UFP and PM$_(2.5) concentrations were monitored concurrently inside and outside of their taxis for 6-hour a day and four consecutive days under four exposure mitigation strategies. The results showed under realistic working condition (no mitigation, NM), the average UFP and PM$_(2.5) levels inside taxis were 2.57x10$^4 particles per cm$^3 and 26.00 microgram/m$^3, respectively, and the average in-cabin to on-roadway (I/O) ratios for UFP and PM$_(2.5) were 0.60 and 0.75, respectively. When the taxi ventilation was set to outside air (OA) mode and windows were all kept closed (WC) with high efficiency cabin air (HECA) filter working, the average in-cabin UFP and PM$_(2.5) levels were observed to achieve the lowest among all four mitigation conditions, at 1.13x10$^4 particles/cm$^3 and 13.57 microgram/m$^3 respectively, and the average I/O ratios for UFP and PM$_(2.5) were significantly reduced to 0.47 and 0.52 respectively. Taxi vehicles provided higher reduction on in-cabin UFP concentrations than on PM$_(2.5) concentrations under all four mitigation conditions. Setting the vehicle ventilation to OA mode consistently and closing taxi windows (WC) doubled the HECA filter reduction on both UFP and PM$_(2.5) I/O ratios.