AAAR 33rd Annual Conference
October 20 - October 24, 2014
Rosen Shingle Creek
Orlando, Florida, USA
Abstract View
Assessment of In-cabin Human Exposure to Ultrafine Particles under Different Conditions of Urban Traffic in Salvador, Bahia, Brazil
Egídio Guerreiro, Paulo Pinho, Márcio de Carvalho, Danilo Leão, João Marçal, José Róbson de Luna, Rodrigo Vieira, Lílian Guarieiro, Jailson de Andrade, ANTONIO MIGUEL, University of California, Los Angeles
Abstract Number: 542 Working Group: Urban Aerosols
Abstract In large urban centers commuters, are exposed to toxic ultrafine particles (UFP, aerodynamic diameters, dp<100 nm, and nanoparticles (NP, dp < 50 nm) under a variety of weather and traffic conditions. Limited information is currently available on commuter exposure to freshly emitted UFP and NP while driving on major roads and freeways. As commuters are spending more time on the road, it is important to know their exposure levels to harmful pollutants in microenvironments. The major goal of this study was to evaluate passenger in-cabin exposure to UFP under different traffic conditions in the urban area of Salvador, Bahia, Brazil. UFP number concentrations (100 nm nominal) were measured using a TSI model 3910 particle counter placed on the center of the back seat of a model year 2010 Toyota Hilux 3.0 light duty 4x4 diesel car in five sites, under different traffic conditions: (A) high traffic volume (HTV) and no building corridors; (B) HTV with high impact of marine spray; (C) low flow of vehicles; (D) HTV with building corridors; and (E), a Tunnel with HTV.
In-cabin UFP concentrations show that the commuters can be exposed to high concentrations of UFP in roads with both HTV, under low airflow conditions (sites D and E). As expected, with windows open, the highest 300nm particle concentrations were observed in site E (990 particles/cm3). With closed windows, the lowest concentration was observed in Site C (40 particles/cm3). Roads without building barriers favor particle dissipation resulting in lower number concentrations. Ambient temperature appeared to influence particle number concentrations, suggesting that passenger exposure to UFP may be higher under higher solar radiation conditions. Taken these data together, commuters are advised to close the vehicle’s windows while driving in places with high traffic and low road airflow in order to reduce their exposure to vehicle exhaust and resuspended air pollutants.