AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Indoor and Outdoor Levels of Traffic-Related Air Pollution and Effectiveness of Remediation Measures in a Near-Freeway School
AURELIE LAGUERRE, Pradeep Ramasubramanian, Matthew Survilo, Megan Duenas, Naveen Weerasekera, Linda George, Elliott Gall, Portland State University
Abstract Number: 159 Working Group: The Air We Breathe: Indoor Aerosol Sources and Chemistry
Abstract Traffic related air pollution (TRAP) poses a threat to health and cognition, yet many buildings are located in proximity to high-traffic thoroughfares. School-age children are a susceptible population and spend a large percentage of their time inside and near schools. In this study, we investigate levels and dynamics of TRAP in a middle school located 20 – 125 m from an interstate that serves >120,000 vehicles per day. Intensive indoor and outdoor measurements are made in three phases, each consisting of ~6-weeks of monitoring. Phases consisted of i) outdoor air monitoring prior to school renovations, ii) indoor and outdoor monitoring post-renovation, following installation of remediation measures in the HVAC system and to the building envelope, and iii) indoor and outdoor monitoring six months post-renovation, following occupancy for one school year. Measurements of TRAP enable exposure assessment and evaluation of the efficacy of the renovations to reduce student exposures, including high-efficiency particle filtration and activated carbon (AC) sorbents installed in the ventilation system. Outdoor air at the school was impacted by freeway emissions, with school day-averages of black carbon, nitrogen dioxide, and ultrafine particles (UFP) of, 1490 ng/m3, 12.5 ppb, and 32700 #/cm3, respectively, with TRAP levels decreasing as function of distance away from the freeway. School day-averages of benzene, toluene, ethylbenzene and xylenes (BTEX) in outdoor air ranged 0.24 ppb to 1.10 ppb. Following renovation, comparison of upstream and downstream measurements shows filters and sorbents are generally protective for TRAP, e.g., BC removal efficiency averaged 93% while average BTEX removal efficiency ranged 63-85%, resulting in supply air pollutant levels below that of urban background. However, results show return air levels of some TRAP constituents higher than supply air, implying infiltration of TRAP is of concern in schools near freeways.