American Association for Aerosol Research - Abstract Submission

AAAR 38th Annual Conference
October 5 - October 9, 2020

Virtual Conference

Abstract View


Spatial Pattern of Trace Metal Concentrations in Southern California Associated With Brake and Tire Wear Emissions

FARZAN OROUMIYEH, Irish Del Rosario, Michael Jerrett, Jonah Lipsitt, Jonathan Liu, Suzanne E. Paulson, Beate Ritz, Jiaqi Shen, Yifang Zhu, University of California Los Angeles

     Abstract Number: 605
     Working Group: Urban Aerosols

Abstract
With a reduction in exhaust emissions in response to technology advancements and rigorous regulations, the significance of non-exhaust emission sources is increasing. Non-exhaust emission sources including brake and tire wear are rich in metals and therefore they can cause oxidative stress and contribute to overall health effects of particulate matter (PM). The aim of the current work is to provide information on spatial pattern of metals associated with brake and tire wear in southern California.

Using gravimetric measurement, the abundance of 55 metals in fine and coarse PM was studied in 51 sampling sites across southern California. The samples were collected during two sampling periods in summer and winter. The average concentration of fine PM in summer and winter was shown to be at 9.0 and 9.8 µg/m3 respectively while the average concentration of coarse PM was 8.9 µg/m3 in both seasons. The average concentrations of trace metal elements in fine PM were Ba (17.4 ng/m3), Cu (8.8 ng/m3 ), Fe (188.8 ng/m3), Sb (3.0 ng/m3), Zn (10.2 ng/m3) while the concentrations in coarse PM were Ba (18.6 ng/m3), Cu (8.4 ng/m3), Fe (302.5 ng/m3), Sb (1.6 ng/m3), Zn (6.9 ng/m3).

Multi-criteria decision analysis (MCDA) model was implemented to categorize the sampling sites based on the braking frequency by incorporating spatial criteria such as the traffic intensity, slope variance and intersection density. Analysis of correlation matrix and enrichment factors of the trace elements allowed to verify the locations with higher brake and tire wear frequency. Primary tracers of brake wear particles showed relatively high correlation suggesting that these metals are potentially generated by abrasive vehicular emissions.