Elemental Content of Brake and Tire Wear PM2.5 and PM10 at Near-Road Environments

BRENDA LOPEZ, Xiaoliang Wang, L.-W. Antony Chen, Tianyi Ma, David Mendez-Jimenez, Ling Cobb, Chas Frederickson, Ting Fang, Brian Hwang, Manabu Shiraiwa, Minhan Park, Kihong Park, Qi Yao, Seungju Yoon, Heejung Jung, University of California, Riverside

     Abstract Number: 53
     Working Group: Urban Aerosols

Abstract
Brake and tire wear particulate matter (PM) have become the dominating source of traffic related emissions in California, USA. The EMission FACtor (EMFAC) model from California Air Resources Board predicts these non-tailpipe emissions to remain dominant contributors of on-road PM. Brake and tire wear contain traces of heavy metals, therefore may dominate metal emissions near major roadways and highways. This creates concern as these particulate sources can increase toxicity and impact the health of exposed populations and nearby communities.

The objective of this study is to assess the level of exposure of non-tailpipe emissions in near-road environments. The study investigates metal contents and size distributions found in PM2.5 and PM10 measurements next to two major highways in California, USA.

Real time and gravimetric measurements occurred over a two-week period in the winter of 2020 prior to the COVID-19 pandemic. PM measurements were collected at the proximity of both sides of the highways to subtract urban background at the measurement location. This study is a part of a Real-World Tire and Brake Wear Emissions Project funded by California Air Resources Board. The results of this analysis are in conjunction to chemical analysis, source apportionment, and health effects of the particles in the near road environment studies by project collaborators [1-3]. The presentation includes the signature brake mode in particle size distributions measured near-road, size speciated elemental analysis to identify markers for brake, tire, and road dust.

[1] Chen, L. -W. Antony, Xiaoliang Wang, Brenda Lopez, Guoyuan Wu, Steven Sai Hang Ho, Judith C. Chow, John G. Watson, Qi Yao, Seungju Yoon, and Heejung Jung. 2023. “Contributions of Non-Tailpipe Particles to near-Road PM2.5 and PM10: A Chemical Mass Balance Study, In Review.”
[2] Hwang, Brian, Ting Fang, Randy Pham, Jinlai Wei, Steven Gronstal, Brenda Lopez, Chas Frederickson, et al. 2021. “Environmentally Persistent Free Radicals, Reactive Oxygen Species Generation, and Oxidative Potential of Highway PM2.5.” ACS Earth and Space Chemistry 5 (8): 1865–75. https://doi.org/10.1021/acsearthspacechem.1c00135.
[3] Wang, Xiaoliang, Steven Gronstal, Brenda Lopez, Heejung Jung, L. -W. Antony Chen, Guoyuan Wu, Steven Sai Hang Ho, et al. 2023. “Evidence of Non-Tailpipe Emission Contributions to PM2.5 and PM10 near Southern California Highways.” Environmental Pollution 317 (January): 120691. https://doi.org/10.1016/j.envpol.2022.120691.
[4] Lopez, Brenda, Xiaoliang Wang, Antony Chen, Tianyi Ma, David Mendez-Jimenez, Ling Cui Cobb, Chas Frederickson et al. "Metal contents and size distributions of brake and tire wear particles dispersed in the near-road environment." Science of The Total Environment (2023): 163561.