California Air Resources Board

Principal Investigator/Author: Edward, Schelegle

Contractor: University of California, Davis

Contract Number: 17RD011

Project Status: Completed

Relevant CARB Programs: Health

Topic Areas: Ambient Air Quality Standards, Health Effects of Air Pollution, Toxic Air Contaminants

Research Summary:

Epidemiological research has suggested a statistical correlation between adverse health effects and exposure to PM and O3; however, there are few experimental data that support the biological plausibility of these relationships. The current animal study examined lung and heart tissues to determine whether ultrafine particulate matter (UFPM) +O3: 1) Induced myocardial ischemia and nonapoptotic cell death; 2) Increased microthrombi in lung and heart; and 3) altered UFPM deposition and its relation to cellular antioxidant expression within the airways. The current study showed that cardiac fibrosis was significantly greater in mature adult rats with (spontaneous hypertensive, SH) compared to rats without cardiovascular diseases (CVD) (normotensive Wistar Kyoto, WKY). The results of the current study indicate that simultaneous exposure to UFPM and O3 elicits stronger responses than that expected from exposure to O3 or UFPM alone. Further, CVD increases susceptibility to pollutant-induced thrombosis, which may contribute to UFPM+O3-induced myocardial injury. This study advances scientific understanding of the adverse health effects of simultaneous combined-pollutant exposure. The study also provides novel insights into the association between ambient air pollution and increased cardiac morbidity and mortality in mature adult individuals with CVD. This knowledge will support CARB in establishing health-protective ambient air quality standards.

Keywords: air quality, ambient air quality standards, health, health effects, exposure, particular matter (PM), ozone (O3), ultrafine particulate matter (UFPM), toxic air contaminants