AAAR 37th Annual Conference October 14 - October 18, 2019 Oregon Convention Center Portland, Oregon, USA
Abstract View
Black Carbon Exposure during Physical Activity is Associated with Exhaled Markers of Oxidative Stress and Metabolomic Features Involving Oxidative Stress Mediating Pathways
ROBY GREENWALD, Matthew J. Hayat, Elizabeth Finlon, Donghai Liang, Jeremy A. Sarnat, Dean P. Jones, Parinya Panuwet, Lou Ann Brown, Georgia State University
Abstract Number: 670 Working Group: Health-Related Aerosols
Abstract The Study of Air Pollution and Physical Activity measured particulate matter exposure in adolescents and young adults participating in sports programs. We examined biomarkers of airway oxidative stress in exhaled breath, and in a subset of participants, we also conducted a Metabolome-Wide Association Study (MWAS) based on saliva samples collected pre- and post-exposure. We sampled at athletic fields in the Atlanta metropolitan area both near- and far from roadways, and we assessed particulate exposure in terms of PM2.5, particle number concentration, and black carbon concentration (BC). These exposures were modest compared to many other Atlanta-area studies. We calculated the inhaled dose of pollutants using a validated method based on heart rate, breathing rate, and lung capacity. Exhaled biomarkers included expired nitric oxide (eNO) and malondialdehyde (MDA, a marker of lipid peroxidation) and glutathione (both oxidized and reduced) measured in samples of exhaled breath condensate. We observed significant positive associations between eNO and the inhaled dose of BC; however, this was not conclusive for other particulates or ozone. MDA was strongly associated with PM2.5 exposure in the previous 24 hours. Oxidized glutathione was negatively associated with the heat index during exposure but was not associated with any pollutants. MWAS results indicated associations between the body-weight normalized inhaled dose of BC and pathways related to leukotriene, arginine, and glutathione metabolism. These biological pathways have been associated with traffic-related air pollution in numerous studies. In addition, the previous 24 hour exposure to PM2.5 was also associated with leukotriene metabolism. These findings reflect the timing of sample collection immediately following a modest acute exposure. Exhaled biomarkers reflecting airway chemistry might be expected to respond within this time frame to acute exposures, but salivary biomarkers reflecting systemic processes may be more responsive to exposures hours or more in the past.