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Intersections as hot spots: assessing the contribution of localized non-tailpipe emissions and noise on the association between traffic and children’s health

Principal Investigator: 

University of Southern California

This study will assess the effects of metals from nontailpipe emissions on asthma and lung function in the most recent cohort of the Children’s Health Study in Southern California (recruited during 2002-2012), using available filters with particulate matter samples. The investigators will estimate exposure to several pollutants and transportation noise and evaluate the roles of socioeconomic status, green space, physical activity, diet, and stress.

Funded under

Abstract for the 2018 Annual Conference

Intersections as Hot Spots: Assessing the contribution of localized non-tailpipe emissions and noise on the association between traffic and children’s health

Meredith Franklin, Scott Fruin, Rob McConnell
University of Southern California

Traffic emissions are comprised of a complex mixture of components including tailpipe emissions, non-tailpipe emissions, and noise. While regulations have resulted in drastic reductions in tailpipe emissions, growing vehicle fleets and miles traveled have contributed to increased noise and non-tailpipe emissions such as brake wear, tire wear, and associated resuspended road dust. It is critical to assess effects of these lesser-studied non-tailpipe exposures that are high in toxic transition metals, and of noise, which can also amplify the detrimental health effects associated with near-roadway exposure.

In a cross-sectional study of the role of noise on the association between NOx and children’s lung function in the Southern California Children’s Health Study (CHS), we found that a 14.5 mL (95 % CI: -40.0, 11.0 mL) decrease in forced vital capacity (FVC) per interquartile range (13.6 ppb) in NOx was strengthened to a 34.6 mL decrease (95% CI: -66.3, -2.78 mL) after adjusting for noise. Noise was clearly an important factor and without taking it into account we would have underestimated the detrimental effects of exposure to traffic-related pollution.

Following this important finding, our current work focuses on intersections and on/off ramps where non-tailpipe and noise contributions are suspected to possibly disproportionately impact health. We will characterize exposure to non-tailpipe emissions with chemically speciated particulate matter concentrations in three size fractions from a spatially dense sampling campaign. Noise estimates from the Traffic Noise Model will be supplemented with noise contributions measured at intersections and on/off ramps. We will examine these as well as other important factors including greenspace and GIS-derived variables to study the effects this multipollutant mixture on respiratory outcomes in a longitudinal cohort of children from the CHS.