LAUSR

Abstract Ethylene is a ubiquitous industrial gas that is emitted by a wide variety of biogenic, biomass burning, and anthropogenic sources, so the opportunity for human exposure is widespread. We believe that a comprehensive exposure assessment of ethylene from emissions sources has not specifically been evaluated so this study was conducted to estimate the relative contribution of different sources on atmospheric concentrations in the Greater Houston area. Source attribution modeling shows that when averaged over the full modeling domain, inclusive of industrial, urban, rural and water areas, ethylene concentrations are dominated by natural source emissions (fires and biogenic) with an annual mean of 69% of total ethylene concentration. Of the anthropogenic sources, which account for the remaining 31% of the annual ethylene concentration, the largest contribution was from area/non-road sources (annual mean of 16%) with industrial source (annual mean of 11%) and on-road motor vehicle (annual mean of 4%) sources showing relatively lower concentration contributions.