Impact of aromatics and monoterpenes on simulated tropospheric ozone and total OH reactivity

Abstract

The accurate representation of volatile organic compounds (VOCs) in models is an important step towards the goal of understanding and predicting many changes in atmospheric constituents relevant to climate change and human health. While isoprene is the most abundant non-methane VOC, many other compounds play a large role in governing pollutant formation and the overall oxidative capacity of the atmosphere. We quantify the impacts of aromatics and monoterpenes, two classes of VOC not included in the standard gas-phase chemistry of the chemical transport model GEOS-Chem, on atmospheric composition. We find that including these compounds increases mean total summer OH reactivity by an average of 11% over the United States, Europe, and Asia. This increased reactivity results in higher simulated levels of O[subscript 3], raising maximum daily 8-h average O[subscript 3] in the summer by up to 14 ppb at some NO[subscript x]-saturated locations. Keywords: Tropospheric ozone; VOCs; Atmospheric chemistry; Air quality modeling