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UNDERSTANDING REGIONAL OXIDATION CAPACITY BY COMPREHENSIVE OBSERVATIONS TO CONSTRAIN HYDROXYL RADICAL SOURCES AND SINKS DURING THE SOUTHERN OXIDANT AEROSOL STUDY (SOAS)
Impact/Purpose:
The overall goal of this project is to improve our understanding of oxidation capacity in the Southeastern U.S. region where biogenic volatile organic compounds (BVOCs) play a significant role in regional photochemistry to produce photochemical ozone and secondary organic aerosols (SOA) with different anthropogenic pollution influences (especially, NOX). Our specific objectives include:
- Providing high-resolution datasets of OH, HO2+RO2, H2SO4, NOx, and OH reactivity to the SOAS study participants and the entire scientific community.
- Constraining OH sources including photolytic and recycling sources and OH chemical sinks by measurements
- Understanding HOx budget and implications for SOA production by comparing measured OH ([OH]MEA), measurement constrained steady-state model calculated OH ([OH]SS) and University of Washington Chemical Mechanism (UWCM), which embedded the near-explicit chemical mechanism (MCM 3.2) calculated OH ([OH]UWCM) to assess our current HOx and SOA modeling capacity in isoprene rich environments for various NOX levels.
Description:
The proposed field measurements and data analysis will provide an important constraint to understand oxidation capacity in the Southeastern U.S. that determines SOA and photochemical ozone formation. Unexpectedly high levels of OH determining oxidation capacity have been consistently reported in high isoprene environments. Therefore, the comprehensive dataset from this proposed study is needed to seamlessly constrain OH sources and sinks and improve our understanding of OH primary production and recycling mechanisms in the Southeastern U.S. These outcomes, eventually, will improve modeling capability to predict SOA and photochemical ozone in the Southeastern U.S. region.