2013 Progress Report: Understanding regional oxidation capacity by comprehensive observations to constrain hydroxyl radical sources and sinks during the Southern Oxidant Aerosol Study (SOAS)EPA Grant Number: R835400
Title: Understanding regional oxidation capacity by comprehensive observations to constrain hydroxyl radical sources and sinks during the Southern Oxidant Aerosol Study (SOAS)
Investigators: Kim, Saewung
Institution: University of California - Irvine
EPA Project Officer: Chung, Serena
Project Period: April 1, 2013 through March 31, 2016
Project Period Covered by this Report: April 1, 2013 through April 30,2014
Project Amount: $299,895
RFA: Anthropogenic Influences on Organic Aerosol Formation and Regional Climate Implications (2012) RFA Text | Recipients Lists
Research Category: Air Quality and Air Toxics , Global Climate Change , Climate Change , Air
- Provide high-resolution datasets of OH, HO2+RO2, H2SO4, NOx, and OH reactivity to the SOAS study participants and the entire scientific community.
- Constrain OH sources including photolytic and recycling sources and OH chemical sinks by measurements.
- Understand 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.
Progress has been made on the following activities:
- Deploying a H2SO4, OH, and HO2+RO2 chemical ionization mass spectrometer (CIMS) to the SOAS campaign.
- Deploying a comparative reactivity method (CRM)-OH reactivity system to the SOAS campaign.
- Deploying a commercial CRDS NO2 analyzer (Los Gatos) to the SOAS campaign.
- Participating FIX (Focused Isoprene-chemistry eXperiment) for CRM OH reactivity intercomparison.
- Reporting preliminary results of above observational parameters to the community data server.
- Presenting preliminary results and discussion at the SAS (Southern Atmospheric Study) data meeting.
The following activities will be conducted in the next year:
- Further laboratory calibration for OH and especially HO2+RO2 in various isoprene conditions.
- Quantitative evaluations of the roles of Cregee bi-radical and SO2 reaction dynamics in sulfuric acid formation.
- Systematic intercomparison between CRDS NO2 and other NO2 observational results especially in different NOY conditions.
- In depth analysis of FIX datasets and follow up laboratory experiments to characterize the CRM-OH reactivity system.
- Quantitative evaluation of roles of multifunctional isoprene oxidation products in missing OH reactivity.