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: Hunt, Sherri
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

Objective:

  • 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 Summary:

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.

Future Activities:

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. 

Journal Articles:

No journal articles submitted with this report: View all 5 publications for this project

Supplemental Keywords:

ambient air, tropospheric OH, SOA, observation, Southeast

Progress and Final Reports:

Original Abstract
2014 Progress Report
Final Report