2010 Progress Report: Impact of Climate Change on Air Quality in the U.S.: Investigations With Linked Global- and Regional-Scale Models

EPA Grant Number: R833377
Title: Impact of Climate Change on Air Quality in the U.S.: Investigations With Linked Global- and Regional-Scale Models
Investigators: Sillman, Sanford , Keeler, Gerald J. , Penner, Joyce
Institution: University of Michigan
EPA Project Officer: Hunt, Sherri
Project Period: February 1, 2007 through January 31, 2010 (Extended to January 31, 2012)
Project Period Covered by this Report: February 1, 2010 through January 31,2011
Project Amount: $899,468
RFA: Consequences of Global Change For Air Quality (2006) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Climate Change , Air


The project will use global and regional-scale models for chemistry and transport to investigate the impact of future climate and emissions on air quality in the United States, with focus on ozone and mercury. It will use models that include gasphase and aqueous photochemistry and an updated representation of the interaction between aerosols and tropospheric chemistry. A major focus will be on observation-based methods – an attempt to identify atmospheric measurements that can be used to estimate the impact of climate change and global increases in emissions on air quality.

Progress Summary:

Work has focused on the global-scale simulation for current conditions (1997/2001). Results showed that the model is able to match the observed increase in ozone with temperature in the United States, and also matches with measured correlations between reactive nitrogen species (PAN, HNO3) and temperature.

This finding suggests that the model can successfully predict the effect of future temperature changes on ozone. Model results used tracers to identify transport of O3 and reactive nitrogen precursors from emission sources outside the United States. For current conditions transport to the United States from Asian emissions coincides with transport from other source regions and from the stratosphere. Events dominated by transport are associated with a higher slope for O3 vs CO and O3 vs PAN relative to events dominated by production within the United States. Future work will evaluate whether this model prediction is confirmed by measurements and whether it can be used to identify changes in response to future emissions.
Modeling activity has now been expanded to include both ozone and aerosols, with emphasis on methods of forming secondary organic aerosols (SOA). SOA formation pathways include direct photochemical pathways developed here, formation from glyoxal and methyl glyoxal (Fu et al., 2008), formation from epoxides derived from isoprene (Paulot et al., 2009) and possible formation based on HAC (Ervens et al., 2008, Matsunaga et al., 2004). Results from global-scale modeling suggests that significant SOA was present for pre-industrial conditions. Anthropogenic aerosols have a net cooling impact on climate, but this impact is much smaller if SOA are included (-1.2 W/m2 vs. -1.9 W/m2).

Future Activities:

During the final year of the project, we expect to complete the following tasks:

  1. Simulations for the year 2050 in a global-scale model.
  2. Evaluations of changes in measured species concentrations between 2001 and 2050 as evidence for identifying changes as they happen.
  3. Evaluation of predicted correlations between O3 and CO and O3 and PAN in comparison with measurements, and its use to identify the impact of transport.
  4. Publication of results pertaining to (i) tracers for identifying transport of ozone and measurements of evidence for transport; and (ii) SOA model and predicted effect on climate.
  5. In comparison with the original plan, the project has developed comparisons with measured O3 versus temperature somewhat ahead of schedule. The project is behind schedule in the addition of mercury to the global-scale model, and in the development of regional simulations linked to the global model for current conditions.

Journal Articles on this Report : 2 Displayed | Download in RIS Format

Other project views: All 15 publications 6 publications in selected types All 6 journal articles
Type Citation Project Document Sources
Journal Article Ito A, Sillman S, Penner JE. Global chemical transport model study of ozone response to changes in chemical kinetics and biogenic volatile organic compounds emissions due to increasing temperatures:sensitivities to isoprene nitrate chemistry and grid resolution. Journal of Geophysical Research 2009;114(D9):D09301 (19 pp.). R833377 (2009)
R833377 (2010)
R833377 (Final)
  • Full-text: Wiley-Full Text PDF
  • Abstract: Wiley-Abstract
  • Journal Article Steiner AL, Davis AJ, Sillman S, Owen RC, Michalak AM, Fiore AM. Observed suppression of ozone formation at extremely high temperatures due to chemical and biophysical feedbacks. Proceedings of the National Academy of Sciences of the United States of America 2010;107(46):19685-19690. R833377 (2010)
    R833377 (Final)
  • Full-text from PubMed
  • Abstract from PubMed
  • Associated PubMed link
  • Full-text: PNAS-Full Text PDF
  • Abstract: PNAS-Abstract & Full Text HTML
  • Supplemental Keywords:

    RFA, Air, climate change, Air Pollution Effects, Atmosphere

    Relevant Websites:

    http://www-personal.umich.edu/~sillman/obm.htm Exit
    http://www-personal.umich.edu/~sillman/CMAQ_corrections_2010.htm Exit
    http://www.sph.umich.edu/ehs/umaql Exit
    http://aossresearch.engin.umich.edu/gcl/default.html?url=research_project_sites/gcl/default.html Exit

    Progress and Final Reports:

    Original Abstract
  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • Final Report