2007 Progress Report: Impact of Climate Change on Air Quality in the U.S.: Investigations With Linked Global- and Regional-Scale ModelsEPA 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, 2007 through January 31, 2008
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 U.S., 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.
Work during the first year 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 U.S. 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 U.S. For current conditions transport to the U.S. from Asian emissions coincides with transport from other source regions and from the stratosphere. This makes it difficult to identify a signal for Asian emissions based on observations in the U.S.
During the second year of the project we expect to complete the following tasks.
- Simulations for the year 2050 in a global-scale model.
- Evaluations of changes in measured species concentrations between 2001 and 2050 as evidence for identifying changes as they happen.
- Simulations for the present (2001) in a regional-scale model with links to the global model.
In addition, the global-scale model will be modified to include explicit formation of secondary organic aerosols.
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.