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: Chung, Serena
Project Period: February 1, 2007 through January 31, 2010 (Extended to January 31, 2012)
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 of air quality in the U.S., with focus on ozone and mercury. The models include linked gas-phase and aqueous photochemistry and a new approach for representing the interaction between aerosols and tropospheric chemistry. Meteorology will be derived from linked global circulation and chemistry/transport models that include event-specific aerosol impacts on climate.
For ozone, the study will identify future changes based on a range of model scenarios with changed climate and global emissions. The study will use model correlations of O3 with temperature as a basis for evaluating accuracy of the predicted response to climate. Other species correlations (O3-CO, O3-NOy, O3-PAN) will be investigated as indicators for the effect of global emissions on air quality.
For mercury, the project will identify the relative impact of local emissions and global transport in two regions where mercury has caused environmental damage (the Great Lakes and Florida). EPA field measurements in those regions will be used to evaluate model accuracy. A series of species correlations will be investigated as possible measurement-based evidence for the impact of local versus global emissions. Correlations between reactive mercury and O3 will be investigated to determine whether ozone formation also affects mercury.
The NCAR Finite-VolumeCommunity Climate Model (FVCCM) will be used to provide climate scenarios for 2050. These scenarios will be used to drive a global-scale model (IMPACT) for chemistry and transport, including O3, mercury, and nitrate and sulfate aerosols. The global model will be linked to a modified version of CMAQ that includes fully integrated gas-aqueous chemistry and mercury chemistry in addition to ozone and aerosols. CMAQ will be used to simulate air quality during events in the Midwest and eastern U.S. EPA data for O3 versus temperature, EPA field measurements for reactive mercury, and global networks of measured O3, CO and reactive nitrogen will be used to evaluate results.
The project would establish lower and upper limits for the effect of climate change on air quality and for the effect of global emissions on air quality over the next 50 years. These estimates would include impacts in urban areas during extreme events and in rural areas, where prolonged exposure may affect agricultural crops and increase the frequency of violations of health standards. The project would identify measurable species correlations that could monitor the global impact on urban air quality, and could also evaluate model accuracy. The project would advance the understanding of atmospheric ozone and mercury through the use of new model techniques and by investigating the relationship between mercury and O3.