Global Change and Air Pollution (GCAP) Phase 2: Implications for U.S. Air Quality and Mercury Deposition of Multiple Climate and Global Emission Scenarios for 2000-2050

EPA Grant Number: R833370
Title: Global Change and Air Pollution (GCAP) Phase 2: Implications for U.S. Air Quality and Mercury Deposition of Multiple Climate and Global Emission Scenarios for 2000-2050
Investigators: Jacob, Daniel J. , Byun, Daewon , Fu, Joshua , Mickley, Loretta J. , Rind, David , Seinfeld, John , Streets, David G.
Institution: Harvard University , Argonne National Laboratory , California Institute of Technology , NASA Goddard Institute for Space Studies , University of Houston , University of Tennessee - Knoxville
EPA Project Officer: Chung, Serena
Project Period: May 1, 2007 through April 30, 2011
Project Amount: $900,000
RFA: Consequences of Global Change For Air Quality (2006) RFA Text |  Recipients Lists
Research Category: Global Climate Change , Climate Change , Air


The objective of GCAP Phase 2 is to better quantify and understand the effects of global change on air quality and mercury deposition in the United States over the coming decades. As the United States tightens its controls on domestic emissions, we need to determine how external perturbations associated with global change may affect the success of these controls. Such external perturbations include changes in climate (driven in particular by greenhouse gas emissions) and changes in pollutant emissions outside North America. We will apply the coupled global-regional model capability developed under GCAP Phase 1 to address three critical issues over the 2000-2050 time horizon: (1) assessment of the potential range of global change impacts on air quality through consideration of multiple scenarios, (2) intercontinental transport of pollution, and (3) mercury deposition to ecosystems, including the role of climate change in perturbing the cycling of mercury between the atmosphere and surface reservoirs.


In GCAP Phase 1, we constructed interfaces between the GISS general circulation model, the GEOS-Chem global model of atmospheric composition, and the MM5/CMAQ regional air quality model to produce a powerful and versatile machinery for investigating the effects of climate change on air quality and mercury deposition. In GCAP Phase 2, we will apply this machinery to an ensemble of scenarios for 2000-2050 changes in global greenhouse gas and pollutant emissions. These will include the standard IPCC projections as well as ACCENT projections that assume aggressive pollution controls at northern mid-latitudes. We will construct 2000-2050 global projections of anthropogenic mercury emissions for the IPCC scenarios, and take advantage of the GEOS-Chem capability for dynamic coupling of mercury between atmospheric, oceanic, and terrestrial reservoirs. We will use the results to assess confidence and uncertainties in projections of future U.S. air quality and mercury deposition, particularly with regard to the effect of climate change. We will conduct a series of sensitivity simulations to investigate the effects of global climate and emission changes on intercontinental transport of pollution to the U.S.

Expected Results:

Our work will expand understanding of the effects of global change on regional air quality and mercury deposition in the U.S. It will provide important information on the co-benefits of greenhouse gas regulations for public health. Our use of multiple climate and emissions scenarios will help bracket the range of air quality responses expected in the coming decades. This will enable improved long-term planning of air quality management, and help determine to what extent international cooperation may be necessary to achieve domestic air quality and mercury goals. Our work will guide policymakers as they develop improved strategies for protecting public health in a changing world.

Publications and Presentations:

Publications have been submitted on this project: View all 52 publications for this project

Journal Articles:

Journal Articles have been submitted on this project: View all 24 journal articles for this project

Supplemental Keywords:

chemical transport, volatile organic compounds (VOCs), nitrogen oxides, sulfates, organics, pollution prevention, environmental chemistry, modeling, climate models, tropospheric ozone, tropospheric aerosol, mercury deposition, intercontinental transport,, RFA, Scientific Discipline, Air, climate change, Air Pollution Effects, Environmental Monitoring, Ecology and Ecosystems, Atmosphere, air quality modeling, mercury deposition, Baysian analysis, climate models, atmospheric models

Progress and Final Reports:

  • 2007 Progress Report
  • 2008 Progress Report
  • 2009 Progress Report
  • Final Report