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Global Change Air Quality Assessment
CCSP and role of EPA
In 1990, the United States Congress enacted the U.S.
Global Change Research Act 
,
with the goals of “understanding and responding to climate change,
including the cumulative effects of human activities and natural processes
on the environment.” A key component of the act was the creation
of the U.S. Global Change Research Program (USGCRP). Thirteen government
agencies are part of the program, including the National Science Foundation,
the Environmental Protection Agency (EPA), the National Aeronautics and
Space Administration, the Agency for International Development, the Smithsonian
Institution, and the Departments of Commerce, Energy, State, Interior,
Agriculture, Health and Human Services, Transportation, and Defense. The
activities of each of these agencies in support of the USGRCP are described
on the USGCRP website.
In 2001, the President announced the establishment of the U.
S. Climate Change Research Initiative (CCRI) . CCRI
was developed to complement the USGRCP, with the goal of supporting policy
makers in the short term through “the integration of scientific
knowledge, including measures of uncertainty, into effective decision
support systems.” To achieve this goal, CCRI is focusing on reducing
the uncertainties in climate science and modeling, improving the monitoring
and analysis of climate change signals, and improving resources for supporting
decision-making. There are two major components of the CCRI: (i) the Climate
Change Science Program (CCSP), and (ii) the Climate Change Technology
(CCTP) program. While CCTP focuses on technology issues, such as how to
mitigate greenhouse gas emissions, CCSP focuses on understanding climate
change and its impacts.
The EPA’s primary role under CCSP is to develop an understanding of the potential consequences of global change on human health, ecosystems, and socioeconomic systems in the United States. This information will support stakeholders and policy makers as they decide whether and how to respond to the risks and opportunities presented by global climate change. A central component of the EPA’s activities is to examine the interrelationships among economic growth, population growth, climate-induced meteorological change, land use change, technology change, and government policy, with a focus on characterizing their effects on future ambient air quality. In this context, the U.S. EPA’s Office of Research and Development (ORD) is carrying out a Global Change Air Quality Assessment for the year 2050.
The Assessment includes six primary modeling activities related to this objective, including:
- Developing future global change scenarios, which involve assumptions about factors such as future economic conditions, energy demands, availability of fossil fuels, technology characteristics (e.g, cost, energy source, and fuel efficiency), land-use changes, meteorology, and policies;
- Estimating regional meteorology through downscaling the results of global meteorological models;
- Modeling the energy and economic systems under various scenarios to characterize future fuel usage by type and quantity, technology adoption, and economic growth;
- Estimating future emissions of specific pollutants (NOx, SOx, PM10) as a function of these factors;
- Processing emissions to generate future-year emissions files suitable for air quality modeling (e.g., in this step, emissions are speciated, temporalized, and gridded);
- Modeling air quality to determine ambient concentrations of pollutants, with a focus on tropospheric ozone and fine particulate matter (PM2.5).
Each of these modeling activities is typically carried out using one or more computer models. Figure 1 is a flow diagram of the modeling activities showing which model is used in each.
Figure 1. Flow Diagram Showing the Modeling Activities
and Models Making up the Global Change Air Quality Assessment
The modeling activities making up the Air Quality Assessment are being performed by a number of different groups within ORD. For example, the National Center for Environmental Analysis (NCEA) is coordinating the Assessment and is developing the overall scenario assumptions. The National Risk Management Research Laboratory (NRMRL) is responsible for characterizing the role of technological change in estimating future year emissions. The National Exposure Research Laboratory (NERL) is responsible for global and regional meteorological modeling, as well as emissions and air quality modeling. NERL and NRMRL are working together to ensure that these efforts are compatible. Also, the National Center for Environmental Research (NCER) is funding related research through the Science To Achieve Results (STAR) grant program.