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National Carbon Dioxide Emissions from Fossil Fuel-Burning Power Plants as Measured by Acid Rain Program Continuous Emissions Monitoring Systems (CEMS)

Cap and Trade

The Acid Rain Program (ARP), created under Title IV of the 1990 Clean Air Act (CAA) Amendments, works to reduce emissions of SO2 and NOx, primarily from fossil fuel-burning electricity generation, to reduce acid deposition and improve air quality. The program employs continuous emissions monitoring systems (CEMS) that measure smokestack emissions of SO2, NOx, and carbon dioxide (CO2). CO2emissions from ARP sources (primarily coal-burning power plants) constitute about 40 percent of total U.S. CO2 emissions.

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(Clicking on the Play button in the bottom left corner of the map sets the map in motion.)

Note that emissions of CO2 (red dots in the map above) fluctuate, but do not necessarily decline, beginning in 1995 with the advent of the ARP and CEMS monitoring. CO2 did not decline as SO2 and NOx did under their respective cap and trade programs. Emission control strategies for SO2 and NOx would have included scrubber technology, fuel-switching to lower sulfur coal or natural gas, or buying allowances that would not have affected to a significant degree CO2 emissions or heat input, another metric of fuel-to-generation capacity. In fact, between 1995 and 2009, total annual emissions of CO2 from ARP sources increased from 2.2 billion tons to 2.3 billion tons.

* Note that there are no data for CO2 emissions prior to 1995; continuous emissions monitoring systems (CEMS) were required of all program sources for CO2 starting in 1995.

These animations are based on data and interactive mapping applications at EPA's Airmarkets website. For complete ARP and NBP data overlay files, as well as air quality and deposition data for interactive mapping applications (i.e., Google Earth), go to the Airmarkets Interactive Mapping page.

Additional Resources

Air Quality and Deposition Data and Maps

Emissions Monitoring Data

U.S. Greenhouse Gas Inventory Information

Cap and Trade Legislative Analysis

Greenhouse Gas Reporting Rule


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