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Progress Reports

2015 Program Progress – Cross-State Air Pollution Rule and Acid Rain Program

This report summarizes annual progress through 2015 under the Acid Rain Program (ARP) and the first year of the Cross-State Air Pollution Rule (CSAPR).This reporting year marks the twentieth anniversary since the implementation of the ARP.

A cornerstone of effective emission reduction programs is transparency and data availability. This report highlights data, that EPA systematically collects, on emissions, compliance, and environmental effects. The success of these programs is demonstrated through substantial reductions in power sector emissions of sulfur dioxide (SO₂) and nitrogen oxides (NOₓ) and improvements in air quality and the environment.

CSAPR Program Map

2015 ARP and CSAPR at a Glance

  • SO₂ emissions:
    CSAPR - 1.8 million tons (77 percent below 2005)
    ARP - 2.2 million tons (86 percent below 1990)
  • Annual NOₓ emissions
    CSAPR - 0.9 million tons (61 percent below 2005)
    ARP - 1.3 million tons (79 percent below 1990)
  • CSAPR ozone season NOₓ emissions: 450,000 tons (48 percent below 2005)
  • Compliance: 100 percent compliance for power plants in the ARP and CSAPR SO₂ Group 2 programs. Over 99 percent compliance for power plants in CSAPR SO₂ Group 1, NOₓ annual, and NOₓ ozone season programs.
  • Ambient particulate sulfate concentrations: decreased 66 to 70 percent in the East between 1989–1991 and 2013–2015.
  • Ozone NAAQS attainment: Based on 2013-2015 data, all 92 areas in the East originally designated as in nonattainment for the 1997 ozone NAAQS are now meeting the standard.
  • PM₂.₅ NAAQS attainment: Based on 2013-2015 data, 34 of the 36 areas in the East originally designated as in nonattainment for the 1997 PM₂.₅ NAAQS are now meeting the standard (two areas have incomplete data).
  • Wet sulfate deposition: All areas of the eastern United States have shown significant improvement with an overall 64 percent reduction in wet sulfate deposition from 1989–1991 to 2013–2015.
  • Levels of acid neutralizing capacity (ANC): This indicator of recovery improved (i.e., increased) significantly at lake and stream monitoring sites in the Adirondack region, New England and the Catskill mountains.

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