Note: EPA no longer updates this information, but it may be useful for historical purposes. See

http://www.epa.gov/airtransport/ for information about the Transport Rule, EPA's response to the Court remand of CAIR which will replace CAIR when final.

You are here: EPA Home Air & Radiation Clean Air Interstate Rule Basic Information



# Basic Information

Basic Facts on CAIR Cap and Trade Basics Why Control SO2 and NOx? CAIR Timeline CAIR Nonattainment Maps EPA Press Release

Basic Facts on CAIR

Citing significant health and clean air benefits, EPA finalized the Clean Air Interstate Rule (CAIR) on March 10, 2005. This rule will result in the deepest cuts in sulfur dioxide (SO2) and nitrogen oxides (NOx) in more that a decade.

The December 23, 2008 ruling leaves CAIR and the CAIR FIPs -- including the CAIR trading programs -- in place until EPA issues a new rule to replace CAIR in accordance with the July 11, 2008 decision. Read the court decision (PDF) (4pp, 22k). EPA informed the Court that development and finalization of a replacement rule could take about two years.
The U.S. Court of Appeals for the D.C. Circuit has ruled on petitions for review of the Clean Air Interstate Rule (CAIR) and CAIR Federal Implementation Plans (FIPs), including their provisions establishing the CAIR NOX annual and ozone season and SO2 trading programs. On July 11, 2008, the Court issued an opinion vacating and remanding these rules; however, parties to the litigation requested rehearing of aspects of the Court's decision, including the vacatur of the rules. On December 23, 2008, the Court granted rehearing only to the extent that it remanded the rules to EPA without vacating them.
On March 10, 2005, the Environmental Protec tion Agency (EPA) announced the Clean Air Interstate Rule (CAIR), a rule that will achieve the largest reduc tion in air pollution in more than a decade. This action, called the "Interstate Air Quality Rule" when it was proposed in January 2004, offers steep and sustained reductions in air pollution as well as dramatic health benefits at more than 25 times greater than the cost by 2015.
Through the use of the proven cap-and-trade approach, CAIR achieves substantial reductions of sulfur dioxide (SO2) and nitrogen oxides (NOx) emissions and is a powerful component of the Administration's plan to help over 450 counties in the eastern U.S. meet EPA’s protective air quality standards for ozone or fine particles.
SO2 and NOx contribute to the formation of fine particles and NOx contributes to the formation of ground-level ozone. Fine particles and ozone are associated with thousands of premature deaths and illnesses each year. Additionally, these pollutants reduce visibility and damage sensitive ecosystems.
By the year 2015, the Clean Air Interstate Rule will result in: -- $85 to $100 billion in annual health benefits, annually preventing 17,000 premature deaths, millions of lost work and school days, and tens of thousands of non- fatal heart attacks and hospital admissions. -- nearly $2 billion in annual visibility benefits in southeastern national parks, such as Great Smoky and Shenandoah. -- significant regional reduc tions in sulfur and nitrogen deposition, reducing the number of acidic lakes and streams in the eastern U.S. 

## Clean Air Interstate Rule http://www.epa.gov/cair/basic.html Last updated on Friday, July 09, 2010 3/15/2011 EPA: Clean Air Interstate Rule - Basic ...

http://www.epa.gov/cair/basic.html 1/3CAIR covers 28 eastern states and the District of Columbia. In this rule, EPA finds that

SO2 and NOx emissions from 25 states and the District of Columbia contribute to unhealthy levels of fine particles in downwind states. In addition, NOx emissions in 25 eastern states and the Distric t of Columbia contribute to unhealthy levels of 8-hour ozone in other downwind states. (See map on the Where You Live page for information on affected states)

Based on an assessment of the emissions contributing to interstate transport of air pollution and available control measures, EPA has determined that achieving required reductions in the identified states by controlling emissions from power plants is highly cost effec tive.

States must achieve the required emission reduc tions using one of two compliance options: 1) meet the state’s emission budget by requiring power plants to participate in an EPA-administered interstate cap and trade system that caps emissions in two stages, or 2) meet an individual state emissions budget through measures of the state’s choosing.
CAIR provides a Federal framework requiring states to reduce emissions of SO2 and NOx. EPA anticipates that states will achieve this primarily by reducing emissions from the power generation sector. These reductions will be substantial and cost-effective, so in many areas, the reductions are large enough to meet the air quality standards. The Clean Air Ac t requires that states meet the new national, health-based air quality standards for ozone and PM2.5 standards by requiring reductions from many types of sources. Some areas may need to take additional local ac tions. CAIR reductions will lessen the need for additional local controls.
This final rule provides cleaner air while allowing for continued economic growth. By enabling states to address air pollutants from power plants in a cost effective fashion, this rule will protect public health and the environment without interfering with the steady flow of affordable energy for American consumers and businesses.
If states choose to meet their emissions reductions requirements by controlling power plant emissions through an interstate cap and trade program, EPA’s modeling shows that: In 2010, CAIR will reduce SO2 emissions by 4.3 million tons -- 45% lower than 2003 levels, across states covered by the rule. By 2015, CAIR will reduce SO2 emissions by 5.4 million tons, or 57%, from 2003 levels in these states. At full implementation, CAIR will reduce power plant SO2 emissions in affected states to just 2.5 million tons, 73% below 2003 emissions levels. CAIR also will achieve significant NOx reductions across states covered by the rule. In 2009, CAIR will reduce NOx emissions by 1.7 million tons or 53% from 2003 levels. In 2015, CAIR will reduce power plant NOx emissions by 2 million tons, achieving a regional emissions level of 1.3 million tons, a 61% reduction from 2003 levels. In 1990, national SO2 emissions from power plants were 15.7 million tons compared to 3.5 million tons that will be achieved with CAIR. In 1990, national NOx emissions from power plants were 6.7 million tons, compared to 2.2 million tons that will be achieved with CAIR.
In upcoming but closely related ac tion, EPA will impose the first ever federallymandated requirements that coal-fired electric utilities reduce their emissions of mercury. Together the Clean Air Mercury Rule and the Clean Air Interstate Rule create a multi-pollutant strategy to reduce emissions throughout the United States.
The Bush Administration continues to believe that the President’s Clear Skies legislation is a more efficient, effec tive, long-term mechanism to achieve large-scale national reductions. Clear Skies legislation applies nationwide and is modeled on the highly successful Acid Rain Program. The Agency remains committed to working with Congress to pass legislation.

Cap and Trade Basics

The Clean Air Interstate Rule establishes a cap-and-trade system for SO2 and NOx based on EPA's proven Acid Rain Program. The Acid Rain Program has produced remarkable and demonstrable results, reducing SO2 emissions faster and cheaper than anticipated, and resulting in wide-ranging environmental improvements. 3/15/2011 EPA: Clean Air Interstate Rule - Basic ...

http://www.epa.gov/cair/basic.html 2/3EPA already allocated emission "allowances" for SO2 to sources subject to the Acid

Rain Program. These allowances will be used in the CAIR model SO2 trading program. For the model NOx trading programs, EPA will provide emission "allowances" for NOx to each state, according to the state budget. The states will allocate those allowances to sources (or other entities), which can trade them. As a result, sources are able to choose from many compliance alternatives, including: installing pollution control equipment; switching fuels; or buying excess allowances from other sources that have reduced their emissions.
Because each source must hold sufficient allowances to cover its emissions each year, the limited number of allowances available ensures required reductions are achieved.
The mandatory emission caps, stringent emissions monitoring and reporting requirements with significant automatic penalties for noncompliance, ensure that human health and environmental goals are achieved and sustained.
The flexibility of allowance trading creates financial incentives for elec tricity generators to look for new and low-cost ways to reduce emissions and improve the effec tiveness of pollution control equipment.

Why Control SO2 and NOx?

Why EPA is Addressing Emissions of SO2 and NOx

EPA established more protective fine particle and 8-hour ozone national air quality standards in 1997. Litigation and the need to establish a nationwide air monitoring system for fine particles delayed the implementation of these standards, but implementation is now moving forward. Areas not meeting these standards, known as “nonattainment” areas, were designated in 2004. These state and local governments are moving forward with plans to protect public health by attaining the standards as quickly as possible.
Sulfur dioxide (SO2) and nitrogen oxides (NOx) contribute to the formation of fine particles (PM) and NOx contributes to the formation of ground-level ozone.
Many sources contribute to levels of fine particle pollution and ozone that exceed national air quality standards. Some of these pollutants may originate hundreds or thousands of miles from the areas where violations are detected. The Clean Air Act's "good neighbor provisions" require states to eliminate emissions that substantially contribute to dirty air in downwind states.
Under the Clean Air Act, states are required to submit plans to EPA within three years after the Agency revises a national air quality standard. Among other requirements, these plans must limit emissions in states that contribute significantly to unhealthy air downwind.
Although states have not yet developed plans for meeting the national air quality standards for fine particle pollution and 8-hour ozone, EPA's analyses show that even substantial local emission controls still would leave many areas in the eastern US with unhealthy air in 2010.
By limiting emissions of SO2 and NOx on a regional scale, the Clean Air Interstate Rule will help all areas in the eastern US achieve healthier air quality at reduced costs than a strategy that relies solely on local controls.

CAIR Timeline

Promulgate CAIR Rule 2005 State Implementation Plans Due 2006 Phase I Cap in Place for NOx 2009 Phase I Cap in Place for SO2 2010 Phase II Cap in Place for NOx and SO2 2015 3/15/2011 EPA: Clean Air Interstate Rule - Basic ...

http://www.epa.gov/cair/basic.html 3/3