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Cross-State Air Pollution Rule (CSAPR)

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What's New

August 21, 2012 - The U.S. Court of

Appeals for the D.C. Circuit issued its

ruling on CSAPR.

June 8, 2012 - On June 5, 2012, EPA

issued the final set of minor adjustments

to the Cross-State Air Pollution Rule

(CSAPR).

May 11, 2012 - On May 10, 2012, EPA

w ithdrew the Direct Final Revisions Rule.

The Agency w ill take final action on the

proposed revisions rule expeditiously.

April 20, 2012 - EPA has review ed the

comments submitted in response to the

Direct Final Revisions Rule. EPA intends

to w ithdraw the Direct Final Revisions

Rule prior to its effective date and take

final action on the proposed revisions

rule expeditiously.

March 1, 2012 - EPA filed its brief on

the merits of the legal challenges to the

CSAPR.

Click on the map to see a larger image | View this map as a table

Cross-State Air Pollution Rule (CSAPR)

The U.S. Court of Appeals for the D.C. Circuit issued its ruling on CSAPR. EPA is review ing the court decision. CAIR remains in place.

On July 6, 2011, the US Environmental Protection Agency (EPA) finalized a rule that protects the health of millions of Americans

by helping states reduce air pollution and attain clean air standards. This rule, known as the Cross-State Air Pollution Rule

(CSAPR), requires states to significantly improve air quality by reducing power plant emissions that contribute to ozone and/or

fine particle pollution in other states. In a separate, but related, regulatory action, EPA finalized a supplemental rulemaking on

December 15, 2011 to require five states - Iowa, Michigan, Missouri, Oklahoma, and Wisconsin - to make summertime NOX

reductions under the CSAPR ozone season control program. CSAPR requires a total of 28 states to reduce annual SO2

emissions, annual NOXemissions and/or ozone season NOXemissions to assist in attaining the 1997 ozone and fine particle

and 2006 fine particle National Ambient Air Quality Standards (NAAQS). On February 7, 2012 and June 5, 2012, EPA issued two

sets of minor adjustments to the Cross-State Air Pollution Rule (CSAPR).

This rule replaces EPA's 2005 Clean Air Interstate Rule (CAIR). A December 2008 court decision kept the requirements of CAIR

in place temporarily but directed EPA to issue a new rule to implement Clean Air Act requirements concerning the transport of air

pollution across state boundaries. This action responds to the court's concerns.

Read more about the Cross-State Air Pollution Rule (CSAPR)

Press Release

Presentation (PDF 33pp, 1.80 MB) Updated December 15, 2011 to reflect the final supplemental rule for CSAPR, the proposed

technical revisions rule, recent implementation activities, and other information.

Fact Sheet Updated July 18, 2011 (PDF 7pp 138 kb)

Recording of Webinar presented on July 7, 2011 on "CSAPR Website Walkthrough" (WMV 46.77 MB)

Public Docket for CSAPR.

The Cross-State Air Pollution Rule provides cleaner air and healthier lives for millions of Americans

Estimated Annual Number of Adverse Health Effects Avoided Due to Implementing the CSAPR

*

Health Effect Number of Cases Avoided

Premature mortality 13,000 to 34,000

Non-fatal heart attacks 15,000

Hospital and emergency department visits 19,000

Accute bronchitis 19,000

Upper and lower respiratory symptoms 420,000

Aggravated asthma 400,000

Days when people miss work or school 1.8 million

*

Impacts avoided due to improvements in PM2.5 and ozone air quality in 2014

The CSAPR will help avoid tens of thousands of premature deaths and illnesses, achieving hundreds of billions of dollars in public health benefits. Pollution reductions

will also lead to improvements in visibility in national and state parks, and increased protection for sensitive ecosystems including Adirondack lakes and Appalachian

streams, coastal waters and estuaries, and forests.

The benefits of the Cross-State Air Pollution Rule far outweigh the costs of the rule.

The final rule yields $120 to $280 billion in annual health and environmental benefits in 2014, including the value of avoiding 13,000

to 34,000 premature deaths. This far outweighs the estimated annual costs of CSAPR. The $800 million in annual projected costs of

this rule in 2014, along with the roughly $1.6 billion per year in capital investments already under way as a result of CAIR, are

improving air quality for over 240 million Americans. This rule will not disrupt a reliable flow of affordable electricity for American

consumers and businesses. Health benefits will be achieved at a very low cost, and while the effect on prices for specific regions or

states may vary, they are well within the range of normal electricity price fluctuations. Any such costs will be greatly outweighed by the

benefits.

The Cross-State Air Pollution Rule improves air quality throughout the eastern half of the United

States, helping states achieve national clean air standards.

The rule requires significant reductions in sulfur dioxide (SO2) and nitrogen oxide (NOX)

emissions that cross state lines. These pollutants react in the atmosphere to form fine

particles and ground-level ozone and are transported long distances, making it difficult

for other states to achieve NAAQS. To see how the rule affects each state in the CSAPR

region, view the table "States that are included in the CSAPR" on the Resources for
10/3/12 Air Transport | US EPA

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Last updated on Tuesday, August 21, 2012

Implementation page.

Emission reductions will take effect quickly, starting January 1, 2012 for SO2and annual

NOXreductions, and May 1, 2012 for ozone season NOXreductions. By 2014,

combined with other final state and EPA actions, the Cross-State Air Pollution Rule will

reduce power plant SO2emissions by 73 percent and NOXemissions by 54 percent

from 2005 levels in the CSAPR region.

The emission reductions expected from EPA's recently-finalized Mercury and Air Toxics

Standards (MATS) are not included in the estimated emission reductions from the

Cross-State Air Pollution Rule; once those standards are implemented, SO2emissions

from the power sector are likely to be reduced even further.
1 

FACT SHEET 

The Cross-State Air Pollution Rule: 

Reducing the Interstate Transport of Fine 

Particulate Matter and Ozone 

ACTION

On July 6, 2011, the US Environmental Protection Agency (EPA) finalized a rule 

that protects the health of millions of Americans by helping states reduce air 

pollution and meet Clean Air Act standards. This final rule replaces EPA’s 2005 

Clean Air Interstate Rule (CAIR). A December 2008 court decision found flaws in 

CAIR, but kept CAIR requirements in place temporarily while directing EPA to 

issue a replacement rule. In order to replace CAIR as quickly as possible, 

addressing the problem of air pollution that is transported across state 

boundaries, EPA is adopting federal implementation plans, or FIPs, for each of 

the states covered by this rule. This final Cross-State Air Pollution Rule meets 

the Clean Air Act requirements and responds to the court’s concerns. 

The Cross-State Air Pollution Rule requires 27 states in the eastern half of the 

United States to significantly improve air quality by reducing power plant 

emissions that cross state lines and contribute to ground-level ozone and fine 

particle pollution in other states. This action builds on more than fifteen years of 

progress in implementing Clean Air Act reductions of sulfur dioxide (SO2) and 

nitrogen oxides (NOX). 

At the same time, the Agency also issued a supplemental proposal that would 

require six states — Iowa, Kansas, Michigan, Missouri, Oklahoma, and 

Wisconsin — to make summertime NOX reductions under the Cross-State Air 

Pollution Rule ozone-season control program. Five of those states are already 

covered in the final rule for interstate fine particle pollution (PM2.5). Finalizing this 

supplemental proposal would bring the total number of covered states under the 

Cross-State Air Pollution Rule to 28. 

The $800 million spent annually on this rule in 2014, along with the roughly $1.6 

billion per year in capital investments already under way as a result of CAIR, are 

improving air quality for over 240 million Americans and will result in $120 to 

$280 billion in annual benefits, including the value of avoiding 13,000 to 34,000 

premature deaths each year. These estimates include the costs and benefits of 

the supplemental proposal. Moreover, states where investments in control 

technology are required also receive large benefits. 

This final rule requires significant reductions in SO2 and NOX emissions from 

power plants in the eastern half of the United States. These pollutants react in 

the atmosphere to form PM2.5 and ground-level ozone and are transported long 

distances, making it difficult for a number of states to meet the national clean air 

standards that Congress directed EPA to establish to protect public health. 

Emission reductions under the Cross-State Air Pollution Rule will begin to take 

effect quickly. The first phase of compliance begins January 1, 2012 for SO2 and 
2 

annual NOX reductions and May 1, 2012 for ozone season NOX reductions. The 

second phase of SO2 reductions begins January 1, 2014. By 2014, the CrossState Air Pollution Rule and other final state and EPA actions will reduce power 

plant SO2 emissions by 73 percent from 2005 levels. Power plant NOX emissions 

will drop by 54 percent. 

This rule also lays out a process for determining each upwind state's 

responsibility to protect downwind air quality. Each time the NAAQS are 

changed, EPA can apply this process and determine if interstate pollution 

transport contributes to exceedances of the new standard and whether new 

emission reductions should be required from upwind states. For example, 

additional emission reductions from power plants or other sources in upwind 

states – in addition to actions taken in downwind states – may be needed in 

order for many areas to meet future ozone or PM2.5 standards. EPA will work 

expeditiously with states to meet these future challenges using as a precedent 

the Cross-State Air Pollution Rule’s approach to determining upwind 

responsibility. 

Cross-State Air Pollution Rule Region 
3 

KEY FEATURES OF THE CROSS-STATE AIR POLLUTION RULE

Of the states affected by the final Cross-State Air Pollution Rule: 

 Twenty-three states are required to reduce both annual SO2 and NOX

emissions. By reducing emissions in upwind states, the rule improves 

PM2.5 air quality in downwind states and helps them attain and maintain 

the 24-hour PM2.5 air quality standards established in 2006 and the 1997 

annual PM2.5 standards. 

 Twenty states are required to reduce NOX emissions during the ozone 

season (May through September) because they contribute to downwind 

states’ ozone pollution. By reducing emissions in upwind states, the rule 

improves ozone air quality in downwind states and helps them attain and 

maintain the 1997 8-hour ozone standard. 

Additionally, EPA is issuing a proposed rule requesting comment on inclusion of 

the following six states in the Cross-State Air Pollution Rule ozone season 

program: Iowa, Kansas, Michigan, Missouri, Oklahoma, and Wisconsin. The final 

Cross-State Air Pollution Rule does not include ozone season NOX reduction 

requirements for these six states. However, all of these states, except for 

Oklahoma, are included in the final Cross-State Air Pollution Rule annual NOX

program for PM2.5 that begins January 1, 2012. EPA intends to finalize the 

supplemental proposal as soon as possible. Once final, it would increase the 

total number of covered states in the Cross-State Air Pollution Rule region to 28 

and the number required to reduce ozone season NOX emissions to 26. 

The table at the end of this fact sheet identifies the states covered by the final 

rule and the emissions they will need to control, including the six states proposed 

in the supplemental notice of proposed rulemaking to be included for ozone 

season NOX emission reductions. 

EPA carefully considered the court’s direction in developing the Cross-State Air 

Pollution Rule. The rule defines what portion of an upwind state’s emissions 

“significantly contribute” ozone or PM2.5 pollution to nonattainment or 

maintenance areas in downwind states. This definition considers the magnitude 

of a state’s contribution, the air quality benefits of reductions, and the cost of 

controlling pollution from various sources. Once these obligations are 

determined, the rule requires states to eliminate the portion of their emissions 

defined as their “significant contribution” by setting a pollution limit (or budget) for 

each covered state. 

The rule allows air-quality-assured allowance trading among covered sources, 

utilizing an allowance market infrastructure based on existing, successful 

allowance trading programs. The final Cross-State Air Pollution Rule allows 

sources to trade emissions allowances with other sources within the same 

program (e.g., ozone season NOX) in the same or different states, while firmly 

constraining any emissions shifting that may occur by requiring a strict emission 

ceiling in each state (the budget plus variability limit). It also includes assurance 
4 

provisions that ensure each state will make the emission reductions necessary to 

fulfill the “good neighbor” provision of the Clean Air Act. 

In response to the court’s direction to replace CAIR as quickly as possible, EPA 

is adopting federal implementation plans, or FIPs, for each of the states covered 

by this rule; states may replace the FIPs with State Implementation Plans (SIPs). 

 The Cross-State Air Pollution Rule includes an expedited process for 

states to adjust specific aspects of the FIP, such as allowance allocations, 

as early as 2013, including crediting sources for NOX allowances banked 

under earlier programs. 

 A state also may choose to develop a state plan (SIP) to achieve the 

required reductions, replacing its federal plan, and may choose which 

types of sources to control by 2014. 

EMISSION REDUCTIONS AND COMPLIANCE WITH THE CROSS-STATE AIR 

POLLUTION RULE

Compared to 2005, EPA estimates that by 2014 this rule and other federal rules 

will lower power plant annual emissions in the Cross-State Air Pollution Rule 

region by: 

 6.4 million tons per year of SO2 (2005 emissions were 8.8 million tons) 

 1.4 million tons per year of NOX (2005 emissions were 2.6 million tons) 

o Including 340,000 tons per year of NOX during the ozone season. 

The Cross-State Air Pollution Rule, including states proposed for inclusion in the 

supplemental notice of proposed rulemaking, covers 3,632 electric generating 

units at 1,074 coal-, gas-, and oil-fired facilities in 28 states. EPA’s modeling 

projects that by 2014, in the states covered by the Cross-State Air Pollution Rule: 

 Approximately 70 percent of the power generated from coal-fired power 

plants will come from units with state-of-the-art SO2 controls (such as 

scrubbers). 

 Approximately 50 percent of the power generated from coal-fired power 

plants will come from units with state of the art NOX controls (such as 

SCR). 

EPA modeling shows that coal use will continue to grow under the Cross-State 

Air Pollution Rule and power plants may achieve the necessary emission 

reductions by: 

 Maintaining effective and frequent operation of already installed control 

equipment, 

 Using low sulfur coal, 

 Increasing generation from relatively cleaner units, and/or 

 Installing existing, commercially proven technologies that are widely 

available and frequently used in this industry, such as low NOX burners, 

scrubbers (flue gas desulfurization), or dry sorbent injection. 
5 

AIR QUALITY IMPROVEMENTS UNDER THE CROSS-STATE AIR 

POLLUTION RULE

The Cross-State Air Pollution Rule will improve air quality in thousands of 

counties throughout the eastern, central, and southern U.S. – counties that are 

home to over 75% of the U.S. population. State, local and federal actions have 

already improved air quality so that many counties meet the National Ambient Air 

Quality Standards for ozone and fine particle pollution. Many areas have already 

been brought into attainment with these standards, this rule will help to bring 

several more areas into attainment and help many more areas continue to meet 

the level of the standards. 

BENEFITS AND COSTS OF THE CROSS-STATE AIR POLLUTION RULE 

The emission reductions from this final rule will have significant and immediate 

public health benefits. By 2014, this rule will annually prevent: 

 13,000 to 34,000 premature deaths, 

 19,000 cases of acute bronchitis, 

 15,000 nonfatal heart attacks, 

 19,000 hospital and emergency room visits, 

 1.8 million days when people miss work or school, 

 400,000 cases of aggravated asthma, and 

 420,000 cases of upper and lower respiratory symptoms. 

These emission reductions will also improve visibility in national and state parks, 

and increase protection for sensitive ecosystems including Adirondack lakes and 

Appalachian streams, coastal waters and estuaries, and forests. 

The $800 million spent annually on this rule in 2014, along with the roughly $1.6 

billion per year in capital investments already under way as a result of CAIR, are 

improving air quality for over 240 million Americans and will result in $120 to 

$280 billion in annual benefits. These estimates include the costs and benefits of 

the supplemental proposal. 

The employment effects of this rule are modest, but by our analysis positive. 

EPA examined some employment impacts using two methodologies which are 

detailed in the RIA. Both show that some jobs are lost, but more are gained as 

some companies construct and operate pollution control equipment to comply 

with the rule. 

BACKGROUND

This Cross-State Air Pollution Rule replaces the 2005 Clean Air Interstate Rule 

(CAIR) starting January 1, 2012. EPA issued CAIR on May 12, 2005 and the 

CAIR federal implementation plans (FIPs) on April 26, 2006. In 2008, the US 

Court of Appeals for the DC Circuit remanded CAIR to the Agency, leaving 

existing CAIR programs in place while directing EPA to replace them as rapidly 

as possible with a new rule consistent with the Clean Air Act. 
6 

The Cross-State Air Pollution Rule was proposed July 6, 2010. EPA held three 

public hearings on the proposed rule during the 60-day comment period. EPA 

also issued three notices of data availability (NODAs) to provide additional 

opportunities for public comment on data, modeling, and other key aspects of the 

rule. The Agency received hundreds of detailed comments from states, 

environmental and public health groups, industry, and other stakeholders during 

the comment periods for the proposed rule and NODAs. 

FOR MORE INFORMATION

To see or download a copy of the final rule, go to www.epa.gov/airtransport. 

For more information, call Meg Victor of EPA’s Office of Atmospheric Programs 

at 202-343-9193 or email at victor.meg@epa.gov.
7 

State

Reducing Emissions of NOX

during the Ozone Season

(1997 Ozone NAAQS)

Reducing Annual Emissions of

SO2 and NOX (1997 Annual

PM2.5 NAAQS)

Reducing Annual Emissions of

SO2 and NOX (2006 24‐Hour

PM2.5 NAAQS)

Alabama X X X

Arkansas X

Florida X

Georgia X X X

Illinois X X X

Indiana X X X

Iowa X (proposed) X X

Kansas X (proposed) X

Kentucky X X X

Louisiana X

Maryland X X X

Michigan X (proposed) X X

Minnesota    X

Mississippi X

Missouri X (proposed) X X

Nebraska    X

New Jersey X X

New York X X X

North Carolina X X X

Ohio X X X

Oklahoma X (proposed)

Pennsylvania X X X

South Carolina X X

Tennessee X X X

Texas X X

Virginia X X

West Virginia X X X

Wisconsin X (proposed) X X

Number of States 20 (excludes proposed states) 18 21