Skip to agency navigation
Skip to main content

Official Website

of the Commonwealth of Pennsylvania

    The .gov means its official.

    Local, state, and federal government websites often end in .gov. Commonwealth of Pennsylvania government websites and email systems use "pennsylvania.gov" or "pa.gov" at the end of the address. Before sharing sensitive or personal information, make sure you're on an official state website. 
    Pollutant Topics

    Interstate Transport of Pollution

    Ground-level ozone and fine particulate air pollution is a serious and persistent national public health threat. These pollutants and their pre-cursors drift into Pennsylvania from areas to the west and south of the Commonwealth. Therefore, air crossing Pennsylvania's borders is often already unhealthy - above federal health-based standards. The following information describes how Pennsylvania has been addressing this issue recently, but a short history (PDF) is also available.

    Animated Maps

    See how ozone pollution was transported from areas outside of Pennsylvania by viewing EPA's AirNow animated maps.

    Interstate Trading Programs

    Comments to Federal Proposals

    DEP Comments on Revisions to the US EPA's proposed "Revisions to Federal Implementation Plans to Reduce Interstate Transport of Fine Particulate Matter and Ozone"

    Recent Proposals - CSAPR/CAIR

    2018 NOx Emissions CAP was not Exceeded

    The Statewide cap for 2018 was not exceeded. Therefore, non-EGUs do not need to purchase allowances to meet their 2018 Ozone Season NOx emission limitations established under 25 Pa.Code § 145.8(d). The NOx emissions for the 2018 Ozone Season (May through September) reported to the United States Environmental Protection Agency by the owners and operators of the affected non-EGUs are 815 tons. The Department's permanent retirement of 3,438 allowances under 25 Pa.Code § 145.8(b) covers all the NOx emissions from the affected non-EGUs in 2018.

    On Saturday, April 21, 2018, the Department finalized the Interstate Pollution Transport Reduction: 2018 Ozone Season Nitrogen Oxide Emission Limits for Nonelectric Generating Units. The notice was published in the PA Bulletin:

    Alternative Compliance Option - Transport Rule Allowance Retirement Option for Excess Nitrous Oxides (NOx) Emissions

    For each ozone season beginning after Jan. 1, 2015, the Department intends to accept the surrender of annual and ozone season Transport Rule (TR) NOx allowances as a compliance alternative to the surrender of annual and ozone season CAIR NOx allowances if the TR allowances are surrendered for compliance purposes in a manner consistent with the surrender provisions for CAIR allowances set forth in the applicable sections specified in the notice.

    Interstate Pollution Transport Reduction; Final 2015 Ozone Season Nitrogen Oxide Emission Limits for Nonelectric Generating Units

    The Department of Environmental Protection is providing notice of finalization of the Nonelectric Generating Unit 2015 Ozone Season Nitrogen Oxide (NOx) emission limitations established in accordance with 25 Pa.?Code § 145.8(d) (relating to transition to CAIR NOx trading programs).

    Clean Air Interstate Rule; Final 2018 New Unit Annual and Ozone Season CAIR Nitrogen Oxides Allowance Allocations.

    In accordance with 25 Pa. Code Sections 145.211(d)(3) and 145.221(d)(3) (relating to timing requirements for CAIR NOx allowance allocations; and timing requirements for CAIR NOx Ozone Season allowance allocations), the Department of Environmental Protection is providing notice of the finalization on the 2018 annual and ozone season Clean Air Interstate Rule nitrogen oxides allowance allocations for new units.

    Clean Air Interstate Rule; Proposed 2018 Annual and Ozone Season CAIR Nitrogen Oxides Allowance Allocations; Proposed Extension of CAIR Nitrogen Oxides Set Aside Program for Offsetting Sulfur Dioxide Emissions; Proposed Redistribution of 2012 Allowances for Certain Facilities

    In accordance with 25 Pa.?Code §§ 145.211(d) and 145.221(d) (relating to timing requirements for CAIR NOx allowance allocations; and timing requirements for CAIR NOx Ozone Season allowance allocations), the Department of Environmental Protection on May 24, 2014, is providing notice and an opportunity to comment on the proposed 2018 annual and ozone season Clean Air Interstate Rule (CAIR) nitrogen oxides (NOx) allowance allocations. The 30 day public comment period ended on June 23, 2014.

    Final 2017 Annual and Ozone Season CAIR Nitrogen Oxides Allowance Allocations; Final 2017 New Unit Allowance Allocations; Final Redistribution of 2011 Allowances for Certain Facilities; and Extension of CAIR Nitrogen Oxides Set Aside Program for Offsetting Sulfur Dioxide Emissions

    On Saturday, May 11, 2013 and Saturday May 25, 2013, Notice was given in the Pennsylvania Bulletin that the Pennsylvania Department of Environmental Protection (Department) is providing notice of the finalization of the referenced allocations and extension. On December 10, 2009, the U.S. Environmental Protection Agency (EPA) adopted a final rule approving the Pennsylvania CAIR State Implementation Plan (SIP) revision (74 FR 65446, Dec. 10, 2009). Therefore, these allocations replace those under the EPA's Federal Implementation Plan. Questions concerning this notice should be directed to Mr. Randy Bordner, Chief, Stationary Source Section, Bureau of Air Quality at (717)772-3921 or to ranbordner@pa.gov.

    Previous Proposals (CAIR)

    Final distribution of Clean Air Interstate Rule; 2014 Allocation of 2013 Vintage Nitrogen Oxides Allowances Set Aside to Offset Sulfur Dioxide Emissions

    The department has evaluated the requests for annual CAIR NOx allowances for 2013 Sulfur Dioxide emissions from waste coal cogeneration owners in accordance with 25 PA Code Section 145.212 (f) (5). On March 22, 2013, the department published the notice in the Pennsylvania Bulletin. On Wednesday, March 26, 2013, EPA confirmed that the transfers into the facility accounts were completed.

    Final 2016 Annual and Ozone Season CAIR Nitrogen Oxides Allowance Allocations, Final 2016 New Unit Allowance Allocation, Final Redistribution of 2011-2015 Allowances for Certain Facilities, and Extension of CAIR NOx Set-Aside Program for Offsetting Sulfur Dioxide Emissions

    Final 2015 Annual and Ozone Season CAIR Nitrogen Oxides (NOx) Allowance Allocations and Redistribution of 2010-2014 Allowances for Certain Facilities

    Final 2014 Annual and Ozone Season CAIR Nitrogen Oxides (NOx) Allowance Allocations (PDF)

    Final 2010-2013 Annual and Ozone Season CAIR Nitrogen Oxides (Nox) Allowance Allocations (PDF)

    Section 110 Information

    EPA issued final regulations under Section 110 of the Clean Air Act to require 22 eastern states with ozone problems to substantially reduce NOx emissions that are the primary cause of transported ozone. This is known as the Section 110 NOx SIP Call (State Implementation Plan). In other words, affected states were to develop a plan to reduce total summertime emissions of nitrogen oxides by 28 percent beginning in the year 2003.

    NOx Budget Program, Chapter 145

    Subchapter A

    Pennsylvania's NOx reduction program was adopted in 1994, and the second phase of the program, including emissions trading, was implemented in 1999. Resulting emissions of NOx from affected sources in 1999 were reduced 60 percent from 1990 levels. Pennsylvania's Chapter 145 regulations, the answer to EPA's Section 110 NOx SIP Call, will improve on the market-based trading program starting in 2003.

    Subchapter B, C

    Phase II of the NOx SIP Call requires states to control emissions from cement kilns and large internal combustion engines by May 1, 2005. Pennsylvania adopted regulations to meet these requirements contained under Subchapter B and C to Chapter 145 on December 11, 2004.

    Ozone Transport Commission

    The 1990 Clean Air Act Amendments established the Ozone Transport Commission (OTC) to coordinate the development of control plans for ground-level ozone in the Northeast and Mid-Atlantic Region.

    The OTC developed a NOx Memorandum of Understanding that Pennsylvania signed, leading to regulations that reduced NOx emissions by 55 to 65 percent from 1990 levels. This program was replaced in 2003 by the NOx Budget Program contained in Chapter 145.

    Other Transport Information

    Section 126 Information

    The OTAG process demonstrated that states to Pennsylvania's west and south contribute significantly to violations of the ozone standard in the Commonwealth and throughout the northeast. Under Section 126 of the Clean Air Act, Pennsylvania petitioned the Environmental Protection Agency (EPA) to establish emission limitations on groups of sources necessary to achieve and maintain the ozone standard in Pennsylvania.

    • Northeast Governors Request EPA to Move Ahead With NOx Rules (8/17/01)
    • Findings of Significant Contribution and Rulemaking on Section 126 Petitions for Purposes of Reducing Interstate Ozone Transport; Final Rule (PDF) (1/18/00)
    • Pennsylvania's Action to Require (PDF) Other States to Do Their Share to Control Air Pollution.(9/97)
    • Pennsylvania's Section 126 Petition to EPA. (8/97)