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Maryland Department of the Environment

Multi-state panel approves Maryland petition seeking to reduce air pollution from upwind sources


Ozone Transport Commission vote advances Maryland’s call for Pennsylvania power plants to run equipment to limit emissions that lead to harmful ozone pollution; recommendation now goes to U.S. EPA under Clean Air Act Section 184(c)

BALTIMORE (June 3, 2020) – A multi-state commission formed to find regional solutions to air pollution problems has approved a recommendation that power plants in Pennsylvania be required to reduce harmful emissions that are carried by the wind into Maryland.

Acting on a petition filed by the Maryland Department of the Environment, the Ozone Transport Commission (OTC) voted yesterday to approve a recommendation for additional air pollution control measures that will be submitted to the U.S. Environmental Protection Agency (EPA).

“We’re pleased with the outcome on Maryland’s petition and appreciate the continuing collaboration among OTC members,” said Maryland Environment Secretary Ben Grumbles. “The OTC vote is progress, and it shows states will continue to lead on regional partnerships and local solutions grounded in science and the Clean Air Act.”

Maryland’s air quality continues to improve. Emissions of air pollutants continue to decrease because of Maryland and federal regulations, improvements in technology and good operating practices from businesses, Maryland’s 2020 Clean Air Progress report states. These impacts are experienced within the state and extend throughout the northeastern states.

Nonetheless, ground-level ozone, or smog, remains one of Maryland’s most pervasive and challenging air pollution problems – and about 70 percent of Maryland’s ozone problem originates from emissions in upwind states. This ozone “transport” threatens the ability of downwind states, including Maryland, to meet federal, health-based standards for air quality.

The OTC, created under the federal Clean Air Act, is responsible for advising EPA on transport issues and for developing and implementing regional solutions to the ground-level ozone problem in the Northeast and Mid-Atlantic regions. Its membership is 12 states in New England, the Northeast and the Mid-Atlantic, and Washington, D.C.

In May 2019, the Maryland Department of the Environment (MDE) filed a petition under Section 184(c) of the Clean Air Act asking OTC to recommend to EPA that the federal agency require additional air pollution control measures in Pennsylvania. OTC members voted 9-2 in favor of that recommendation, with two members abstaining.

Ground level ozone is created when two types of air pollutants – nitrogen oxides (NOx) and volatile organic compounds (VOC) – react in the presence of sunlight and warm temperatures. The petition states that despite making significant progress in long-term NOx emissions from coal-fired power plants, Pennsylvania rules still allow excess emissions on a daily basis.

Reducing excess daily emissions is critical to meeting air quality standards – and is especially important on hot summer days when ozone is likely to form. Maryland addressed this problem by implementing regulations that require the state’s largest coal-fired power plants to optimize their air pollution controls to minimize NOx emissions during the summer ozone season.

Maryland has also been engaged in several legal actions designed to reduce air pollution from other states and to strengthen federal policies that are critical to support the state’s efforts. These include a lawsuit against EPA for its rejection of Maryland’s petition, under Section 126 of the Clean Air Act, asking the agency to require 36 power plant units in Pennsylvania and four other upwind states to run their air pollution controls to reduce emissions. The U.S. Court of Appeals for the District of Columbia Circuit issued a ruling in that suit last month.

“The OTC vote is a positive step forward, particularly as the recent decision on the section 126 petition was only a partial victory. Maryland is committed to clean air progress, working respectfully with all states, and fighting to uphold Clean Air Act requirements and good neighbor programs,” Secretary Grumbles said. “We will continue to track Pennsylvania’s efforts, offering assistance where we can, and pledging to work collaboratively with all of our partner jurisdictions to keep improving air quality for all.”


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