Ozone Air Pollution - A Recap of 2017

This purpose of this status report is to summarize the continuing progress that Maryland is making on ground-level ozone and to issue the first annual report card on how effectively air pollution controls are operated at coal-fired power plants in upwind states.

Ozone air pollution, sometimes called smog, has been Maryland's most difficult and pervasive air pollution problem. Compelling upwind power plants to run their air pollution controls effectively is the most important emission reduction strategy for reducing ozone levels in Maryland. Approximately 70% of Maryland's ozone problem originates in states upwind of Maryland.

Maryland has made dramatic progress cleaning up air pollution over the past ten years. Fine particle pollution is below the federal health-based standards statewide and continues to get cleaner each year. Maryland is also in compliance with the health-based standards for carbon monoxide, nitrogen dioxide and lead.

 Click the Clean Air Progress button below to view clean air trends.
Access denied. You do not have permission to perform this action or access this resource.

A detailed summary of the 2017 ozone season is available 

Maryland is still working on attaining compliance for two air pollutants: sulfur dioxide (SO2) and ozone. Maryland's first plan for SO2 is due in 2018. Ozone levels have dropped dramatically since 1990, and Maryland is closer to being in "attainment" than ever. Most of the State is very close to meeting the 2015 ozone standard (70 parts per billion) but there is still more work to do. The following slides illustrate improvements in ozone levels.

Maryland's Shrinking Ozone Problem


2017 was also a good year for emissions reduction programs. Maryland initiated the adoption process for six regulations. These regulations will aid in the progress toward ozone attainment. All of these regulations are expected to be effective in 2018.

2017 Maryland Air Quality Regulatory Actions

Regulation Status
Amendment to Vehicle Emissions Inspection Program Effective January 1, 2018
Amendments to Distributed Generation Effective February 12, 2018
Small Wood Boiler Amendments Effective February 12, 2018
Interprecursor Trading Effective April 9, 2018
NOx Ozone Season Emission Caps for Non-trading Large NOx Units Effective April 23, 2018
NOx RACT for Municipal Waste Combustors Effective September 1, 2018

Other key emission reduction efforts also began in 2017. Federal rules for low-sulfur fuels became effective in 2017. These cleaner fuels will be fully phased in by around 2020 and will help significantly. Federal rules for power plants in upwind states that contribute to Maryland's ozone problem were also improved in 2017. This improvement is clearly very helpful, but Maryland's 2015 power plant regulations, that require air pollution controls to be run optimally every day of the summer ozone season, are still more stringent than federal rules. Maryland is pushing hard to "level the playing field" in this area.

If power plants in states across the eastern U.S. simply ran their existing air pollution controls optimally, approximately 46,000 tons of nitrogen oxide (NOx) emissions reductions could have been achieved throughout the 2017 summer ozone season. NOx reductions are the key to continued progress on ozone. Running controls can reduce NOx up to 400 tons on a high ozone day, which is a huge emission reduction.

Maryland has initiated legal actions under two sections of the Clean Air Act to compel power plants in states upwind of Maryland to reduce NOx emissions. Maryland has filed a petition under Section 126 of the Clean Air Act to compel reductions at 36 power plant units in five upwind states. Maryland is also part of a nine-state petition under Section 176 of the Clean Air Act which would help level the playing field by adding nine new states to the Ozone Transport Commission. Both of these legal petitions are expected to be resolved in 2018.

Maryland has also done extensive analysis of power plant NOx emission data and, with this report, is issuing an annual report card for eastern power plants based upon how well they are using their existing control technology. For a detailed summary of the first annual power plant report card, click here. ​​​​​

Human Trafficking GET HELP

National Human Trafficking Hotline - 24/7 Confidential

1-888-373-7888 233733 More Information on human trafficking in Maryland

Customer Service Promise

The State of Maryland pledges to provide constituents, businesses, customers, and stakeholders with friendly and courteous, timely and responsive, accurate and consistent, accessible and convenient, and truthful and transparent services.

Take Our Survey

Help Stop Fraud in State Government

The Maryland General Assembly’s Office of Legislative Audits operates a toll-free fraud hotline to receive allegations of fraud and/or abuse of State government resources. Previous reports have led to elimination of fraud.

More Information