The state Department of Energy and Environmental Protection announced Monday that it has filed two petitions with the U.S. Environmental Protection Agency seeking actions that will improve the state’s air quality and public health.

In these petitions, DEEP asks EPA to:

• require the Brunner Island Steam Electric Station in York County, Pa., to reduce air pollution generated from its three coal-fired electric generating units, and

• set stricter limits on emissions from large on-road diesel trucks that travel through Connecticut.

“Connecticut has the highest ozone levels in the northeast — which adversely impacts the health of our citizens and the quality of life in our state,” DEEP Commissioner Robert Klee said in a news release. “Air pollution transported into Connecticut from upwind sources and emissions from diesel-powered trucks are beyond our jurisdiction and these petitions are part of our ongoing effort to have EPA address these sources.”

In the DEEP petition to EPA, DEEP asks for an abatement emissions from the three coal-fired units in York County, Pa., because they alone significantly contributes to ozone levels that exceed the 2008 ozone National Ambient Air Quality Standard in Connecticut, DEEP said.

Granting the petition would require Brunner Island to reduce nitrogen oxide emissions, a precursor pollutant of ozone, such that the plant no longer emits at an amount that contributes to exceeding ozone levels in Connecticut. The petition asks that meaningful reductions be achieved in no more than three years.

In the other petition, Connecticut joined with nine other state and local environmental agencies from across the nation asking EPA to set stricter air pollution engine limits for large on-road diesel trucks traveling through the state. The petition, led by the South Coast Air Quality Management District in California, seeks a reduction in emissions of nitrogen oxides from heavy-duty highway truck engines that are 90 percent greater than current requirements, DEEP said.

Nitrogen oxides are important contributors to the formation of ground-level ozone (smog) that adversely affects the health of Connecticut’s citizens, DEEP said. Because trucks often operate across multiple state borders and are typically registered outside of Connecticut, the state has limited authority to control their pollution. Under federal law, only California and EPA can set engine standards, and only EPA can adopt standards that apply nationally.

Heavy-duty highway trucks are one of the largest source groups contributing to poor air quality in Connecticut, and account for about 12.5 percent of statewide emissions of nitrogen oxides, according to a recent state air pollutant emissions inventory, DEEP said. Furthermore, emissions from on-road heavy duty trucks operating in upwind regions outside of Connecticut impair Connecticut’s air quality through the long-range transport of their air pollution into the state.

A 90 percent reduction in diesel engine emissions is achievable through current technology, and is highly cost-effective at about $500 to $1,000 per engine control system, DEEP said. This is a small cost relative to the price of a truck. A new 18-wheeler truck cab can sell for $130,000 to $260,000, with the trailer costing an additional $30,000 to $80,000.

The nine other agencies that have signed on to the petition include:

• Akron (Ohio) Regional Air Quality Management District

• Bay Area Air Quality Management District

• Delaware Department of Natural Resources and Environmental Control, Division of Air Quality

• New Hampshire Department of Environmental Services

• New York City Department of Environmental Protection

• Pima County (Arizona) Department of Environmental Quality

• Puget Sound (Washington) Clean Air Agency

• Washington State Department of Ecology

• Washoe County Health District, Air Quality Management.