During my service as Maine’s attorney general, I filed several lawsuits against the Environmental Protection Agency because of its failure to take action under the Clean Air Act to reduce emissions of climate-changing pollutants.

In 2003, Maine and 10 other states joined with Massachusetts to challenge the EPA’s ruling that it lacked legal authority under the Clean Air Act to regulate heat-trapping greenhouse gas emissions. We eventually won.

This month, Maine and the nation celebrate the fifth anniversary of that landmark decision.

The case, Massachusetts v. EPA, remains one of the most significant environmental decisions rendered by the U.S. Supreme Court. The court directed the EPA to decide whether carbon dioxide and other greenhouse gas emissions were pollutants under the Clean Air Act. The

decision ultimately forced the EPA to regulate those emissions. This occurred at a time when pressure from large corporate polluters prevented Congress from tackling carbon emissions.

Coincidentally, earlier this month, despite intense pressure from those same polluters — most from the coal industry — the EPA announced a new rule that would place the first nationwide limits on carbon pollution from new power plants. This is an essential step to protect the health of the American people as well as our nation’s environment and economy.

The new rule is not the only essential step, however. At some point soon, the EPA will need to take action to reduce carbon pollution from existing power plants as well. After all, existing plants represent the largest source of heat-trapping pollution in the United States.

Each and every year, power plants emit more than 2 billion tons of dangerous carbon and other pollutants into the air. The buildup of this pollution creates warmer temperatures. Warmer temperatures increase the risk of harmful smog levels. More smog means more chronic respiratory problems, asthma attacks and serious complications for people with lung disease.

Unquestionably, children face the highest risk. Each year, thousands of Maine children experience asthma attacks. Because infants and children generally breathe more rapidly than adults, they have a higher rate of exposure to pollutants in the air. Moreover, because children’s

immune systems and organs are not mature, they are more susceptible to the deleterious health effects of air pollution, including reduction in lung function and other permanent damage.

Other adverse health effects associated with climate change and warmer temperatures include an increase in waterborne diseases as well as animal-borne diseases such as Lyme disease and West Nile virus. Due to increasing temperatures and changes in rainfall patterns, mosquitoes, ticks and other disease carriers survive warmer winters and expand their range,

bringing health threats with them.

By issuing the rule with new power plant carbon emission standards, the EPA is simply doing its job under the Clean Air Act. Reducing harmful emissions and holding polluters accountable is what Americans want and need the agency to do.

Together with new clean car standards that will cut pollution from new vehicles nearly in half by 2025 (while helping rebuild the American auto industry and reducing gasoline costs), the new power plant standards will make significant reductions in harmful carbon pollution that threatens public health and causes climate change.

When Sen. Ed Muskie led the creation of the Clean Air Act more than four decades ago, he did not believe that government should compromise either on setting standards for environmental protection or on its responsibility to achieve those standards. That’s why he created a law that set deadlines, required the use of best available technology and established health-related air quality levels.

Through this monumental accomplishment, Sen. Muskie defined the environment as a core value for the nation. He believed that the air we breathe should be clean enough to protect the health of the most sensitive among us. He also believed that no person or entity had a “right” to pollute.

It’s good to know the EPA is on the job taking action consistent with the fundamental values expressed by Sen. Muskie in the Clean Air Act. Because of that action, the health of people in Maine and throughout our nation will be better protected.

Steve Rowe served as Maine’s attorney general from 2001 to 2009.