The U.S. Environmental Protection Agency proposed Friday new protections against carbon pollution, a leading contributor to climate change. The standard will lower carbon emissions from new power plants fired by fossil fuels.

“Climate change is one of the most significant public health challenges of our time,” EPA Administrator Gina McCarthy said in announcing the proposal. “By taking common-sense action to limit carbon pollution from new power plants, we can slow the effects of climate change and fulfill our obligation to ensure a safe and healthy environment for our children.”

The announcement fulfills a major part of President Barack Obama’s Climate Action Plan announced this summer, which outlines steps to both lessen and prepare for climate change. Power plants are the nation’s largest source of carbon pollution, accounting for roughly one-third of U.S. carbon emissions.

APHA and other public health groups announced strong support for the proposal.

“EPA’s common-sense standard will limit harmful carbon pollution and strengthen our public health protections for current and future generations,” APHA Executive Director Georges Benjamin said in a statement. “Our most vulnerable communities, including children, older adults, those with serious health conditions and low-income families, are at particular risk.”

Rising temperatures, more extreme weather events and increased levels of unhealthy air associated with climate change threaten the health of all Americans from the risk of illness and death due to respiratory ailments, heat-related stress and insect-borne diseases.

“Addressing carbon pollution will help protect public health. Higher temperatures can enhance the conditions for ozone formation,” said Harold Wimmer, president of the American Lung Association. “More smog means more childhood asthma attacks and complications for others with lung disease.”

EPA is seeking public comment on the proposal.