Reducing air pollution to help prevent chronic diseases will grow more challenging and have a big impact unless aggressive, collaborative action is taken, said public health leaders who met this week.

Nearly 150 million people, roughly half the U.S. population, live in areas with unhealthy air pollution levels. Air pollution is linked to serious health issues like asthma, lung cancer, heart attacks and strokes.

Additional work is needed to cleanup major air pollution sources despite improvements through the Clean Air Act on vehicles and power plants, according to Gina McCarthy, U.S. Environmental Protection Agency administrator, Dr. Howard Koh, M.D., MPH, U.S. Department of Health and Human Services assistant secretary for health, the American Lung Association and other health organizations.

Still needed are reductions in carbon pollution from power plants, and preparations for climate change, which exposes Americans to conditions and extreme weather events that result in premature illness and death, the federal agencies stressed during the web-based event on Wednesday.

Pollution has inflammatory effects on the heart, causing chronic cardiovascular problems, according to the American Heart Association, which was a town hall sponsor.

Short-term exposure can increase the risk of heart attack, stroke, arrhythmias and heart failure in susceptible people. The risk of death is greater from long-term exposure. Air pollution may also play a role in high blood pressure, heart failure and diabetes, the association previously has said.

McCarthy said the EPA is committed to improving air quality through the Clean Air Act to prevent illnesses like lung disease and asthma, especially in underserved communities and for children. Air pollution can have a big impact on children because their lungs are still developing, and on vulnerable populations with asthma, heart disease and chronic obstructive pulmonary disease.