New research in the New England Journal of Medicine reveals improved air quality in the United States has added months to people’s lives.

Between 1978 and 2001, the average lifespan in the U.S. increased to 77 years old, up 3 years from previous figures, experts attribute the jump to lower levels of harmful particulates.

Particulate matter in air pollution, like grit, dust, soot and chemicals from factories and cars, can lodge deep in people’s lungs and heighten risk of lung disease, heart attack and stroke.

Scientists examined government census data and death records from 51 U.S. cities and after adjusting for variables, such as smoking habits, income, education and migration, they determined from 1978 to 2001 particulate matter in the air fell from 21 micrograms per cubic meter of air to 14 micrograms per cubic meter in the studied cities and during this time Americans lived an average of 2.72 years longer; the Associated Press reports.

The Clean Air Act, passed in the 1970s, is credited for the improvements. The legislation gave the Environmental Protection Agency the power to establish and enforce national standards to protect people from particulates and other pollutants.

Now, states like California are doing their part to improve air quality. Starting this year, all new cars sold in the state will display labels ranking the vehicle’s smog emissions and impact on global warming.