Long-term exposure to air pollutants may be linked to an increased risk of premature death, according to a recent study. The study used data from 60 million Americans aged 65 and or more years, which is 97% of that population.

The air pollutants that are associated with premature death, according to the researchers, include airborne fine particulate matter and ozone. These pollutants still cause a risk when the exposure levels are below the national standard.

If the particulate matter level could be lowered 1 microgram per cubic meter across the country, then premature death numbers would decrease by 12,000 per year, they said. If the ozone level could be lowered one part per billion across the country, it would result in 1,900 less premature deaths in the country.

High-risk populations for premature death by air pollutant exposure include men, black people and those with low incomes. Black people had a mortality risk three times the national average for the general population.

“This is a study of unprecedented statistical power because of the massive size of the study population,” said Francesca Dominici, MPH, Ph.D., principal investigator of the study, professor of biostatistics at the Harvard T.H. Chan School of Public Health and co-director of the Harvard Data Science Initiative. “These findings suggest that lowering the [National Ambient Air Quality Standards] for fine particulate matter will produce important public health benefits, especially among self-identified racial minorities and people with low incomes.”

The standards she cited were established by the Environmental Protection Agency.

The study was published June 29 in the New England Journal of Medicine.

Another new study, in the August issue of Ecological Indicators, found that, on average, an increase in pollution particles in the air of 10 micrograms per cubic meter cuts people’ life expectancy by nine to 11 years, which is more than previously thought.