Even air pollution at levels within federal standards damages the heart, said the researchers from medical schools at New York University, Mt. Sinai and the University of Michigan.
The researchers said they also have first-of-its-kind information on how pollution damages the blood vessels.
"We established a causal link between air pollution and atherosclerosis," says Lung Chi Chen, associate professor of environmental medicine at NYU School of Medicine and a lead author of the study.
Atherosclerosis -- a hardening, narrowing and clogging of the arteries --is a key component of cardiovascular disease, the scientists said.
In the mouse study, the lab animals breathed air at the same level of pollution as that of New York City. The researchers pinpointed specific mechanisms and showed that air pollution can be particularly damaging when coupled with a high-fat diet, according to the study published in the Dec. 21 issue of JAMA.
The research focused on the effects of airborne particles measuring less than 2.5 microns, referred to as PM2.5, which is the size linked most strongly with cardiovascular disease.
The particles come mostly from power plants and vehicle exhaust.
The Environmental Protection Agency says people's average PM2.5 exposure should be no more than 15 micrograms per cubic meter. The air particles are blamed for about 60,000 premature deaths every year in the United States, the researchers noted.