Recent studies published in the Archives of Internal Medicine suggest that exposure to air pollution, no matter how minute, may have serious and debilitating implications on your cardiovascular and cognitive health.

In a study conducted at Brown University’s Center for Environmental Health and Technology in Providence, Rhode Island, Dr. Gregory A. Wellenius found that even at levels deemed acceptable by the United States Environmental Protection Agency, or the EPA, any exposure to air pollution may significantly increase one’s risk for an ischemic stroke, or a stroke that stems from atherosclerosis, the build-up of fat deposits on an artery to the brain.

Using data pooled from 1,705 patients in the Boston area confirmed by a neurologist to have an ischemic stroke, Dr. Wellenius and his team of researchers conducted a step by step comparison from the time that the patients’ symptoms first occurred against the fine particulate matter concentrations of under 2.5 µm diameter recorded at a Boston central monitoring station to gauge if there are indeed any relevant association between the two.

The team discovered that following a 24-hour period classified by the EPA’s Air Quality Index as a moderate fine particle pollution of 15 to 40 µg/m3 34% as compared to one classified as good, with 15 µg/m3, there was a 34% increased risk of ischemic stroke. They also found what is called a “dose-response relationship,” where there was an 11% increased risk of experiencing a stroke for every 6.4 µg/m3 increase in fine particulate matter concentration.

The risk, Dr. Wellenius and his team found, was greatest within 12 to 24 hours from exposure to fine particles traced to traffic-related pollution, leading them to conclude that exposures to fine particular matter that have been deemed safe by the EPA still increases the risk of ischemic stroke “within hours of exposure.”

Meanwhile, in the study conducted at the Rush University Medical Center’s Institute for Healthy Aging in Chicago, Illinois, Dr. Jennifer Weuve and her colleagues pooled results of cognitive tests conducted between 1995 to 2005 by the Nurses’ Health Study Cognitive Cohort, and participated in by approximately 19,500 women aged 70 to 81.

The assessments, conducted over the telephone, approximately thrice within a two-year interval, tested verbal memory, working memory, attention, and general cognition, so as to track the natural progression of cognitive decline brought on by aging.

Dr. Weuve and her team compared these test results against estimated exposure to particulate matter air pollution, both fine (under 2.5 µm) and coarse (2.5 to 10 µm) in the month before the cognitive tests were administered, as well as a longer period of 7 to 14 years prior.

Results of the tests significantly showed that increased levels of long-term exposure to both types of particular matters were not only linked to an increased cognitive decline, but also had a dose-response relationship, where an increase of 10 µg per cubic meter likewise increased aging by approximately 2 years.