Even small changes in outdoor air pollution levels can have a significant impact on heart health, according to a study in The Lancet Planetary Health, which examined data from 157,436 people ages 35 to 70 in 21 countries.
The researchers focused on the participants’ exposure to fine particle air pollution (called PM2.5, for particulate matter that is 2.5 microns or smaller), which, when inhaled, can penetrate deep into the lungs and cause local injury and inflammation. For every 10 microgram-per-cubic-meter (μg/m3) increase in the average PM2.5 level, the risk of a cardiovascular event (heart attack, stroke, or death from cardiovascular disease) over an average of nine years rose by 5 percent. The relationship was especially pronounced for strokes.
The findings were consistent even in low-income countries with high levels of air pollution (defined as 35 μg/m3 or higher), which account for 80 percent of cardiovascular disease cases worldwide—suggesting that even minor reductions in outdoor pollution in these countries could save many lives.
Detected levels of PM2.5 varied widely among the places studied, from a low of 6 μg/m3 in Vancouver to a high of 140 μg/m3 in Jaipur, India.
