Checking the level of outdoor pollution before you leave the house could save your life.
When researchers in Boston tracked 772 heart attack patients, they found that the risk of an attack was around 40 per cent greater on days with the poorest air quality than on clear days. Exposure to high levels of pollutants from motor vehicle exhaust, power plants and other sources of small airborne particles posed the greatest risk.
Weather reports increasingly carry warnings of air pollution, and the worst times tend to be hot, hazy summer days. The study did not take into account whether patients had been sitting quietly indoors or exercising outdoors, which would increase their exposure. Nevertheless, those with heart disease or factors that increase the risk of a heart attack could benefit from not being outdoors for long periods of time on high pollution days (Circulation, 2001; 103: 2810-5).