Those with asthma or other respiratory conditions are often advised to limit time outdoors on days with poor air quality, so the public has come to associate pollution with breathing difficulties. Now a team of researchers from the University of Edinburgh has identified a link between diesel particulates and heart attacks.
The issue is ultrafine particles released by the combustion of diesel fuel in older diesel cars and trucks. Starting in 2009 for cars, and 2010 for heavy trucks, stricter emissions standards required more aggressive exhaust aftertreatment to reduce emissions of these particulates.
These ultrafine particles are invisible to the naked eye, measuring less than a millionth of a meter in size, but they produce highly reactive free radicals that damage blood vessels and increase the potential for blood clot formation.
Long-term exposure can lead to heart attacks or strokes, and this effect is amplified in patients with existing heart conditions or vascular disease.
While scientists can agree that the ultrafine particulates are hazardous to human health, they don’t yet know the specific compounds that cause free radicals to form. Studies are underway to identify the chemicals carried by the particulates, so that they can potentially be removed from diesel fuel in the future.
In the mean time, the Edinburgh researchers have this piece of common-sense advice: if you already suffer from heart disease, try to limit your time outdoors in high pollution areas.