Air pollution increases heart risk

High-pollution days may trigger heart attacks in some people, elderly and people with existing heart or lung disease are most vulnerable.

It is recommended that people with heart disease and others at risk - including the elderly and people with diabetes or high blood pressure - stay clear of congested roadways and spend less time outside on days when air quality is poor.
The evidence of harm is strongest against pollutants known as fine particulate matter. Fine particulate matter is released into the air when wood or fossil fuels are burned, so car exhaust, home heating and industrial sources like power plants all contribute. The particles are small enough that they can be inhaled deeply into the lungs. The researchers suspected they may trigger heart attacks in vulnerable people by causing inflammation in the blood vessels and irritating the nerves of the lungs.



For this study, researchers looked at data on 11,450 hospitalisations for heart attack between 2002 and 2005. They used local air-quality monitors to see how those hospitalisations correlated with changes in air pollution levels.

Overall, it was found that for each fine-particle increase of 10 micrograms per cubic metre of air, heart attack hospitalizations inched up 0.01 percent over the next two days. There was a similar pattern when the researchers looked at two other traffic pollutants: carbon monoxide and nitrogen dioxide.

The association between pollution spikes and heart attack was strongest among the elderly (people aged 75 years or older), those with the lung diseases (like emphysema or chronic bronchitis), and those with high blood pressure.

The findings alone do not prove that air pollution, itself, triggers heart attacks, but they do add to other studies that have found a similar link.

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