“There is strong evidence that particulate matter (PM) emitted mainly from diesel road vehicles is associated with increased risk of heart attack, heart failure and death,” said Nay Aung, from the Queen Mary University of London in the UK. The study examined whether PM2.5 may damage the heart directly. It included 4,255 participants.

Cardiac magnetic resonance imaging was conducted to measure left ventricular volume (structure) and left ventricular ejection fraction (function).

Annual average exposure to PM2.5 was calculated based on participants’ home address. Researchers adjusted for factors that could influence health such as age, gender, diabetes and blood pressure.

“We found that as PM2.5 exposure rises, the larger the heart gets and the worse it performs. Both of these measures are associated with increased morbidity and mortality from heart disease,” said Aung.

The researchers also looked for potential factors that could modify the relationship. They found that people with degree-level education were less prone to having a larger heart and had a smaller reduction in ejection fraction when exposed to PM2.5 than people with a lower level of education.

“This could be due to a number of factors including better housing and workplace conditions, which reduce pollution exposure,” said Aung.

“Educated people may also be more aware of their health, have healthier lifestyles, and have better access to healthcare,” he said.