Air pollution exposure may cause heart attack within hour

Exposure to air pollutants – even at levels below World Health Organization (WHO) air quality guidelines – may trigger a heart attack within an hour, according to a new study from China.

The study found exposure to any level of four common air pollutants could quickly trigger the onset of acute coronary syndrome (ACS), where blood supply to the heart muscle is blocked, with the strongest risk within the first hour of exposure.

The researchers found the risks were highest among older people and when the weather was colder.

‘The adverse cardiovascular effects of air pollution have been well documented. But we were still surprised at the very prompt effects,’ said Haidong Kan, a professor in the School of Public Health at Fudan University in Shanghai, who led the study.

‘Another surprise was the non-threshold effects of air pollution,’ he said. ‘In other words, any concentrations of air pollutants (such as fine particulate matter, nitrogen dioxide, sulfur dioxide and carbon monoxide) recorded in the present study may have the potential to trigger the onset of a heart attack.’

high-angle photography of city buildings and green trees

The researchers analysed medical data for nearly 1.3 million people treated for heart attacks and unstable angina at over 2,000 hospitals in 318 Chinese cities between 2015 and 2020.

They compared hourly onset times of heart events with concentrations of fine particulate matter, coarse particulate matter, nitrogen dioxide, sulfur dioxide, carbon monoxide and ozone.

Short-term exposure to any level of fine particulate matter, nitrogen dioxide, sulfur dioxide and carbon monoxide was associated with the onset of all types of acute coronary syndrome.

As levels of the studied pollutants rose, so did the risk for heart attacks. Exposure to nitrogen dioxide was most strongly associated, followed by fine particulate matter, and was most dangerous during the first hour following exposure.

The link was strongest among adults age 65 and older with no history of smoking or other respiratory illnesses and for people exposed during the colder months.

‘The cardiovascular effects of air pollution should be a serious concern for all, including policymakers, clinicians and individuals,’ Kan said. ‘For policymakers, our findings underline the need of further tightening air quality standards, more stringent air pollution control and prompt public health response.’

Photo by Danijel Durkovic


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2 years ago

We need to get this information to far more people. It is atrocious that closely spaced homes are allowed to have fire pits in the back yards. It’s the equivalent (worse) of smoking on an airplane! Neighbors are captive to being smothered with toxins from smoke. I’ve written to Home Improvement Shows, they need to be held accountable. They very frequently put a fire pit outside of a remodeled home as if it’s a benefit! Even a gas one is better than wood. But the reality is, we don’t need to sit in front of flames…ever. The biggest excuse I hear is “childhood memories”. How stupid!

2 years ago

This is scary. We really do need to tighten up on air quality. I always find the air at airports is very stuffy. It makes me feel poorly if I have to wait long. It’s the hot greasy cooking smells, aviation fuel fumes, passengers’ scented clothes, perfumed Duty Free, chemical cleaning products wafting out of the toilets, diesel from airport vehicles on the tarmac. All that and hardly any ventilation because the doors keep closing and whatever air is brought in is also polluted.It’s the same at some of the larger railway stations, particulary where there are diesel engines running. Fragranced shopping malls aren’t very pleasant either. I woulnd’t be at all surprised if some customers are at risk of heart attacks in this way. The thing about airports is that once you are in the departure lounge, or shopping zone, you can’t come out again for a breath of fresh air, if there is any.Maybe there are air filtering systems now in some airports?

Jewel Crawford, MD
Jewel Crawford, MD
2 years ago

This connection, between air pollution and mortality from cardiovascular events, was established years ago in 1993, by the Harvard Six Cities Study. The medical community seemed to pay very little attention to it. Environmental medicine, has never been taken seriously by academic medicine, despite the well documented global burden of disease related to environmental exposure. Maybe this new report, in the era of climate change, will elicit a more pro active response.

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