As delegates return from the Cop26 in Glasgow, the 2021 virtual conference of the American Heart Association will start. At the conference, scientists will present preliminary evidence that reduced air pollution due to Covid lockdowns resulted in a lower incidence of heart attacks.

Provided by the shelter in place orders in March 2020, the researchers took advantage of the natural experiment to investigate the effects of reduced airborne concentrations of PM2.5. This term refers to a particulate matter under 2.5 micrometers in diameter. These muscles particles can penetrate deep into the lungs and cardiovascular system. They are released through the burning of fossil fuels in motor vehicles, factories, and power plants.


One of the risks factors for the most severe form of heart attack ST-elevation myocardial infarction (STEMI) is high airborne levels of PN2.5. In this, there is a total blockage of the coronary artery that disturbs the blood supply to the heart muscles, and this causes can cause extensive damage to the tissue. If the PM2.5 could be reduced then the incidence of these severe heart attacks will also reduce. 

The National Emergency Medical Information System database was used by the scientist at the University of California, San Francisco, to determine the daily incidence of STEMIs between January 1, 2019, and April 30, 2020. From the Environment Protection Agency website, they gleaned average daily PM2.5 concentrations across the U.S. There were 60722 STEMIs during this period. As per the scientists, 6% fewer of these severe heart attacks were seen for every ten micrograms per cubic meter reduction in the concentration of PM2.5. For every 10000 person-years, this is equivalent to 374 fewer heart attacks.

Sidney Aung a 4th-year medical student at UCSF led the research. According to Sidney, “This study highlights the importance of reducing air pollution, which could, in turn, prevent heart attacks. We also hope our study may influence other investigators to pursue similar research to corroborate these results or to investigate other forms of air pollutants outside of [PM2.5] that may have also declined during the pandemic lockdowns.”

Other factors may have also contributed to the reduced incidence of heart attacks during the lockdown. But the previous researchers have emphasized that lower exposure to outdoor air pollution plays a significant role. There is a possibility that other factors related to shelter in place orders and Covid, such as staying indoors and reducing stress, may have contributed to the reduction in a heart attack, in addition to a decrease in PM2.5. But the Sidney and the team believe the decrease in the PM2.5 is the main reason.

The acute effects of air pollution tend to affect older people and people with heart disease. Short-term exposure to air pollution increases the risk of heart attacks along with heart failure, arrhythmias, and stroke. In the atmosphere, high concentrations of delicate particulate matter also increase the rate of hospitalization for dementia and Parkinson’s disease. Long-term exposure can cause the development and progression of atherosclerosis, narrowing of the arteries, high blood pressure, heart failure, and diabetes. In the year 2016, a study suggests that concentrations of PM2.5 and nitrogen oxides in the air lead to the hardening of arteries among people living in metropolitan areas.







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