Days with both extreme temperatures and high air pollution heighten the risk of fatal heart attacks, a new study showed.
The risk was found to be higher on days of heatwaves and poor air quality, it added. “The combination of soaring heat and smothering fine particulate pollution may double the risk of heart attack death,” the authors noted in the report published in the American Heart Association’s journal Circulation.
The researchers analysed 202,678 heart attack deaths from 2015-2020 that occurred in China’s Jiangsu province. The region was chosen for its wide range of temperatures and PM2.5 concentrations.
They compared the impact of extreme temperatures with and without high levels of fine particulate pollution, according to the report. Particulate levels were considered high on any day with an average level of fine particulate matter above 37.5 micrograms per cubic metre.“The deaths were among older adults with an average age of 77.6 years; 52 per cent were older than age 80; and 52 per cent were male,” the researchers observed. 
The risk of deaths from heat attacks was particularly higher in women and the elderly during days of heatwaves, cold snaps and high levels of fine particulate pollution, the report added.
The risk of fatal heart attacks was twice as high during 4-day heatwaves that had fine particulate pollution above 37.5 micrograms per cubic metre, the analysts found.
“Up to 2.8 per cent of heart attack deaths may be attributed to the combination of extreme temperatures and high levels of fine particulate pollution (> 37.5 micrograms per cubic metre), according to WHO targets,” the authors estimated.
Following weather forecasts, staying inside when temperatures are extreme, using fans and air conditioners during hot weather, dressing appropriately for the weather, proper hydration and installing window blinds to reduce indoor temperatures were some of the measures suggested by the authors to deal with the impact of extreme temperatures.
To reduce exposure to air pollution on days with high levels of fine particulate pollution, the experts advised using an air purifier in the house, wearing a mask outdoors, staying clear of busy highways when walking and choosing less-strenuous outdoor activities.
The researchers were unsure how the co-exposure was increasing the risk of heart attacks. They called for further research on the possible interactive effects of extreme weather events and fine particulate pollution on heart attack deaths in areas with different temperature and pollution ranges.