By YUSUKE OGAWA/ Staff Writer
May 17, 2020 at 08:00 JST
Significantly high PM2.5 concentrations were reported over Fukuoka in March 2015. (Asahi Shimbun file photo)
Going out on days when PM2.5 air pollutants are up raises the risk of cardiac arrest for people, including those with chronic cardiac disease, research by scientists shows.
The average daily level of PM2.5, or fine particulate matter in the air with a diameter of 2.5 micrometers or less, was 13.9 micrograms per cubic meter, lower than Japan's safety standard, between April 2011 and December 2016, when the scientists collected data for their study.
They found the number of people who had cardiac arrests out of hospitals rose by 1.6 percent on the days that had a 10-microgram rise in the airborne PM2.5 level from a day earlier.
The effect was stronger on men than women with reports of 2.1 percent more cardiac arrests on the days of rising PM2.5 levels.
People aged 75 or higher experienced 2 percent more cardiac arrests on those days.
“Individuals with cardiac disorders should refrain from venturing out on days with higher PM2.5 levels,” said Sunao Kojima, a cardiovascular professor at Kawasaki Medical School, which carried out the study with researchers from other organizations such as the National Institute for Environmental Studies.
PM2.5 is said to be generated from automobile exhaust fumes and smoke from factories. The substances are reported to exacerbate asthma and cardiac diseases by invading deep areas of the lungs.
From among cardiac arrest cases that resulted from acute myocardial infarction and other causes outside hospitals in Japan between April 2011 and December 2016, the researchers chose and analyzed 103,000 cases in which the exact times of the cardiac arrests were known because bystanders witnessed the incidences.
The scientists also examined changes over time in PM2.5 concentration measured by prefectural governments and other parties to analyze how the atmospheric particles are connected to cardiac problems.
The team’s findings were published on April 18 in the international medical journal JAMA Network Open. Readers can view them at (https://jamanetwork.com/journals/jamanetworkopen/fullarticle/2764652).
Data on Japan's PM2.5 concentration is also available on the Environment Ministry’s website at (http://soramame.taiki.go.jp/).
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