There is a 1%-4% increased risk of cardiac arrest associated with every 10 µg/m3 increase in PM2.5, the fine particulate matter linked to a slew of respiratory diseases and cardiac ailments, according to report in the latest edition of Lancet Planetary Health . The study analysed a quarter of a million patients and was among the largest of its kind. It sought to proffer evidence that even low levels of particulate matter pollution are dangerous.
“Our study supports recent evidence that there is no safe level of air pollution — finding an increased risk of cardiac arrest despite air quality generally meeting the standards,” Professor Kazuaki Negishi, co-author and Professor, University of Sydney School of Medicine, said in a statement.
The study was conducted in Japan and correlated cardiac arrests and PM2.5, carbon monoxide, nitrogen dioxide and sulphur dioxide exposure. The researchers also studied pollution levels a day before and up to three days after a reported attack.
The records analysed were from Jan 1, 2014, to Dec 31, 2015. The scientists chose Japan because it had consistent and detailed measurements of cardiac events as well as pollutant records. A key objective of the study, the authors said, was to investigate a link between cardiac events and exposure to pollution levels that were within, or below, World Health Organisation (WHO) standards.
“More than 90% of (cardiac events) in our study occurred with PM2·5 levels lower than the WHO guideline and Australian standard daily average concentration of 25 μg/m3, while 98.5% of them happened at levels lower than the Japanese or American daily standard level of 35 μg/m3,” the authors note.
Older people were overwhelmingly more likely to be susceptible. The mean age of those with cardiac events was 74 years and 57% were male. “Given the growing body of evidence in areas with poor air quality or even where the target standard has been achieved, current air quality standards need to be reassessed with consideration for efficient strategies to reduce air pollutants to as low a level as possible,” the study added.
The State of Global Air 2019, published by the Health Effects Institute (HEI), said exposure to outdoor and indoor air pollution contributed to over 1.2 million deaths in India in 2017. In India, air pollution is the third-highest cause of death among all health risks, ranking just above smoking.
Each year, more people globally die from air pollution related disease than from road traffic injuries or malaria.