Air pollution impacts can be heart-stopping, warns new Lancet Study

Japan: There is an increased risk of out-of-hospital cardiac arrest (OHCA) even from short-term exposure to low concentrations of fine particulate matter PM2.5, an Australian-led study has found, noting an association with gaseous pollutants such as those from coal-burning/mining, bushfires, and motor vehicles.

The nationwide study in Japan, chosen for its superior monitoring, population density, and relative air quality, is believed to be by far the largest of its kind. It provides comprehensive evidence of the relationship between PM2.5 and cardiac arrests, using a sample three times larger than all previous research combined and demonstrating the impacts on groups such as the elderly.

The study concludes that worldwide, standards should be tightened; the implications of the research, led by the University of Sydney, are also that we need to transition to cleaner energy sources.

The findings published in the high-impact journal The Lancet Planetary Health.

The corresponding author, from the University of Sydney School of Medicine, Professor Kazuaki Negishi, said previous research into air pollution and acute cardiac events had been inconsistent, especially at air concentrations that met or bettered the World Health Organization (WHO) guidelines.

Inconsistencies in previous data were addressed through the size and robustness of this study, which found that more than 90 percent of OHCAs occurred at PM2.5 levels lower than the WHO guideline (and Australian standard level), a daily average of 25 micrograms per cubic meter (µg/m3). As well, 98 percent of OHCAs happened at levels lower than the Japanese or American daily standard level of 35 µg/m3.

"Out-of-hospital cardiac arrest is a major medical emergency – with less than one in 10 people worldwide surviving these events – and there has been increasing evidence of an association with the more acute air pollution or fine particulate matter such as PM2.5," said Professor Negishi, who is Head of Medicine, Nepean Clinical School, at the University's Faculty of Medicine and Health, Charles Perkins Centre Nepean and a cardiologist at Nepean Hospital.

"We analysed almost a quarter of a million cases of out-of-hospital cardiac arrests and found a clear link with acute air pollution levels.

"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.

"Given the fact that there is a tendency towards worsening air pollution – from increasing numbers of cars as well as disasters such as bushfires – the impacts on cardiovascular events, in addition to respiratory diseases and lung cancer – must be taken into account in health care responses."

Professor Negishi, who previously conducted fieldwork after the 2014 massive Hazelwood coal mine fire in Victoria, said that where cardiovascular impacts were concerned, those generally at risk were the elderly: "If you're young and healthy, there should be no immediate risk of devastating consequence." However, he highlights these findings are only in relation to short-term exposure and that the effects can last for up to five years.

The paper concludes that there is an "urgent" need to improve air quality. "As no boundary exists in air quality among countries, a global approach to tackle this crucial health issue is necessary for our planet," the authors state. 

For more details click on the link: https://doi.org/10.1016/S2542-5196(19)30262-1