Air pollution from wildfires may increase risk of cardiac arrests, and other sudden acute heart problems, researchers have found.
Lead author, Dr Anjali Haikerwal, Department of Epidemiology and Preventive Medicine at Monash University, said while breathing wildfire smoke was linked to respiratory problems such as asthma - evidence of an association between wildfire smoke exposure and heart problems has been inconsistent.
In the new study, published in the Journal of the American Heart Association, researchers examined the association between exposure to tiny particulate pollutants found in wildfire smoke and the risk of heart-related incidents in the state of Victoria between December 2006 and January 2007. During these two months, smoke reached cities far from the blazes and on most days the levels of fine particulate air pollutant exceeded recommended air quality limits.
The particles studied by researchers were smaller than 2.5 thousandths of a millimetre in diameter, which is significantly smaller than a speck of dust or 1/30th diameter of a human hair, and typically not visible to the human eye.
Using data from the Victorian Ambulance Cardiac Arrest Registry from Ambulance Victoria and data from the Department of Health and Human Services, researchers found that for an increase from the 25th to 75th percentile in particulate concentration over two days, after adjusting for temperature and humidity, there was a:
- 6.98 per cent increase in out-of-hospital cardiac arrests, with a stronger association between pollution and cardiac arrests in men and people 65 and older;
- 2.07 per cent increase in emergency department visits for acute cardiac events;
- 1.86 per cent increase in hospitalisations for acute cardiac events, with a stronger association in women and people 65 and older.
"These particles may act as a trigger factor for acute cardiovascular events, therefore its important to not delay seeking medical help if you experience symptoms of heart problems during smoke episodes from wildfires," Dr Haikerwal said.
Fine particulate matter may be the most common and hazardous type of air pollution. Besides burning wood, it also comes from burning coal, car exhaust and other sources.
Given the increase in frequency and intensity of wildfires experienced worldwide in recent years, Dr Haikerwal said it's important to understand the impact of wildfire smoke exposure on acute health effects in the community.
"During a fire, please take precautionary measures as advised by public health officials," Dr Haikerwal said.
"This is especially important for older adults who are at higher risk of adverse health effects during wildfire smoke exposure."
Bushfire & Natural Hazards Cooperative Research Centre, Australia, funded the study.
Co-authors are Muhammad Akram, Ph.D.; Anthony Del Monaco, M.P.H.; Karen Smith, Ph.D.; Malcolm R. Sim, M.D., M.Sc., Ph.D.; Mick Meyer, Ph.D.; Andrew M. Tonkin, M.D.; Michael J. Abramson, M.D., Ph.D.; and Martine Dennekamp, M.Sc., Ph.D.