Air pollution from wildfires may increase risk for cardiac arrest


Exposure to fine particle air pollution during wildfires may increase risk for cardiac arrest and other acute heart problems, particularly in the elderly, a new study has found.

“While breathing wildfire smoke is linked to respiratory problems such as asthma, evidence of an association between wildfire smoke exposure and heart problems has been inconsistent,” says Anjali Haikerwal, study author and a doctoral candidate at the School of Public Health & Preventive Medicine at Monash University in Melbourne, Australia.

In the study, recently published in the Journal of the American Heart Association, researchers examined the association between wildfire related tiny particulate pollutant exposure and the risk of heart-related incidents in the state of Victoria, Australia, from December 2006 to January 2007. During these two months, smoke reached cities far from the blazes and on most days during the wildfire the levels of fine particulate air pollutant exceeded recommended air quality limits.

The particles studied by researchers are smaller than 2.5 thousandths of a millimeter in diameter, which is much smaller than a speck of dust or 1/30th diameter of a human hair, and typically not visible to the human eye.

Using Victoria health registry data during the wildfire period, researchers found that for an increase from the 25th to 75th percentile in particle concentration over two days, after adjusting for temperature and humidity, there was a:

  • 6.9% 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% increase in emergency department visits for ischaemic heart disease; and
  • 1.86% increase in hospitalisations for ischaemic heart disease, with a stronger association in women and people 65 and older.

“These particles may act as a trigger factor for acute cardiovascular health events,” Haikerwal says. “Do not delay seeking medical help if you experience symptoms of heart problems during smoke episodes from wildfires.”

Fine particulate matter may be a common and hazardous type of air pollutant. 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, Haikerwal says it is 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,” Haikerwal says. “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 of Melbourne, Australia, funded the study