Air pollution from wildfires has been linked to an increased risk of cardiac arrests and other sudden acute heart problems, according to a recent study.

Researchers at Monash University in Victoria, Australia found a 7 percent increase in out-of-hospital cardiac arrests when ambient air is contaminated by wildfire smoke, MedPage Today reported.

"Finer particulate matter is present in extremely high concentration in smoke," Anjali Haikerwal, lead author of the study, told Reuters Health. "These particles are harmful because they are small and easily inhaled."

For the study, researchers collected and analyzed data from the Victorian Ambulance Cardiac Arrest Registry from Ambulance Victoria and the Department of Health and Human Services to examine 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 millimeter 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.

They 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 2 percent increase in emergency department visits for acute cardiac events and a 1.86 increase in hospitalizations 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 it's important to not delay seeking medical help if you experience symptoms of heart problems during smoke episodes from wildfires," Haikerwal said in a statement.

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.

The findings are detailed in the Journal of the American Heart Association.