The effects of bushfire smoke explained
With smoke from Australia's devastating bushfires blanketing Melbourne this week, many people have experienced an onset of coughs, sore throats and more severe respiratory complications like asthma. Associate Professor Mark Hew, respiratory specialist at The Alfred, explains why bushfire smoke can be so dangerous for some people.
A/Prof Mark Hew, Service Head of Allergy, Asthma and Clinincal Immunology Service at Alfred Health, said people in regions impacted by the smoke may encounter breathing difficulties because small particles contained in the smoke, known as 'PM 2.5 particles', get into the lungs and irritate them.
"Bushfires release smoke particles made of carbon. Breathing in such particles of any size can irritate our throat (the larynx) and our windpipe (the trachea), which can cause coughing and a hoarse voice," A/Prof Hew said.
"PM2.5 refers to particles (smoke or dust) less than 2.5 micrometers in diameter. These are small enough to be inhaled into the small airways of the lungs. In some people, this may cause the airways to narrow and spasm, making it difficult to breathe. This is most likely to happen in people with known asthma or COPD (chronic obstructive lung disease)."
Professor Hew said A P2 or N95 mask is able to filter out PM2.5, but only if a perfect airtight seal is achieved around the mask.
"Currently, the best avoidance measures are to leave the area (not always possible), or to remain indoors with the air-conditioning on. Use the recirculate mode.
"It is best not to exercise outdoors during periods with high concentrations of smoke particles. This is because during exercise, we increase our breathing and inhale more particles. People known to have asthma or COPD should also ensure they are taking their prescribed preventive inhalers regularly. It is known that exposure to bushfire smoke increases the risk of worsening existing asthma or COPD. If this occurs, patients should activate their action plan which may include seeking medical attention.
"Exposure to bushfire smoke also appears to slightly increase the risk of heart attacks during and after that period."
Professor Hew said symptoms like a hoarse voice and irritated throat can indicate significant exposure to smoke particles, but the symptoms are not dangerous in themselves. However, he said people with more severe symptoms should seek help urgently.
"Any trouble with breathlessness, chest tightness or chest discomfort following exposure to bushfire smoke may represent narrowing of the airways, and medical attention should be sought urgently. In the meantime, using a ventolin inhaler (if available) is likely to help."