Bushfires are a regular occurrence in Australia, destroying homes, decimating bushland and harming people and wildlife. However, bushfires also result in vast amounts of pollutants being released into the air and have a long-lasting impact on air quality.
What exactly is bushfire smoke?
Bushfire smoke is made up of gases such as carbon dioxide, carbon monoxide, sulphur dioxide and nitrogen dioxide, as well as water vapour, particulate matter, volatile organic compounds and ozone.
What effect can bushfire smoke have on human health?
The pollutants found in bushfire smoke can cause a range of health problems, from burning eyes and a runny nose to aggravated heart and lung conditions. The biggest health threat from bushfire smoke comes from the finest particles, known as particulate matter (PM). Bushfires generate particles less than 1 micron in size (PM1), meaning they are fine enough to penetrate deep into the lungs and enter the blood stream. Long-term exposure to PM1 particles has been linked to cancer, as well as diseases of the liver, kidneys and nervous system.
How is bushfire smoke different to other forms of air pollution?
Bushfire smoke contains many of the same pollutants produced in the burning of fossil fuels. Whilst industrial and automotive air pollution can also contain dangerous heavy metal pollutants, all forms of air pollution can represent a significant threat to human health.
How do HVAC systems deal with bushfire smoke?
In Australia, most HVAC systems are fitted with air filters that focus on filtering coarse particles and dust greater that 10 microns in size. Coarse filters remove less than 5% of the PM1 particles being drawn in through the intake air system. This means that the most dangerous particles for our health are not being removed from the air we breathe in our homes, at work, and in many public buildings. During periods when air pollution levels are high, such as when bushfires are active, indoor air can be just as dangerous as the outdoor air.
What can be done to improve indoor air quality and remove bushfire smoke from indoor air?
The best solution, to address the particulate and molecular contamination associated with bushfire smoke is to upgrade the HVAC systems air filtration setup. Camfil recommends a two-stage setup with a fine particle filter such as the Hi-Flo, followed by a carbon filter. As a minimum, the fine particle filter should be rated at ePM1 60% (according to ISO 16890). A compact carbon filter, such as the CityCarb should be used instead of a pleated carbon filter to ensure effective, long-term removal of odours and molecular contaminants, such as VOCs and ozone. Pleated carbon filters have a minimal, temporary impact and can allow trace odours and chemicals to progress into occupied spaces. In domestic and commercial applications where the above upgrade is not achievable, air cleaners or air purifiers can offer suitable indoor air quality improvements.
What maintenance do HVAC systems require after periods of intense bushfire smoke?
After periods of intense smoke, air filters should be checked and replaced if necessary. Due to the high concentration of particulates in the air, filters may have reached their load holding capacity earlier than usual. Failing to replace filters when necessary can result in higher energy consumption, contaminant bypass and accumulation of dust throughout ductwork and on cooling coils.
For more information on selecting air filters to address problems with bushfire smoke, please contact us at the link below.
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