Where there’s smoke…
Parts of Victoria and New South Wales are still smothered with smoke haze and so many of our people are suffering trauma and loss.
Very fine particles have been inhaled almost everywhere by citizens who have a right to expect common property such as the atmosphere to be safe. Even the disgraced former US President, Richard Nixon, said that people have a right to clean air.
Of course we need to make extensive cultural, economic and social adjustments to address climate change, but climate hysteria is distracting attention from the immediate health impacts of the fires.
Future fire management strategies will need to be based on a thorough understanding of the bushfire impacts, and not only from the climate change perspective.
The density of small particles (PM2.5) is becoming a popular air quality indicator but that’s like checking your temperature to avoid a headache.
Bushfires release particles which are likely to be chemically reactive.
Bushfires contribute a lot of dioxin-like compounds to the environment in Australia, for example, but the health effects are not well understood.
Photochemical changes to vehicle and industrial emissions mixed with smoke from bushfires, dust and pollen can be expected to produce a harmful cocktail unfit to breathe.
The law protects us from passive cigarette smoking but we seem less concerned about the health risks and ‘nuisances’ caused by bushfires, especially so-called ‘cool’ burns.
What happens when particles from different sources mix? What is the effect of lightning and humidity on particle surfaces exposed to a range of reactive pollutants?
Authorities issue and regularly update air quality information and warnings. Air quality can range from good to hazardous with special consideration given to susceptible individuals and groups.
Air quality index scores include the weight of small airborne particles per cubic metre of air.
Susceptible people are advised to remain indoors when air quality is poor, unhealthy or hazardous.
However, while remaining indoors when air quality is rated ‘hazardous’ may reduce exposure to PM 2.5 particles, indoor air can still be hazardous and unhealthy. Indoor PM 2.5 levels can be more than 50% of the outdoor level.
Air pollutants entering a house from outside can mix with domestic heating and cooking gas residues, pesticides, cleaning chemicals, vapours and fumes.
The weight of PM 2.5 in the air seems to be a fairly crude indicator of potential health impacts for individuals who may react variously to different particles.
The chemistry and other characteristics of airborne particles can be expected to differ and change depending on their origin and the prevailing atmospheric conditions.
European scientists have begun to classify airborne particles according to their physico-chemical properties in addition to particle size and density. This work might be expected to produce health and safety criteria directly related to risk.
Research is urgently needed to answer these and other questions in the Australian setting.
Policies for fire prevention and management are no doubt on Australian government agendas at all levels. There’ll be the usual controversy about fuel reduction burns and poorly concealed political point-scoring on all sides.
It would be good to see a recognition by all that what’s good for the environment is good for the people it supports.
Max Thomas, Dip. Agric. (retired) worked in the public sector and in private consulting on a range of land, water and waste management projects. He prepared guidelines for irrigation with recycled water for EPA Victoria and developed a number of Environmental Management Systems in the water industry.
