Air Pollution: Killer PM2.5 Fine Particles


Winter Haze Over Auckland. Source: Auckland Council

Ambient air pollution is the largest environmental health problem in the western world. Fine particulate matter smaller than 2.5 millionths of a metre known as PM 2.5 were the fifth leading cause of death in the world in 2015, approximately 4.1 million deaths annually. In the US PM 2.5 particles contributed to 88,000 deaths in 2015 alone, that is more than diabetes, influenza, kidney disease or suicide. Current evidence suggests that PM2.5 alone causes more deaths and illnesses than all other environmental exposures combined.


Developed countries have made progress in reducing particulate air pollution, but much remains to be done to further reduce this hazard. And the situation has worsened in many developing countries — notably China and India, which have industrialised faster and on vaster scales than seen before.

The World Health Organisation says more than 90 per cent of the world's children breathe air so polluted it threatens their health and development.


As clean air specialists, we believe the problem of fine particulate air pollution deserves much more attention. Research is links PM2.5 exposure to an alarming array of health effects.

Particulate matter is produced mainly by burning things. In New Zealand, the majority of PM2.5 emissions come from industrial activities, motor vehicles, cooking and fuel combustion, often including wood. There is a similar suite of sources in developing countries, but often with more industrial production and more burning of solid fuels in homes.


Most deaths and many illnesses caused by particulate air pollution are cardiovascular — mainly heart attacks and strokes. Obviously, air pollution affects the lungs because it enters them as we breathe. But once PM enters the lungs, it causes an inflammatory response that sends signals throughout the body, much as a bacterial infection would.

The smallest particles and fragments of larger particles can leave the lungs and travel through the blood.

The most notable new concern is that it appears to affect brain development and has adverse cognitive impacts. The smallest particles can even travel directly from the nose into the brain via the olfactory nerve. There is growing evidence that PM2.5, as well as even smaller particles called ultra-fine particles, affect children's central nervous systems. They also can accelerate the pace of cognitive decline in adults and increase the risk in susceptible adults of developing Alzheimer's.

Other types of particles also raise concerns. Ultra-fines are less studied than PM2.5 and are not yet considered in risk estimates or air pollution regulations. Coarse PM, which is larger and typically comes from physical processes such as tyre and brake wear, may also pose risks.


The first regulatory limits on PM2.5 were proposed in the 1990s, after two key studies showed it had major health impacts. But industry push-back was fierce, and included accusations that the science behind the studies was flawed or fraudulent. Ultimately government regulations were enacted, and follow-up studies and reanalysis confirmed the original findings.


IQAir have taken great care to engineer products that are designed to remove PM 2.5 particles in a manner that is more efficient than any of it's competitors. They are designed for use in your home, office and schools to function in a way the

their presence while maximising their impact on the air you breathe.


Source: Douglas Brugge and Kevin James Lan, NZ Herald 23Nov11.

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