Even low-level PM10 exposure can harm the lungs

Even a low level of exposure to particulate matter (PM10) can have a detrimental effect on the lungs, scientists have concluded.

An international research team, led by the University of Technology Sydney (UTS) and the Woolcock Institute of Medical Research (WIMR) in Australia, say the findings have implications for people living next to major traffic corridors, warning that residents should be aware of how it may affect their respiratory health.

The study, published in the American Journal of Physiology – Lung Cellular and Molecular Physiology (AJP-Lung), exposed mice to low levels of traffic-related PM10.

It found that after three weeks, the mice developed inflammation in their lungs as a direct result of their PM10 exposure.

Dr Yik Chan from UTS and WIMR, a co-lead author on the paper, said: ‘In Sydney and other Australian capital cities the levels of traffic-related air pollution (TRAP) are low by world standards and not often considered a problem in terms of developing chronic lung disease. However, almost everyone living in an urban area is exposed to TRAP.

‘Sydney has a lot of new construction taking place, as well as a growing population and increased traffic is inevitable.’

Particulate matter (PM10) often forms part of fumes from car exhausts. Scientists now say that even low-level exposure to PM10 can cause lung damage.

Chief Investigator Associate Professor Brian Oliver said: ‘Our results indicate that PM is a pro-inflammatory molecule, which exerts effects even at low concentrations. In our model we found strong, and statistically significant evidence of, lung inflammation and dysregulated mitochondrial activity.

‘The mitochondria are the powerhouse of the cell, which means that any changes to the mitochondria effects energy production by the cell, and therefore how the cell divides and responds to external stimuli.’

This study adds to the growing number of studies exploring the health impact of low levels of air pollution, an area of research which had previously been under-explored.

Earlier this year, American academics found that exposure to carbon dioxide (CO2) can have harmful effects on the human body at much lower levels than previously thought, including inflammation, reduced cognitive performance and kidney and bone problems.

Researchers now believe that health problems can be caused by exposure to CO2 levels as low as 1,000 parts per million (ppm) — a far lower limit than the 5,000 ppm level that had previously been widely accepted.

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