THE evidence for harmful health effects from particulate air pollution has become stronger over the years, so periodic review of air quality regulations in keeping with current science is vital for the protection of human health.
Compared to 20 years ago, our current understanding of the health impacts from air pollution is of a greater burden from fine rather than coarse particles, although both are important.
There is a greater burden from long-term exposures than from occasional severe bad air days, and greater burden from heart disease than from lung disease.
There is also an increasing understanding of the effects on lung growth in children, and that ill health effects occur down to much lower levels of exposure than previously recognised.
Since July 2014 the NSW Environmental Protection Agency has been leading a national review and consultation process to revise Australia’s particulate air pollution standards, which will be considered by a meeting of all the state environment ministers this week.
The review of all available evidence by Australia’s leading air and health scientists led to a recommendation for a new standard for annual average PM10 exposure, with consideration of possible limits of 12, 16 or 20 micrograms per cubic meter.
This would replace the current NSW standard of 30 micrograms per cubic metre, which was based on the evidence available in 1982. PM10 is the dust smaller than 10 microns in diameter, which can be breathed in to human airways.
Air quality in Newcastle is monitored at three longstanding and three new sites by the EPA, and the results show that there is a serious problem, the results are in excess of the highest new recommendation.
The annual PM 10 results for Newcastle 22.0, Stockton 33.7, Carrington 23.6 and Mayfield 22.5, are all above even the highest level for the proposed new annual PM10 standard. Only Wallsend and Beresfield are below the 20 microgram per cubic metre level.
The results for the finer particles, PM2.5, are no better, with Newcastle 8.8, Stockton 8.9 and Carrington 8.2; with Mayfield, Beresfield and Wallsend below the standard of 8 micrograms per cubic metre.
The new Carrington and Mayfield monitoring sites have only 11 months of data, but the last month is unlikely to change the average by much.
Against this background, the Planning Assessment Commission has been holding public hearings this week into a proposal to build a fourth coal-loader for Newcastle, which will add extra dust into the local air both from coal handling (mostly PM10), and locomotive and ship exhaust (mostly PM2.5).
Should they assess this proposal against the 33-year-old air quality standard, or the standard that is about to be introduced?
Does the fact that approval is being sought now but construction will probably not commence for five years change how the approval should be approached?
Prudent planning for an already polluted local atmosphere could include such measures as pollution offsets under which a new polluting industry can be approved only if it buys and shuts down another source of air pollution so at least the situation is not made worse.
Air pollution is unlike other public health threats as it never appears on a death certificate.
It is not possible to attribute any individual instance of heart or lung disease to polluted air, yet it is estimated to cause 3000 deaths a year in Australia.
The sources of urban air pollution include road vehicles, wood-burning heaters and bushfires, so improving air quality will require a range of measures but it would seem that the first step should be to stop adding to the problem.
Dr Ben Ewald is a Newcastle GP, teaches epidemiology at the University of Newcastle and is a member of Doctors for the Environment Australia
This comment piece was first published in the Newcastle Herald on 15 July 2015