A YEAR-LONG study of the air in Muswellbrook and Singleton surprised many people when it found that household wood fires produced more fine particulate pollution than the open-cut coalmines widely viewed as the cause of the region’s dirty air.
The Upper Hunter Valley Particle Characterisation Study, as the report was called, found that household wood smoke was by far the biggest single contributor to PM2.5 particulates in Muswellbrook with 30per cent of the annual total, rising to 62per cent of a significantly elevated total in winter.
In Singleton, this same type of smoke accounted for 38per cent of the winter PM2.5s, although only 14per cent when measured across the full year. In both centres, types of particles classified as ‘‘secondary sulphates’’, identified in the study as mainly coming from power stations, were also leading causes of PM2.5 pollution.
For some years now, the power stations have been the subject of increasingly rigorous pollution controls that have seen both major Upper Hunter stations – Liddell and Bayswater – fitting new filtering equipment to remove as much particulate matter as they can from their emissions.
Households, by way of contrast, have been more or less left alone in their choice of indoor fires, but the results thrown up the particle characterisation study have led to calls for restrictions on this popular method of winter heating.
The NSW Environment Protection Authority says it supports tougher national standards for wood heaters and the NSW Greens – having led the push, politically, against the environmental impacts of coalmining – are also backing changes to household wood-fired heaters. Within overall state and national standards, policing of household fireplaces is a local government issue, and the modern woodburning combustion stove is a far more efficient and cleaner user of fuel than the old-style open fireplace.
Despite such improvements, thousands of Hunter homes are still fitted with open fires, and it may be these that are contributing more heavily to the picture in Singleton and Muswellbrook. Indeed, wood fires may well be affecting air quality across the region, and the time may come when urban Australians, at least, must bid these sentimental favourites goodbye.
This is unlikely to be an overnight change. But we cannot ignore aspects of health-impacting air pollution simply because the cause is not the one that people expected.
If the study results are replicated, and health impacts suspected, then action must eventually follow.