Woodheaters in Launceston - Impacts on air quality
CSIRO Atmospheric Research
Department of the Environment and Heritage, September 2005
The Department of the Environment and Heritage (DEH) commissioned this study to:
- Assess the contribution of the Launceston Woodheater Replacement Programme (LWHRP) in reducing particle pollution in the Tamar Valley region since the implementation of the programme in June 2001.
- Determine the carrying capacity of woodheaters for the Launceston airshed so that national air quality benchmarks for PM10, PM2.5, and polycyclic aromatic hydrocarbons (PAHs) can be met.
- Assess through the analysis of trends in woodheater numbers when national air quality benchmarks for PM10, PM2.5, and polycyclic aromatic hydrocarbons (PAHs) are likely to be met.
The impacts of the LWHRP on air quality in Launceston were estimated through a systematic analysis of regional air quality concentrations and meteorological data. Woodheater carrying capacity in Launceston was determined using the air pollution model, TAPM.
Results indicate that the Launceston Woodheater Replacement Programme contributed to improved regional air quality by accelerating the existing downward trend in the number of woodheaters in Launceston. The key projections based on current trends were:
- The PM10 particle standard of the Air Quality National Environment Protection Measure (Air NEPM) is estimated to be met by 2007.
- The PM2.5 advisory reporting standard for fine particles of the Air NEPM is estimated to be met by 2009.
- The PAH benchmark under the Air Toxics NEPM is estimated to be met by 2009.
Modelling results indicate that the PM10 NEPM would be met anywhere in Launceston (assuming typical meteorological conditions and no significant change in dwelling density and background concentration from the levels used here) when the total number of woodheaters is 20% of the total number of dwellings, of which 76%, 18%, 6% would be compliant woodheaters, non-compliant woodheaters and open fireplaces, respectively.
The modelling estimates for woodheater carrying capacity and exceedences of the Air NEPM are based on a number of assumptions and as such the results should be used as an indicative guide, rather than as an accurate prediction.
The analyses of PM2.5 and PAHs concentrations highlighted the lack of monitoring data for these compounds in Launceston. The four major data deficiencies in Launceston with regard to woodheaters and air quality were:
- Actual particle emissions rates from woodheaters in the city and surrounding region.
- Ambient concentrations of PM2.5 and their ratios to PM10 concentrations.
- Ambient concentrations of PAHs and their ratios to PM10 concentrations.
- The number of residences with woodheaters, the type of woodheater (compliant, non-compliant and open fireplaces) and the spatial distribution of these woodheaters.
While results from this study show that the LWHRP contributed to improved air quality in the Launceston airshed, through the replacement of older polluting woodheaters with cleaner appliances, the results reinforce the need for continued action to improve air quality in Launceston, as NEPM benchmarks for a number of air pollutants are unlikely to be met for some years without further intervention.