3.9 Orange
3.9.1 Description of the region
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Figure 19: Population density and topography of Bathurst, Orange and environs
Place names indicate population centres.
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Orange is a regional centre in the Central Tablelands at the foot of Mt Canobolas (see
Figure 19). It experiences cold winters and wood burning is prevalent. The population of the city is 31,000 therefore at least one monitoring station is required.
3.9.2 Overall air quality
Limited campaign monitoring of particles has been undertaken in Orange using a nephelometer. This technique reported elevated concentrations in the cooler months. It is not straight-forward, however, to equate these measurements to concentrations of PM10. These data will be interpreted using the results from regional monitoring of co-located nephelometer and TEOM instruments.
3.9.3 Proposed AAQ NEPM assessment scheme
Clause 14(2) of NEPM allows fewer performance monitoring stations where it can be demonstrated that "pollutant levels are reasonably expected to be consistently lower than the standards mentioned in this Measure". PRC (2000d) sets out criteria which when met provide a basis for determining that there is a reasonable expectation that pollutant concentrations are consistently lower than the standards. These screening procedures will be applied.
The urban centre of Orange is small, less than six kilometres radius. Because the production of ozone by photochemical processes takes some hours, it is unlikely that emissions from the region could be retained for a sufficient length of time to generate significantly elevated concentrations. This reasoning is offered in lieu of screening arguments as there are currently no ozone data from regional centres in New South Wales from which to apply the criteria in PRC (2000d). The need for monitoring will be reviewed in light of the results of campaign monitoring at Bathurst, and the results of the CSIRO TAPM modelling consultancy.
Monitoring data from the Sydney CBD site demonstrates that CO arising from motor vehicles in Orange will be low and the screening criteria are satisfied (section 3.1.2). There may be potential for elevated concentrations of CO arising from the use of solid fuels. No monitoring of CO is proposed in Orange at this stage. NSW EPA will await the outcome of monitoring of CO in other regional centres such as Kalgoorlie (2001) and Toowoomba (2002) before making a final decision.
Data from the Sydney region allows screening of sulfur dioxide and lead (section 3.1.2). In addition, monitoring data from Newcastle (section 3.2.2) allows screening of nitrogen dioxide. Thus monitoring of these three parameters is not required in this region. There is currently insufficient data within New South Wales to allow screening for ozone.
Campaign monitoring of PM10 is scheduled to commence in January 2004.
Page last updated: 26 February 2011
