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3.2 The Lower Hunter region

3.2.1 Description of the Region

Figure 13: The Lower Hunter Region Current monitoring stations are indicated by . Shading shows height above sea level (metres)

The natural Lower Hunter Region is defined to be that part of the Hunter River valley where it opens out to a coastal plain. It is bounded by the coast to the east, and otherwise by the higher terrain enclosing this end of the valley. It is separated from the remainder of the Hunter River valley by the rise in the valley floor northwest of Maitland. The coastal strip extends to the south to include the northern part of the Central Coast urban centre.

Within the natural Lower Hunter Region are the cities of Maitland, Kurri Kurri, and Newcastle. It also includes Port Stephens and the settlements around it. Note that with this separation in the Hunter Valley, the town of Cessnock is excluded from the region. As noted in section 2.3.4, for the purposes of this plan the Lower Hunter region includes the northern part of the Central Coast being the settlements around Lake Macquarie and Tuggerah Lake. The topography of the region is shown in Figure 13.

As defined above, the Lower Hunter region is the location of a substantial industrial base including primary metallurgical works, fertiliser manufacturing, and coal-fired power generators. Emissions from a substantial motor vehicle fleet also contribute to pollution concentrations in the region.

The natural Lower Hunter region is the second most heavily populated region in NSW with a regional population estimated at over 350,000. As used here, including the northern part of the Central Coast, the population of the region is estimated to be a little more than 450,000. Thus the population criterion in clause 14 of the NEPM requires at least two monitoring stations in the region.

Intensive EPA monitoring in the region commenced only in the early 1990s with the establishment of three monitoring stations, as shown in Figure 13. Instruments currently located at each monitoring station are shown in Table 11. Focussing on Newcastle and its immediate surrounds, the monitoring locations were selected to capture the higher concentrations of regionally significant pollutants and to be in receptor regions for major emission sources under generally prevailing wind conditions.

Table 11: Monitoring in the Lower Hunter (2000)

Station	Year Est.	Ozone	Nitrogen Oxides	Patricles as PM10		Carbon Monoxide	Sulfur Dioxide	Lead	Met.
				HiVol	TEOM
Bersefield	1993	X	X	X	X	X	X		X
Newcastle	1992	X	X	X					X
Wallsend	1992	X	X		X		X		X

Synoptic conditions leading to elevated concentrations of air pollutants are similar to those of Sydney (which is only a hundred kilometres to the south). With a high pressure system in the Tasman, light synoptic winds prevail, allowing the generation of local flows such as katabatic drainage flows and sea breezes. Down-valley drainage flows are generated overnight, with up-valley flow established in the afternoon with the onset of the sea breeze (Hyde et al 1981, Hyde et al 1997). It is these local flows that have the greatest influence on the distribution of pollutants emitted by sources in the region. Relatively small variations in the direction of flows can see alterations to this basic pattern. For example, a more north-easterly component in the sea breeze or gradient wind can see emissions from the Newcastle area advected down to the Central Coast area towards the Sydney airshed. The role of these flows in pollution episodes in the region is also demonstrated by airshed modelling of the Lower Hunter region undertaken as part of the Metropolitan Air Quality Study (Hyde et al 1997).

3.2.2 Overall air quality

Carbon monoxide

Monitoring of carbon monoxide in the Lower Hunter region has been undertaken at Newcastle. The Newcastle station is a regional monitoring station, located in the vicinity of the Newcastle CBD (approximately 1.5 to 2 kilometres to the west). It is influenced by some of the higher traffic densities in the region, and is thus an upper bound station. Table 12 shows that concentrations at the Newcastle station are substantially below the NEPM standard and never exceed 60% of the standard.

As expected given the monitoring results in the Sydney region (section 3.1), the data satisfy the criteria of PRC Screening Procedure B, Table 1 of PRC (2000d). Thus the data would justify reduction of the network from the population-based minimum of two. This also provides a screening argument for other regions with smaller emissions.

Ozone

In the Lower Hunter, there have been exceedences of the ozone standard at both the Newcastle and Wallsend monitoring stations as shown in Table 13. These exceedences occur under light northerly sector synoptic winds where precursors are recirculated by a pattern of nocturnal drainage flow followed by an afternoon sea breeze. The Newcastle station captures all the one-hour events occurring in the region.

Table 13: Lower Hunter ozone data for period 1993-98

Station	1-hour concentrations (ppm)			Number of days exceeding standard
	maximum	99th percentile	90th percentile	1 hour	4 hour
Newcastle	0.14	0.04	0.03	2	2
Beresfield	0.09	0.04	0.03	0	0
Wallsend	0.13	0.04	0.03	1	3

Nitrogen dioxide

Concentrations of nitrogen dioxide are consistently below the standard in the Hunter as shown in Table 14. Indeed the maximum one-hour concentration in the three years 1996-98 is 0.06 ppm, less than 65% of the AAQ NEPM standard (0.12). This satisfies the criteria of Screening Procedure B, Table 1 of PRC (2000d). Thus other regional centres with lower emissions may be screened using these data.

Table 14: Nitrogen dioxide concentrations in the Lower Hunter, 1996-1998

Station	1-hour concentrations (ppm)			Season of maximum
	maximum	99th percentile	90th percentile
Newcastle	0.05	0.03	0.02	Spring
Beresfield	0.06	0.03	0.02	Spring
Wallsend	0.06	0.03	0.02	Summer

Particles as PM₁₀

PM₁₀ is currently monitored in the region both by TEOM and by high volume sampler (one-day-in-six-cycle). The highest concentrations of PM₁₀ (as measured by TEOM) recorded at Beresfield and Wallsend in the Lower Hunter are shown in Table 15. Data from high volume samplers in the region are summarised in Table 16.

Particle concentrations observed at Beresfield by TEOM are significantly higher than those at Wallsend. No detailed investigation has been undertaken to determine why this station has such a greater frequency of elevated concentrations. Local primary industry is thought to be an influence. As in the Sydney region, wildfires and hazard reduction burning are a major influence on particulate pollution in the region.

Sulfur dioxide

Monitoring for sulfur dioxide is undertaken at Beresfield and Wallsend in the Lower Hunter. As shown in Table 17, Wallsend concentrations are generally higher than those at Beresfield, but neither records an exceedence of the one-hour standard. Indeed the maximum hourly concentrations are lower than the daily standard. These data satisfy the criteria of Screening Procedure B, Table 1 of PRC (2000d). This would justify reducing the monitoring in this region, and in other regions with lesser emissions.

Note that specific industries are required, as condition of licence, to measure sulfur dioxide at twelve locations in the Lower Hunter. These sites are recognised as peak stations under the Standards Australia classification and are generally located in the vicinity of major industrial emission sources. The impact of major sulfur dioxide emitters in these regions can therefore be effectively gauged, yielding data relating to the frequency of elevated ambient sulfur dioxide concentrations. This is outside the AAQ NEPM protocol, but provides important additional air quality information.

Lead

As there is an industrial source of lead in the region, screening procedures should not be applied. No monitoring complying with NEPM standard conditions is undertaken in the Lower Hunter at present. Nevertheless, campaign monitoring is scheduled to commence at Wallsend by February 2002. The need for permanent monitoring will be reviewed in light of the results from this campaign monitoring.

Figure 14:AAQ NEPM Monitoring in the Lower Hunter Region  denotes trend stations;   denotes performance stations Note that the Maitland site is yet to be established — Wallsend and Beresfield will be reported in the interim.

3.2.3 Proposed AAQ NEPM Assessment Scheme

The population criterion of section 14(2) of the AAQ NEPM requires at least two monitoring sites in the Lower Hunter region. The region contains two major population centres, Newcastle and Maitland. Current monitoring has focussed on Newcastle and its environs. NSW EPA plans to establish a trend site in the Maitland area by January 2003. Until this site is established, data from the existing stations at Wallsend and Beresfield will be reported, thus these are campaign monitoring stations. Beresfield will report PM₁₀, while Wallsend will report ozone, nitrogen dioxide, sulfur dioxide, and lead. Together, the trend stations at Newcastle and Maitland will characterise the gen-eral air quality to which the urban population of the Lower Hunter is exposed and will capture any pollution events that may occur. The monitoring network for the Lower Hunter Region is shown in Figure 14 and summarised in Table 18 which notes the parameters to be reported from each station.