THE state government faces potential legal action for failing to include key data about Upper Hunter air pollution - which is among the worst in Australia - to the National Environment Protection Council.
The omission of the data gives a significant boost to the state's overall air quality report card.
"This is slap in the face to Upper Hunter residents because it says: 'We don't care about you'. People who live near power stations are already suffering an unacceptable health burden and they have a right to know the pollution levels in the air they breathe," said Environmental Justice Australia lawyer Nick Witherow, who is advising the Hunter Environment Lobby.
National Environment Protection Council sets National Environment Protection Measures (NEPM). The NEPM specifies the number and performance criteria of air quality monitoring standards for regions with populations of more than 25,000.
The latest census data shows the Upper Hunter 30,658 residents.
The government's reservations about applying the NPEM to Upper Hunter air quality first surfaced in a 2001 document about the requirements of the National Protection Measure for Ambient Air Quality (1998).
It shows bureaucrats argued the Upper Hunter should be classified into two sub-regions for the purposes of air quality monitoring.
"The topography of the area is not simple. In particular, a ridge about 10 kilometres south of Muswellbrook separates Muswellbrook and Scone from the power stations around Lake Liddell. Singleton is some 25 kilometres to the southeast of the lake. Indeed, the river itself flows around this ridge, running southwest from Muswellbrook to Denman where the Goulburn River joins it. It then resumes a coastal path to Singleton....
"The topography shows clearly that there is no region containing a population of 25,000 or more," the document said.
The state government launched the Upper Hunter Air Quality Monitoring Network in 2010.
It consists of 14 monitors between Merriwa and Singleton and is operated by the Department of Planning, Industry and Environment on behalf of the Environment Protection Authority.
A spokeswoman said network reporting met the requirements and intent of the NEPM.
"With 14 air quality monitoring stations, the Upper Hunter community is well served," she said.
"Monitoring is overseen by a committee, the Upper Hunter Air Quality Monitoring Network Advisory Committee, which provides advice to DPIE on the needs of the community."
But, Mr Witherow said serious doubts existed about accuracy and adequacy of National Environmental Protection (Air Quality) Measure data for NSW.
"The Upper Hunter Air Monitoring Network only collects a fraction of what is required. It primarily collects PM10 (coarse particle pollution) data, rather than the full suite of pollutants required under the National Environmental Protection (air quality) measure," he said.
"The most toxic particulates for people's health is PM2.5. Only three of the region's 14 monitoring stations collect data about PM2.5 (fine particles).
"NSW has excluded the Upper Hunter from its NEPM Monitoring network because the Upper Hunter appears to be classified as two sub-regions, thereby avoiding monitoring and reporting of exceedances of air quality standards to the National Environmental Council.
"The NSW government must get serious about cutting toxic air pollution from the country's biggest sources to improve the health of people living in the Upper Hunter."
The president of the Hunter Environment Lobby, Jan Davis, said Upper Hunter residents had been "tricked by government obfuscation".
"Our health is being overlooked. We need more adequate air quality monitors that measure the PM 2.5s for a true and accurate picture in real time for the health of people and the environment," Ms Davis said.
"Added to the already overburdened air quality from open cut coal mine operations, it can be seen that our air shed is one of the most severely impacted in Australia.
"This is just not good enough.
"Thousands of people suffer with asthma-related effects, as well as the increase in heart and lung problems we find with increased air pollution, our lives are made shorter just by living here."