Of these breaches, 33 were at 11 o’clock at night.

The pollution was recorded by state government air monitors at Singleton, Singleton north west, Maison Dieu, Camberwell and Mount Thorley for dust particles known as PM10s which can damage people’s respiratory tracts.

Singleton Shire Healthy Environment Group spokesman John Drinan said he was puzzled by the regular, late night pollution.

“I’ve noticed many health alerts at 11pm and when I’ve checked back over figures for the previous 24 hours I’ve quite often found the health limit exceeded in the daytime yet no alert has been issued.

“It’s not good enough from a health perspective that this continues, people with respiratory problems should be alerted on the hour, every time there’s an exceedence.

“It’s a good thing that we can now get some air quality figures, they show what we’ve been enduring for years, but more needs to be done to reduce the problem, especially as coalmining keeps expanding.”

Following state government media protocol, The Argus emailed state Environment Minister Robyn Parker a series of questions about the situation.

These included requests for her comment on the 55 breaches, the fact 33 were at 11 o’clock at night, asked where the pollution was coming from, what action had been taken as a result of the health alerts and what had been done to prevent the situation being repeated.

Mrs Parker’s media advisor Steve Warnock said she was then advised by the state Office of Environment and Heritage that the Hunter had recently experienced a number of dry and very windy days.

During these type of days it was not uncommon to experience high particle pollution which could be caused by mining, wood smoke, hazard reduction burning, bushfires and dust from agriculture and bare soil, Mrs Parker’s statement said.

The statement said the government’s 14 Upper Hunter monitors were part of one of the most comprehensive air monitoring networks in Australia and information from it would support further research and health programs to help assess the effectiveness of dust control programs designed to improve air quality in the long term.

The state government had produced a six monthly interim report on the monitoring network’s operation and would also do an annual report.

The government was working to improve the Hunter’s air quality and the Environment Protection Authority had required all 60 New South Wales operating coalmines to assess their operations against best practice guidelines and determine the most effective way to significantly reduce on-site dust emissions.

The authority had also placed pollution reduction program conditions in coalmining environmental protection licenses, Mrs Parker’s statement said.

In addition, the government commissioned a 12 month study, which began eight months ago, into the composition of particles in air samples taken near Singleton and Muswellbrook.

Dr Drinan said: “With so much bare mining land around Singleton, even Blind Freddy could see what’s happening.

“A lot more attention needs to be paid to air pollution health alerts with a view to progressively reducing what is being blown from the mines.

“As part of the Upper Hunter mining dialogue involving the mines, New South Wales Minerals Council and the community we have discussed an early warning system, say 24 or 48 hours before predicted windy weather, so that the mines can take steps to avoid operations that will add to the dust.”

Dr Drinan said he was disappointed to see coalmine blasting and other dusty operations continuing as usual despite recent windy weather.

“We’ve had some huge exceedences recorded by the air monitors lately that are unacceptable from a health point of view,” Dr Drinan said.