"Today we are coming together to raise awareness of the fact that Vales Point has been allowed to pump out excess pollution for way too long," Greens MLC Abigail Boyd said.

"We have the EPA currently considering an extension to their exemption which would allow them to pollute for another five years."

Delta Electricity, the power station owner, is seeking approval from the NSW EPA to exceed emission limits of nitrogen dioxide at the Mannering Park power station until 2027. A five year extension of their current exemption.

Charlestown GP Dr Kathleen Wild was part of the crowd who gathered in Centennial Park, Cooks Hill, on Wednesday before marching to the EPA offices on Bull Street. Dr Wild said the exemption has a range of potential health impacts.

"It's a mystery to me as to why the children living near Vales Point don't deserve the same health guidelines as those living near other power stations," she said.

"We know that exposure to this kind of air pollution increases the rates of chronic disease, airway disease like asthma and COPD. There's evidence that other health impacts like heart disease and cognitive disease are also increased by exposure."

Epidemiologist and Adamstown GP Dr Ben Ewald looked at modelling from the University of Exeter to estimate the number of children "affected by emissions from Vales Point".

"I've worked out that we would expect 320 kids in Lake Macquarie and 334 kids in the Central Coast to have asthma because of nitrogen dioxide exposure," he said.

According to Dr Ewald, due to upgrades, Eraring power station produces twice the energy of Vales Point but emits the same level of nitrogen dioxide. Future Sooner spokesperson Will Belford said "the money is there" for Vales Point to bring emissions in line with other power stations.

"We've estimated the cost to be about $80million but as I said they have made about $248million in profit from that station since they bought it for $1million from the state government in 2015," he said.

Even then, Mr Belford said, emissions would be too high.

"At the moment in NSW the emission limit for nitrogen dioxide is 800 milligrams per cubic metre of emission, in Japan it's 57," he said.

IN THE NEWS:

Our journalists work hard to provide local, up-to-date news to the community. This is how you can continue to access our trusted content: