Coalmines and coal-fired power stations again featured among the big polluters, emitting millions of kilograms of pollutants into the atmosphere, with the potential to be a hazard to both health and the environment.

In NSW, the Hunter Valley and the Lithgow regions rated as the state's most polluted areas because of the number of coal-based activities there.

Singleton is one of the worst towns, surrounded by at least seven mines that together produced more than 18 million kilograms of dust, 7.4 million kilograms of nitrogen oxides and 4.9 million kilograms of carbon monoxide in 2008-09.

Inhalation of low levels of carbon monoxide can cause headache, dizziness, light-headedness and fatigue.

Nitrogen oxides, which can be inhaled or absorbed through the skin, may irritate eyes, nose, throat and lungs. And inhaled dust is also an irritant to the eyes, throat and lungs.

The figures also reveal the state's six largest power stations - Bayswater, Liddell, Mount Piper, Eraring, Wallerawang and Vales Point - produced more than 160 million kilograms of nitrogen oxides, 5 million kilograms of carbon monoxide and a massive 235 million kilograms of sulphur dioxide, which also irritates eyes and throat and can cause headaches and anxiety.

In contrast, renewable energy produced only a fraction of those emissions.

The Eastern Creek renewable energy facility, for example, reported 100,000 kilograms of carbon monoxide, 32,000 kilograms of nitrogen oxides and 10,000 kilograms of sulphur dioxide.

Besides coal, the other major emitters in NSW were the BlueScope Steel plant at Port Kembla, which produced 300 million kilograms of carbon monoxide, and the Tomago aluminium smelter north of Newcastle, with 44 million kilograms of carbon monoxide.

Nationally, Mount Isa Mines in Queensland, which mines copper, zinc and lead, was possibly the biggest polluter, emitting 260 million kilograms of sulphur dioxide, 16 million kilograms of carbon monoxide and 2.9 million kilograms of dust. SMH