A pioneering bid to cut air pollution in Norwich's city centre has been hailed by the government for helping families to breathe more easily.

New statistics have revealed that the air around Norwich is getting cleaner - with levels of harmful emissions in the city's air falling.

That's good news for the health of families across the city, because scientific studies suggesting links between air pollution and asthma, bronchitis, heart disease and cancer.

The measures taken in Norwich to make the air cleaner have now been recognised in Parliament, where the introduction of a low emission zone in Castle Meadow has been highlighted as a model from which other cities could learn.

In 2003 Castle Meadow was identified as an air quality management area (AQMA) because the levels of nitrogen dioxide were above government and European Union targets.

Five years later it was declared a low emission zone to get bus companies to clean up their act and the move has been credited with cutting pollution levels.

Norfolk County Council and Norwich City Council imposed stricter limits on exhaust emissions from buses and encouraged bus operators to get on board by offering grants to get greener vehicles and engines.

The aim was to drive down annual mean levels of nitrogen dioxide to a target of less than 40 micrograms per cubic metre and annual mean levels of particulate pollution (PM10) to 20 micrograms per cubic metre.

Statistics from continuous monitoring in Castle Meadow show that the annual mean concentration of nitrogen dioxide have dropped from 46 micrograms per cubic metre in 2007 to 45 in 2008 and 41 in 2009, while the level of particulates has fallen from 23 micrograms per cubic metre in 2007 in 21 in 2009.

The government has now highlighted the work done in Norwich - including it as a case study in a local transport white paper which outlines how councils can do more to encourager greener transport.

Steve Morphew, leader of Norwich City Council, said: 'The quality of the environment in the city has an effect on people's quality of life and we need to make sure the air we breathe is doing us good.

'Because we have been designing that into what we do, we are looking at a generally sustainable improvement to air quality. We are not looking for quick fixes, but to get it right in the longer term.'

As well as Castle Meadow, the city has air quality management areas in Grapes Hill, St Augustine's Street and, for the past 12 months, Riverside Road.

The measurements have shown that pollution in Grapes Hill has been well below the objective level for the past four years.

Broadland District Council also has an air quality management area on the ring road near where Bottoms Up used to be at the junction with Aylsham Road, but that was revoked last April.

Mr Morphew said he was optimistic the introduction of the so-called St Augustine's gyratory road system would cut the pollution in that area and added it was good to see the government recognised the success of Castle Meadow scheme.

Measurements for nitrogen dioxides in 34 parts of the city using devices known as diffusion tubes have also shown drops in most areas.

They are checked each month, so are less accurate than the continuous monitoring in Castle Meadow.

They revealed eight sites where the objective of 40 micrograms per cubic metre had not been achieved.

As well as two in Castle Meadow, the others were in St Stephen's, St Augustine's, Cattle Market Street, Bull Close Road, King Street and Riverside Road.

But concentrations of carbon monoxide, lead, particulates and sulphur dioxide are not considered to be in excess of air quality objectives anywhere in the city.

In March last year, the government's environmental audit committee reported that long term exposure to air pollution may be a contributory factor in the deaths of between 35,000 and 50,000 people each year in the UK.

Claire Stephenson, leader of the Green Party, said: 'Something needed to be done in Castle Meadow because it is not acceptable for bus companies which charge their passengers to have them waiting in a polluted area, so it's right that they play their part in solving the problem.

'You are always going to have problems with pollution in a city. Maybe electric cars could be the answer. They are not the answer to everything, but on the pollution issue they could be.'

• If you spot something you believe is causing a problem with air pollution in Norwich call Norwich City Council on 0344 980 3333.

• Do you have a story about a local council? Call Evening News reporter Dan Grimmer on 01603 772375 or email dan.grimmer@archant.co.uk.