Drivers could be fined for leaving their engines running while stationary in a bid to cut traffic pollution.

The enforcement is being considered by the city council among a raft of new measures following the revelation that more areas of the city are failing air quality guidelines.

The authority's new plans, published today, emphasise "pulling together" to beat air pollution and encourages reductions in car journeys and cleaner vehicles as well as promoting more responsible driver behaviour and alternative ways of travelling.

But only last week it came under fire for granting planning permission for a new multi-storey car park in Station Road West which environmental opponents say will simply lead to more city centre traffic.

The new plan also comes as the council battles legal action by clean air campaigners in the High Court over its Local Plan which opponents claim fails to adequately tackle traffic pollution.

Bosses says its plan will now form part of its defence to those proceedings brought by clean air campaigner Emily Shirley.

Council leader Simon Cook says one of the challenges facing the authority, and many others around the country, was mitigating air pollution while meeting government targets for new home building.

But he insists the authority is serious about tackling the problem with its new detailed action plan but says there is no "silver bullet" to a solution.

"While we will do all we can as an organisation to improve air quality, the district needs to come together to make a positive impact," he said. "Individuals can make a massive difference with the choices they make.

"We are asking people to be a bit more considerate in places like St Dunstan's when they are stopped for a few minutes waiting for a train to pass. Or outside a school waiting for children to come out. But not, of course, simply in slow moving traffic if they have to come to a halt.

"It takes absolutely no effort to turn a car engine off while stationary and we will ask them nicely before deciding whether it needs a bit more stick. It's about changing behaviours because there is no one silver bullet answer to it."

But clean air campaigner Stephen Peckham, who is Professor of Health Policy at the Centre for Health Services Studies at the University of Kent, says it is "a bit rich" for the council leader to talk of taking air quality seriously when the authority should be apologising for not taking action earlier.

"I welcome any action but in the short term I suspect that based on current development proposals, levels of pollution will either stay the same or increase.

"Park and ride buses to the station, for example, is a good idea but that further undermines the need for a multi-storey car park."

The proposals, due to be considered by the council's policy and resources committee on April 18, come as wider pollution monitoring of city roads revealed new areas breaching limits.

An AQMA has to be declared when, as a result of evidence gathered by the council, when nitrogen dioxide (NO2) levels exceed an annual average of 40 micrograms per cubic metre. But the council says it has extended the area even when levels touch an average of 36 mgms, to ensure a 10% buffer.

They have been found in sections of Rheims Way, London Road, Chaucer Road, Military Road, St George's Place, Lower Chantry Lane and Old Dover Road and now form part of the council newly-extended air quality management area.

A new AQMA has also been established in the centre of Herne where the A291 meets the mini roundabout and there is regular traffic congestion.

Cllr Cook also believes the growing use of electric cars, encouraged by the government, will, in itself, cut emissions significantly in the longer term, although the latest figures show that only 140 such vehicles are registered in the district.

The council has enlisted the services of a leading independent air quality experts Bureau Veritas to monitor levels and is also working on a signage project with the University of Kent.

Some of the measures the city council is proposing to cut air pollution include:

* Adopt anti-idling enforcement powers to implement at level crossings, coach parks, taxi ranks and on-street parking bays.

* Pilot a scheme at some schools to raise the issue of idling engines when parents drop children off.

* Review park and ride contract to ensure use of low emission buses.

* Investigate the feasibility of running park and ride buses to and from railway stations.

* Provide new and improved cycle routes, including working with new housing developments south and east of Canterbury

* Ensure all city council car parks have electric car charging points where suitable.

* Establish a Canterbury Car Club to encourage car sharing.

* Continue negotiations over a potential cycle hire scheme for the city.

* Promote the clean air message with variable roadside message signs on major routes into Canterbury.

Professor Stephen Peckham said the extension of the AQMA was expected but he would have like to have seen it widened further.

"It is now clear the plans set out in the council's original action plan in 2009 have failed and not revising it in 2011is particularly negligent because it has allowed air quality just get worse over the years," he said.

"Clearly traffic levels are the key cause of emissions and pollution. Any plans that reduce levels of cars - especially diesel vehicles in very congested areas, is useful but will rely on approaches that restrict as well as persuasion.

"Low emission buses and taxis are welcome and should be electric as in other cities. Linking them to the stations would be important but safer cycling will need substantial investment."

Prof Peckham agrees the combination of all the measures if given the appropriate levels of investment and an actual reduction in traffic flows, will have an effect on air pollution levels.

But he fears that small decreases in levels of nitrogen dioxide will lead to an increase in low level ozone - a significant problem, he says, in Canterbury which has breached national levels for a number of years.

He says: "A key question is how quickly these actions will be put in place - is there a time frame? Actions also need to balanced against other decisions which increase traffic and congestion - for example, Mountfield, Thanington, Kingsmead and the multi-storey car park.

"Hopefully there will be some estimates of how far these suggestions will go to reducing pollution levels in the near future.

"Also, will the council be willing to invest the needed capital and revenue to support these plans? If they are reliant on developer contributions then this appears to be a contradiction."

"The plan could be more visionary, for example, restricting diesel lorries by working with the Canterbury 4 Business to develop some kind of city unified delivery service, using new technologies."

He added: "I am still not sure that councillors have yet to take air quality seriously, despite words to that effect.

"Local people want to work with the council but I think it needs to show willingness and action and not, as it has done in the past, simply dismiss people's concerns about air quality.

"I hope the councillors will now - albeit very late - back some real action."