"Car-free days" were first introduced in France in 1998 to enhance awareness of pollution from motor vehicles. The event is also an opportunity for real-life tests of some alternatives as traffic is barred to entire urban areas.

The Belgian capital Brussels got in on the act a day early on Sunday with parties and concerts in balmy late-summer temperatures on unusually quiet streets.

Bicyclists, skateboarders and pedestrians had the run of the city as part of the Europe-wide initiative to reclaim city streets from cars.

This year's car-free day should be especially welcome in Paris where, as elsewhere in Europe, hot summer weather caused dangerous levels of ozone concentration.

The August heatwave officially killed some 15,000 people in France, more than 4,000 in Italy and as many as 7,000 in Germany, according to reports.

But Jean-Felix Bernard, President of France's National Air Council, predicted that the overall French death toll in the heatwave in August alone would surpass the 15,000 figure.

Precise figures of the effects of pollution were not avaialble, "but thousands died because of it," he told the newspaper Journal du Dimanche.

"Everyone should take note that this year the effects of pollution on the mortality rate could be higher than that due to car accidents," he warned.

France's ozone levels for August were the highest since records began in 1991. At one point in Paris, ozone concentration topped 200 microgrammes per cubic metre -- 65 percent above the 120 microgrammes considered "safe" for humans.

In Paris Monday the only exceptions to car-free day were to be taxis, environmentally friendly vehicles such as those driven by liquid propane gas or electrically powered, emergency services and local residents allowed to drive around at less than 30 kilometres (18 miles) an hour in the heart of the city.

Bicycles were available for rental at parking stations, and City Hall was lending 200 for free.

In London, a light-hearted phrasebook aiming to persuade motorists to take the bus to work was launched ahead of European In Town Without My Car Day.

The book contains phrases its authors say drivers may have got out of the habit of using, including: "Is that seat free?", "Is this the correct bus stop for...?" and "Are you my neighbour?"

The phrasebook comes as part of a Car User's Survival Kit.

Commenting on the car-free day, British junior transport minister Alan Whitehead told local authorities:

"It should be about helping us to rediscover town centres and should aim to encourage all of us to think about the way we travel into them....

"The government sees most merit in initiatives such as car-sharing, better facilities for walkers and cyclists."

But he added: "This initiative is not an anti-car one and should not be portrayed as such. We recognise the valuable role the car plays in an integrated transport system."

In France, motor vehicles produce 50 percent of the nitrogen dioxide that contributes to ozone concentration at ground level. Cars and trucks also generate 25 percent of the greenhouse gas emissions blamed for climatic changes.

In Paris, public notice boards urge drivers to reduce speed by 20 kilometers (12.5 miles) per hour during pollution peaks.

But even if every single driver abided by the recommendation, this would reduce noxious emissions by a mere three percent, according to critics.

Paris has experimented with alternate traffic, whereby only vehicles with odd numbers are allowed on the road on odd-number dates.

Vehicles with more environmentally friendly engines are exempt from alternate traffic restrictions. But up to 85 percent of vehicles in France now meet the standards required for exemption. Therefore the impact of the scheme is dubious.

One proposal is that northern European countries should put together an "ozone plan" before every summer.

On top of making catalytic converters mandatory, a comprehensive plan would look to restrict industrial gas emissions, change the ingredients in fuels and industrial paints and encourage both rail freight and combined rail-road freight transport.

Two cities not participating Monday were Lisbon and Oporto, Portugal's second city.

"I am not going to turn people's lives into hell," said Oporto Mayor Rui Rio.

TERRA.WIRE