Paris is experiencing severe air pollution, prompting a rethink over how to tackle the problem, which is already yielding ideas from which other cities could benefit.

First Beijing, now Paris is choking. At the end of last week the threshold for particulate pollution in the French capital was exceeded for the fourth consecutive day, in Ile-de-France and thirty departments covering a large part of the North and the region Rhône-Alpes. According to the European Environment Agency (EEA) there were 147 micrograms of particulate matter (PM) per cubic meter of air in Paris compared with 114 in Brussels, 104 in Amsterdam, 81 in Berlin and 79.7 in London.

And pollution watchdog airqualitynow.eu said that air pollution topped is 100 maximum index, compared to 81 in London and 76 in Berlin. A lack of wind and unseasonally high temperatures were blamed. The pollution levels are not as high as experienced recently in many cities in China, but still exceed guidelines issued by the World Health Organization (WHO).

What air pollution are we talking about?

WHO says that the four air pollutants particularly dangerous to health are:

• fine particulate matter (PM₁₀ and PM_2.5);
• nitrogen dioxide (NO₂);
• carbon monoxide (CO);
• and ozone (O₃).

The fine particles are mostly emitted by traffic. They can cause chronic bronchitis, asthma, lung cancer, strokes, myocardial infection or placental problems. There are no regulations affecting PM_2.5, which is more dangerous than PM₁₀.

Nitrogen oxides (NO_x) form during combustion at high temperature and cause bronchitis, especially in asthmatics and children. Along with sulfur dioxide they help create acid rain.

Carbon monoxide is a blood poison and can cause headaches, nausea, vomiting and dizziness.

Ozone is formed by a chemical reaction between automotive and industrial gases and ultraviolet sunshine. It can cause bronchial inflammation, respiratory problems and eye irritation.

What is Paris doing?

Two of the culprits for the air pollution are recent fiscal support favouring the use of diesel over gasoline in automobiles, and heavy private traffic in the capital.

Emergency measures

As a temporary measure the government is telling drivers to only drive in on alternate days: those with odd-numbered registration plates will be allowed to drive today, Monday, and those with even-numbered the following day, and so on until the problem eases.

While this is seemingly a sensible option, it has not succeeded very well in other cities where it has been tried. Operated over a longer term people will borrow each other's cars with appropriate numberplates or buy a second vehicle to the same end.

Secondly, public transport has also be made free of charge for four days from Friday, to encourage people to leave their cars behind.

However tradespeople and delivery vehicle drivers are complaining that they cannot run their businesses.

Longer term solutions

In an attempt to tackle air pollution incidents in the past, the authorities a while ago introduced bike and car sharing schemes which have since been emulated in other cities, such as London.

Electric vehicles and car sharing

Electric vehicles emit no pollution at their point of use. Any pollution happens at the power station, although since most of France's electricity is low carbon (nuclear), this provides benefits all round.

Autolib is an electric car sharing service which was introduced on the initiative of Mayor Bertrand Delanoë.

It is very easy for drivers to sign up to Autolib: all they need is a driving licence, a valid ID and a credit card. They are then given a badge and can go to any rental station to hire their 'Bluecar' (see picture). Various recharging stations are around the city where drivers can leave the car recharging while they go about their business.

Subscription costs just €120 a year, plus €5.5 per half hour of usage. Companies can take out a package for their employees.

It's estimated that the 3000 Bluecars rented out in Paris replace the equivalent of 22,500 private vehicles on the city's streets and 164.5 million kilometers driven per year by polluting combustion engine vehicles.

While the pollution emergency is continuing, Autolib is offering a rental-free hour to all current subscribers as well as new subscribers.

Autolib has been so successful that it is franchising to other cities. The CEO of Bollore, the company which owns the scheme, Vincent Bollore, is now a billionaire. Just last week he unveiled plans for a similar scheme with 3,000 electric cars on London streets by 2016. They have already been dubbed 'Boris cars', after the Mayor of London's bike-sharing scheme's cycles being named 'Boris bikes'.

Bike sharing

Vélib was one of the first public bike sharing schemes in the world to be a instituted in a city. It now operates about 14,000 bicycles with 1230 bicycle stations, like the one pictured right, across Paris and some surrounding municipalities. It's estimated that there are about 100,000 trips per day using the bicycles.

The familiar grey bikes are produced in Hungary. Subscription costs from €29 per year, which gives bike rental free for the first half hour of every individual trip. Each subsequent 30 minute period costs between one euro and four euros. This keeps the bikes in circulation. The system uses credit cards which take a €150 deposit to protect against bikes not being returned.

The whole deal is sponsored by the the JCDecaux advertising corporation, in return for the city of Paris signing over the income from a substantial portion of on?street advertising hoardings.

Further into the future

Electric buses

Looking into the future, another idea to prevent recurrence of the smog problem is to convert the entire bus fleet in Paris to electricity by 2025, according to Pierre Mongin, CEO of RATP in an interview with Le Monde newspaper last week. He cited "a strong demand for solution to pollution-neutral transport" from Parisians.

He gave the example of London, where a certain number of buses have already been converted to hybrid (diesel-electric). When asked about the high cost, he said that once the decision had been made large orders will be placed which would bring the unit price down. He will issue a tender later this year.

Increasing electric vehicle ownership

Another solution is to extend ownership of electrical vehicles. This is already happening, with the cooperation of local authorities and mayors. France is already the largest market for electric vehicles in Europe. Since launching a plan to develop electric and hybrid vehicles in October 2009 many city councils and local authorities have become involved in promoting it.

Many French cities have copied the Autolib system, with "l'Auto bleue" in Nice, "Sunmoove" in Lyon and "Bluecub" in Bordeaux, etc. Municipalities are encouraged with an award, the "Electromobile City Trophy", presented every year to regional and local authorities (cities, inter-municipal associations, etc.) which have shown especial commitment to sustainable mobility, especially electric mobility, in their region.

The policy has boosted the French auto manufacturing industry, with Renault selling the largest number of electric vehicles in Europe (6,000 cars during the first half of 2013), ahead of Nissan (5,500 cars) and Smart (1,500 cars). In 2013, electric and hybrid vehicles reached 3.1% of all passenger cars sold in France, up 50% on the previous year, with 8,779 electric passenger cars registered.

Towards cleaner air

Air pollution incidents like the one happening in Paris now cause economic damage as well as poor health and early mortality. That France is doing well in tackling the problem is evidenced by the fact that other cities and nations are taking up its ideas.

Meanwhile, Parisians suffering from the smog are praying for rain, which will have more effect than any of the above measures, in immediately washing the pollution from the atmosphere.