Air pollution spikes bring shift in transport thinking

A period of calm weather meant that normal emissions levels suddenly became threatening to human health. The city’s pollution monitor sounded the warning when concentrations of PM10 particles exceeded 80 micrograms per cubic metre; they were reported to have peaked at 120.

The mayor of Paris Anne Hidalgo said any cars with an even-numbered registration had to stay off the roads, and public transport was made free. Exemptions were made for ‘clean’ cars – generally electric and hybrid vehicles. Lorries had to avoid the city centre, while a maximum speed limit of 20 km/h was introduced for the day (23 March). Around 750 police officers were sent to patrol the main roads, fining anyone not entitled to be there €22 and telling them to leave their vehicle where it was.

The ban lasted just one day because fresher winds arrived the following day, but it is thought to have reduced traffic levels by 40%. It is not yet clear how much pollution it saved.

As well as Paris, London and Brussels also recorded dangerously high pollution levels but did not introduce any restrictions. The British health agency Public Health England warned ‘vulnerable groups such as those with existing heart or lung conditions’ to be careful. And Brussels recorded particulate matter levels more than twice the European annual average. The levels brought comparisons with Shanghai and Beijing, as the two Chinese cities regularly top global air pollution tables.

Recent urban air pollution spikes have resulted in a shift in transport thinking from reducing greenhouse gases to reducing the air pollution responsible for thousands of premature deaths every year. Diesel cars had been favoured because they emit less CO₂ than petrol, but T&E says that because of its higher lifecycle emissions – in part because over its lifetime it will be driven much further on cheaper fuel – the average diesel car bought in the EU emits more CO₂ than the average gasoline car.