Smoky signals

pollution alerts have become frequent in France. Paris authorities issued pollution alerts twice last month. The first was issued on August 13, when a northwesterly wind significantly reduced levels of oxygen. Authorities urged city residents to leave their cars at home and use public transport. Later, they lifted the alert as winds helped to disperse a concentration of ozone over the city that had led to the health warnings.

Then on August 17, officials issued new pollution alerts for Paris and Strasbourg. Public health officials said that the two cities registered pollution levels at 'level two', the midpoint on the official scale and one step below the 'level three' alert requiring curbs on private cars and free public transport in large cities. The pollution alert has triggered a debate about France's environmental policy.

The French government is now considering imposing tougher controls on car emissions. "I would like France to adopt an 'eco-tax' on energy and carbon dioxide," said environment minister, Dominique Voynet.