According to the Federal Office of the Environment, at least 40% of the Swiss population are exposed to excessive particles. On the whole these are urban dwellers, and people living close to busy roads.

It is estimated that more than 3,700 people die prematurely in Switzerland as a result of air pollution each year. Fine particles are the main cause. In badly polluted areas a person can take in some 50 million particles with every breath. They reach the lungs and from there enter the bloodstream.

They can cause chronic coughing, bronchitis, asthma, lung cancer, and circulatory problems, including heart attacks.