[Pollution and allergy: the epidemiological data]

This area is controversial, mostly because of disagreement between experimental and epidemiological data. Even though modulation of asthma by the level of atmospheric pollution has been well shown by panel and ecological studies, the relationship between pollution and genesis of allergic diseases has not been confirmed by epidemiological studies. Comparison of the frequency of asthma in urban and rural surroundings in general shows, in the urban environment, an advantage of irritation symptoms but not for asthma. In contrast, the prevalence of atopy seems higher in the urban environment, which is perhaps a reflection of a different way of life, like that shown in east-west studies. Several recent investigations showed that at the centre of a development additional respiratory symptoms related to the intensity of automobile traffic, but no relationship was shown with atopy. In the same way, no epidemiological investigation has shown a relationship between automobile pollution and prevalence of atopy. Thus, at present no solid elements exist to support an increase of the frequency of asthma and especially atopy, in a relationship with modern atmospheric pollution, essentially of automobile origin.