[Metals, air pollution, and health: mosses to the rescue of epidemiology].

While evidence has accumulated about the links between long-term exposure to air pollution and health, little is known about the health effects of airborne metals. In France, the law makes it mandatory to monitor atmospheric concentrations and deposition of some airborne metals, through measurements or modelling. But the available data are either too scarce or irregular, making them difficult to use in large-scale epidemiology: using mosses in the wild offers a welcome alternative. Mosses belong to the few vegetal organisms able to accumulate airborne metals. As such, they have been used for decades in air quality survey networks in Europe. They provide data to assess population exposure to airborne metals and may complement classical research programmes on air pollution epidemiology. As an example, we estimated associations between exposure to airborne metals of anthropogenic origin and increased mortality in France.