The prefecture has raised the alert level for the whole valley of the Arve. In the valley of Chamonix, the rates of fine particles in the air are above the threshold of information and recommendations (80 micrograms per cubic meter) and values (87 micrograms per cubic meter) and they are even above the level of Pollution found in Cluses and Sallanches (79 micrograms per cubic meter). The weather in France provides a high pressure for at least 10 days, the air mass will be very stable. It is therefore necessary to minimize the pollution causes. The Prefecture has decided to reduce the speed to 20 km / h in the valley of the Arve, on road and highway. Radio Mont Blanc
