Ozone

The ozone at an altitude of 10 to 40 km in the atmosphere is vitally important. The ozone layer protects us from dangerous UV radiation from the sun.
On the other hand, when ozone is close to the ground in higher concentrations, it is damaging to our health. The limit value of 120 ug/m3 as hourly average is often exceeded between May and September. The highest ozone values are reached on sunny days during the course of the afternoon.

The way people react to high ozone values varies greatly from person to person. Whereas some do not notice it all, certain people suffer from sore eyes and tickly throats. The higher the ozone concentration, the greater the number of people affected and the more acute the irritation to the eyes and respiratory system. People who have repeatedly displayed medical symptoms as a result of reacting to high levels of ozone should only carry out strenuous, physical activities in the morning or evening.

The National Air Impurities Observation network ("NABEL") issues up-to-date information on conditions at 16 locations all over Switzerland. You can get the average hourly value from 15:00 to 16:00 hours of the current day for each location from SAEFL.

Every day from the beginning of May to the end of September, MeteoSwiss puts together a forecast of the maximum hourly ozone value for the next 3 days. The values specified apply to the zones shown on the map which appear when you put your mouse pointer over the station names. Zones at that level appear in green, whereas zones at approximately the altitude of the measuring station are in red.