Benzene is a carcinogenic air pollutant, and at high concentrations it can also affect the eyes, the respiratory tract and the central nervous system. For such pollutants, no limit level has been determined, below which a health hazard no longer exists. In view of this, the presence of benzene in the air we breathe is undesirable.
Benzene is primarily produced through the burning and evaporation of engine fuels and combustibles. The main sources are motorised transport, filling stations, furnaces and heating systems, and tobacco smoke.
In the past few years, benzene immissions have decreased, primarily as a result of the reduction of the maximum permissible benzene content in engine fuels and vapour recovery at filling stations and tank depots. Nonetheless, the present-day level of benzene pollution is too high and represents a cancer risk for the population that is greater than the tolerable level specified by the Federal Commission for Air Hygiene. Emissions from combustion processes and the evaporation of fuels and combustibles therefore have to be further reduced.
EU member states also measure benzene immissions and produce corresponding indicators. The levels of benzene are lower in Switzerland than in some parts of its neighbouring countrie.
The current status and development of air pollution throughout Switzerland are measured and recorded by the National Air Pollution Monitoring Network (NABEL), which is jointly operated by the FOEN and EMPA (Swiss Federal Laboratories for Materials Science and Technology). It comprises 16 measurement stations distributed throughout the country, which provide data relating to all the most important pollution situations. For the assessment of benzene immissions, data are collected from NABEL stations with permanent measurement cycles.
|Targeted trend||Initial value||Final value||Variation in %||Observed trend||Assessment|
|Decrease||(1) Average 2011-2013, (2) Average 2001-2003, (3) Average 1995-1997, (4) Average 2001-2003||(1) Average 2016-2018, (2) Average 2015-2017, (3) Average 2016-2018, (4) Average 2015-2017||(1) -31.40%, (2) -60.14%, (3) -86.28%, (4) -60.07%||(1) Decrease, (2) Decrease, (3) Decrease, (4) Decrease||positive|
|(1) urban, heavy traffic (Bern-Bollwerk), (2) urban (Zürich-Kaserne), (3) suburban (Dübendorf-Empa), (4) pre-alpine/Jura range (Rigi-Seebodenalp)|