Former radio transmitter site
Measuring air quality at Beromünster
The new NABEL measuring station is on the site of the former international radio transmitter at an altitude of 800 m above sea level, and enjoys an unobstructed view on all sides. This feature, once ideal for the transmission of medium wave radio programs to the rest of the world, now proves to be a great advantage in terms of air-quality measurement – thanks to its location on an unforested hill and far away from large emitters of air pollution, the measurement station can record data of emissions from all sources and from every direction in central Switzerland.
The new Beromünster station is a replacement for the previous site at Lägeren (Canton Aargau), where NABEL measurements will be ended. In contrast to the situation at Lägeren, which was located in a forested area, at Beromünster it will be possible to make measurements of fine particulate concentrations and that of various nitrogen compounds such as ammonia and nitrate.
The 217 metre high tower below which the measurement station is sited (and which is listed as a protected historical structure), also allows air samples to be taken at different levels over ground. This allows additional data on air quality and air pollutant transport to be inferred. Radio transmissions from the tower ended in 2008 – now the structure has a new function, housing not only the historical transmitting equipment but also the newest station in the NABEL network with the very new measurement instrumentation for monitoring air quality.
Continuous air-quality monitoring
The Swiss federal government has been measuring trends and developments in national air-quality since 1979 by means of a network of 16 NABEL stations. These cover a range of typical sites, not just in the immediate vicinity is of emission sources (such as motorways), but also in towns and cities, in typical residential areas and in rural zones such as Beromünster. These measurements over an extended period of time show that air quality has improved markedly during the last decades, but there still remains a certain degree of pollution. Our air continues to show excessive concentrations of some pollutants, such as fine particulates. According to the recently published NABEL Annual Report 2015, it is primarily fine particulates, nitrogen oxides, ammonia and ozone, which continue to represent a challenge in terms of clean air in Switzerland.
The NABEL monitoring network is essential to enforce the Swiss Ordinance on Air Pollution as the data enablethe authorities to measure how successful their efforts to reduce air pollutant emissions are in reality.
NABEL – National Air Pollution Monitoring Network
The NABEL, operated by the Swiss Federal Office for the Environment (FOEN) and Empa, serves to monitor the current state of air-quality and trends in air pollution over the country as a whole. Measurements made by the network include the most important air pollutants, which affect human health or damage the environment, regardless of whether they appear in gas or particle form or are found in precipitation (i.e. rain, snow etc.). Priority is given to measuring the concentrations of those pollutants, which are covered by the Swiss Ordinance on Air Pollution Control, or those which must be monitored in the context of international agreements including air pollution reduction measures (nitrogen dioxide, ozone, fine particulates, sulphur dioxide, benzene, ammonia etc.)
Monitoring and research projects complement each other
The NABEL station at the bottom of the transmitter tower in Beromünster houses not only the measurement equipment but also instruments involved in research on air pollutants and climate-active gases performed by the University of Bern and Empa. The inlet system installed on the tower draws in air at five different heights between 12 m and 212 m above ground and this offers scientists an unique opportunity, in particular for the measurement of greenhouse gas concentrations. The combination of continuous measurement of gas concentrations over a range of different heights, together with the modelling of air mass transport processes, allows the researchers to determine the quantity and origin of greenhouse gases in the air samples.