Tallinn Environmental Department organises random measurements to monitor the level of ambient air pollution. There are three monitoring stations for measuring city air and they belong to national monitoring network. 1. Õismäe monitoring station is located on Õismäe road. It is a measuring station for measuring air quality in the district of high-rise apartment buildings. 2. Rahu monitoring station is located on Kopli street. It is a monitoring station for city's air. 3. Kesklinna monitoring station is located on Liivalaia street. It is a monitoring station for city's air that measures air quality in a region in the centre of the city that has with dense traffic. The results of last week's measurements in the form of diagrams are located here in real time.