The locations of sites were chosen in order to achieve results representative for the conditions in various sub-areas of Tallinn.

The measurement sites were classified into four types according to exposure to road vehicle emissions and street ventilation conditions, and the measurements were made at urban as well as at background sites. The classification of sites enables comparison of similar environments in a whole region, and of the variations in air pollution levels in different typical local environments.

The four classes of sites were:
A = busy street environment, poor ventilation
B = busy street environment, good ventilation
C = residential area
D = general pollution level, local background

A total of around 90 measurement sites have been used. The locations of the stations were selected by the Environmental Department in Tallinn in co-operation with IVL.

The map of Tallinn with the station network where the classification of sites is included.

Click for larger image (1500x1200 pixels, 176kb).