In Turku region lives approximately 250 000 inhabitants.
According to the EU air quality directive (96/62/EC) there is not a need to
have several monitoring stations in the region when the concentrations of different
pollutants are quite low. The ambient air quality monitoring in the Turku region
is carried out in co-operation with the municipalities and the largest
polluters in the region so the number of monitoring stations is six.
The basic locations of the monitoring stations were
studied by using a dispersion modelling carried out by the Finnish
Meteorological Institute (FMI). In this study the point sources of the
pollutants were recognised and so were the trans-boundary emissions and traffic
emissions. Some of the monitoring stations are situated in the prevailing wind
direction from the polluting sources because of the need of the polluters to be
aware of the effects of their emissions in the ambient air. Most of the
monitoring stations are located in the areas where there are people e.g. in the
city centre because people are exposed to the impurities in the ambient air.
The reason of the several monitoring stations in the city centres is based on
the legislation demand that the municipality must be aware of the state of the
environment within its region.
The monitoring stations in the city centres are located
according to the EU directive location demands (99/30/EC), e.g. at least 25
meters from junction area, when the concentrations of nitrogen oxides are
monitored. Whether the locations represent a larger area of the city centre is
difficult to estimate. The final location of the monitoring stations is of
course a compromise of the electricity, telephone line and the undisturbed
sampling.
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