SO2 concentration in Copenhagen(1988-92)
As regards SO2, the most important limit is that the concentration in the air 98% of the year (the 98% percentile) must not exceed 250 µg/m3. The winter mean value must not exceed 130 µg/m3 and the annual mean must not exceed 80 µg/m3.
In the case of NO2, the current limit value is 200 µg/m3 (98% percentile).
With particulates the annual mean must not exceed 150 µg/m3 and the 95% percentile must not exceed 300 µg/m3. The limit value for the lead content of the air is stipulated in Directive 82/884 as an annual mean of 2 µg/m3.
A common provision of these Directives is that if the limit values are exceeded, the environmental authorities have to implement measures to remedy the situation and inform the EC Commission.
SO2 concentration in Copenhagen(1988-92)
Finally, Directive 92/72 regulates ozone pollution of the air. The Directive requires the implementation of a monitoring programme and stipulates a number of threshold values. For example, the population has to be informed if the hourly mean exceeds 180 µg/m3.
NO2 concentretion in Copenhagen(1988-92)
The Directives regulating the air content of SO2, NO2 and particulates have been directly implemented in Danish legislation. The Directive on the lead content of the air has not been implemented because the lead content of the air in Denmark is well below the limit value. The ozone directive has been implemented directly.
Actual conditions in Denmark11 are such that the SO2 concentration in the centre of Copenhagen in 1992 was approx. 55 µg/m3 (98% percentile) while the annual mean was 15 µg/m3. In the beginning of the 1970s the annual mean SO2 concentration at the same location was around 80 µg/m3.
The NO2 concentration of the air in the centre of Copenhagen in 1992 was approx. 115 µg/m3 (98% percentile) while the annual mean was approx. 55 µg/m3.
The air concentration of particulates in the centre of Copenhagen was around an annual mean of 75 µg/m3 in 1992.
The lead content of the air of Danish towns was around 0.6 µg/m3 in 1984, but has now fallen to 0.1 µg/m3 .
The yearly mean ozone concentration in the Danish countryside is approx. 60 µg/m3, but varies between approx. 90 µg/m3 in the spring and 40 µg/m3 in the winter. Over an 8-year period of hourly measurements the hourly mean concentration only exceeded the Directive’s limit level of 180 µg/m3 for 14 measurements spread over 3 days.
Progress with respect to the regulation of air pollution is difficult to assess, most of the decrease in the air content of SO2, particulates and lead being largely attributable to factors other than the environmental requirements per se. Thus the decrease in the lead content of the air closely correlates with the decrease in the consumption of leaded petrol. In the case of SO2 and particulates, the concentrations started to fall in the 1970s as a result of the construction of high smokestacks; further factors of importance were the introduction of particulate abatement measures for flue gasses in 1970s and the introduction of low sulphur fuels and SO2 abatement measures for flue gasses in the 1980s.
Concentration of TSP(total suspended particulates) in Copenhagen (1988-92)
The tendency with respect to NO2 is probably a fall since 1988, although
the figures are somewhat unclear. The figures for ozone have been relatively constant
since measurements were started in 1985.
