SO2 concentrations exceed limit values near the border to Russia
SO2 has been measured continuously at Svanvik in Norway and at Maajavri and in Nikel in Russia. At Viksjøfjell in Norway the sampling of SO2 was stopped at the beginning of August 1996. To register the high short term peak concentrations during episodes continuous measurements of SO2 are necessary.
A typical feature of SO2 concentrations at the monitoring stations is represented by low long-term average concentrations whereas the peak values (24-hour averages or shorter) are well above air quality guideline values.
At Svanvik the average SO2 value during the monitoring period 2001-2002 was 6,5 µg/m3, the highest 24-hour average was 107 µg/m3 and the highest 1-hour average value was 503 µg/m3. The limit values for protection of human health are 90 µg/m3 (daily, as a daily national long term objective value given by SFT for Norway), 125 µg/m3 (daily, Norwegian limit value and EU limit value), 350 µg/m3 (hourly limit value) and 500 µg/m3 (10 minutes, World Health Organization, WHO), respectively.
The 24-hour value of 90 µg/m3 was exceeded twice during the winter half year 2001/02. The EU 1 hour limit value of 350 µg/m3 was exceeded once during the summer half year, and twice during the winter half year. The EU limit value permits 24 exceedances a year.