High SO2 concentrations in the Norwegian Russian border areas

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Very high concentrations of SO2 were recorded in the border area between Norway and Russia during the first two weeks of July 2007. Concentrations exceeding 20 times the EU limit concentration value were recorded in the town of Nikel. The reason for this was a combination of meteorological conditions with low wind blowing from the nikel smelter towards the monitoring station for almost one week. It was assumed that the low level emissions of SO2 around the factory buildings were higher than normal.

NILU has been measuring air pollutants close to the border between Norway and Russia since 1974. Presently air quality is being measured at one station, precipitation chemistry data were collected at two locations and meteorological parameters were measured at one location on the Norwegian side of the border. On the Russian side SO2 is being measured at one site in the town of Nikel about 600 m from the nikel smelter area.

High SO2 concentrations in the Norwegian Russian border areas

The average emissions of SO2 have been reduced during the last ten years. Exceeding of Norwegian and EU limit values for SO2 are still being recorded. In 2005-2006 there were 64 days of daily concentrations of SO2 in Nikel exceeding 125 µg/m3. In Svanvik, on the Norwegian side of the border, there was one such exceedance.

On 2 July 2007 the 24-hour average SO2 concentration in Svanvik again exceeded 125 µg/m3. This incident was followed by a ten day period of SO2 concentrations in Nikel ranging between 1000 and 7000 µg/m3.

High SO2 concentrations in the Norwegian Russian border areas

It was believed that together with very low wind conditions there must also have been an elevated emission rate of SO2 from the low sources at the building complex of the smelter.

After 14 July the situation normalised, and the wind conditions changed. Concentrations of SO2 in Nikel still occasionally exceeded EU limit values, but this is quite normal. On 24-25 July the daily SO2 concentrations again were more than twice the EU limit values. In Svanvik we have until 1 Sept. 2007 not recorded any more exceeding of the limit values.

The episode during the beginning of July 2007 was a combination of elevated SO2 emissions around the buildings combined with meteorological conditions. It was followed by discussions of improved monitoring, surveillance and air quality information to the public in the area. Also a better co-ordination and collaboration between Norwegian experts and Russian experts has been proposed. NILU will participate actively in this process.

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