Measurement of nitrogen dioxide concentration in cold and warm seasons using a passive sampling method

Abstract

The aim of the present study was to assess distribution of nitrogen dioxide concentration in Kaunas city during cold and warm sea­sons. A passive sampling method was used. Nitrogen dioxide con­centration was measured at 39 sampling sites in Kaunas city. The study was performed in 2010–2011. The study results showed that mean of nitrogen dioxide concentration in Kaunas city was 12.0 µg/m³. Nitrogen dioxide concentration in cold season (winter) was 18.2 µg/m³, in warm season (summer) 5.7 µg/m³. The high­est nitrogen dioxide concentration was obtained near street site (14.9 µg/m³), the lowest  –  near regional background site (9.4 µg/m³) and near urban background site it was 11.4 µg/m³.
The results of the study were introduced to the ESRI Geographic Information System software ArcGIS and the ex­tension Geostatistical Analyst was used to obtain maps of dis­tribution of nitrogen dioxide concentration.
The lowest nitrogen dioxide pollution area was in districts which are located in the periphery of the city. The highest concen­tra­tion of nitrogen dioxide was in Centras, Žaliakalnis, Šančiai, Kalnie­čiai, Sargėnai. It was caused by intensive traffic and unfavourable geographical position. In these districts there are more busy roads and more buildings. Centras district is located in a valley; there are unfavourable conditions for pollution dispersion.