Investigation of NO2 Behaviour in the Temperate Continental Climate Road Environment

During an extended period from 2010–2012 ambient air quality researches, concentration of nitrogen dioxide (NO2) in the air was measured applying the passive method. In order to evaluate the spatial distribution of pollutants and the major sources, 12 sampling sites across the region were chosen. Additionally, the seasonal changes of this pollutant under different meteorological conditions (air temperature, humidity, wind speed and direction) were investigated. The long-term study showed 3.8 times higher NO2 concentrations in the Mažeikiai urban area (24.2 μg m−3) as compared to other locations in the region (6.3 μg m−3). This confirms the assumption that the main source of NO2 in this area is motor vehicle exhaust fumes. The analysis of the results obtained in different seasons showed a significant difference (p