Investigation of NO2 behaviour in the temperate continental climate road environment

Abstract

During an extended period from 2010–2012 ambient air quality researches, concentration of nitrogen dioxide (NO 2) 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 NO 2 concentrations in the Mažeikiai urban area (24.2 μ gm−3)ascomparedto other locations in the region (6.3 μ gm − 3). This confirms the assumption that the main source of NO 2 in this area is motor vehicle exhaust fumes. The analysis of the results obtained in different seasons showed a significant difference (p <0.05) in NO 2 concentrations under different meteorological conditions. The increase in NO 2 concentrations was recorded in the winter and late autumn seasons, due to reduced solar radiation and lower temperatures. Cluster analysis results showed that sampling sites can be grouped into different classes based on NO 2 main source, motor vehicles and traffic intensity.