Abstract:

A short but intensive snowfall occurred in Nanjing on February 19, 2013. Based on meteorological and environmental monitoring data, the impact of this process on various pollution sources and concentrations of pollutants was analyzed. Correlations between different pollutants and meteorological factors were discussed by a Pearson correlation analysis method. The results indicate that this snowstorm has significant impact on area pollution sources in Nanjing. In particular, fugitive dust emissions are almost not found. Mobile sources are mainly influenced by the number of vehicle during morning and evening rush hour peaks. Very little impact is found for industrial point sources. After this process, the ambient air quality reaches the excellence grade. AQI on February 19 decreases by 35% compared with that on February 18 or 20, 2013. SO₂ diurnal variation on February 19 remains to be a single peak, while PM and NO₂ diurnal variation in this day is not bimodal pattern as usual. PM_2.5 concentration has a significant positive correlation with concentrations of PM₁₀, SO₂, NO₂ and CO, and corresponding correlation coefficients are 0.979, 0.663, 0.837, and 0.875 respectively, which means the similar sources of those pollutants emissions. Concentrations of pollutants are significant negative correlations with wind speed and relative humidity and positive correlations with air temperature and pressure.

Key words: Snowstorm, Pollution source, Pollutant, Meteorological element