EVALUATION OF LITHUANIAN AIR QUALITY MONITORING DATA APPLYING SYNOPTICAL ANALYSIS

Abstract

Relationship between synoptical patterns and different pollutants was analysed in the study. Cases with ozone concentrations higher or equal to the 95th percentile of monthly ozone concentrations were analysed over the period 2002–2005. Ozone concentration cases were grouped into seven concentration intervals and analysed according to synoptical patterns (cold, warm and occluded fronts). Relationship between SO2, SO4 and NO2 and synoptical objects was analysed during warm and cold seasons. The influence of cold, warm and occluded fronts on the high ozone level formation are very similar at both Lithuanian rural stations of Preila and Rūgšteliškes. The influence of all the fronts was more significant during night hours at a relatively low (50–100 μg/m3) and high (>100 μg/m3) ozone levels during day hours. The concentrations of gaseous SO2, NO2 and aerosol SO4 pollutants for the cases with hourly ozone concentration values ≥95th percentile were analysed. The influence of different synoptical patterns was found to be stronger during a warm season and lower during a cold season of the year.