VARIATION OF PM10 MASS AND AEROSOL NUMBER CONCENTRATIONS IN ŠIAULIAI

The urban environment is distinguished by higher aerosol and gaseous pollutant concentrations than those in rural areas. A study of aerosol pollutant behavior was performed in an industrial Lithuanian city of Šiauliai. The PM10 mass concentration and meteorological parameter monitoring data were analysed. The aerosol number concentration was measured during a 10‐day experiment in Šiauliai. Analysis of PM10 showed that the workdays‐weekends phenomenon in the PM10 mass concentration distribution was prevailing. The PM10 mass concentration on workdays was higher in comparison with the concentration at weekends, 24,6 μg/m3 and 21 μg/m3, respectively. Clear PM10 mass concentration dependence on the wind parameters (speed and direction) was found. Linear relationship between aerosol number and PM10 mass concentrations was found at a high particle number concentration (more than 18000 cm−3). PM10 level in Šiauliai was defined as a sum of three sources: regional background, urban background and local sources. Contribution of these sources to the total PM10 mass concentration was estimated to be 36 %, 30 % and 34 %, respectively, during June‐October of 2005.