Measurements of air bone particles in Riga city and identification of their possible sources

Full text: There is increasing attention to particulate matter with aerodynamic diameter of 10 micro m and less due to hostile effects on human health (Clarke et. al., 1999). Many countries are monitoring atmospheric particles, but this monitoring is concentrated mainly to urban areas. In Latvia, the monitoring of air pollution is mainly focussed on gaseous pollutants such as sulphur dioxide, nitrogen oxides, ozone, benzene, toluene, formaldehyde, p-xylene (Danilane et.al. 1999). The pollution level is measured with DOAS type air monitoring stations. The measurements of airborne particle matter and its size distribution are still not used for air quality control in Latvia. In the current project airborne particles were investigated in Riga city central part during October 2000. Mass concentration, elemental concentrations and size distribution of the airborne particles were measured. A dichotomous impactor was used for sampling fine (<2.5 micro m) and coarse (2.5-10 micro m) fractions of airborne particles. For size distribution of different elements (0.25-16 micro m), a seven stage Batelle cascade impactor was used. The dichotomous impactor samples were collected on 37 mm Teflon membrane filters (Gelman Science, PIN R2PJ037), but for the collection of samples with the cascade impactor quartz plates treated with silicone grease were used. Total reflection X-ray fluorescence (TXRF) and energy dispersive X-ray fluorescence (EDXRF) were used for analysis of the collected samples (Standzenieks et al. 1979). The obtained results were treated by Pearson correlation, cluster and factor analysis. The results show that whereas naturally generated soil particles are a major part in the coarse particles fraction, whereas particles generated by human activities are dominating in the size fraction of 0.25 micro m