Impact of meteorological conditions on airborne fine particle composition and secondary pollutant characteristics in urban area during winter-time.

The assessment of airborne fine particle composition and secondary pollutant characteristics in the case of Augsburg, Germany, during winter (31 January-12 March 2010) is studied on the basis of aerosol mass spectrometry (3 non-refractory components and organic matter, 3 positive matrix factorizations (PMF) factors), particle size distributions (PSD, 5 size modes, 5 PMF factors), further air pollutant mass concentrations (7 gases and VOC, black carbon, PM10, PM2.5) and meteorological measurements, including mixing layer height (MLH), with one-hourly temporal resolution. Data were subjectively assigned to 10 temporal phases which are characterised by different meteorological influences and air pollutant concentrations. In each phase hierarchical clustering analysis with the Ward method was applied to the correlations of air pollutants, PM components, PM source contributions and PSD modes and correlations of these data with all meteorological parameters. This analysis resulted in different degrees of sensitivities of these air pollutant data to single meteorological parameters. It is generally found that wind speed (negatively), MLH (negatively), relative humidity (positively) and wind direction influence primary pollutant and accumulation mode particle (size range 100-500 nm) concentrations. Temperature (negatively), absolute humidity (negatively) and also relative humidity (positively) are relevant for secondary compounds of PM and particle (PM2.5, PM10) mass concentrations. NO, nucleation and Aitken mode particle and the fresh traffic aerosol concentrations are only weakly dependent on meteorological parameters and thus are driven by emissions. These daily variation data analyses provide new, detailed meteorological influences on air pollutant data with the focus on fine particle composition and secondary pollutant characteristics and can explain major parts of certain PM component and gaseous pollutant exposure