The variability of PM₁₀ and PM_2.5 concentrations in selected Polish agglomerations: the role of meteorological conditions, 2006–2016

<p>The research focuses on the analysis of PM₁₀ and PM_2.5 concentrations variability at 11 stations in selected urbanized areas of Poland (Tricity, Poznań, Łódź, Kraków). Methods comprised: the analysis of basic statistical characteristics in yearly/monthly/daily/hourly scale and threshold exceedance frequencies. Also, correlations between PM₁₀ and meteorological variables were investigated. GEV distribution analysis allowed the estimation of the return levels of monthly maxima of PM₁₀ and PM_2.5. Results show that in Tricity there are fewer than 5 % of days with PM₁₀ and PM_2.5 threshold exceedance. In Kraków, the standards are only met during summer and the frequency of daily PM limit exceedance in winter was around 65–90 %. GEV analysis indicates that 10<i>y</i> return level of PM₁₀ monthly maximum daily average do not usually exceed 250 μg/m³ at most of the stations (Kraków agglomeration is an exception here). In winter, the meteorological conditions unfavourable to the pollutant’s dispersion comprise: high-pressure systems, stable equilibrium in the atmosphere and limited turbulence occur quite often together with low wind speed and reduced height of the planetary boundary layer.