Chemical Profile of Atmospheric Particulate Matter During High Concentration Events
Atmospheric pollution due to airborne fine particles is an environmental issue of great concern in the metropolitan area of Milan. The most critical situation for the air quality usually occurs in winter when days with PM10 concentrations greater than 100 µg m-3 are frequently measured by the regional monitoring network. Sampling campaigns were performed for these periods with a high volume sampler. Carbonaceous and ionic species were analyzed, in particular, elemental and organic carbon have been determined by thermal optical transmittance method, nitrate, sulfate, ammonium, and chloride by high pressure liquid chromatography technique. PM speciation data are studied in combination with the concentration levels of criteria pollutants for the air quality and the meteorological parameters (atmospheric stability and boundary layer daily evolution) for the purpose of determining the behavior of the different particulate components during these events. The results of the analyses indicate increased contribution of nitrate and particulate organic matter to the PM bulk mass. Principal component analysis (PCA) is applied to speciated PM data, meteorological parameters and criteria pollutants for the area in order to tentatively point out the origin of particulate species. The main goal of this work is to define the priority of the various actions in air pollution prevention and control strategies.