Particulate matter in urban area of Bologna (Italy): Data dissection

Particulate matter arising from usual activities in urban area is generally indicated as dangerous pollutant. We are reporting some data obtained by aerosol spectrometer which allowed us to know the concentration of three classes of particulate matter (PM10, PM2,5, PM1). The comparison of data recorded in summer and in winter and in some days presenting a particular social situation or in particular weather conditions, indicates the possibility to discriminate the particulate matter amount arising from traffic and arising from other human activities, mainly from heating house. This possibility is due to the values of ratio of the amount of particulate matter: PM10/PM2,5 and PM10/PM1 ratio are near to 1 value for PM deriving from heating house and they are much higher for PM deriving from traffic. The tentative evaluation of the relative importance of the two main sources of particulate matter is about half for one, but the emission of particulate matter of heating house is largely predominant in the presence of some meteorological events such as thermal inversion. The fashion regarding heating house by firewood heaters, without any check or abatement, aggravates the hazards associated to the home heating. However, the pollution from traffic regards the whole year, while the pollution from heating house is on 5 or 6 months only. Consequently, the relative importance of the two sources in releasing PM10 in air in a year results in four times higher for traffic than for home heating.