Particulate PAHs in two urban areas of Southern Italy: Impact of the sources, meteorological and background conditions on air quality.

The present work studied how much the meteorological parameters and the emission sources can influence the particulate polycyclic aromatic hydrocarbons (Invalid Journal Information PAHs) concentrations in two areas located in Southern Italy (Bari and Taranto). It was found that when the vehicular traffic is the main source of PAHs, there is a negative correlation between ambient temperature, wind speed and PAHs concentration (Bari). This is because these parameters are generally correlated with the dispersion capacity of the atmosphere. In the presence of a large industrial area, the wind direction becomes an important parameter able to determinate large changes in PAHs concentrations. This happened in Taranto where PAHs concentrations are exceptionally high. During the study the seasonal trend of particulate PAHs and PM10 was compared. PM10 did not show a significant seasonal cycle during the year because it is conditioned from a high regional aerosol background, especially during the summertime. On the contrary, particulate PAHs exerted distinct seasonal variation with higher concentrations in the winter and lower concentration during other months of the year. This evidence suggested that PAHs concentrations can be considered a more reliable index for air-quality assessment. In order to identify an index that considers the contributions of other particulate PAHs, it is necessary to calculate the carcinogenic potency of total PAHs (i.e., total BaPeq) obtained by the sum of the benzo[a]pyrene equivalent concentration (BaPeq) for each PAH.