Sources and atmospheric concentrations of polycyclic aromatic hydrocarbons and heavy metals in two Italian towns (Genoa and La Spezia)

The same sampling and analytical methods were used to compare atmospheric pollution due to polycyclic aromatic hydrocarbons (PAHs) and heavy metals (Tl, Pb, Mn, Fe, Cr, V, Zr, Ni. Cd) in two towns in Italy, Genoa and La Spezia, whose populations are 746 785 and 112 602, respectively. Knowledge of the organic and inorganic composition of airborne particulates permits a reliable identification of the main sources of pollution which is required in order to identify populations at risk. In the urban area of Genoa and in La Spezia, traffic appears to provide a diffuse source of carcinogenic and toxic compounds in the atmosphere producing high and constant exposures to PAHs and lead along busy streets. In Genoa ∼ 70 000 people (10% of residents) are considered to be exposed to the highest concentrations of toxic and cancerogenic pollutants emitted from this source. The highest daily PAH concentrations were found in the industrial areas; in Genoa, coke ovens were identified as the main localised sources of these compounds. According to meteorological and orographic characteristics of this area, for ∼ 25 000 people (3% of the general population) may be exposed to pollutants emitted from this source over a maximum period equivalent to ∼ 3 months each year. The highest individual doses of PAHs due to urban pollution inhaled by the population of Genoa and La Spezia were comparable to those produced by high exposure to passive smoke; the exposure to carcinogenic metals (Cr, Ni, Cd) was relatively low. The mean concentrations of the analysed pollutants appeared to depend strictly on urban characteristics; no correlations were found with the size of the towns.