[Carcinogens in the urban environment of Italian cities: benzene and benzo(a)pyrenes].

: In Italian urban areas air pollution from benzene and benzo(a)pyrene-B(a)P--is mostly caused by traffic. The concentration limits in the atmosphere fixed by Italian legislation up to December 31, 1998 expressed as annual means are 15 micrograms/m3 and 2.5 ng/m3 for benzene and B(a)P respectively and, starting from January 1, 1999, 10 micrograms/m3 and 1 ng/m3. In the city of Florence the concentrations detected and expressed as annual means of benzene and B(a)P in an area with heavy traffic (32.1 micrograms/m3 and 3.5 ng/m3), in a densely populated area (9.2 micrograms/m3 and 1.86 ng/m3), and in a city park (6.0 micrograms/m3 and 0.25 ng/m3), suggest a marked progressive reduction in the atmospheric levels of these chemicals with the distance from the main roads. The environmental data obtained from densely populated areas of a number of Italian cities (Firenze, Milano, Roma, Bologna, Bolzano, Pavia, Modena), the only ones that allow evaluation of the health risk, show benzene concentrations ranging from 6.0 to 11.3 micrograms/m3 and B(a)P levels, measured in heavy traffic areas, from 1.0 to 3.5 ng/m3 respectively (annual mean in 1996). The data obtained in the city of Florence show that the population is exposed weekly to average concentrations of 14.3 micrograms/m3 for benzene and 2.0 ng/m3 for B(a)P. These results suggest that, regarding benzene and B(a)P pollution, the situation in Florence is far from being critical but not such as to ensure that long-term exposure is without adverse effects.