[Air-dispersed asbestos fiber pollution in urban areas: current and previous levels]

Over the last twelve years (since the Lombard Regional Law n 41 on asbestos came out in 1986) I have had the opportunity to actively take part into monitoring campaigns both in working environments and in several urban areas. At the beginning analysis were performed almost exclusevely using phase contrast optical microscope (MOCF). This technique, even with its well known limits, has lead to measurments of asbestos pollution never exceeding 4-5 fibers L(-1) in urban areas. The reported value had lowered to 1-2 fibers L(-1) by the beginning of the nineties and, in the following years it has become even lower. The introduction of scanning electronic microscope (SEM) has not only confirmed these data but also shown lowered values of asbestos fibers in air (< 0.05 fibers L(-1)). This is to be related with the use of artificial fibers (glass and synthetical fibers) in cars braking systems instead of natural mineralfibers (asbestos). Nowadays the concrete-asbestos roof coverages can be a potential environmental pollution source if their surfaces are not protected. The reported indoor levels of pollution are similar to the outdoor ones and to levels reported in areas nearby rock-caves. The levels of asbestos pollution reported in the previous years using MOCF have been nowadays confirmed using SEM, expecially as far as buildings reclaimed from asbestos are concerned.