Urban Benzene Pollution and Population Exposure

Benzene is among the gasoline components and is airborne by vehicular traffic. It is a myelotoxic and leukaemia-inducing compound (Snyder et al., 1993; Ward et al., 1992; Vigliani and Saita, 1964). The risk level, expressed as myeloid leukaemia cases increment estimate among the population not professionally exposed to benzene, has been stated to range 3.8 to 7.5 cases every million people exposed during the lifetime to 1 μg/m (Rinsky et al., 1981; Bond et al., 1986; WHO, 1996). All the estimates deal with exposure, not with environmental concentration. Since the two parameters can be not coincident, the citizens’ risk level, which depends on actual exposure, can not be simply estimated by means of urban pollution. Therefore, once a socially acceptable exposure risk level is stated by a political decision, one can set a limiting value for benzene concentration in urban air only if the relationship between personal exposure and urban pollution is known. We find the citizens’ exposure level, whatever their occupation or the fraction of time spent outdoors, is higher than urban average level and is equal, on average in Europe, to twice its value.