The risk of lung cancer from polycyclic aromatic hydrocarbons in Sydney air

Air pollution often is suggested as being partly responsible for an increased incidence of lung cancer in cities. A problem with epidemiological studies is that the comparatively-small effect of air pollution is difficult to identify in the presence of larger and variable effects of cigarette smoking and other factors. This article describes an alternative approach to the estimation of cases of lung cancer that may be a result of air pollution. The concentration of a number of carcinogenic polycyclic aromatic hydrocarbons has been measured at two sites in Sydney and the relative contributions from various pollutant sources have been deduced. By means of a source inventory and an atmospheric dispersion model, concentrations have been derived for the whole Sydney region. Lung-cancer induction is calculated from the population that is exposed and the concentration of benzo(a)pyrene, which is used as a surrogate for the carcinogenic products of incomplete combustion. For the Sydney region, it is estimated that about 30 lung cancers a year could arise from polycyclic aromatic hydrocarbons in the ambient air.