Benzene exposure assessment at indoor, outdoor and personal levels. The French contribution to the life MACBETH programme

Many VOC represent hazards to human health through chronic exposure. Recent European and world-wide legislation proposes limit values for ambient conc entrations of these compounds. However, very little experimental data exist s for true population exposure. In 1996, the European MACBETH initiative se t out to measure population exposure to benzene in six European cities. Thi s study details the French contribution to this program. Six campaigns were carried out, each comprising measurements at 100 outdoor sites and the par ticipation of 50 non-smoking volunteers who wore personal samplers and had passive monitors installed in their homes. Iso-concentration maps were draw n for each campaign and the results showed that outdoor concentrations were significantly lower than indoors. Almost 75% of the volunteers were expose d to mean concentrations higher than the limit value of 5 mu gm(-3). It is demonstrated that personal exposure levels cannot be deduced simply by comb ining indoor and outdoor background concentrations. It is also shown that t here is need for better knowledge of the contributions to overall exposure of outdoor microenvironments and the authors hope that future European dire ctives will take this into account.