standardized epidemiological study on indoor exposure to both allergens in house dust and volatile compounds in the
air of the home environment has been performed. The purpose of this paper is to describe the spatial and seasonal
?. variability of indoor and outdoor BTX Benzene, toluene, ethyl benzene, ortho-xylene, meta- and para-xylene
concentrations for the study period from June 1995 to November 1996. Within this framework, air concentrations of
?. ?. volatile organic compounds BTX were measured in 204 households in Erfurt Eastern Germany and 201
?. households in Hamburg Western Germany . BTX sampling was conducted over one week using OVM 3500 passive
?. ?diffusion sampling devices in the indoor living room and bedroom and outdoor environment outside the window of
. the living room . Indoor and outdoor median BTX concentrations in Erfurt were slightly, but significantly higher
?3 than those in Hamburg. This gap was most pronounced in the levels of indoor toluene 37.3 gm for Erfurt and
3 . 20.5 gm for Hamburg, P0.0001 . In both cities, winter indoor and outdoor concentrations for the five
compounds exceeded the summer values. Outdoor concentrations of ethyl benzene and ortho-xylene were very low
?. 50%L.D. . In general, the indoor BTX air concentrations were significantly higher than the outdoor concentra-tions, the lowest I
