In the framework of new European directives in the field of ambient
air quality assessment specific requirements for measurement methods for benzene
will be defined and have to be met in the future. In a residential area in
the vicinity of a cokery a comprehensive monitoring programme for BTX compounds
(benzene, toluene, xylenes) was carried out with diffusive samplers. Measurement
results from 20 sites show a distinct spatial distribution of benzene concentrations
which is caused by the emissions of the plant. Comparisons with two pumped
measurement methods reveal excellent agreement in the case of benzene. An
assessment of measurement uncertainty for the diffusive method is presented
in terms of standard deviations from parallel measurements (precision)
and by comparison with a reference method according to national and international
standards. Data quality objectives required by an upcoming European directive
for benzene can be met by diffusive sampling.