Environmental Health Criteria 214

HUMAN EXPOSURE ASSESSMENT
In 1991 a subsample of the German Environmental Survey (see
Chapter 2.6) of 113 people took part in a study to assess exposure to
VOCs by personal sampling. The subjects wore passive samplers
(OVM-3500, 3M Company) for 7 consecutive days and simultaneously
documented the length of time spent indoors, the room characteristics
and any specific exposure such as that caused by renovation
activities. Seventy-four VOCs were analysed by gas chromatography
(Ullrich, 1992).
The results of personal sampling showed, for example, that from
the various types of environments the workplace has the highest impact
on exposure to C 8 - and C 9 -aromatic hydrocarbons (Figs. 42 and 43).
Other important factors that need to be considered are renovation
activities, use of paints and lacquers and the frequent reading of
newspapers and journals (printing inks contain many VOCs). Smoking
contributes significantly to human VOC exposure. In the case of
benzene, the multivariate model contained five variables: two related
to smoking exposure indoors, two related to vehicle traffic and the
residential density (Fig. 44). The two smoking variables alone
accounted for 20% out of a total variance of 40% that could be
explained (Hoffmann et al., 1996; Ullrich et al., 1996).
Three large studies of VOCs, involving 300-800 homes, have been
carried out in the Netherlands (Lebret et al., 1986), Germany (Krause
et al., 1987) and the USA (Wallace, 1987). A small study of 15 homes
was carried out in Northern Italy (De Bortoli et al., 1986). Observed
concentrations were remarkable similar for most chemicals, indicating
similar sources in these countries. One exception is chloroform,
present at typical levels of 1-4 µg/m 3 in the USA but not found in
European homes. This is to be expected, since the likely source is
volatilization from chlorinated water (Wallace et al., 1982; Andelman,
1985a,b); Germany and the Netherlands do not chlorinate their water.
12.3.8 Commuter exposures
In crowded urban areas it is not uncommon to find substantial
populations living near busy roads. Still others make their living
working among cars or vending goods along busy streets. Around the
world the routine of commuting between home and workplace exposes most
of the urban population to motor vehicle exhaust (carbon monoxide,
oxides of nitrogen, PAHs, VOCs and lead, in many cases) on a daily
basis. There have been several studies designed to assess exposures to
vehicle exhaust.
In a study conducted in Stockholm, Sweden, Bostrom et al. (1991)
demonstrated that nitrogen oxides can be used as tracers for VOCs
originating from vehicular traffic. The most important sources of VOCs
in Swedish cities are motor vehicles. Also, some 80-90% of NO x
(nitric oxide and nitrogen dioxide) in large Swedish cities originates
from motor vehicle traffic. Quantitative relationships were developed
between NO x and individual hydrocarbons, independent of traffic
intensity and time of year. For instance, a PAH/NO x ratio of 2.0 ×
10 -2 was reported for Gothenburg, Sweden, and a benzene/NO x ratio of
0.16 was reported for Stockholm.
Chan et al. (1991) assessed in-vehicle levels of carbon monoxide
in Raleigh, North Carolina, USA during the summer of 1988. The ratio
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