IARC MONOGRAPHS ON THE EVALUATION OF CARCINOGENIC ...

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water assuming a water concentration of 0.001–2.0 μg/L naphthalene and water consumption
of 2 L per day is 0.002–4.0 μg per day (Howard, 1989).
(a) Air
IARC MONOGRAPHS VOLUME 82
Most of the naphthalene entering the environment is discharged to the air (92.2%),
the largest releases (more than 50%) resulting from the combustion of wood and fossil
fuels and the off-gassing of naphthalene-containing moth-repellents and deodorants. In
1989, about 12 million pounds [5.5 million kg] were released from these sources. The
highest atmospheric concentrations of naphthalene have been found in the immediate
vicinity of specific industrial sources and hazardous waste sites (Agency for Toxic
Substances and Disease Registry, 1995a). Air emissions in the USA reported to the
Environmental Protection Agency decreased from 1598 tonnes for 473 industrial facilities
in 1989 to 1224 tonnes for 744 industrial facilities in 1999 (Environmental Protection
Agency, 2001).
The median ambient air concentration of naphthalene determined at nine locations
(84 samples) in the USA was 1.2 μg/m 3 (Kelly et al., 1994). In another series of data from
1970–87, the average concentration of naphthalene in ambient air at several locations in
the USA was 0.991 ppb [5.19 μg/m 3 ] for 67 samples, 60 of which were from sourcedominated
locations (Shah & Heyerdahl, 1988).
In the USA, the Environmental Protection Agency (2000) reviewed studies and
calculated summary statistics for concentrations of chemicals in indoor air from selected
sources, including naphthalene. Studies were selected which provided the best available
estimates of ‘typical concentrations’ in indoor environments. These sources included the
Building Assessment Survey and Evaluation (BASE) study, National Association of
Energy Service Companies (NAESCO) study and School Intervention Studies (SIS). The
data are reported in Table 6. [The Working group noted the unusually high outdoor air
concentration in the School Intervention Studies, the fact that it is based on only three
positive observations and that the original data in this review are unpublished.]
Table 6. Typical concentrations of naphthalene in indoor and outdoor air
according to the Building Assessment Survey and Evaluation (BASE) study
and the School Intervention Studies (SIS)
BASE (μg/m 3 ) SIS (μg/m 3 )
Indoor Outdoor Indoor Outdoor
Arithmetic mean concentration 0.95 0.31 1.3 290
95th percentile upper limit 2.6 0.81 1.7 1500
No. of buildings 70 69 10 10
No. of observations 209 69 39 10
Frequency of detection 83% 58% 21% 30%