Appendix D - Dossier (PDF) - Tera

date: 20–JUL–2005
3. Environmental Fate and Pathways Substance ID: 71–43–2
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June – 1 July 1997 and 18–21 October 1997.
16–MAR–2004 (1290)
Type of measurement: concentration at contaminated site
Medium: air
Method: A differential optical absorption spectrometer was used to
monitor the concentrations of different inorganic and
organic compounds on different wavelengths in the UV region.
The measured atmospheric spectrum was divided by the
pre–recorded light source reference spectrum to eliminate
the wavelength dependence of the optical parts of the
instrument. The quotient is divided by the fifth order
polynomial which suits the broad band wavelength variations
of the spectrum. The resulting spectrum (= differential
spectrum) is free of the extinction effects of atmospheric
particles.
The spectral interval used for the measurement of aromatics
(incl. benzene) is 240 – 275 nm. The mathematical algorithm
used for the determination of the concentrations of trace
gases is based on the multiple correlation of the measured
spectrum with a reference spectrum which is calculated from
pre–recorded reference differential absorption
cross–sections of the main interfering atmospheric gases in
the same spectral region.
For the distance of 165 m, the minimum detectable quantity
for the aromatics as provided by the manufacturer is around
0.5 ppb while the linearity is 2 ppb in the 0}250 ppb range.
Remark: In 1997, the passenger car fleet in Greece comprised about
60 % conventional cars and 40 % cars with catalysts and
about 1 % cars with diesel engines (all diesel passenger
cars were taxis that accounted for about 10 % of total
mileage in Athens and Thessaloniki), whereas all heavy duty
vehicles were diesel vehicles. With further introduction of
catalysts in passenger cars and diesel passenger cars, the
concentration of benzene will change in the atmosphere.
Result: The time coverage during the period of measurements was 71 %
for benzene.
The daily averages of benzene concentrations vary between 1
and 6 ppb (= 3.2 – 19 µg/m**3).
The frequency distribution of hourly average benzene
concentrations from December 1993 to August 1994 divided
into intervals of 0.5 ppbV (= 1.6 µg/m**3) is as follows
(ppbV / µg/m**3):
< 0.5 / < 1.6: 6.08 %
0.5 – 1.0 / 1.6 – 3.2: 6.97 %
1.0 – 1.5 / 3.2 – 4.9: 11.89 %
1.5 – 2.0 / 4.9 – 6.5: 13.34 %
2.0 – 2.5 / 6.5 – 8.1: 12.52 %
2.5 – 3.0 / 8.1 – 9.7: 9.77 %
3.0 – 3.5 / 9.7 – 11.3: 9.6 %
3.5 – 4.0 / 11.3 – 13.0: 7.69 %
4.0 – 4.5 / 13.0 – 14.6: 6.75 %
4.5 – 5.0 / 14.6 – 16.2: 5.04 %
5.0 – 5.5 / 16.2 – 17.8: 3.11 %
5.5 – 6.0 / 17.8 – 19.4: 2.24 %
6.0 – 6.5 / 19.4 – 21.1: 1.52 %
Appendix D: Benzene SIDS Dossier
– 144/957 –