TABLE 22
Volatile Organic Compounds (VOCs)
Pollutant
Ontario MOE AAQC
U.S. EPA Benchmark
(for continuous lifetime exposure)
1,2-dichloroethane
3
3
0.038 µg/m
(ethylene dichloride)
24h AAQC is 2 µg/m
3
1,3 butadiene
No AAQC
0.0036 µg/m
3
1,4 dichlorobenzene
24h AAQC is 95 µg/m
further review required
3
Benzene
No AAQC
0.12 µg/m
3
3
Carbon tetrachloride
24h AAQC is 65 µg/m
0.07 µg/m
3
Chloroform
Interim AAQC Annual is
0.043 µg/m
3
0.2 µg/m .
3
24h is 1 µg/m
3
3
Formaldehyde
24h is 2.4 µg/m
0.077 µg/m
3
Perchloroethylene
Interim AAQC 24h is
.0000059 µg/m
3
(tetrachloroethylene)
360 µg/m
Trichloroethylene
Interim AAQC 24h is
under review
3
115 µg/m
As noted above the Ontario MOE recently adopted a more stringent objective for carbon tetrachloride,
3
3
which was decreased from 600 µg/m  to 2.4 µg/m .
the Greater Detroit-Windsor area contributed 84
1,3-butadiene
percent of  the airborne concentrations of  benzene in
At present, there is no Provincial AAQC
Windsor.
The annual means were rather constant at 0.1 and 0.2
Carbon tetrachloride
3
µg/m .  The maximum 24-hour concentrations peaked
3
24-hour Provincial AAQC is 2.4 µg/m
3
in the early 1990s between 2 and 3 µg/m , and seem to
3
have stabilized at 0.4 µg/m .  Mobile and industrial
The annual means for data obtained in 1999 and 2000
sources are responsible for about 98 percent of the
3
ranged from 0.65 to 0.73 µg/m  and the maximum
airborne concentrations of  1,3-butadiene in Windsor
3
values recorded were 0.78 and 0.96 µg/m .  The provin-
(Ref. 30).  These concentrations are in excess of  the
3
cial objective was lowered in 2001 from 600 µg/m  to
3
lifetime exposure benchmark of  0.0036 µg/m  for this
3
2.4 µg/m .  Carbon tetrachloride is the VOC compound
contaminant under the Clean Air Act.
on this list that most closely approaches any of  the 24-
hour VOC objectives of  the Ministry.
Benzene
At present, there is no Provincial AAQC
Formaldehyde
3
24-hour Provincial AAQC is 65 µg/m
Although the lowest annual means were recorded in the
last three years of  the reporting period, it is difficult to
The annual means and the magnitude of  the maximum
conclude from this data set that the benzene levels are
24-hour values were observed to have decreased over
decreasing with time.  More data are required before any
the review period, 1990-2001.  In the first half of the
such conclusion can be drawn.  The annual means varied
3
period, the means were in the range of  3.1 to 8.8 µg/m ,
3
from 1.7 to 2.8  µg/m , which is typical for an urban
3
falling to the range of  2.6 to 3.3 µg/m  during the
environment with a myriad of  vehicular and fuel com-
second half.  Likewise the maximum values in the first
bustion sources.  These concentrations are in excess of
half  of  the monitoring period ranged from 12 to 31 µg/
3
the lifetime exposure benchmark of  0.12 µg/m  for this
3
3
m  and from 4.5 to 9.9 µg/m  in the second half.  These
contaminant under the Clean Air Act.  The Windsor Air
maximum values are well below the provincial objective
Quality Study (1991-1993) determined that  sources in
28