representative of the Greater Detroit Area (GDA).
from Essex County, which is to be expected given the
difference in population of approximately a factor of 10.
However, it should be noted that the boundary of Essex
County exceeds the Windsor region, while the three
Michigan counties cover most, but not all, of the
Table 31 indicates this difference is not proportionally
Greater Detroit Area.
consistent for some specific contaminants. For example,
arsenic emissions from the GDA are a factor of 50
For the majority of the contaminants, based on compila-
greater than Essex County, while 1,3 butadiene emis-
tions available in the GLRATEI, emissions from the
sions on a per capita basis would nearly be equivalent (a
three counties in the GDA significantly exceed those
factor of 14.6).
Comparison of Greater Detroit Area (GDA) and Windsor Emission Data
(data from 1998 Great Lakes Regional Air Toxic Emissions Inventory)
Total Essex County
Total Macomb, Oakland,
and Wayne County
Oakland and Wayne/Essex)
A large difference was also observed for
The total emissions values for Essex County and the
benzo(a)pyrene (GDA emits an approximate factor
GDA are a factor of approximately 12 different, consis-
of 182 greater than Essex County), the result of
tent with the population size difference.
greater point and area source emissions in the
GDA. (Emission data from mobile and non road
For GDA, arsenic data indicate the significant
sources was not provided in the GLRATEI.)
difference is as a result of the point source sector
contribution (814.21 lb/yr) compared to the 2.88
The data for trichloroethylene indicate significantly
lb/yr from point sources in Essex County, suggest-
greater emissions from the GDA (an approximate
ing one or more discrete and significant point
factor of 6,000). This difference is attributed to
sources of arsenic in the GDA.
both the point and area source categories.