2.5
Sault Ste. Marie, Ontario
Sulphur Dioxide (SO )
2
The city of  Sault Ste. Marie, Ontario is situated on the
Historically, ground level concentrations of  sulphur
north shore of  the St. Mary’s River, which connects
dioxide in Sault Ste. Marie, ON have been well below
Lake Superior to Lake Huron.  Sault Ste. Marie, Ontario
Ministry AAQC and not of  significant concern for local
is directly linked to Sault Ste. Marie, Michigan by the
air quality.
International Bridge.  Sault Ste. Marie, Ontario is more
developed, with an industry based largely on the natural
During the 1990s, mean annual concentrations ranged
resources of  the area, including an integrated steel mill
from 1.5 to 2.2 ppb and the annual maximum 1-hour
with coking operations and a pulp and paper facility.
averages varied from 60 to 190 ppb.  These values are
well within the Ministry’s annual mean objective of  20
ppb and maximum 1 hour objective of  250 ppb.
There are two air quality monitoring stations within
Sault Ste. Marie, Ontario.
There is no obvious trend in the annual mean concentra-
Bonney St. Pumphouse
tions as the year-to-year variability is small and not
considered to be significant.  From the available Ontario
Patrick St. WM. Merrifield School
MOE emissions inventory for the major point sources
emissions from
in Sault Ste. Marie, ON, annual SO
2
Algoma Steel Inc. dominate ( > 99 percent) and re-
2.5.1
Common Air Pollutants
mained fairly constant at 9,000 to 12,000 tonnes per year
(9,900 to 13,228 tons) from 1990 to 1997.  Since 1998,
Ambient Concentrations
these emissions have marginally decreased, ranging from
The Criteria pollutants trends for the review period
7,000 to 9,000 tonnes per year (7,716 to 9,900 tons).
(1990-2000):
This reduction may have contributed to the reduced
hourly concentrations observed since 1997.  However,
Annual SO
meteorological dispersion conditions also play a key role
means were within Ministry AAQC and
2
did not noticeably vary with time; the magnitude of
in the magnitude and frequency of  occurrence of  short
term elevated concentrations and correlations between
the annual maximum concentrations were slightly
lower in the second half  of  the review period, 1990-
emissions and measured concentrations are not always
evident.
2000.
Annual NO  means displayed a weak downward
2
trend; this trend was more noticeable for the annual
maximum values and these conformed to Ministry
objectives during the review period, 1990-2000.
Mean Total Reduced Sulphur (TRS) levels showed a
noticeable downward trend throughout the decade;
there were few exceedances of  the hourly objective
and none during the last three years of the review
period
Annual mean ground level ozone values were
slightly higher in the latter part of  the reporting
period; however the year-to-year variability in ozone
levels prevents drawing any conclusion on trends
over such a short time frame.
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