TABLE 47
Three-year Summary for SO  in Sault Ste. Marie, Ontario
2
SO  1-hour Ontario MOE AAQC is 250 ppb
2
SO  24-hour Ontario MOE AAQC is 100 ppb
2
1-year Ontario MOE AAQC is 20 ppb
SO
2
Station
1998
1999
2000
[a]
[b]
[c]
[d]
[a]
[b]
[c]
[d]
[a]
[b]
[c]
[d]
Patrick St.
Merrifield
0
1.9
93
25.4
0
1.9
113
25.8
0
2
94
21.2
School
[a]
Number of  times above any AAQC
[c]
1-hour max
[b]
Annual Mean
[d]
24-hour max
Nitrogen Dioxide (NO )
NOx emissions from the Algoma Steel Inc. facilities in
2
the late 1990s.  The influence of  traffic emissions on
In Sault Ste. Marie, ambient measurements reveal that
NO  concentrations is very site-specific and is not well
2
NO  comprises about 60 to 65 percent of  the oxides of
known at this site.  Annual means at this site are slightly
2
nitrogen (NO + NO ).  This is about five percent higher
more than half  of  the levels in most other major centers
2
than the provincial average.  The annual means and the
in the province.
annual maximum concentrations for NO  revealed a
2
downward trend during the review period from 1990-
The Ontario Ministry of  the Environment’s 1-hour
2000.  This is especially evident for the annual maximum
objective for NO  of  200 ppb was never exceeded
2
values.  Due to instrumentation failures in 1999, there
during the review period; the highest recorded value
were insufficient data to compute the annual mean.
being 160 ppb in 1991.
Lower ambient concentrations coincide with reduced
in Sault Ste. Marie, Ontario
TABLE 48
Three-year Summary for NO
2
NO  1-hour Ontario MOE AAQC is 200 ppb
2
NO  24-hour Ontario MOE AAQC is 100 ppb
2
Station
1998
1999
2000
Mean
1hr-
24h-
Mean
1hr-
24h-
Mean
1hr-
24h-
max
max
max
max
max
max
Patrick St.
Merrifield
10.3
55
29.6
INS*
113
25.8
10.9
58
35.7
School
*INS - insufficient valid data
55