Standards/Criteria
TABLE 9
Standards (Michigan) / Criteria (Ontario) for Lead
Michigan (U.S. EPA NAAQS)
Pollutant
Primary (Health Related)
Secondary
3
same as Primary standard
Lead
Maximum Quarterly Average
1.5 µg/m
Values are collected for three consecutive
months (by calendar quarter), averaged and
then compared to the standard.
Ontario (MOE)
Pollutant
Criteria
3
Lead
24-hour AAQC
2.0 µg/m
Smog
Ontario Air Quality Index (AQI)
Formed
In Ontario, the Ministry of  Environment (MOE)
The term smog frequently refers to a mixture of
operates the Air Quality Index (AQI) program.  The
ozone and (fine) particulate matter.
AQI provides real-time air quality information to the
public.  Concentrations of  pollutants that have adverse
Sources
effects on human health and the environment, including
See sources for ozone and particulate matter
SO , O , NO , TRS compounds, CO, and fine particu-
2
3
2
late matter (PM ), are determined and at the end of
2.5
Effects
each hour the concentration of  each pollutant is con-
Individuals with respiratory or cardiovascular
verted into a number that ranges from zero upwards.
disease, the elderly and small children are most
The calculated number for each pollutant is called a sub-
affected.  Those with compromised immune
index.  The highest sub-index for any given hour
systems who spend a large amount of  time outside
becomes the AQI.  As a result, in any given time-frame,
may also experience symptoms of  distress (Ref. 16).
values associated with a single pollutant determine the
U.S. researchers have found that inhalation of  smog
Index (Table 10).  The lower the index, the better the air
laden air has a direct effect on the cardiovascular
quality is.
system (Ref. 17).
The Ministry of  the Environment will declare a Ňsmog
Standards/Criteria
watch” or a Ňsmog advisory” if  a forecast indicates the
At present time, there are no direct measurements,
AQI may exceed a reading of  50 over a wide geographic
standards, objectives or established criterion for
area.  A 50 percent chance of  poor air quality in the next
smog per se.  Although not considered a Criteria
three days would trigger a smog watch.  A smog advi-
pollutant, recent research indicates that there is no
sory is issued when there is a high probability that
‘safe’ or threshold level of  human exposure to either
widespread, elevated and persistent smog levels are
ground-level ozone or particulate matter below
expected within next 24 hours.  The Ministry of  the
which health effects do not occur (National Ambi-
Environment publishes information for citizens regard-
ent Air Quality Objectives For Ground-Level
ing actions to be taken when such events are issued
Ozone and For Particulate Matter, Science Assess-
(Ref. 19).
ment Documents, 1999) (Ref. 18.).
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