Sarnia Ambient Monitoring Stations
and Pollutants Measured
Common Air Pollutants
Station Name
Pollutants Monitored
In Sarnia, the Sarnia-Lambton Environmental Associa-
Grace Church
Sulphur Dioxide
tion (SLEA) has operated an ambient air monitoring
(operated until 1994)
network on a voluntary basis for more that 40 years; the
Ontario MOE operates additional monitoring sites in
LaSalle Road
Sulphur Dioxide
the area.  Membership in SLEA is comprised of  various
industries located in the Sarnia area.  At present, there
Centennial Park
Fine Particulate Matter (2000-
are five monitoring stations within the area.
), Carbon Monoxide,
Nitrogen Dioxide, Ozone,
Monitoring station locations are provided on the Map
Sulphur Dioxide, Total Reduced
of  Sarnia and Port Huron Monitoring Stations in
Appendix A, Diagram 3.  Stations are situated in loca-
tions that may be subject to localized influences.
River Bend
Sulphur Dioxide, Nitrogen
Dioxide, Ozone, Volatile
Organic Compounds
Sulphur Dioxide (SO )
Front St.
Sulphur Dioxide, Nitrogen
The Centennial Park, Front St. and River Bend sites are
Dioxide, Ozone, Volatile
specifically located where dispersion modeling predicts
Organic Compounds
the highest expected concentrations of  SO  to occur.
These stations are located to trigger the Lambton
Moore Line
Coarse Particulate Matter
Industry Meteorological Alert (LIMA) regulation.
)(from March 1997-
LIMA is designed to maintain or lower local ambient
February 2002), (began in 2000),
SO  concentrations during periods of poor dispersion
Fine Particulate Matter (PM )
by requiring local sources switch to lower suphur fules
or curtail production activities.
List of  pollutants measured may not be complete
*Source: SLEA and OMOE
As of  2001, the SLEA accepted responsibility for
advising the Ontario MOE that the LIMA trigger value
had been reached; the Ontario MOE would then declare
a LIMA.  Once an advisory LIMA is issued by the
In 2001, concentrations reached an unusually high one-
Ontario MOE, local industries subject to the regulation
hour peak of  473 ppb at the Corunna monitoring site;
reduce their SO  emissions by switching to lower
concentrations continued to exceed the 1-hour provin-
sulphur fuels or by curtailing production (Ref. 41).  Until
cial objective of  250 ppb over three consecutive hours
April 1 2001, it was the discretion of  the Ontario MOE
on the same day as the peak was recorded.
to issue LIMA events when the 24-hour rolling average
SO  concentrations rose above 70 ppb, and adverse
The Front St. monitoring site in downtown Sarnia
weather conditions were expected to continue for at
showed daily average concentrations to be in excess of
least six hours.  Since 2001, SLEA now alerts the
the provincial objective of  100 ppb for two days in
Ontario MOE that the LIMA trigger values have been
November, 2001 (Ref. 43).  These excedances occurred
reached as soon as 70ppb is reached.  This change may
during two separate LIMA (November 1 and November
explain the increased frequency of  events in 2001 (Ref.
13, 2001).
42).  It remains the Ontario MOE’s responsibility to
issue the LIMA.