a lack of  ambient air monitoring data, emissions
tions of  selected air toxics in large and small urban
inventories and health related studies....make it
settings.  Areas in which sampling networks are to be
difficult to analyze the potential human health and
operated include Seattle, Washington; San Jacinto,
environmental effects of  many toxic chemicals.
California; Grand Junction, Utah; Rio Rancho, New
(Ref. 1)
Mexico; Cedar Rapids, Iowa; Detroit, Michigan; Charles-
ton, West Virginia; Providence, Rhode Island; Tampa,
Florida; and San Juan, Puerto Rico.
Current Joint Government Activities
All areas will provide at least 12 months of  data; sam-
pling for 18 core volatile organic compounds (VOCs),
In 2002, Canada and the United States published the
carbonyls and metals (smaller centers will not sample for
Progress Report under Canada-United States Air Quality
this latter class of contaminants) will be conducted with
Agreement in which both governments emphasized the
a one-in-six-day sampling frequency in the large urban
importance of  the  Ozone Annex,  including the devel-
areas and on a one-in-12 day basis in the smaller centers.
opment of  PEMAs (Pollutant Emission Management
Areas).  Their stated intent in these areas is the co-
The data generated will be combined with other sam-
ordination of  air quality improvements and joint manage-
pling and analytical outputs from urban settings into a
ment of  the airshed.  The Ozone Annex commits the
larger air toxics data analyses project which, in addition
United States and Canadian governments to report
to providing information on spatial and temporal trends,
ozone, VOCs and NOx  ambient air concentrations
will allow estimation of  the risks associated with these
monitored within 500 km  (310 miles) of the US-Canada
contaminants in various urban settings, using the Clean
border starting in 2002, and industrial facility emissions
Air Act one in one million lifetime cancer risk as one
by 2004.
benchmark.  The sampling program in Detroit will be
described further later in this report.
In Canada, the PEMA includes an area of 301,330km
(116,300 sq. miles) (Ref. 2) which covers all of  the
Canadian territory south of  about the 48th parallel
Air Pollutants of  Interest: Sources, Impacts,
beginning east of  Lake Superior to the Ottawa River, and
and Standards
south of  the corridor that extends from the Outaouais
Region east to Quebec City.  For the United States, the
Measuring Air Pollution
area includes the states of  Connecticut, Delaware,
Illinois, Indiana, Kentucky, Maine, Maryland, Massachu-
Measuring or monitoring ambient air concentrations,
setts, Michigan, New Hampshire, New York, New Jersey,
compiling emission inventories and the subsequent
Ohio, Pennsylvania, Rhode Island, Vermont, West
application of  air quality models are all important tools
Virginia, Wisconsin and the District of Columbia.
used to determine air quality in a region.
While the airsheds of  interest in this report (Detroit-
Ambient concentration is the direct measurement of the
Windsor, Port Huron-Sarnia and Sault Ste. Marie,
quantity of  a pollutant in outdoor air.  Monitoring air
Michigan and Sault Ste. Marie, Ontario) are included
pollution at stations throughout the area is the basis for
within the PEMAs, they are only a small portion of  these
determining ambient air quality.  Generally, the more
designed areas and not a particular focus of  this effort.
extensive the ambient monitoring program, the more
precise the determination of  air quality in a particular
region will be.  Ambient air quality monitoring networks
are used to determine the extent to which a region is
The United States Ten City Study
complying with applicable ambient air quality standards
or guidelines.  Trends in air quality can also be deter-
The USEPA and 10 states and local agencies are partici-
mined using data from these networks.  Such networks
pating in a pilot project to generate information on the
often require a substantial investment of  resources, thus
spatial and temporal variability of  ambient concentra-