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2.0 Ambient Air Monitoring and NAPS Network
2.1 National Air Pollution Surveillance (NAPS) Network
2.2 NAPS Toxics Sampling Program
2.3 Particulates Monitoring Program
2.4 Research in Application of Ion Chromatography and Capillary Electrophoresis
2.5 NAPS Toxics Sampling Program
2.1 National Air Pollution Surveillance (NAPS) Network
The NAPS network is a joint program of the federal and provincial
governments for monitoring and assessing the ambient air quality at
271 air monitoring stations in 163 urban areas across Canada.
Particulate samplers at a NAPS station
The NAPS program changed considerably in 2001/2002 as a result
of Minister David Anderson's announcement, on February 22nd,
2001, of an additional $22M of funding over 4 years. This
translates into approximately $5.3M annually, a considerable
addition to the $2M of base funding. Various cooperating
agencies will also benefit directly, as some $10M of the
funding will serve to purchase and install monitors and
samplers across Canada. This funding moves the NAPS program
from a barely sustainable program to one that can begin to
address the challenges of the upcoming decade, namely meeting
the monitoring requirements for Canada-Wide Standards (CWS)
on both PM and Ozone and the Canada US Agreement on Air
Quality Ozone Annex.
A major achievement was to negotiate a Memorandum of
Understanding (MOU) for the NAPS program, including
bi-lateral annexes between the federal government and
each of the other cooperating agencies. Although
established in 1969, the program has successfully
been delivered by all the cooperating agencies (federal,
provincial, territorial and regional governments)
without a formal agreement. The Commissioner for
the Environment and Sustainable Development in his
2000 Annual Report recommended that the federal
government develop an agreement with cooperative
agencies to "clarify the direction of its national
ambient monitoring network, identify national needs
and document the roles and responsibilities for
maintaining and enhancing the network".
The draft MOU was approved by the Deputy Ministers
Committee of the Canadian Council of the Ministers
of the Environment and will now be published in the
Canada Gazette and then submitted for an Order in
Council. Similarly, provincial jurisdictions,
which require a public consultation process for
this type of federal provincial agreement, will
also be proceeding in a similar manner.
To develop the Annexes, a complete review of federal
needs for air quality information from the NAPS
network was undertaken. This review indicated w
hich Designated NAPS Sites would satisfy the
requirements of the following federal programs:
Criteria Pollutant monitoring; Canada-Wide
Standards Achievement Monitoring; Air Quality
Forecasting; Toxics Monitoring; and Special Studies.
The review indicated a requirement for 20 new
Designated NAPS Sites in the next three years.
NAPS Network Data Archiving and Reporting, Operations,
Quality Assurance, and Support
The NAPS Network Annual Summary for 2000 was published and
distributed to NAPS agencies at the end of January 2002.
The NAPS Annual summaries from 1995 to 2000 are also available
from the ETC web site http://www.etc-cte.ec.gc.ca. The
1999 and 2000 Annual Reports include the addition of six
volatile organic compounds (VOC) data summaries, and
Canada-Wide Standard (CWS) reporting of data for ozone
and PM2.5 for the current year and the two previous years
with a 3-year average of air quality levels, as prescribed
by the new CWS. Technical information and data reports
were prepared and provided to the Pollution Data Analysis
Division, the Meteorological Service of Canada (MSC),
Environment Canada regional offices, provincial agencies,
the U.S. Environmental Protection Agency (USEPA), the
World Health Organisation (WHO), and various non-government
organisations (universities, consultants, and industries).
The NAPS Network participating agencies and others were
provided with a variety of specialised technical support
relating to ambient air quality measurement, including
instrument calibration services and standards, technical
consultation, overhauling and installing VOC and PAH samplers,
and training in the field. In support of the Canada-U.S. Air
Quality Accord Ozone Annex, the NAPS capital equipment replacement
plan was updated and new and replacement monitoring equipment
totalling $3.5M and replacement parts totalling $500K were
requisitioned. Monitoring instruments totalling over $3.1M
were delivered to the NAPS network provincial and territorial
network agencies. Equipment purchases were largely targeted at
the need to meet information requirements of the CWS for PM and
Ozone, and the Canada-US Ozone Annex. Three different speciation
particulate samplers and a nitrate sampler were evaluated for
suitability of operation in the network. New stations in
Whitehorse, Yukon and Corner Brook, Newfoundland were established
including instrument installation and operator training.
Training on the operation of instruments was provided to
operators from Edmonton, Montréal, Rivière-des-Prairies,
l'Acadie, Egbert, Hamilton, and the Pacific 2001 study in
Greater Vancouver.
In support of the NAPS network quality assurance program,
15 stations were audited in the following provinces: Quebec
(1), Montreal Urban Community (4), Ontario (4), Manitoba (2),
Saskatchewan (1), Greater Vancouver Regional District (2),
British Columbia (1). Sixteen calibrators were certified
in the following provinces, territories and regions: Nova
Scotia (1), Quebec (3), Ontario (3), Greater Vancouver
Regional District (3), British Columbia (1), Northwest
Territories (2), Meteorological Services Ontario Region
(2), Meteorological Services Quebec Region (1). A total
of 42 flow calibrators, 70 span gases and 111 calibration
gases were certified. Calibration services were provided
to Health Canada, Agriculture Canada, Newfoundland Hydro
and a Hong-Kong Government Environmental organization.
A 3-day technical seminar organized by the ETC was held
in Ottawa for 35 technicians and operators of the NAPS
network from the ten provinces and the Northwest Territories.
ETC and a manufacturer of monitoring equipment co-organized
a second 3-day technical seminar that was attended by
technicians and operators of the NAPS network from six
provinces. CAEAL compliance requirements for performing
Method 2.2/1.1/M, Certification of Calibration Gas Mixtures
for Ambient air Analysers, were met in October 2001. A
comparison of the ozone reference standard with the Ontario
Ministry of the Environment was completed.
Two air-monitoring stations in the National Capital Region
were operated in cooperation with the Ontario Ministry of
the Environment. Data were collected, compiled, and validated
for the year 2001. In support of the NAPS network operations,
technical support, calibration services, and consultation
were provided to technicians of the network. Training in
the field was provided to operators of New Brunswick and
Nova Scotia and advice was given on the site selection of
a monitoring station. Technical assistance was provided to
the following non-government organizations: Alcan, New
Brunswick Power, Saskatchewan Power, Rotech Inc., Ferro,
SAIC, and Magnola Mines.
2.2 Ozone and NOX Monitoring Program
On June 5, 2000, in accordance with the 1998 Canada-Wide Accord on
Environmental Harmonization and its Canada-Wide Environmental
Standards Sub-Agreement, the Canadian Council of Ministers of the
Environment (CCME) - except Quebec - endorsed Canada-Wide Standards
(CWSs) for PM and Ozone. The CWS Agreement confirms that PM and
Ozone negatively affect human health and the environment and
establishes the need for nationally coordinated, long-term management
toward minimizing risk from these pollutants.
In agreeing to the CWSs, federal, provincial, and territorial
jurisdictions across Canada have made strong commitments to
implement the CWSs, to share information respecting implementation,
and to be accountable to their respective publics. Annex B to the
CWSs for PM and Ozone (the Reporting Protocol) contains provisions
designed to help ensure consistency and comparability in
jurisdictional reporting and improve understanding by the public
on how jurisdictions plan to track and report on progress. To help
meet this objective, CCME committed in the Reporting Protocol to
"cooperate in the preparation and periodic update, as required,
of a Guidance Document on Achievement Determination for the PM
and Ozone CWSs". The Reporting Protocol also commits each jurisdiction
to maintain its own data on ambient measurements of PM2.5, PM10,
and ozone and make it publicly accessible. To ensure the coordination
of such monitoring data, a PM and Ozone Monitoring Protocol has been
developed to be used by monitoring experts in Canada to ensure
consistent and comparable monitoring procedures and methodologies.
AAQD staff have participated in both these efforts.
Air monitoring at a NAPS station
The NAPS database is the primary Canadian source of integrated air
quality monitoring data. The database currently includes all
Canadian observations of ozone (O3), nitric oxide (NO), and
nitrogen oxides (NOX) for 1980 to 2001. Ozone data for 150
sites in rural and urban United States for 1980 to 2000 are
also incorporated into the database. The NAPS database has
been converted to ORACLE 7 and is located on a UNIX workstation
system in Dorval, Québec. It has been developed in a common
format with the MSC Climate Archive (ATIS/CAP) and Environment
Canada staff across Canada can access both air quality and
meteorological data through common routines. The NAPS web
site can now be found at http://www.etc-cte.ec.gc.ca/naps
Technical support analyst administrating and providing
connectivity to the ETC Network
Several improvements were made for the input to and extraction of data
from the NAPS Database. Several new software tools using the latest
technology were also developed. For example, the NAPS Web Based Annual
Raw Data Extractor is a tool to allow access to the NAPS raw annual
data. This tool allows the bulk downloads of the NAPS data for local use..
The NAPS Web Based Mapping Tool and Data Visualization is a map-based
visual search tool for selecting and then displaying graphs and charts
of the NAPS data. This application presents a map of Canada that allows
the user to zoom into a region that displays the local NAPS monitoring
stations. Users can select from a variety of options for plotting
pollutant data by year for any station selected. The specific address
is http://www.etc-cte.ec.gc.ca/napsdata
.
NAPS Web Services are Application Program Interface (API) that allows direct access to the NAPS database. This set of tools allows Internet clusters and NAPS data users to directly integrate NAPS data into client databases. This also includes the ability to discover a Web Service, maximizing the site's reach and ultimate success. The Web Service includes a document describing how to use the services. Once a client can access a descriptive document, he/she should have enough information to know how to interact with the Web Service and, therefore, have direct access to the NAPS data. The appropriate address is
http://www.etc-cte.ec.gc.ca/napswebservices/napswebservices.asmx.
http://www.etc-cte.ec.gc.ca/napswebservices/napswebservices.asmx
.
2.3 Particulates Monitoring Program
Recent health research indicates that airborne particulate matter (PM) is
one of the most important air quality problems. Serious health effects,
including human mortality, have been linked to particles in the air.
Whether directly or indirectly, particles also significantly influence
the scope and magnitude of other environmental issues such as
visibility, acid rain, and climate change. Particles and their precursors
(i.e., gaseous emissions) are produced throughout the processes involved
in generating and consuming energy from fossil fuels. These processes
include extraction, refining, power generation, heating, and transportation,
all of which lead to primary particle emissions. More importantly,
they also release gaseous NOx, SO2, and VOCs, which react in the
atmosphere to form organic and inorganic fine particles (PM2.5).
Particles in this size range are of greatest interest with respect
to human health effects because they penetrate deeply into the lungs.
As they contain a relatively high proportion of harmful chemicals
and can penetrate indoors, potential for human exposure is high..
Since 1984, the ETC has co-ordinated a measurement program for PM10
and PM2.5 using dichotomous samplers. This program also reports 40
elements, measured by Energy Dispersive X-ray Fluorescence (EDXRF)
and 21 inorganic and organic ions including sulphate, ammonium,
and chloride. An expanded speciation program was designed during
2001 and will be implemented during 2002. Measurements of nitrate,
black carbon, organic carbon, and ammonia will be added to the
existing suite of species.
Recently developed, reliable real-time monitors (the Rupprecht and
Patashnick Tapered Element Oscillating Microbalance or TEOM)
that can measure PM10 or PM2.5 mass are now widely used in Canadian
monitoring programs. As of October 1999, 70 instruments were measuring
PM10 and 122 instruments were measuring PM2.5 in Canada. Fifty sites
have continuous PM10 measurements and 102 sites have continuous PM2.5
measurements. At 73 monitoring sites, Environment Canada has either
purchased the sampling equipment and/or provides analytical support.
All the sites are reporting data to the NAPS database..
A 1-day technical workshop organized by the Division was held in
Ottawa for the staff of the NAPS network from the ten provinces
and territories to discuss the experience of using TEOMS to measure
PM. In attendance were two representatives from the US-EPA. Further
to recommendations from the workshop, operating conditions for
TEOMS have been standardized and upgraded to reflect current best
practice. Also, existing TEOM data will be re-evaluated to
reflect changes in various operating parameters. Technical procedures
were prepared and distributed to the managers and station operators
of the NAPS network for implementing the changes in operating
parameters. Starting January 1, 2002, TEOM PM2.5 monitors were
to be operated with a slope of 1.00 and an offset of zero.
A number of special intensive PM measurement activities have
been carried out at sites in Toronto and Vancouver. Areas of
research have included: characterising the carbonaceous
fraction of ambient aerosol, comparing manual and automated
methods of PM measurement, and investigating losses of nitrate
in current sampling methods. Data sets were provided to Health
Canada researchers to support a number of ongoing investigations
of the relationship between PM components and mortality and
morbidity. The ETC is a partner in a Toxic Substances Research
Initiative (TSRI) project to study the health effects of urban
air pollution mixtures. Sampling began in Toronto and Vancouver
in February 2000 and continued through April 2002. MSC and
AAQD carried out a joint scientific review of the contribution
of precursor gases (NOX, SO2, VOCs and NH3) to secondary particle
formation. The purpose of the review was to support the
development of risk management strategies by EC to meet
obligations under CEPA and to implement the Canada-Wide Standard
or PM2.5.
2.4 Research in Application of Ion Chromatography and Capillary Electrophoresis
Highly skilled technicians are required to isolate toxic substances
A major objective of the analytical chemistry research program in the
Inorganic Laboratory of the AAQD is to foster and advance the adoption of
new environmental monitoring technologies especially suited to pollutants
for which conventional analytical approaches fail. The laboratory always
seeks to improve or replace official methods that may have become outdated
with methods that are faster, more sensitive, and more accurate. An analytical
separation technique that has enormous, untapped potential for environmental
analysis is capillary electrophoresis (CE).
Capillary electrophoresis and related techniques, including micellar
electrokinetic chromatography (MEKC) and capillary electrochromatography
(CEC), are rapidly and profoundly changing the way analytical separations
and measurements are carried out. The utility of CE has been shown in
many different areas of separation science and its significance is
still increasing.
Improved environmental monitoring and site characterization demand
analytical methodology that is faster, cheaper and based on green
chemistry and technology (e.g., generates less waste). The capillary
electrophoresis, with its great efficiency, speed, simplicity and economy,
shows great promise in addressing these requirements. Based on different
separation principles and instrumentation, CE can also provide complementary
separation for gas chromatography (GC) and high-performance liquid chromatography (HPLC).
A number of joint research projects has been carried out with Canadian
and international scientists to study the potential of CE and related
techniques in the environmental field. Some typical examples of the use
of CE and related techniques in atmospheric aerosol analysis include
those associated with the analysis of inorganic anions and cations,
organic acids anions, amines, polynuclear aromatic hydrocarbons and
carbonyl compounds. Results have been published in scientific journals
and presented at numerous scientific conferences.
A simple and reliable CE method for the quantitative direct determination
of hydroxymethanesulfonic acid (HMSA) in atmospheric aerosols and other
environmental samples was developed. HMSA is the product of the reaction
between dissolved SO2 and formaldehyde (HCOH); both reactants are common
airborne pollutants. As an organo-sulfur compound, HMSA is a special case
of a secondary organic aerosol. Since HMSA is a strong acid, its formation
will acidify droplets without S(IV) oxidation. It has been estimated that
HMSA accounts for one-third of the S(IV) present in condensed phase.
Under certain circumstances, HMSA may also contribute to the aerosol mass
and aerosol sulfur concentrations if it is retained in aerosol particles
during cloud evaporation. Therefore, the determination of HMSA is needed
to assess the importance of HMSA to droplet acidity and to describe the
sulfur budget.
This fast, simple and robust method has been successfully applied to
the routine analysis of HMSA and other LMW carboxylic acids in atmospheric
aerosols and vehicle-emitted samples. This study was part of two collaborative
departmental research programs (PERD and TSRI Projects) related to the
determination of the concentration, composition, and sources of airborne
carbonaceous particles in Canada.
In conjunction with Carleton University (Ottawa, Canada) and University
de Vigo (Vigo, Spain), research continued on the use of a new technology,
capillary electrochromatography (CEC), for the analysis of various pollutants,
including marine toxins. CEC can be considered a hybrid technique of
micropacked high-performance liquid chromatography (micro- HPLC) and
capillary electrophoresis (CE), which couples the separating power of
HPLC and the high efficiencies of CE. CEC employs an electroosmotic flow
generated by an applied electric field to drive the liquid mobile phase
through the packed bed, whereas m-HPLC uses pressure. The preliminary
study on the CEC application for the analysis of Amnesic Shellfish
Poisoning toxins shows promise in the analysis of such toxins in
environmental samples.
Research and development work was started on the application of capillary
electrophoresis and other separation techniques for the chemical speciation
and/or fractionation of trace metals in particulate matter in ambient air,
to support research work by Health Canada and others on their bio-availability
and impact on human health. A reliable CE method with direct UV detection
has been developed and validated for the determination of the distribution
of metals in particulate matter after three-stage sequential extraction.
Five metals - namely, Fe, Zn, Cu, Mn and Cd - can be simultaneously and
quantitatively analysed within 10 min using 1,10-phenanthroline as a pre-capillary
derivatization reagent.
Research on Fine PM/Inventory and Ambient Air Data on PM for Control Options
A multi-year, PERD-sponsored university/government (Natural Resources Canada-NRCan,
Health Canada, National Research Council, Meteorological Service of Canada, and
the ETC) collaborative research project was undertaken to determine the
concentration, composition and sources of airborne carbonaceous particles i
n Canada.
The project is developing the tools and knowledge to evaluate possible fuel
and transportation standards and/or codes that may be needed to meet future
particulate matter (PM) air quality objectives in Canada. In support of
these objectives, particles and gases emitted from vehicles must be fully
characterised.
The ETC is conducting the exhaust emissions measurements from transportation
sources, and coordinating the analytical method development needed for
chemical characterisation of particulate matter emitted from sources and
in ambient air.
Characterisation measurements are being conducted on inorganic anions
and cations, and organic acids. Teflon-filter-collected particulate matter
samples were analysed for 12 inorganic and organic anions and 8 cations
using ion chromatography (IC) and for 14 organic acid anions using
capillary electrophoresis (CE). KOH-coated filters were routinely
analysed for 14 organic acids including hydroxymethanesulfonic acids
by the CE method. Gaseous ammonia and sulfur dioxide in vehicle-emitted
samples were determined in citric acid-coated and carbonate-coated filters
by IC.
Research to Characterise Particulate Matter (PM)/Data on Chemicals Associated with PM
The ETC has participated in a 3-year project funded by the Toxic Substances Research
Initiative. The work, done in conjunction with the Meteorological Service of Canada,
will greatly increase understanding of the human health effects of PM.
Characterisation measurements were conducted on Volatile Organic Compounds
(VOCs), carbonyls, inorganic ions, and organic acids.
2.5 NAPS Toxics Sampling Program
The program includes measurement of volatile organic compounds (VOC), including toxics and
ground-level ozone precursors, polar volatile organics
(PVOCs) such as aldehydes and ethers, components of fine particulate matter
(PM) including metals and inorganic and organic ions, and persistent, toxic semi-volatile
organic compounds (SVOCs), such as benzo(a)pyrene and polychlorinated dibenzo-p-dioxin
and furans.
The purposes of the monitoring effort are: 1) to support CEPA priority substances
assessments by providing information on exposures of the Canadian population
to ambient air concentrations of toxic substances; 2) to provide data on trends
in air concentrations of toxics and thus measure the success of initiatives
carried out under the Toxic Substances Management Policy (TSMP) and under the
Canada-Ontario Agreement (COA) respecting the Great Lakes basin ecosystem; 3)
to measure important precursors and products related to photochemical oxidant
production (smog); 4) to characterise potentially toxic components of fine
particulate matter; 5) to identify and characterize major sources of toxic
substances and to determine the importance of long-range transport vs.
domestic releases in terms of measured ambient concentrations; and 6) to
provide improved information on the fate, transport, and deposition of
toxic substances.
Over 34 substances on the CEPA Schedule 1, Priority Substances List (PSL) 1
and PSL 2 are measured routinely at up to 40 sites across Canada. Method
development for other important substances is carried out on a routine
basis as part of the program. During the year 2000, over 2,500 VOC samples
were collected from across the country and analysed for up to 170 different
VOC species (requiring multiple analytical runs per sample). In the same
year, more than 450 PAH samples and 250 PCDD/PCDF samples were analysed
from 19 sites in Canada. Another 200 samples from 7 Ontario sites were
analysed for hexachlorobenzene (HCB), pentachlorophenol (PCP),
octachlorostyrene (OCS), and nitro-PAH. For the particulate sampling
program, over 1500 fine and coarse mass measurements were made at 23
sites and most samples were submitted for both XRF (47 elements) and
IC (21 organic and inorganic ions) analysis.
In Ontario, the list of compounds was expanded to include a number of
additional species that are targeted in the Canada-Ontario Agreement
(COA) respecting the Great Lakes basin ecosystem. These include Tier I
substances (targeted for virtual elimination) and Tier II substances
(persistent, bio-accumulative, and toxic substances of concern) as
identified by the International Air Quality Advisory Board of the
International Joint Commission. The new COA substances sampling program,
which began in September 1996, includes nitro-PAH, OCS, HCB, and PCP. A
number of reports and presentations have been prepared summarising
results from Ontario sites for Tier I and Tier II substances and to
provide recommendations for future monitoring activities. Urban and
rural concentrations are compared as an indicator of source strengths
of the species measured.
Special Projects
The ETC was invited by the Meteorological Service of Canada (MSC)
to participate in the Pacific 2001 Air Quality Study in the Lower
Fraser Valley of British Columbia. The objective of the study was
to provide a better understanding and reduce the uncertainty of the
sources, formation, and distribution of PM and ozone in the Lower
Fraser Valley. The ETC participated in the intensive sampling and
analyses of VOCs and carbonyls at two sites. Results were presented
at the Pacific 2001 Data Analysis Workshop at York University in
April 2002. ETC staff also provided support for the installation
of PM monitors and assisted in the inter-comparison study of
different continuous PM monitors.
The ETC assisted Alberta Environment Compliance Branch in carrying out
sampling and analyses of VOC from the Fort Saskatchewan area to
monitor emission of VOC from local industry. The Division also
assisted the provinces of New Brunswick, Manitoba, and Saskatchewan
in investigating odour-related complaints associated with VOC.
The ETC participated in field inter-comparison studies of formaldehyde
measurement techniques at the Centre for Atmospheric Research Experiments
(CARE). Scientists from York University, Purdue University, and the
Meteorological Service of Canada (MSC) took part. The inter-comparison
studies are shedding new light on how organic species are transported
and chemically transformed in the atmosphere.
To characterise oxidant precursor emissions from both mobile and stationary
sources, the ETC has successfully developed unique VOC analytical methods.
The research involved developing means of eliminating water vapour and
carbon dioxide interference from collected samples. This makes it possible
to characterise source strength relationships for landfill gases and to
assess the environmental impacts of burning oil.
The third year of research was completed on two projects funded by the
Toxic Substances Research Initiative (TSRI). One project, carried out
in conjunction with the Meteorological Service of Canada (MSC), will
greatly increase understanding of the human health effects of PM.
Characterisation measurements are being conducted on VOCs, carbonyls,
inorganic ions, and organic acids at sites in Toronto and Vancouver.
The other project that is in conjunction with the University of Toronto
and the MSC will provide key information on the nature and some potential
health effects of the complex mixture of toxic chemicals in urban air.
As part of this aim, the project is designed to provide guidance and
supportive information that will assist Environment Canada in achieving
its objectives of monitoring air toxics in urban areas. The "air toxics"
include PAHs, dioxins/furans (PCDDs/Fs), and persistent organic
pollutants or POPs, e.g., PCBs and other semi-volatile chlorinated
organics. This also includes selected "new" compounds or those not
traditionally measured, notably polychlorinated naphthalenes (PCNs)
and nitrogen-substituted PAHs. Six different methods of obtaining
time-integrated air samples are being employed.
The major achievement of this program is the production of a high-quality
database of systematic observations, which is the most extensive long-term
data record of its kind in North America. It is now possible to produce
nationally representative trend data for a large number of species,
including those that are important in Climate Change.
Results from the program have been used extensively in the CEPA PSL1
assessment program and in the selection process for the PSL2. The ambient
air-monitoring program supports both the Ground-level Ozone and Toxics
issues and uses the existing federal/provincial infrastructure of the
NAPS network. Data from the program were used extensively in developing
the Canada-Wide Standard for benzene.
The ETC is a partner in a Toxic Substances Research Initiative (TSRI)
project entitled "Urban Air Toxics: Source Signature and Health Effects".
The project will characterise compounds contributing to urban air toxics,
develop cost-effective monitoring methods for PAHs, PCBs, and other
compounds, determine source-receptor relationships, and explore genotoxicity
of complex air mixtures. Sampling is being carried out at sites in
Toronto and the surrounding areas.
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appendices
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