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Air Quality Agreement - Progress Report 2006
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Section 1: Commitments
Acid Rain Annex
Overview
 The Air Quality Agreement (AQA) established Annex I with specific
sulfur dioxide (SO2 ) and nitrogen oxides
(NOx ) emission target levels and a timetable
for their achievement and made commitments to address visibility, prevent
air quality deterioration in clean areas, and monitor emissions continuously.
The commitments are based on both countries' acid rain reduction programs,
which address the different emissions sources in the two countries.
Together, we have made significant progress in preventing impacts from
acid rain and reducing the acid rain on each side of the border. However,
recent studies in both countries continue to show that further reductions
are necessary to restore damaged ecosystems, particularly in the east.
Key Commitments and Progress: Sulfur Dioxide Emission Reductions
CANADA
Canada has been successful in reducing emissions of SO2,
a principal contributor of acid rain. In 2003, SO2 emissions
in the seven easternmost provinces, where elevated acid deposition continues
to damage sensitive ecosystems, were 29 percent below the eastern Canada
2.3 million tonne1 cap, even though the cap expired in December
1999. Canada's total SO2 emissions have decreased about 50
percent since 1980 to 2.3 million tonnes in 2004, or 28 percent below
the national cap of 3.2 million tonnes (see Figure
1).
Figure 1 Canadian SO2 Emissions from
Acid Rain Sources, 1980-2004
Click to enlarge
Source: Environment Canada
In the east, where acid rain continues to damage sensitive ecosystems,
three provinces, Nova Scotia, Quebec, and Ontario, developed tighter
regulations in 2005 to reduce emissions from major acid rain- causing
sources. Details on these and other provincial actions are found at the
end of Section 1.
Despite these efforts, the control of acidifying emissions has not occurred
to the extent necessary to reduce acid deposition below critical loads
(harmful levels) and ensure the recovery of aquatic and terrestrial ecosystems.
A critical load is the maximum amount of acidifying deposition an ecosystem
can tolerate in the long term without being damaged.
The goal of Canada's acid rain program-to reduce acid deposition
to aquatic and terrestrial ecosystems to below critical loads for sulfur
and nitrogen-is far from being achieved.
UNITED STATES
The United States has succeeded in meeting its goal to reduce SO2 emissions
from all sources by 10 million tons. Created by Title IV of the 1990
Clean Air Act Amendments, the Acid Rain Program employs a cap and trade
mechanism to achieve high levels of SO2 emission reductions
from the highest emitting SO2 sector, the electric power sector.
In 2005, electric generating units in the United States reduced SO2 emissions
by 5.5 million tons, or 35 percent, compared with 1990 levels, and more
than 40 percent compared with 1980 levels (see Figure
2). For further
details, including a listing of affected units and complete emissions
and allowance data related to the Acid Rain Program, visit http://cfpub.epa.gov/gdm.
Figure 2 U.S. SO2 Emissions from
Acid Rain Program Electric Generating Units, 1980-2005
Click to enlarge
Source: EPA
The Clean Air Act sets a nationwide annual cap on SO2 emissions
from electric generating facilities. The number of SO2 allowances
allocated in a given year to a particular unit was determined by provisions
in the Clean Air Act and the total allowances allocated each year must
not exceed the national cap. Each allowance authorizes 1 ton of SO2 emissions.
Every year, each individual source must hold enough allowances to cover
its annual emissions. Unused allowances may be sold, traded, or banked
(saved) for future use. Banked allowances give sources the flexibility
to determine how they will comply with program requirements. Many sources
chose to substantially decrease their emissions during Phase I and to
use or sell their banked allowances in the program's later years. Thus,
annual fluctuations in SO2 emissions are expected as sources
move towards the final cap of 8.95 million tons in 2010.
In 2005, 3,446 electric generating units were subject to the SO2 provisions
of the Acid Rain Program. Variations in the number of units participating
in the program can result from retirements of some units and start-up
of other units.
In 2005, a total of 9.5 million allowances were allocated. Sources actually
emitted 10.2 million tons of SO2, decreasing the allowance
bank by 0.7 million tons to 6.2 million tons. Over the next several years,
affected sources will continue to use banked allowances to help comply
with the increasingly stringent requirements of the program. In addition,
some sources in the eastern United States may also rely on banked allowances
to comply with the lower cap for SO2 under the Clean Air Interstate
Rule (CAIR), promulgated in March 2005 and due to take effect beginning
in 2010.
In addition to the electric power generation sector, other sources achieved
reductions in SO2 emissions, including smelters and sulfuric
acid manufacturing plants. Smelters reduced emissions from 1.84 million
tons in 1980 to 271,000 tons in 2002. The use of cleaner fuels in residential
and commercial burners also contributed to the 10.6 million ton decline
of SO2 emissions from all sources, compared with the 1980
level of 25.9 million tons. (For more details, visit the 2002 National
Emissions Inventory (NEI) at www.epa.gov/ttn/chief/trends/.)
Key Commitments and Progress: Nitrogen Oxides Emission Reductions
CANADA
Though Canada has surpassed its NOx emission reduction target
at power plants, major combustion sources, and metal smelting operations
by 100,000 tonnes below the forecast level of 970,000 tonnes, the country
is continuing to develop programs to further reduce NOx emissions
nationwide (see section on Ozone Annex).
Mobile sources (cars, light-duty trucks, etc.) are the most significant
sources of NOx emissions, accounting for just over half (51
percent) of Canadian total emissions, with the remainder caused by power
plants and other sources (see Figure 26, U.S. and Canadian National Emissions
by Sector for Selected Pollutants, 2004). The Canadian federal government
recently passed stringent standards for NOx emissions from
on-road and off-road sources effective between 2004 and 2009. Details
can be found in the Ozone Annex section of the report.
UNITED STATES
Coal-fired electric utility units affected by the NOx component
of Title IV of the 1990 Clean Air Act Amendments (the Acid Rain Program)
continue to exceed the annual goal of reducing emissions by 2 million
tons below what they would have been without the program. In 2005, the
982 NOx program-affected units reduced their combined NOx emissions
to 3.3 million tons (see Figure 3).
Figure 3 U.S. Title IV Utility Unit NOx Emissions,
1990-2005
Click to enlarge
Source: EPA
Acid Deposition Monitoring, Modeling, Maps, and Trends
Airborne pollutants are deposited on the earth's surface by three processes:
1) wet deposition (rain and snow); 2) dry deposition (particles and gases);
and 3) deposition by cloud water and fog. Wet deposition is comparatively
easy to measure using precipitation samplers, and wet sulfate and nitrate
deposition is regularly used to assess the changing atmosphere as it
responds to decreasing or increasing sulfur and nitrogen emissions. In
Canada, measurements of wet sulfate deposition are typically corrected
to omit the contribution of sea salt sulfate at near-ocean sites (less
than 62 miles (100 kilometers, or km) from the coast) to facilitate this
comparison.
Figures 4 and 5 show the
spatial patterns of wet sulfate deposition for two separate five-year
periods, 1990-1994 and 2000-2004. Figures 6 and 7 present
maps of wet nitrate deposition for the same five- year periods. No deposition
contours are shown in Canada in Figures 5 and 7,
because Canadian experts judged that the locations of the contour lines
were unacceptably uncertain because of data paucity. This paucity is
related to the following factors: the Province of Ontario ceased collecting
wet deposition data in 1999; at this time, no validated wet deposition
data are available from the Province of Quebec for years after 2002;
the Province of Newfoundland and Labrador closed its monitoring network
early in 2004; and the provinces of British Columbia, Saskatchewan, and
Manitoba do not carry out regional-scale wet deposition monitoring. As
a result, the five-year average deposition values in Canada are shown
as colored circles at the locations of the remaining federal/provincial/territorial
measurement sites. National experts from both countries are collaborating
to determine consistent common uncertainty limits for future analyses.
The maps for 1990-1994 differ slightly from those shown in the 2004 Progress
Report because stricter criteria for data completeness and improved detail
were used to develop the new maps shown here.
Figure 4 Mean sulfate wet deposition for 1990-1994, for comparison
with Figure 5
Figure 5 Mean sulfate wet deposition for 2000-2004
Note: Sulfate measurements are corrected for sea salt composition where
appropriate.
Figure 6 Mean nitrate wet deposition for 1990-1994, for comparison
with Figure 7
Figure 7 Mean nitrate wet deposition for 2000-2004
Source: National Atmospheric Chemistry (NAtChem) Database (www.msc-smc.ec.gc.ca/natchem/index_e.html)
and National Atmospheric Deposition Program (NADP)
It can be seen from the maps that wet sulfate deposition remains highest
in eastern North America, and the gradient follows an axis running from
the confluence of the Mississippi and Ohio rivers through the lower Great
Lakes. A comparison of the 2000-2004 sulfate deposition map (Figure
5)
with the 1990-1994 map (Figure 4) shows significant reductions in wet
sulfate deposition in both the eastern United States and much of eastern
Canada between the two periods.
The pattern for wet nitrate deposition (Figures 6 and 7) shows a similar
southwest-to-northeast axis, but the high-deposition area is more tightly
focused around the lower Great Lakes. Reductions in wet nitrate deposition
between the two five-year periods were more modest than for wet sulfate.
The absence of data for Quebec and Newfoundland and Labrador precludes
any firm conclusions on deposition trends for those provinces.
The foregoing changes in sulfate and nitrate wet deposition from the
first half of the 1990s to 2000 through 2004 are considered to be directly
related to decreases in SO2 and NOx emissions in
both Canada and the United States. These emission reductions are outlined
in the previous sections dealing with key commitments and progress on
SO2 emission reductions and NOx emission reductions.
In Canada, wet and dry deposition are measured by the Canadian Air and
Precipitation Monitoring Network (CAPMoN) (www.msc-smc.ec.gc.ca/capmon),
and wet deposition alone is measured by several provinces and one territory.
In the past two years, a few additional measurement sites were added
to CAPMoN in the more remote regions of Canada in order to provide more
extensive deposition data. However, the data available for 2000-2004
in Canada were insufficient to permit interpolation and contouring.
The United States has three coordinated acid deposition monitoring networks:
- The National Atmospheric Deposition Program/National Trends Network
(NADP/NTN), a collaboration of federal, state, and nongovernmental
organizations measuring deposition chemistry (http://nadp.sws.uiuc.edu).
- The NADP/Atmospheric Integrated Research Monitoring Network (AIRMoN),
a subnetwork of NADP funded by the National Oceanic and Atmospheric
Administration (http://nadp.sws.uiuc.edu/AIRMoN/).
- The Environmental Protection Agency (EPA)/ National Park Service
Clean Air Status and Trends Network (CASTNET), which estimates dry
deposition based on observational data (www.epa.gov/castnet).
Wet deposition measurement procedures for all U.S. and Canadian networks
are acceptably comparable, and the wet deposition data are available
from the individual networks and from a binational database that is accessible
to the public at www.msc.ec.gc.ca/natchem/index_e.html. Canada and the
United States have developed different methods for estimating dry deposition
based on measured data and modeled dry deposition velocities. These methods
have improved over the years, and both indicate the importance of dry
deposition as a major contributor to total deposition in some areas of
the continent. However, the results differ in detail, and no joint analysis
is available at this time. Efforts are under way between the two countries
to reconcile the different methods and results.
Acid Rain Program Benefits Far Exceed Costs
A recent analysis2 of the U.S. Acid
Rain Program estimates annual benefits of the program in 2010 to both
Canada and the United States at $122 billion and costs for that year
at $3 billion (in 2000 dollars)-a 40- to-1 benefit/cost ratio.
These quantified benefits in the United States and Canada are the result
of improved air quality prolonging lives, reducing heart attacks and
other cardiovascular and respiratory problems, and improving visibility.
The complete report is available in volume 77, issue 3, of the Journal
of Environmental Management at www.sciencedirect.com/science/journal/03014797.
Emissions Monitoring
CANADA
Canada has met its commitments to estimate emissions of NOx and
SO2 from new electricity utility units and existing electricity
units greater than 25 megawatts (MW) using a method of comparable effectiveness
to continuous emission monitoring systems (CEMS) and to investigate the
feasibility of using CEMS by 1995.
In Canada, trading of SO2 and NOx emissions is
not currently a driver for electronic data reporting and CEMS installation.
In December 2005, Environment Canada published an update of its guidelines
for CEMS (Protocols and Performance Specifications for Continuous
Monitoring of Gaseous Emissions from Thermal Power Generation,
Report EPS 1/PG/7 (revised)). The report can be viewed at www.ec.gc.ca/cleanair-airpur/CAOL/electricity_Generation/protocols_performance/toc_e.cfm.
This update was based, in part, on experience gained from the use of
40 CFR Part 75 specifications for CEMS in the United States. Although
CEMS and data reporting requirements for power plants and industrial
sources involved in emissions trading in the United States are not fully
mirrored in Canada, it has been concluded that EPS 1/PG/7-compliant CEMS
in Canada would meet Canadian monitoring requirements for domestic purposes
and would achieve accuracy comparable to that achieved through 40 CFR
Part 75.
As laid out in the Canada-U.S. Emissions Cap and Trading Feasibility
Study, if a cross-border emissions cap and trading system were established,
40 CFR Part 75 requirements would need to be implemented in Canada. One
major difference between Canada's EPS 1/PG/7 guidance and 40 CFR Part
75 is the emission data acquisition and reporting requirements in the
United States.
A study is being undertaken to estimate the costs of upgrading from
existing emission monitoring systems in place at Canadian electric generating
units to CEMS that would be compliant with 40 CFR Part 75. Preliminary
conclusions from this work indicate that the costs for Canadian electricity
generators would relate to the type of CEMS chosen and to the type of
unit (coal-fired, oil or gas, peaking, low mass emitter) in which the
monitor would be installed, with coal- fired generators being the most
affected. As well, all facilities would be required to add 40 CFR Part
75 data acquisition and reporting capabilities, and there would be some
incremental control system costs for each unit in each facility.
UNITED STATES
Under the Acid Rain Program, affected units are required to measure
and record emissions using CEMS (usually a concentration monitor in conjunction
with a flow monitor to determine mass emissions) or an approved alternative
measurement method and to report emissions electronically on a quarterly
basis. All of the monitoring systems must pass rigorous quality assurance
tests and operate with a high degree of accuracy and reliability.
In fact, the average percent monitor data availability (a measure of
monitoring systems' reliability) for 2005 was 99 percent for coal-fired
units. This number is based on reported monitor data availability for
SO2 monitors (99.5 percent), NOx monitors (97.5
percent), and flow monitors (99.1 percent). Additionally, in recent years,
new audit capabilities have been added, including software that performs
hourly checks to catch errors, miscalculations, and oversights in monitoring
and reporting systems. These audits help ensure the completeness, high
quality, and integrity of emissions data as well as highlight a number
of potential "red flags" that require additional verification.
Accurate emissions monitoring remains the backbone of trading program
integrity. Initially, electronic audits were conducted on the units that
used continuous emission monitors. Beginning in 2006, EPA increased its
electronic audit capabilities and now conducts audits on all affected
units, regardless of the monitoring methodology used. For instance, all
oil and gas units-
including those that use alternative methods-are also audited.
Results from the audits are promptly sent to the source, and correction
of critical errors is required. In addition to the electronic audits,
targeted field audits are conducted on sources that report suspect data.
Compliance was virtually 100 percent in 2005, with only one of 3,446
units out of compliance.
Preventing Air Quality Deterioration and Protecting Visibility
CANADA
Pollution prevention, continuous improvement (CI), and Keeping Clean
Areas Clean (KCAC) activities are all part of the Canada-wide Standards
for particulate matter (PM) and ozone to prevent the deterioration of
air quality and address the pollutants involved in visibility impairment.
Visibility (how far an object can be seen) is often the first perception
of smog, since PM reduces the clarity of what we see when present at
high enough levels in the air.
Clean areas in Canada include our national parks. Environment Canada
and Parks Canada have begun to informally explore options for air quality
monitoring in these areas, including a program for visibility monitoring.
As part of the options being explored, Environment Canada has made an
agreement with EPA and the U.S. Interagency Monitoring of Protected Visual
Environments (IMPROVE), the program that supports visibility monitoring
in U.S. national parks and wilderness areas. Under this agreement, IMPROVE
has lent its visibility monitoring equipment to Environment Canada for
evaluation with comparable equipment designed by Environment Canada.
The IMPROVE equipment is currently deployed at the Environment Canada
air quality research monitoring station located at Egbert, Ontario.
The Province of British Columbia continues to elaborate its approach
to addressing CI and KCAC. For example, the Greater Vancouver Regional
District (GVRD) adopted a new Air Quality Management Plan (AQMP) in October
2005 to maintain and improve air quality in the lower Fraser Valley airshed.
The new AQMP aims to minimize the risk to human health from air pollution,
improve visibility, and reduce the GVRD's contribution to global climate
change. As the Canada-wide Standard for PM2.5 (particulate
matter less than or equal to 2.5 microns) is being met throughout the
lower Fraser Valley and the Canada-wide Standard for ozone is exceeded
only in the eastern part, the AQMP supports the CI/KCAC provisions of
the Canada-wide Standards. New health-based ambient air quality objectives,
established as part of the AQMP, are more stringent than the Canada-wide
Standards for ozone and PM2.5. In addition, CI, defined as "taking
remedial and preventive actions to reduce emissions from human activities
towards the long-term goal of reducing overall ambient concentrations
and health risks," is a fundamental principle of the AQMP. The AQMP's
emission reduction actions will reduce direct emissions of PM and ozone
and PM precursors.
UNITED STATES
The U.S. Prevention of Significant Air Quality Deterioration Program
protects public health from adverse effects that may occur from the addition
of new sources of air pollution and ensures that air quality in many
areas of the country remains better than levels mandated by the National
Ambient Air Quality Standards (NAAQS). The program preserves and protects
air quality in Class I (pristine) areas by assessing impacts on visibility
before construction permits are issued. Class I areas include national
parks and wilderness areas, such as the Grand Canyon, Yosemite, and the
Great Smokies. The Regional Haze Program requires states to develop plans
to improve visibility conditions in Class I areas with the goal of restoring
natural visibility conditions in about 60 years. The first set of plans
is due in early 2008. Improvements in visibility for the eastern United
States are also expected from implementation of the CAIR.
The pollutants that impair visibility by scattering and absorbing light
include sulfate, nitrate, and organic carbon compounds. Sulfate and nitrate
particles are the result of SO2 and NOx gases that
are transformed in the atmosphere. Sulfates are generally the largest
contributor to visibility impairment in both the east and the west, although
humidity, organic carbon, and soil dust also play important roles.
"Standard visual range" is defined as the farthest distance
a large dark object can be seen. This distance is calculated using fine
and coarse particle data by multiplying concentrations of various types
of particles by their extinction efficiency (how much they block light),
adding those up, then adding the clean atmosphere extinction (scattering
of light from gas molecules). The extinction calculation is done for
each 24-hour period during which particle samples are taken. Currently,
these samples are taken every third day, or 121 days per year. Therefore,
the annual average standard visual range is the average of the calculated
standard visual range for these 121 sample days. The visual range under
naturally occurring conditions without pollution in the United States
is approximately 45-90 miles (75-150 km) in the east and 120-180 miles
(200-300 km) in the west.
Historical data from the IMPROVE network indicate modest improvement
in visibility during the early 2000s. The level of visibility impairment
on the worst visibility days in the west is similar to the levels seen
on the best visibility days in the east. In 2004, the mean visual range
for the worst days in the east was only 20 miles (32 km), compared with
85 miles (136 km) for the best visibility days (see Figure
8). In the west,
visibility impairment for the worst days remained relatively unchanged
over the past decade, with the mean visual range for 2004 (58 miles,
or 94 km) nearly the same as the 1992 range (61 miles, or 98 km). Although
the period showed moderate improvements in some areas, overall visibility
in the eastern United States is still significantly impaired in some
national parks and wilderness areas, especially on days of high relative
humidity.
Figure 8 Annual Average Standard Visual Range in the Contiguous
United States, 2004
Click to enlarge
Source: National Park Service
Each state is a member of an independent Regional Planning Organization
(RPO), which has been established to help member states work together
to develop strategies to address visibility and regional haze. The five
RPOs are the Mid-Atlantic/Northeast Visibility Union, the Visibility
Improvement State and Tribal Association of the Southeast, the Midwest
RPO, the Central States Regional Air Partnership, and the Western Regional
Air Partnership. The RPOs hold their own technical work group sessions
throughout the country to make decisions on joint technical work. The
technical work to support the first round of state plans has resulted
in a better understanding of transport near the border. The RPOs coordinate
technical information on emissions, ambient monitoring, and air quality
modeling activities. The RPOs are seeking ways for more involvement by
air quality agencies in Canada in their assessment of pollutant formation
and transport. For more information on the U.S. visibility program and
RPOs, see www.epa.gov/air/visibility/index.html.
Consultation and Notification Concerning Significant Transboundary
Air Pollution
JOINT EFFORTS
Since 1994, Canada and the United States have continued to follow an
established set of notification procedures to identify possible new sources
and modifications to existing sources of transboundary air pollution
within 62 miles (100 km) of the border. Notifications can occur for new
and existing sources located outside of the 62-mile (100-km) region if
governments believe that there is a potential for transboundary pollution.
Since the last progress report in 2004, Canada has notified the United
States of 7 additional sources, for a total of 44. The United States
has notified Canada of 13 additional sources, for a total of 47.
Transboundary notification information is available on the Internet
sites of the two governments at:
Canada:
www.ec.gc.ca/cleanair-airpur/CAOL/canus/canus_applic_e.cfm
United States:
www.epa.gov./ttn/gei/uscadata.html
Following guidelines approved by the Air Quality Committee in 1998 for
consultations requested by a Party on transboundary pollution concerns,
Canada and the United States report ongoing progress on joint discussions
concerning the Boundary Dam Power Station (BDPS) near Estevan, Saskatchewan,
and Algoma Steel, Inc. (ASI) in Sault Ste. Marie, Ontario.
Boundary Dam
A binational BDPS Informal Consultation Group was formed to address
transboundary pollution concerns around Estevan, Saskatchewan, and Burke
County, North Dakota. Partners included representatives from Environment
Canada, EPA, the North Dakota Department of Health, Saskatchewan Environment,
and SaskPower (the operator of the BDPS). A transboundary ambient air
monitoring network was established to track air quality changes in the
region.
Since that time, SaskPower has completed the installation of electrostatic
precipitators on all of its units, resulting in the virtual elimination
of any visible PM plume. In 2004, an interim report summarized air quality
trends from 1998 to 2003 and concluded that no exceedances of either
U.S. or Canadian standards had been observed at any of the monitoring
sites. Performance audits conducted in 2005 noted that all sites complied
with the necessary operational and quality assurance criteria.
Accordingly, the BDPS Informal Consultation Group has proposed a transition
plan to conclude this successful consultation. A report will be presented
to the Canada-U.S. Air Quality Committee at its annual meeting in the
fall of 2006, detailing the disposition of the monitoring equipment as
well as summarizing the air quality data gathered in the region by the
transboundary monitoring network.
Algoma Steel
The Canada-U.S. Algoma informal consultations began in 1998 to address
concerns regarding local cross-border pollution. Representatives from
the United States and Canada hold regular discussions to coordinate monitoring
programs in the Sault Ste. Marie area and to address progress in abating
potential transboundary pollution from the ASI facility in Ontario. Air
quality monitoring on the Canadian side has been ongoing since the 1960s
and on the U.S. side was initiated by the Inter-Tribal Council of Michigan
in 2001. Sampling of fine PM and toxic air pollutants continues on both
sides of the border.
During the last two years, Canadian and U.S. representatives have continued
to meet to discuss progress towards reducing emissions from ASI and to
share results of air monitoring studies. The data analysis subgroup has
completed a draft report summarizing results of the ambient air monitoring
program in the binational area during 2001-2003. Canadian and U.S. partners
have agreed that this draft report should be identified as an "interim"
document, and future reports will update the monitoring results, including
the 2004-2005 data. The quality assurance/quality control subgroup continues
to evaluate the monitoring equipment and the methods employed by both
countries to ensure comparability of monitoring results.
Trend data from the consultation indicate that although emission rates
have declined, total steel production at ASI has increased. The combined
impact of these changes on air quality is not yet known, and citizen
complaints are still being received by local agencies. The monitoring
data also indicate that there are no exceedances of the NAAQS at the
Michigan monitoring sites. However, several pollutants, such as total
suspended particulates and coarse particulate matter (particulate matter
less than or equal to 10 microns, or PM10), exceed Ontario
air quality criteria in the west end of Sault Ste. Marie. The Algoma
bilateral consultation group will continue to monitor and report on this
facility.
1 One tonne is equal to 1.1 short tons.
2 Chestnut, L.G. and Mills, D.M. (2005) A fresh look at the
benefits and cost of the US Acid Rain Program. Journal of Environmental Management,
Vol. 77, No. 3, pp. 252-266.
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