Canada - United States Air Quality Agreement Progress Report 2014: chapter 1
Section 1: Commitments
- Acid Rain Annex
- Key Commitments and Progress: SO2 Emission Reductions
- Key Commitments and Progress: NOX Emission Reductions
- Emissions/Compliance Monitoring
- Acid Deposition Monitoring, Modeling, Maps, and Trends .
- Preventing Air Quality Deterioration and Protecting Visibility
- Consultation and Notification Concerning Significant Transboundary Air Pollution
- Ozone Annex
Acid Rain Annex
The Acid Rain Annex to the 1991 AQA established commitments for both countries to reduce emissions of SO2 and NOX, the primary precursors to acid rain, from stationary and mobile sources. The commitments also include prevention of air quality deterioration, visibility protection, and continuous emission monitoring. Both countries have succeeded in reducing the impact of acid rain on each side of the border. Studies in each country, however, indicate that further efforts are necessary to restore damaged ecosystems.
Key Commitments and Progress: SO2Emission Reductions
For more than two decades, Canada has reduced SO2 emissions through various actions, including the requirements to reduce sulphur content in fuels and the implementation of the Canada-Wide Acid Rain Strategy for Post-2000. The Strategy serves as the framework for addressing the issues related to acid rain, with the goal that the deposition of acidifying pollutants does not further deteriorate the environment in eastern Canada and that new acid rain problems do not occur elsewhere in Canada. In 2012, Canada’s total SO2 emissions were 1.3 million metric tons (1.4 million short tonsFootnote1), about 60 percent below the national cap of 3.2 million metric tons (3.5 million short tons). This also represents a 58-percent reduction from Canada’s total SO2 emissions in 1990 (see Figure 1).
The largest contribution of SO2 emissions originates from industrial sources, which accounted for approximately 66 percent of national SO2emissions in 2012. Key sources, such as the non-ferrous smelting and refining industry and the upstream petroleum industry, contributed 27 percent and 21 percent, respectively, to national SO2 emissions in 2012.
Electric power generation accounted for 22 percent of the national total. The majority of overall reductions in national SO2 emission levels can be attributed to the SO2 emission reductions undertaken by the four eastern provinces (New Brunswick, Nova Scotia, Quebec and Ontario) targeted by the Acid Rain Strategy and to recent facility closures.
Source: Environment Canada, 2014
Figure 1. Total Canadian Emissions of SO2, 1980 - 2012
Figure1 shows Canadian national SO2 emissions in millions of metric tons from 1980 to 2012. The trend is decreasing. In 2012, Canada’s total SO2 emissions were 1.3 million metric tonnes, or about 60 percent below the national cap of 3.2 million tonnes. This also represents a 58 percent reduction from Canada’s total SO2 emissions in 1990.
Although Canada has been successful in reducing emissions of acidifying pollutants, many areas across Canada have a low capacity to withstand acidic deposition and continue to receive levels in excess of critical loads, most notably in eastern Canada. A critical load can be defined as the maximum amount of acidifying deposition an ecosystem can tolerate in the long term without being damaged (see Ecological Effects in Section 2 for further information).
Additional measures to reduce SO2 and NOX emissions from certain industrial sectors are being undertaken as part of Canada’s Air Quality Management System (see Section 3: New Actions on Acid Rain, Ozone and Particulate Matter).
The United States succeeded in meeting its commitment to reduce annual SO2 emissions by 10 million short tons (9.1 million metric tons) from 1980 levels by 2000. Additionally, since 2007, emissions of SO2 from the electric power sector have been below the 2010 national emission cap of 8.95 million short tons (8.1 million metric tons).
The Acid Rain Program (ARP), established under Title IV of the 1990 Clean Air Act (CAA) Amendments, requires major emission reductions of SO2and NOX, the primary precursors of acid rain, from the power sector. The SO2 program sets a permanent cap on the total amount of SO2 that can be emitted by electric generating units (EGUs) in the contiguous United States, and uses a market-based cap and trade program to achieve emission reductions. The program was phased in, with the final 2010 SO2 cap set at 8.95 million short tons (8.1 million metric tons), a level of about one half of the emissions from the power sector in 1980. NOx reductions under the ARP are achieved through a program that applies to a subset of coal-fired EGUsand is closer to a traditional, rate-based regulatory system.
In 2012, the SO2 requirements under the ARP applied to 3652 fossil-fuel-fired combustion units that served large generators greater than 25 megawatts(MW) at 1 249 facilities across the country providing electricity for sale. ARP units emitted 3.3 million short tons (3.0 million metric tons) of SO2 in 2012, meaning that ARP sources reduced emissions by 12.4 million short tons (11.3 million metric tons, or 79 percent) from 1990 levels and 14 million short tons (12.7 million metric tons, or 81 percent) from 1980 levels. The vast majority of ARP SO2 emissions result from coal-fired EGUs, although the program also applies to oil and gas units.
These reductions occurred while electricity demand (measured as heat input) remained relatively stable, indicating that the reduction in emissions was not driven by decreased electric generation. Instead, there was a drop in emission rate. A drop in emission rate represents an overall increase in the environmental efficiency of these sources as power generators install controls, run controls year-round, switch to different fuels, or otherwise cut their SO2emissions while meeting relatively steady demand for power.
Clean Air Interstate Rule
In 2005, the United States promulgated the Clean Air Interstate Rule (CAIR) to address regional interstate transport of O3 and fine particle (PM2.5) pollution. CAIR requires 24 eastern states and the District of Columbia (D.C.) to limit annual emissions of NOx and SO2, which contribute to the formation of PM2.5 (particulate matter less than or equal to 2.5 microns). CAIR also requires 25 states and D.C. to limit ozone season NOx emissions, which contribute to the formation of smog during the summer ozone season (May to September).
However, in July 2008 the U.S. Court of Appeals for the D.C. Circuit granted several petitions for review of CAIR, finding significant flaws in the rule. In December 2008 the court issued a ruling to keep CAIR and the CAIR Federal Implementation Plans (FIPs), including the CAIR trading programs, in place temporarily until the U.S. Environmental Protection Agency (EPA) issued new rules to replace CAIR and the CAIR FIPs. On July 6, 2011, the EPA finalized the Cross-State Air Pollution Rule (CSAPR) to replace CAIR beginning in 2012. However, prior to implementation, the court stayed CSAPR pending judicial review on December 30, 2011. On August 21, 2012, the court issued an opinion vacating CSAPR. In its August opinion, the court also ordered the EPA to continue administering CAIR. The U.S. Supreme Court subsequently granted petitions from the EPA and several environmental and public health organizations to review the D.C. Circuit Court’s decision. On April 29, 2014, the U.S. Supreme Court reversed the D.C. Circuit opinion vacating CSAPR. On June 26, 2014, EPA requested that the D.C. Circuit lift the CSAPR stay and toll the CSAPR compliance deadlines by three years, to allow implementation of Phase 1 for 2015 and Phase 2 for 2017. On October 23, 2014, the D.C. Circuit granted EPA’s request. CSAPR Phase 1 implementation is now beginning in 2015, with Phase 2 beginning in 2017.
CAIR includes three separate cap and trade programs to achieve the rule’s required reductions: the CAIR NOx ozone season trading program, the CAIR NOx annual trading program, and the CAIR SO2 annual trading program. The CAIR NOx ozone season and annual programs began in 2009, while the CAIR SO2 annual program began in 2010.
In 2012, there were 3336 affected EGUs at 952 facilities in the CAIR SO2 and NOX annual programs. The CAIR programs cover a range of unit types, including units that operate year-round to provide baseload power to the electric grid as well as units that provide power on peak demand days only and may not operate at all during some years. Annual SO2 emissions from sources in the CAIRSO2 program alone fell from 9.1 million short tons (8.2 million metric tons) in 2005 when CAIR was promulgated to 2.8 million short tons (2.5 million metric tons) in 2012, a 69 percent reduction. Between 2011 and 2012, SO2 emissions fell 1.1 million short tons (1.0 million metric tons), or 28 percent. In 2012, the total SO2 emissions from participating sources were about 855 000 short tons (776 000 metric tons) below the regional CAIR emission budget.
The EPA’s Emissions Tracking Highlights site contains the most up-to-date emission and control data for sources subject to the ARP and CAIR: www.epa.gov/airmarkets/quarterlytracking.html.
In addition to the electric power generation sector, emission reductions from other sources not affected by the ARP or CAIR, including industrial and commercial boilers and the metals and refining industries, and the use of cleaner fuels in residential and commercial boilers, have contributed to an overall reduction in annual SO2 emissions. National SO2 emissions from all sources have fallen from nearly 26 million short tons (23.6 million metric tons) in 1980 to just over 5 million short tons (4.8 million metric tons) in 2012 (see www.epa.gov/ttn/chief/trends).
Figure 2 combines emission and compliance data for ARP and CAIR to more holistically show reductions in power sector emissions of SO2 from these national and regional programs, as of 2012.
Note: For CAIR units not in the ARP, the 2009 annual SO2emissions were applied retroactively for each pre-CAIR year following the year in which the unit began operating.
Source: U.S. EPA, 2013
Figure 2. U.S. SO2 Emissions from the CAIR SO2 Annual Program and ARP Sources, 1980-2012
Figure 2 depicts combined emission and compliance data for both the Acid Rain Program (ARP) and Clean Air Interstate Rule (CAIR). In 2012, there were 3,336 affected electric generating units. Annual SO2emissions from sources in the CAIR SO2 program fell from 9.1 million short tons in 2005 to 2.8 million short tons in 2012, a 69 percent reduction. Between 2011 and 2012, SO2 emissions fell 1 million short tons, or 28 percent.
Key Commitments and Progress: NOx Emission Reductions
Canada has met its commitment to reduce NOx emissions from power plants, major combustion sources and metal smelting operations by 100 000 metric tons (110 000 short tons) below the forecasted level of 970 000 metric tons (1.1 million short tons). This commitment is based on a 1985 forecast of 2005 NOx emissions. In 2012, industrial emissions of NOx totaled 612 885 metric tons (674 174 short tons). Emissions of NOX from all industrial sources, including emissions from electric power generation, totaled 778 658 metric tons (856 524 short tons) in 2012.
Transportation sources contributed the majority of NOx emissions in 2012, accounting for almost 54 percent of total Canadian emissions, with the remainder produced by the upstream petroleum industry (23 percent), electric power generation facilities (9 percent), and other sources (see Figure 25). Canada continues to develop programs to further reduce NOx emissions nationwide.Footnote2
The United States has exceeded its goal under the Acid Rain Annex to reduce total annual NOX emissions by 2 million short tons (1.8 million metric tons) below projected annual emission levels for 2000 without the ARP (8.1 million short tons, or 7.4 million metric tons).
Title IV of the CAA requires NOx emission reductions from certain coal-fired EGUs. Unlike the market-based NOx programs in CAIR, the ARP requires NOx emission reductions for older, larger coal-fired EGUs by limiting their NOx emission rate (expressed in pounds per million British thermal units [lbs./mmBtu]). In 2012, 900 units at 368 facilities were subject to the ARP NOx program.
Emissions of NOxfrom all sources covered by the ARP were 1.7 million short tons (1.5 million metric tons) (Figure 3) in 2012. This level is 6.4 million short tons (5.5 million metric tons) less than the projected NOx level in 2000 without the ARP, and over three times the Title IV NOxemission reduction commitment under the Acid Rain Annex.
While the ARP is responsible for a large portion of these annual NOx reductions, other programs, such as the CAIR NOx ozone season and annual programs as well as state NOx emission control programs, also contributed significantly to the NOx reductions that sources achieved in 2012.
Canada continues to meet its commitments to estimate and monitor emissions of NOx and SO2 from new electric utility units and existing electricity units with a capacity rating greater than 25 MW. Continuous emission monitoring systems (CEMS) or other comparable monitoring methods have had widespread use in Canada’s electric utility sector since the late 1990s. Currently, most new and existing baseloaded fossil steam plants and natural gas turbines with high emission rates operate CEMS technology. Coal-fired facilities, which are the largest source of emissions from the sector, have SO2 and NOx CEMS installed at more than 93 percent of their total capacity. In addition, under Canada’s National Pollutant Release Inventory (NPRI) mandatory reporting program, electric power generating facilities are required to report their air pollutant emissions (including NOx and SO2) annually.
The EPA has developed detailed procedures (40 CFR Part 75) to ensure that sources monitor and report emissions with a high degree of precision, accuracy, reliability and consistency. Sources use CEMS or other approved methods. Part 75 requires sources to conduct stringent quality assurance tests of their monitoring systems, such as daily and quarterly calibration tests and a semi-annual or annual relative accuracy test audit. These tests ensure that sources report accurate data and provide assurance to market participants that a ton of emissions measured at one facility is equivalent to a ton measured at another facility.
Source: U.S. EPA, 2014
Figure 3. U.S. Title IV Utility Unit Annual NOx Emissions from ARP Sources, 1990 - 2012
Figure 3 depicts U.S. NOx emissions in millions of tons from coal-fired electric utility units affected by the NOx component of Title IV of the 1990 Clean Air Act. These include NOx program-affected sources and Title IV sources affected by the NOx program. With a few exceptions the trends are decreasing over time. In 2012, 900 coal-fired units at 368 facilities were subject to the Acid Rain Program (ARP) NOx program. Emissions of NOx from all sources covered by the ARP were 1.7 million short tons in 2012.
In 2012, CEMS monitored over 99 percent of SO2emissions from CAIR sources, including 100 percent from coal-fired units and 24 percent from oil-fired units. The relatively low percentage for oil-fired units is consistent with the decline in oil-fired heat input, as most of these units were used infrequently and qualified for reduced monitoring. Although some CAIR units with low levels of emissions are not required to use CEMS, the vast majority of NOx emissions--over 99 percent--were measured by CEMS. Coal-fired units were required to use CEMS for NOx concentration and stack gas flow rate to calculate and record their NOx mass emissions. Oil-fired and gas-fired units could use a NOx CEMS in conjunction with a fuel-flow meter to determine NOx mass emissions. Alternatively, for oil-fired and gasfired units that either operated infrequently or had very low NOx emissions, Part 75 provided low-cost alternatives to conservatively estimate NOx mass emissions.
Using automated software audits, the EPA rigorously checks the completeness, quality and integrity of monitoring data. The Agency promptly sends results from the audits to the source, and requires correction of critical errors. In addition to electronic audits, the EPA conducts targeted field audits on sources that report suspect data. In 2012, all reporting ARP and CAIR SO2 facilities were in compliance with both programs, and held enough allowances to cover their SO2emissions. Similarly, all reporting covered facilities were in compliance with the CAIR NOX annual programs in 2012, and held enough allowances to cover their NOX emissions. Additionally, All 900 units subject to ARP NOx emissions limitations in 2012 were in compliance. Emission data are available to the public within two months of being reported to the EPA, and can be accessed on the Air Markets Program Data website at www.ampd.epa.gov/ampd/.
Acid Deposition Monitoring, Modelling, 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 monitors, and the concentration of sulphate and nitrate in precipitation is regularly used to assess the changing atmosphere as it responds to decreasing or increasing sulphur and nitrogen emissions. In Canada and the United States, to facilitate this comparison, measurements of wet sulphate deposition are typically corrected to omit the contribution of sea-salt sulphate at near-ocean sites (less than 62 miles, or 100 km, from the coast). The annual sea-salt sulphate contribution to total sulphate wet deposition at coastal sites in Canada ranged from 9 to 41 percent between 2010 and 2012 (with an average of 26 percent).
Figures 4, 5 and 6 show the United States-Canada spatial patterns of wet sulphate (sea salt-corrected) deposition for 1990, 2000 and 2012. Figures 7, 8 and 9 show the patterns of wet nitrate deposition for the same three years. Deposition contours are not shown in western and northern Canada, because Canadian experts judged that the locations of the contour lines were unacceptably uncertain due to the paucity of measurement sites in all of the western provinces and northern territories. To compensate for the lack of contours, wet deposition values in western Canada are shown as coloured circles at the locations of the federal/ provincial/ territorial measurement sites.
The three maps indicate that wet sulphate deposition is consistently highest in eastern North America around the lower Great Lakes, with a gradient following a southwest-to-northeast axis running from the confluence of the Mississippi and Ohio rivers through the lower Great Lakes. The patterns for 1990, 2000 and 2012 illustrate that wet sulphate deposition in both the eastern United States and eastern Canada have decreased in response to decreasing SO2 emissions.
By 2000, the region receiving greater than 24 kg per hectare per year (kg/ha/yr) of wet sulphate deposition had decreased in size, and was limited to a small area located at the eastern end of Lake Erie. By 2012, this deposition region had completely disappeared, leaving only one small area (too small to be visible on Figure 6)--located at the eastern end of Lake Erie in New York--that received wet sulphate deposition greater than 16 kg/ha/yr. From 1990 to 2012, the region that received deposition greater than 8 kg/ha/yr decreased markedly from 5.94 to 4.91 to 1.48 million km2, respectively. The wet sulphate deposition reductions are considered to be directly related to decreases in SO2 emissions in both the United States and Canada. The emission reductions are outlined in “Key Commitments and Progress: SO2 Emission Reductions” in Section 1 of this report.
The patterns of wet nitrate deposition (Figures 7, 8 and 9) show a similar southwest-to-northeast axis, but the area of highest nitrate deposition is slightly north of the region with the highest sulphate deposition. Major reductions in wet nitrate deposition occurred in the period between 2000 and 2012, when large NOx emission reductions occurred in the United States and, to a lesser degree, Canada. As a result, by 2012 all regions received less than 15 kg/ha/yr of wet nitrate deposition except one small area (too small to be visible on Figure 9) located at the eastern end of Lake Erie in New York. From 1990 to 2012, the region that received greater than 9 kg/ha/yr decreased from 4.35 to 4.00 to 1.05 million km2, respectively.
Figure 4. 1990 Annual Wet Sulphate Deposition
Figure 4 shows the U.S.-Canada spatial pattern of wet sulphate (sea-salt corrected) deposition in kilograms/hectare/year for 1990. It also shows that wet sulphate deposition is highest in eastern North America around the lower Great Lakes, with a gradient following a southwest-to-northeast axis running from the confluence of the Mississippi and Ohio Rivers through the lower Great Lakes. The pattern illustrates that significant reductions occurred in wet sulphate deposition in both the eastern U.S. and eastern Canada.
Figure 5. 2000 Annual Wet Sulphate Deposition
Figure 5 shows the U.S.-Canada spatial pattern of wet sulphate (sea-salt corrected) deposition in kilograms/hectare/year for 2000. It also shows that wet sulphate deposition is highest in eastern North America around the lower Great Lakes, with a gradient following a southwest-to-northeast axis running from the confluence of the Mississippi and Ohio Rivers through the lower Great Lakes. The pattern illustrates that significant reductions occurred in wet sulphate deposition in both the eastern U.S. and eastern Canada.
Figure 6. 2012 Annual Wet Sulphate Deposition
Figure 6 shows the U.S.-Canada spatial pattern of wet sulfate (sea-salt corrected) deposition in kilograms/hectare/year for 2012. It also shows that wet sulphate deposition is highest in eastern North America around the lower Great Lakes, with a gradient following a southwest-to-northeast axis running from the confluence of the Mississippi and Ohio Rivers through the lower Great Lakes. The pattern illustrates that significant reductions occurred in wet sulphate deposition in both the eastern U.S. and eastern Canada.
Wet deposition measurements in Canada are made by the federal Canadian Air and Precipitation Monitoring Network (CAPMoN) and networks in a number of provinces/territories, including Alberta, the Northwest Territories, Quebec, New Brunswick and Nova Scotia. Dry deposition estimates are made at a subset of CAPMoN sites using an inferential method whereby air concentration measurements are combined with modelled dry deposition velocities. In the United States, wet deposition measurements are made by two coordinated networks: the National Atmospheric Deposition Program (NADP) / National Trends Network (NTN), which is a collaboration of federal government, state government, and non-governmental organizations (nadp.sws. uiuc.edu); and the NADP/Atmospheric Integrated Research Monitoring Network (AIRMoN), which is a sub-network of the NADP funded by the National Oceanic and Atmospheric Administration (NOAA) (nadp.isws.illinois.edu). Dry deposition estimates in the United States are made using the inferential technique based on modelled dry deposition velocities and ambient air concentration data collected by the Clean Air Status and Trends Network (CASTNET) (www. epa.gov/castnet), which is coordinated by the EPA, National Park Service (NPS), and Bureau of Land Management.
The measurements of wet deposition and air concentrations provided by the Canadian and U.S. networks have been shown to be comparable through collocated studies and inter-laboratory comparisons. In contrast to these measurements, the estimated dry deposition velocities from the Canadian (Big Leaf Model) and U.S. (Multi-Layer Model) models are poorly correlated, due to differences in resistance assumptions. Therefore, deposition fluxes at the collocated site, calculated from the measured concentrations and modelled deposition velocities, are significantly different. Given that dry deposition is an important contributor to total deposition, ongoing efforts are underway to study the sources of these differences. At the Borden research station in Ontario, instruments were collocated for a number of years as part of a bilateral inter-comparison study on modelling dry deposition. Studies are underway to quantify the sensitivity of the Canadian and U.S. dry deposition models to a variety of factors that influence dry deposition velocities, with the goal of refining model parameters for better comparability of future dry deposition estimates, reconciling past dry deposition estimates, and identifying further intercomparison needs. Measurement data are available from the websites of the individual networks.
Figure 7. 1990 Annual Wet Nitrate Deposition
Figure 7 shows the U.S.-Canada spatial pattern of wet nitrate deposition in kilograms/hectare/year in 1990. The pattern for wet nitrate deposition shows a similar southwest to-to-northeast axis, but the area of highest nitrate deposition is north of the region with the highest sulphate depositions. Reductions in wet nitrate deposition have generally been more modest than for wet sulphate deposition.
Figure 8. 2000 Annual Wet Nitrate Deposition
Figure 8 shows the U.S.-Canada spatial pattern of wet nitrate deposition in kilograms/hectare/year in 2000. The pattern for wet nitrate deposition shows a similar southwest to-to-northeast axis, but the area of highest nitrate deposition is north of the region with the highest sulphate depositions. Reductions in wet nitrate deposition have generally been more modest than for wet sulphate deposition, except during 2000 to 2012, when large NOx emission reductions occurred in the US, and to a lesser degree in Canada.
Figure 9. 2012 Annual Wet Nitrate Deposition
Figure 9 shows the U.S.-Canada spatial pattern of wet nitrate deposition in kilograms/hectare/year in 2012. The pattern for wet nitrate deposition shows a similar southwest to-to-northeast axis, but the area of highest nitrate deposition is north of the region with the highest sulphate depositions. Reductions in wet nitrate deposition have generally been more modest than for wet sulphate deposition, except during 2000 to 2012, when large NOx emission reductions occurred in the U.S., and to a lesser degree in Canada.
Preventing Air Quality Deterioration and Protecting Visibility
Canada is addressing the commitment to prevent air quality deterioration and ensure visibility protection by implementing the Canadian Environmental Protection Act, 1999 (CEPA 1999) and Canadian Environmental Assessment Act, 2012 (CEAA 2012), and by following the continuous improvement (CI) and keeping clean areas clean (KCAC) principles. These principles are included in Canada’s Air Quality Management System (AQMS) and the associated Canadian Ambient Air Quality Standards (CAAQS) that are replacing the Canada-wide Standards (CWS).
British Columbia continues to make progress towards implementing a pilot visibility management program in the Lower Fraser Valley (LFV) through the work of the British Columbia Visibility Coordinating Committee (BCVCC), an inter-agency group comprising representatives from various levels of government involved in air quality management. In 2010, the BCVCC adopted a visibility protection framework that describes the visibility management actions required to achieve “clean air and pristine visibility for the health and enjoyment of present and future generations.” In 2011, Metro Vancouver adopted its new Integrated Air Quality and Greenhouse Gas (GHG) Management Plan, which includes the goal to “improve visual air quality.” This goal will be accomplished by reducing emissions of visibility-degrading pollutants such as PM2.5, and by developing a visual air quality management program. As part of a pilot project to develop this program for the LFV, the BCVCC is working in four main areas: (1) advancement of visibility science, (2) development of a visibility indicator, (3) development of a business case to quantify the benefits of improved visibility, and (4) improvement of communications and outreach.
Environment Canada contributed to the BCVCC through a number of science activities, including upgrading the visibility monitoring network with cameras and nephelometers, attribution of visibility impairment to emission sources, and photochemical modelling to shed light on the effect of different pollutants on visibility impairment. The development of an LFV-specific visibility indicator is nearly complete; in 2013, a public validation study of the indicator was conducted, and it is expected that the indicator will be made public as a tool to inform residents of visibility conditions throughout the airshed. In addition, it will help develop airshed-specific visibility improvement goals. The BCVCC developed a business case that outlines, in economic terms, the various benefits of improving visibility in the LFV. Elements in the business case include the health benefits of lowering PM2.5 in order to improve visibility, a measure of residents’ willingness to pay for better visibility, and visibility impacts on tourism, the film industry and real estate valuation. In 2013, modelling work was conducted to quantify the health benefits associated with achieving certain levels of visibility improvement. Communication and outreach efforts have resulted in the development of a visibility website for British Columbia (www.clearairbc.ca) as a means of promoting visibility and educating the public on this issue.
Additional activities have been undertaken in other parts of Canada as part of Environment Canada’s National Visibility Monitoring Pilot Study. Visibility monitoring pilot sites, established in 2011 at Barrier Lake, Alberta, and Wolfville, Nova Scotia, continue to operate as does the visibility supersite in Abbotsford, BC. In 2013, a National Air Pollutant Surveillance (NAPS) speciation sampler was installed at the Barrier Lake site to allow comparison with the co-located U.S. Interagency Monitoring of Protected Visual Environments (IMPROVE) sampler, in order to evaluate the suitability of the NAPS samplers to accurately estimate visual extinction. If the Canadian methodology is found to be sufficiently sound for visibility measurements, it would open up the potential for expansion of visibility monitoring at NAPS sites across Canada. Another inter-comparability study is ongoing at Egbert, Ontario, where IMPROVEspeciation data are being compared with data obtained from CAPMoN. In addition, an updated assessment of visibility conditions across Canada, using data from the NAPS speciation network from 2003 to 2012, is in progress.
The United States has various programs to ensure that air quality is not significantly degraded by the addition of air pollutants from new or modified major sources. The CAA requires that pre-construction permits be obtained for major new stationary sources of air pollution and extensive modifications to major existing stationary sources. The permitting process, known as New Source Review (NSR), applies both to areas that meet the National Ambient Air Quality Standards (NAAQS) (attainment areas) and areas that exceed the NAAQS (non-attainment areas). Permits for sources in attainment areas are known as prevention of significant deterioration (PSD) permits, while permits for sources located in non-attainment areas are known as non-attainment area (NAA) permits. PSD permits require air pollution controls that represent the best available control technology (BACT), an emission limitation based on the maximum degree of reduction of each pollutant subject to regulation under the CAA. BACT is determined on a case-by-case basis, and considers energy, environmental and economic impacts. NAA permits require the lowest achievable emission rate (LAER). BACT and LAER must be at least as strict as any existing New Source Performance Standard (NSPS) for sources. One important difference between NSR permits and the NSPS program is that NSR is applied on a source-specific basis, whereas the NSPS program applies to all sources nationwide. The PSD program also protects the air quality and visibility in Class I areas (i.e. national parks exceeding 6 000 acres and wilderness areas exceeding 5 000 acres). The federal land management agencies are responsible for protecting air quality-related values (such as visibility) in Class I areas by reviewing and commenting on construction permits.
The CAA established the goal of improving visibility in the nation’s 156 Class I areas and returning these areas to natural visibility conditions (i.e. visibility that existed before human-caused air pollution). The 1999 Regional Haze Rule requires that states reach that goal by 2064, and specifies the state implementation plan (SIP) provisions that states must develop toward that goal. In July 2005, the EPA finalized amendments to the Regional Haze Rule, which, for the initial regional haze SIPs, required the installation of emission controls, known as best available retrofit technology (BART). The BART requirements apply to certain older, existing combustion sources within a group of 26 source categories, including certain EGUs that cause or contribute to visibility impairment in Class I areas. Many of these older sources have never been regulated, and applying BART will help improve visibility in Class I areas. In addition to BART, the rule also requires states to assess progress toward visibility improvement that could be made by controlling other non-BART emission sources, referred to as “reasonable progress.” Decisions regarding potential emission controls for BART and reasonable progress are informed through an assessment and balancing of factors, including cost effectiveness and the degree of visibility improvement expected.
The first planning period establishes an assessment of expected visibility conditions in 2018. The SIPs must be submitted every 10 years, and states revise their visibility goals accordingly to ensure that reasonable progress is being made to achieve natural visibility conditions by 2064. There is also a reporting check every five years, in which states report their interim progress toward reaching the goals. Additional information on the EPA’s Regional Haze Program can be found at www.epa.gov/visibility/index.html.
Source: U.S. NPS, 2014 (data from IMPROVE website: vista.cira.colostate.edu/improve/)
Figure 10. Annual Average Standard Visual Range in the Contiguous United States, 2008-2012
Figure 10 shows the annual average standard visual range within the U.S. for the period 2008-2012 in kilometres in the contiguous U.S. The visual range under naturally occurring conditions without human-caused pollution in the U.S. is typically 45 to 90 miles (75 to 140 km) in the east and 110 to 150 miles (180 to 240 km) in the west.
Figure 10 shows the annual average “standard visual range” (the farthest distance a large, dark object can be seen during daylight hours) within the United States for the period 2008-2012. This distance is calculated using fine and coarse particle data from the IMPROVE network. Increased particle pollution reduces the visual range. The visual range under naturally occurring conditions without human-caused pollution in the United States is typically 45-90 miles (75-140 km) in the east and 110-150 miles (180-240 km) in the west. Additional information on the IMPROVE program and visibility in U.S. National Parks can be found at vista.cira. colostate.edu/improve/.
Consultation and Notification Concerning Significant Transboundary Air Pollution
The United States and Canada initiated notification procedures in 1994 to identify potential new sources and modifications to existing sources of transboundary air pollution within 100 km (62 miles) of the border. Additionally, the governments can provide notifications for new or existing sources outside of the 100-km region if they believe there is potential for transboundary air pollution.
Since publication of the last Progress Report in 2012, the United States has notified Canada of five additional sources, for a total of 69 U.S. notifications. Canada has notified the United States of four additional sources, for a total of 62 Canadian notifications.Footnote3
The Ozone Annex commits the United States and Canada to address transboundary O3by reducing emissions of NOX and VOCs, the precursors to O3. The commitments apply to a defined region in both countries known as the Pollutant Emission Management Area (PEMA), which includes central and southern Ontario, southern Quebec, 18 states and D.C., and which is where emission reductions are most critical for reducing transboundary O3. The Annex was added to the Air Quality Agreement in 2000.
Key Commitments and Progress
Vehicles, Engines and Fuels
New stringent NOx and VOC emission standards for vehicles, including cars, vans, light-duty trucks, off road vehicles, small engines and diesel engines, as well as fuels.
Canada has implemented a series of regulations to align Canadian emission standards for vehicles and engines with corresponding standards in the United States.
The On-Road Vehicle and Engine Emission Regulations established air pollutant emission standards for on-road vehicles and engines (such as cars, trucks, motorcycles and buses) beginning in the 2004 model year, in alignment with those of the U.S. EPA. Recent amendments to the Regulations introduce new requirements for on-board diagnostic (OBD) systems for on-road heavy-duty engines and vehicles (with a gross vehicle weight rating of more than 6350 kg). The amendments, published in January 2013, are designed to align with U.S. federal requirements, and came into force on January 1, 2014. OBDsystems are designed to monitor emission-related components for malfunctions, to identify such malfunctions, and to facilitate repair and maintenance. On September 27, 2014 Environment Canada published proposed Regulations that would incorporate the U.S. EPA‘Tier 3’ standards in the On-Road Vehicle and Engine Emission Regulations. These standards would introduce stricter limits on air pollutant emissions from new passenger cars, light-duty trucks and certain heavy-duty vehicles beginning with the 2017 model year.
The Off-Road Small Spark-Ignition Engine Emission Regulations established air pollutant emission standards, aligned with U.S. federal standards, for 2005 and later model-year small spark-ignition (typically gasoline) engines found in lawn and garden machines, light-duty industrial machines, and light-duty logging machines. In 2008, the EPA published new, more stringent emission standards. With Canada’s policy of alignment of emission standards in the transportation sector, Environment Canada intends to amend its regulations to further reduce air pollutant emissions by aligning with the new U.S. Phase 3 exhaust and evaporative emissions standards.
The Off-Road Compression-Ignition Engine Emission Regulations, in effect as of January 1, 2006, establish air pollutant emission standards aligned with U.S. federal standards (Tiers 2 and 3), for 2006 and later model-year diesel engines, such as those typically found in agricultural, construction and forestry machines. In December 2011, amendments to the Off-Road Compression-Ignition Engine Emission Regulations were published, further reducing emissions of air pollutants in Canada by establishing more stringent Canadian off-road diesel emission standards. The amended Regulations align Canadian emission standards with the U.S. Tier 4 standards. The new standards are being phased in beginning on January 16, 2012, and will be fully in force by the end of 2018. Environment Canada intends to amend the Regulations to incorporate emission standards for large spark-ignition engines used in off-road applications such as forklifts and ice resurfacers, in alignment with U.S. federal emission standards and test procedures for these engines.
On February 16, 2011, Environment Canada published the Marine Spark-Ignition Engine, Vessel and Off-Road Recreational Vehicle Emission Regulations. These Regulations align air pollutant emission standards with those of the EPA for outboard engines, personal watercraft, sterndrive and inboard engines, vessels powered by these engines, snowmobiles, off-road motorcycles, all-terrain vehicles, and utility vehicles. Most of the standards applied beginning with the 2012 model year, while the emission standards for vessels will apply as of the 2015 model year.
Regulatory initiatives for gasoline include the Sulphur in Gasoline Regulations and Benzene in Gasoline Regulations. The Sulphur in Gasoline Regulations have limited the level of sulphur in gasoline to an average of 30 milligrams per kilogram (mg/kg) since 2005. In June 2013, the Government of Canada announced its intention to further reduce sulphur levels in gasoline to an average of 10 mg/kg to enable more advanced vehicle emissions-control technologies, in alignment with the EPA’s new Tier 3 rules that will further limit emissions of smog-forming air pollutants from new cars and light trucks. The Benzene in Gasoline Regulations have reduced benzene emissions from vehicles by limiting the benzene content in gasoline to 1.0 percent by volume since 1999.
The Sulphur in Diesel Fuel Regulations set maximum limits for sulphur in diesel fuels. Diesel fuel for use in on-road vehicles, off-road vehicles, rail, and small- and medium-sized vessels has a sulphur limit of 15 mg/kg, phased in for the various diesel fuel types between 2006 and 2012. New limits for diesel fuel used in large marine vessels and large stationary engines came into effect on June 1, 2014, limiting sulphur in these fuels to 1000 mg/kg. This new class of diesel fuel for large marine vessels will enable implementation of the North American Emission Control Area under the International Convention for the Prevention of Pollution from Ships. Large ships will be able to switch from using high-sulphur bunker fuel (with sulphur contents up to 3.5 percent [35 000 mg/kg]) to a lower-sulphur diesel fuel, in order to reduce emissions of sulphur oxide (SOx) and PM from ships.
The United States and Canada have agreed to work together to:
- harmonize national vehicle, engine and fuels standards for emissions of smog-forming pollutants;
- optimize vehicle and engine emission-testing activities, taking advantage of unique testing capabilities, and sharing emission test data where appropriate to facilitate regulatory administration activities in both countries; and
- share information and discuss strategies and approaches on GHG emission standards for motor vehicles.
Stationary Sources of NOX
Annual caps by 2007 of 39 000 metric tons of NOx (as nitrogen dioxide [NO2]) emissions from fossil fuel power plants in the PEMA in central and southern Ontario, and 5000 metric tons of NOx in the PEMA in southern Quebec.
In the Canadian portion of the PEMA, the largest source of NOx emissions from industry is the fossil fuel-fired power sector. Canada has met its commitment to cap NOx emissions from large fossil fuel-fired power plants in the Ontario and Quebec portions of the PEMA at 39 000 metric tons (42 900 short tons) and 5000 metric tons (5500 short tons), respectively, by 2007. Emissions from power plants in the Ontario portion of the PEMA were approximately 78 000 metric tons (86 000 short tons) in 1990. In 2013, NOx emissions from Ontario fossil fuel-fired power plants were estimated to be 10 000 metric tons (11 000 short tons), or 74 percent below the 39 000 metric tons (42 900 short tons) Ozone Annex commitment. The only Quebec fossil fuel-fired power plant in the PEMA ceased operations in March 2011; this plant’s NOx emissions for 2011 were below the reporting threshold set at 20 metric tons, and were therefore well below the ceiling.
Ontario’s Cessation of Coal Use regulation (O. Reg. 496/07) came into effect in August 2007 to ensure that coal is not used to generate electricity at the Atikokan, Lambton, Nanticoke and Thunder Bay generating stations after December 31, 2014. In 2013, NOx emissions from coal-fired power plants were 91 percent lower than in 2003. In April 2014, Ontario announced it had eliminated coal-fired electricity generation in advance of the December 31, 2014 deadline. All 19 units at the five coal-fired electricity generating stations in Ontario have now ceased burning coal.
Ontario has been engaged in a number of clean energy initiatives to replace coal-fired electricity generation. For example, the year 2012 marked the first time when more electricity was generated in Ontario using wind power than coal. By the end of the first quarter of 2014, the Ontario Power Authority administered 21 695 renewable energy contracts (including 18 812 contracts for projects 10 kilowatts [kW] or less in size), for a total of 10 690 MW. Of these contracts, 5 873 MW of wind, solar, bioenergy and hydroelectric capacity came online. In addition, 2012 marked the return to service of 1 500 MW at the Bruce nuclear plant.
To ensure that the 5 000 metric ton (5 500 short ton) cap is met for the Quebec portion of the PEMA, Quebec’s Clean Air Regulation, which came into effect on June 30, 2011, introduced a cap of 2 100 metric tons (2 310 short tons) of NOX per year for the Sorel Tracy plant. This plant was used mainly during peak periods. After easily meeting the cap in 2010, with only 16 metric tons (18 short tons) of NOx, this plant permanently ceased activities in March 2011.
Measures to Reduce VOCs and NOx
Reduce VOC emissions by developing two regulations-- one on dry cleaning and another on solvent degreasing-- and using VOC emission limits for new stationary sources. In addition, introduce measures to reduce VOC emissions from solvents, paints, and consumer products and measures to reduce NOx emissions from key industrial sectors.
The final provision of the Tetrachloroethylene (Use in Dry Cleaning and Reporting Requirements) Regulations came into effect in August 2005. The Regulations’ environmental objective is to reduce the ambient tetrachloroethylene (PERC) concentration in the air to below 0.3 micrograms per cubic metre (μg/m3). The risk management goal of the regulations is to reduce PERC use in dry cleaning in Canada to less than 1 600 metric tons (1 760 short tons) per year. In 2009, Environment Canada completed a use pattern study indicating that these objectives had been achieved. In 2013, dry cleaners reporting under the Regulations used less than 800 metric tons of PERC.
The Solvent Degreasing Regulations, which took effect in July 2003, froze the consumption of trichloroethylene (TCE) and PERC in affected cold and vapor-solvent degreasing facilities for three years (2004-2006) at then-current levels, based on historical use. Beginning in 2007, the annual consumption levels were reduced by 65 percent for affected facilities. Under the Regulations, Environment Canada issues annual allowances (consumption units) for use of PERC or TCE to qualifying facilities. Consumption units issued for 2014 represented a reduction of more than 88 percent and 80 percent for TCE and PERC, respectively, relative to the 2004-2006 baseline.
The federal government has taken actions to reduce VOC emissions from consumer and commercial products that contribute significantly to the formation of smog, such as cleaning products, personal care products, and paints. The Volatile Organic Compound (VOC) Concentration Limits for Automotive Refinishing Products Regulations were published in July 2009, while the Volatile Organic Compound (VOC) Concentration Limits for Architectural Coatings Regulations were published in September 2009.
Furthermore, the Proposed Certain Products Regulations were published in the Canada Gazette, Part I, on April 26, 2008, and included concentration limits for VOCs in approximately 100 categories of products, including personal care, cleaning, adhesives, and automotive maintenance products. Since that time, the decision was made to revise the regulatory proposal to include an averaging and trading program and to align the regulations with more recent California regulations. A consultation document outlining a revised regulatory proposal was released in January 2013 for public comment. The revised regulatory proposal covered 130 product categories, including the addition of 30 new product categories as well as updated limits for another 30 categories.
Between 2011 and 2012, Environment Canada contributed to funding of a pilot program to increase awareness of VOCs emitted by portable fuel containers (PFCs) and to facilitate the uptake of new containers that lead to lower VOC emissions. This fuel container exchange program encouraged participants to turn in their old PFCs in exchange for the newly designed containers. In 2012, a total of 700 PFCs were collected. The estimated VOC emissions reductions associated with the PFCs collected was 1 300 kg per year or 6 600 kg over the remaining lifespan of the old PFCs.
A draft Code of Practice for the Reduction of VOC Emissions from the Use of Cutback and Emulsified Asphalt (Code) was published in April 2014 for public consultation. The draft Code recommends VOC limits for cutback and emulsified asphalt used in road construction, maintenance and repairs, with more stringent recommendations during the ozone season (May to September). It also includes provisions to guide procurement practices for paving projects and application guidelines for paving companies. The draft Code aims to reduce VOC emissions from the cutback asphalt sector by 55 percent over a five-year period.
Federal, provincial (with the exception of Quebec) and territorial governments are working collaboratively to implement the AQMS agreed to in October 2012, given that these governments all have roles and responsibilities for managing air quality and protecting human health and the environment.Footnote4 Provinces and territories are expected to take air quality management actions in their air zones to reduce air pollutant emissions (NOx and VOC) such that the established CAAQS are not exceeded.
Actions by the Province of Quebec
Quebec has implemented several regulatory actions to meet its Ozone Annex commitments. The Clean Air Regulation, which came into effect on June 30, 2011, and replaced the Regulation Respecting the Quality of the Atmosphere, contains stricter standards aimed at reducing NOx emissions from new and modified industrial and commercial boilers, consistent with Canadian Council of Ministers of the Environment guidelines. In addition, when burners on existing units must be replaced, the replacements must be low-NOx burners. With respect to VOC emissions, the standards in the Clean Air Regulation aim to reduce emissions from the manufacture and application of surface coatings, commercial and industrial printing, dry cleaning, above-ground storage tanks, petroleum refineries, and petrochemical plants.
In Quebec, the Regulation Respecting Mandatory Reporting of Certain Emissions of Contaminants into the Atmosphere, entered into force in 2007, requires Quebec enterprises to report atmospheric releases of certain contaminants. It determines the reporting thresholds, the information that these enterprises are required to provide, and the parameters applicable to the calculation of the quantities of these contaminants. The Regulation allows for improved information on emission sources of air contaminants across the province, including emissions of VOCs and NOx. Quebec enterprises whose annual VOC emissions exceed 10 metric tons (11 short tons) and whose annual NOx emissions exceed 20 metric tons (22 short tons) are required to report their emissions.
Pursuant to its Regulation Respecting Petroleum Products and Equipment, Quebec is currently applying provisions aimed at reducing gasoline volatility during the summer months in Montreal and the Gatineau to Montreal section of the Windsor-Quebec City corridor. Quebec is also evaluating the possibility of introducing amendments to this regulation in order to address vapor recovery initiatives, including gasoline storage, transfer depots, and service stations, regardless of whether they are new or existing facilities, in the Quebec portion of the Windsor-Quebec City corridor. The City of Montreal is enforcing regulatory provisions concerning gasoline vapor recovery in its territory.
Actions by the Province of Ontario
Ontario has met its commitments under the Ozone Annex to reduce emissions of NOx and VOCs in the Ontario portion of the PEMA. Ontario has implemented a number of programs, regulations and guidelines to meet its commitments, including the following:
- The Ontario Drive Clean Program (established under O. Reg. 361/98, as amended by O. Reg. 41/13) is a mandatory vehicle inspection and maintenance program designed to reduce smog-causing emissions. On January 1, 2013, the new Drive Clean test using OBDs was introduced. The OBD test, which is used in all other emissions testing programs in North America, is a faster, more accurate way of protecting the air from vehicle emissions.
- The Province has enacted the Emissions Trading Regulation (O. Reg. 397/01), which establishes caps for NOx and SO2 emissions from the electricity sector.
- Ontario has implemented the Industry Emissions-- Nitrogen Oxides and Sulphur Dioxide regulation (O. Reg. 194/05), which caps emissions of NOx and SO2 from seven major industrial sectors in Ontario.
- The Province has put in place Guideline A-9: New Commercial/Industrial Boilers and Heaters (2001), which imposes a NOx emission limit on new or modified large boilers and heaters in industrial installations.
- Most recently, Ontario agreed to begin implementation of the national AQMS in 2013, which has a goal of continuous improvement in air quality.
The Province also amended the Air Pollution -- Local Air Quality regulation (O. Reg. 419/05) in 2007, 2009 and 2011, in order to introduce new/updated air standards and other tools to demonstrate and improve environmental performance. Since 2005, new/updated air standards for 68 contaminants have been introduced, including several that address VOCs. Air standards are used under the regulation to assess the contributions of contaminants to air from regulated facilities and identify facilities that may require technology-based compliance approaches to address technical or economic challenges.
In addition, to get the best out of the retired capital stock, Ontario Power Generation (OPG) is converting a set of former coal-fired units for future operations based on alternate fuels. For example, former coal-fired units at the Thunder Bay and Atikokan facilities are being converted to biomass technology. OPG is also preserving some of the Lambton and Nanticoke units for potential future conversion to alternate fuels, e.g., natural gas or others. Such actual and potential fuel-switching are deemed to reduce the historical SO2, NOx and VOC footprint of Ontario’s electricity sector.
NOx and VOC Program Updates
- From 2003 to 2008, implemented the NOx transport emission reduction program, known as the NOxSIP Call, in the PEMA states that are subject to the rule.
- Began implementing the CAIR NOx ozone season program in the PEMA states in 2009.
- Ongoing implementation of existing U.S. vehicle, non-road engine, and fuel quality rules in the PEMA to achieve both VOC and NOx reductions.
- Ongoing implementation of existing U.S. rules in the PEMA for the control of emissions from stationary sources of hazardous air pollutants (HAPs) and of VOCs from consumer and commercial products, architectural coatings and automobile repair coatings.
- Ongoing implementation of 36 existing U.S. NSPS to achieve VOC and NOx reductions from new sources.
Current CAIR Implementation in PEMA States
The U.S. EPA stopped administering the NOX Budget Trading Program (NBP) under the NOX SIP Call following the 2008 ozone season. Starting in 2009, the NOX annual and ozone season programs under CAIR took effect.
Ozone Season Reductions
The CAIR NOx ozone season program includes EGUs as well as, in some states, large industrial units that produce electricity or steam primarily for internal use and that have been carried over from the NBP. Examples of these units are boilers and turbines at heavy manufacturing facilities such as paper mills, petroleum refineries, and iron and steel production facilities. These units also include steam plants at institutional settings, such as large universities or hospitals. In 2012, there were 3 273 EGUs and industrial facility units at 949 facilities in the CAIR NOX ozone season program; of these, 1 879 were covered units in the Ozone Annex PEMA. In 2012, all CAIR ozone season sources were in compliance.
From 2011 to 2012, ozone season NOx emissions from sources in the CAIR NOx ozone season program decreased by 52 251 short tons (47 401 metric tons) (nine percent). Units in the NOx season program have reduced their overall NOx emissions from approximately 1.5 million short tons (1.4 million metric tons) in 2000 to 513 813 short tons (466 123 metric tons) in 2012 (Figure 12), nine percent below the regional emission budget of 567 744 short tons (515 048 metric tons). In addition to the CAIR NOx ozone season program and the former NBP, prior programs such as the Ozone Transport Commission’s (OTC’s) NOx Budget Program and current regional and state NOx emission control programs have also contributed significantly to the ozone season NOx reductions achieved by sources in 2011.
Source: U.S. EPA, 2014
Figure 11. PEMA Region and CAIR
Figure 11 depicts a map of the eastern states in the U.S. illustrating 18 states and the District of Colombia which are located within the Pollutant Emission Management Area (PEMA), indicating which states are controlled for fine particle and ozone pollution (i.e., affected by annual SO2, and NOX and ozone season NOX programs) under the Clean Air Interstate Rule (CAIR). The figure also shows the CAIR states that are not in the PEMA.
Source: U.S. EPA, 2014
Figure 12. Ozone Season Emissions from CAIR NOx Ozone Season Sources
Figure 12 depicts ozone season emissions in thousand short tons under the legacy NOx Budget Trading Program (NBP) and new CAIR units from 2008 to 2012. The ozone season NOX emissions show a decreasing trend.
Annual NOX Reductions
In 2012, the fourth year of the CAIR NOX annual program, NOx emissions from all ARP and CAIR units were 1.9 million short tons (1.8 million metric tons) lower (53 percent) than in 2005 and 3.4 million short tons (3.1 million metric tons) lower (67 percent) than in 2000.
Emissions from CAIR NOx annual program sources alone were 1.17 million short tons (1.06 million metric tons) in 2012, 22 percent below the 2012 CAIR NOx annual program’s regional budget of 1.5 million short tons (1.4 million metric tons). Annual NOx emissions were 1.5 million short tons (1.4 million metric tons) lower (56 percent) than in 2005, and 184 000 short tons (167 000 metric tons) lower (13 percent) than in 2011.
Although the ARP and CAIR NOx programs were responsible for a large portion of these annual NOX reductions, other programs, such as the NBP, the OTC NOx Budget Program, and other regional and state NOX emission control programs, also contributed significantly to the annual NOx reductions achieved by sources in 2012.
NSPS: All 36 categories of the NSPS identified in the Ozone Annex for major new NOx and VOC sources are promulgated and in effect. In addition, the EPA finalized the NSPS for Stationary Compression-Ignition Internal Combustion Engines in July 2006, which is helping these sources achieve significant reductions in NOx and VOC emissions. Furthermore, in December 2007 the EPA finalized an additional nationally applicable emission standard--an NSPS for NOx, carbon monoxide (CO) and VOC emissions from new stationary spark-ignited internal combustion engines (for more information on the Stationary Internal Combustion Engines rule, see www.epa.gov/ttn/atw/icengines/).
In February 2006, the EPA promulgated the NSPS for utility and industrial boilers and combustion turbines. The updated standards for NOx, SO2 and direct filterable PM are based on the performance of recently constructed boilers and turbines. In February 2012, the EPA promulgated amendments to the NSPS for utility boilers to reflect improvement in the controls for NOx, SO2 and direct filterable PM. The EPA amended the 2008 NSPS for petroleum refineries in September 2012 to address issues regarding flares and process heaters.
In September 2010, the EPA promulgated the NSPS for Portland cement kilns. This NSPS for the first time set NOx limits for all new, reconstructed or modified cement kilns. In August 2012, the EPA published a final rule for oil and gas sources. The rule reflects the first VOC controls for upstream sources. The NSPS for Nitric Acid Production was also revised in August 2012; it includes tighter emission limits for NOx on new, reconstructed or modified nitric acid production units.
VOC Controls on Smaller Sources: In 1998, the EPA promulgated national rules for automobile repair coatings, consumer products, and architectural coatings. The compliance dates for these rules were January 1999, December 1998 and September 1999, respectively. From a 1990 baseline, the consumer products and architectural coatings rules are each estimated to have achieved a 20-percent reduction in VOC emissions, and the automobile repair coatings rule is estimated to achieve a 33-percent reduction in VOC emissions.
In addition, the EPA had previously scheduled for the regulation of 18 other categories of consumer and commercial products under section 183(e) of the CAA. To date, the EPA has regulated or issued guidance on all 18 categories, including shipbuilding and repair coatings; aerospace coatings; wood furniture coatings; flexible packaging printing materials; lithographic printing materials; letterpress printing materials; industrial cleaning solvents; flatwood panelling coatings; aerosol spray paints; paper, film and foil coatings; metal furniture coatings; large appliance coatings; portable fuel containers; miscellaneous metal products coatings; plastic parts coatings; auto and light-duty truck assembly coatings; miscellaneous industrial adhesives; and fiberglass boat manufacturing materials.
Motor Vehicle Control Program: To address motor vehicle emissions, the United States committed to implementing regulations for reformulated gasoline; reducing air toxics from fuels and vehicles; and implementing controls and prohibitions on gasoline and diesel fuel quality, emissions from motorcycles, light-duty vehicles, light-duty trucks, highway heavy-duty gasoline engines, and highway heavy-duty diesel engines.
On the fuel side, the EPA fully phased-in requirements for reformulated gasoline in non-attainment areas in 1995, and implemented low-sulphur requirements for gasoline in 2005 and on-road diesel fuel in Fall 2006 (30 parts per million [ppm] and 15 ppm sulphur levels, respectively).
The EPA finalized standards that have significantly reduced NOX, PM and VOCs from on-highway light-duty and heavy-duty vehicles: Tier 2 exhaust and evaporative emissions standards for light-duty cars and trucks were fully phased-in in 2009, and this was followed in 2010 by full implementation of emissions standards for highway heavy-duty engines and motorcycles.
Non-road Engine Control Program: New engine standards in all five non-road engine categories identified in the Ozone Annex, i.e., aircraft, compression-ignition engines, spark-ignition engines, locomotives and marine engines, have also been completed and are in various stages of being fully phased in. Non-road diesel fuel was aligned with on-highway diesel fuel at 15 ppm sulphur in 2010. Locomotive and marine diesel fuel was aligned with on-highway and non-road diesel fuel at 15 ppm in 2012.
The Tier 4 non-road diesel standards, which significantly reduce PM and NOx emissions, will be fully phased in by 2015. Emission standards that reduce PM and NOx by 90 percent for newly-built locomotives and marine (C1 and C2) diesel engines began phase-in during 2009 and will be fully implemented in 2017.
Anticipated Additional Control Measures and Indicative Reductions
The North American Emission Control Area (ECA), covering the waters of Canada and the United States with the exception of the Arctic, took effect on August 1, 2012, setting environmental standards that will reduce NOx emissions from new ships by 80 percent, SOx by 95 percent, and PM by 85 percent, when requirements are fully implemented. The Regulations Amending the Vessel Pollution and Dangerous Chemicals Regulations under the Canada Shipping Act, 2001 were published on May 8, 2013, and implement the ECA in Canada.
On October 13, 2010, the Passenger Automobile and Light Truck Greenhouse Gas Emission Regulations were published in the Canada Gazette, Part II. These regulations establish progressively more stringent fleet average GHG emission standards for new vehicles over the 2011-2016 model years, in alignment with U.S. national standards. On October 8, 2014, the Government of Canada published amendments to these regulations in the Canada Gazette, Part II, to maintain alignment with even more stringent U.S. regulations for the 2017 and later model years.
The Heavy-duty Vehicle and Engine Greenhouse Gas Emission Regulations were published in the Canada Gazette, Part II, on March 13, 2013. These regulations will reduce GHG emissions from new on-road heavy-duty vehicles and engines, such as full-size pick-ups, semi-trucks, garbage trucks and buses, beginning with the 2014 model year. On October 4, 2014, a Notice of Intent was published in the Canada Gazette, Part I indicating Canada’s intention to develop proposed regulations to further reduce GHG emissions from on-road heavy-duty vehicles and engines for post-2018 model years.
Under the AQMS, Canada is implementing the base-level industrial emission requirements to establish nationally consistent emissions performance standards for industrial facilities across the country. Once fully implemented, industries will be required to reduce their emissions of NOx and VOCs as well as SO2, ammonia (NH3) and PM.
Estimates of Future Emission Reductions
In the Ozone Annex, parties provided 2010 NOX and VOC emission reduction estimates associated with applying the control measures identified under Part III of the Annex, and further agreed to update these reduction estimates. In the Canadian PEMA, the largest source of NOX and VOC emissions is transportation. Figure 14 shows that, by 2025, NOX and VOC emissions from transportation sources in the PEMA are expected to decrease by 65 and 61 percent, respectively, from 1990 levels. Canada will be switching to the Motor Vehicle Emission Simulator (MOVES) model in the summer of 2014, as well as incorporating new and additional spatial data to improve the transportation emission estimates.
Source: Environment Canada, 2014
Figure 13. Canadian NOx and VOC PEMA Emissions and Projections
Figure 13 depicts Canadian NOx and VOC PEMA emissions and projections in thousand tonnes from 1990 to 2025. The figure illustrates that NOx and VOC emissions in the PEMA are expected to decrease by 58 percent and by nearly 44 percent, respectively by 2025 from 1990 levels.
By 2012, the specific NOx and VOC emission reduction measures outlined in the Ozone Annex reduced annual NOx and VOC emissions in the PEMA by 50 and 38 percent respectively, from 1990 levels (see Figure 13).
Canada has developed new emission projections for 2025 that are based on the 2010 emissions data, and that are projected into the future using Environment Canada’s energy, emission and economy forecast model. The emission projections took into consideration the impact of the recent economic slowdown and the latest economic projections. Based on the projected Canadian emissions shown in Figure 13, it is estimated that annual NOx emissions in the PEMA will be reduced by 58 percent and annual VOC emissions in the PEMA will be reduced by 44 percent as of 2025, from 1990 levels.
Source: Environment Canada, 2014
Figure 14. Canadian Transportation NOx and VOC PEMA Emissions and Projections, 1990-2025
Figure 14 depicts Canadian NOx and VOC PEMA emissions and projections from transportation sources in thousand metric tons from 1990 to 2025. NOx and VOC emissions from both on-road and off-road vehicles in the PEMA are presented. The figure illustrates that NOx and VOC emissions from transportation sources in the PEMA are expected to decrease by 65 percent and by nearly 61 percent, respectively by 2025 from 1990 levels.
Clean Car Program
In 2010, the EPA and U.S. Department of Transportation (DOT) established the first set of coordinated GHG / fuel economy standards for 2012-2016 model year vehicles, and a second set of standards for 2017-2025 model year vehicles in August 2012. Together, these standards will double the fuel economy of light-duty cars and trucks in the United States by 2025. Under the clean car program, new cars and light trucks are expected to reach an average GHG emission performance of 163 grams per mile, equivalent to 54.5 miles per gallon, by 2025, thereby reducing oil consumption by 2.2 million barrels/day in 2025 and reducing GHG emissions by 6 billion metric tons over the lifetime of vehicles sold during this period.
The Tier 3 program for motor vehicles, finalized in early 2014, is part of this comprehensive approach to reducing the impacts of motor vehicles on air quality and public health. The program is designed to be implemented over the same time frame as the second phase of light-duty vehicle GHG standards, starting in model year 2017, and sets new motor vehicle emissions standards for NOx, PM and other pollutants and lowers the sulphur content of gasoline. The standards reduce both tailpipe and evaporative emissions from passenger cars, light-duty trucks, medium-duty passenger vehicles, and heavy-duty pick-ups and vans.
Together, the Tier 3 and GHG programs provide significant environmental benefits by maximizing reductions in GHGs, criteria pollutants and air toxics from motor vehicles, reducing costs to consumers, and providing automakers with regulatory certainty and streamlined compliance. The standards will be applied in concert with California’s clean cars and fuels program to enable automakers to sell the same vehicles in all 50 states.
Heavy-Duty National Program
The Heavy-Duty National Program is reducing fuel use and GHG emissions from heavy-duty vehicles ranging from semi-trucks and buses to heavy-duty pickup trucks and vans. Specifically, the EPA and DOT finalized heavy-duty GHG and fuel consumption standards in a 2011 joint rulemaking that phases in between 2014 and 2018. In addition to reducing GHG emissions, the heavy-duty GHG standards will also reduce criteria pollutants, including NOx and air toxics emissions. The first round of standards is projected to reduce GHG emissions by approximately 270 million metric tons and save 530 million barrels of oil, saving vehicle operators an estimated $50 billion in fuel costs over the lifetimes of the vehicles covered.
The EPA and DOT, in collaboration with the California Air Resources Board, plan to extend the Heavy-Duty National Program beyond model year 2018, to further reduce GHGs and fuel consumption through the application of cost effective technologies, and plan to continue efforts toward improving the efficiency of moving goods across the United States. Under the timeline established by President Obama in early 2014, the agencies are directed to develop and issue the next phase of standards by March 2016.
The North American Emission Control Area (ECA)
On March 26, 2010, the International Maritime Organization (IMO), a United Nations agency, officially designated waters off the North American coasts as an area in which stringent international emission standards will apply to ships. The effective date of the first-phase fuel-sulphur standard was 2012, and the second phase begins in 2015. Beginning in 2016, NOx after-treatment requirements become applicable. NOx emissions are expected to be reduced by 80 percent, SOx by 95 percent, and PM by 85 percent, when the requirements are fully implemented.
On April 4, 2014, the Marine Environment Protection Committee of the IMO took action to protect the environmental benefits of the North American and U.S. Caribbean Sea ECAs, by excluding them from an amendment to the International Convention for the Prevention of Pollution from Ships (MARPOL) Annex VI that will otherwise postpone the international Tier III NOx standards for marine diesel engines. These technology-forcing engine standards will continue to apply to vessels operating in the ECAs beginning with new ships constructed in 2016.
Source: U.S. EPA, 2014
Figure 15. U.S. NOx and VOC PEMA Emissions and Projections
Figure 15 depicts U.S. NOX and VOC emissions and projections in million short tons for 1990 and 2018. The specific emission reduction obligations in the Ozone Annex are estimated to reduce annual NOx emissions in the PEMA by 70 percent from 1990 levels and to reduce annual VOC emissions in the PEMA by 67 percent from 1990 levels by 2018.
The EPA is implementing NOx and VOC control measures in specific areas, as required by applicable provisions of the CAA. The measures include NOX and VOC reasonably available control technology, marine vessel loading, treatment storage and disposal facilities, municipal solid waste landfills, onboard refueling, residential wood combustion, vehicle inspection and maintenance, reformulated gasoline, cement kilns, internal combustion engines, large non-utility boilers and gas turbines, fossil fuel-fired utility boilers, and additional measures needed to attain the NAAQS.
Estimates of Future Emission Reductions
In the Ozone Annex, the United States provided NOx and VOC emission reduction estimates associated with the application of the control strategies identified under Part III B and Part IV of the Annex. The EPA has updated the estimates using more recent national trends data available in 2012.
The EPA has updated the estimates using the most recent national and state trends data. Figure 15 shows that the emission reduction obligations are now estimated to reduce annual NOx emissions in the PEMA by 70 percent and annual VOC emissions in the PEMA by 67 percent as of 2018, from 1990 levels. The 2018 emissions represent the best estimate for the future year that incorporates the impact of current regulations and projected economic changes and fuel usage for EGUs and mobile sectors. The projected EGU emissions include the final Mercury and Air Toxics Standards (MATS) and the CAIR. Note , this projection preceded recent actions in CSAPR litigation that have reinstated CSAPR, replacing CAIR, with CSAPR Phase 1 implementation beginning in 2015 and CSAPR Phase 2 beginning in 2017. For the non-EGU point sector, projection factors and percent reductions reflect comments received during development of the CSAPR along with emission reductions due to national and local rules, control programs, plant closures, consent decrees and settlements. For mobile sources, all national measures for which data were available at the time of estimation were included. The final EPA Tier 3 standards are represented, which, starting in 2017, will reduce air pollution from passenger cars and trucks and lower the sulphur content of gasoline. The 2018 mobile source emissions were estimated using the EPA mobile model MOVES 2010b, and applied 2011 meteorological conditions.
Reporting PEMA Emissions
Provide information on all anthropogenic NOx and all anthropogenic and biogenic VOC emissions within the PEMA from a year that is not more than two years prior to the year of the biennial progress report, including:
- annual ozone season (May 1 to September 30) estimates for VOC and NOX emissions by the sectors outlined in Part V, Section A, of the Ozone Annex; and
- NOX and VOC five-year emission trends for the sectors listed above, as well as total emissions.
Canada and the United States have complied with emission reporting requirements in the Ozone Annex. In this regard, Canada’s NPRI provides a comprehensive emissions inventory for pollutants such as NOx, VOCs, SO2, total PM, PM10, PM2.5 and CO that contribute to acid rain, O3 and components of smog. This inventory is based on two components:
- mandatory annual reporting of emissions by about 6500 facilities; and
- emission estimates compiled for various sources, such as motor vehicles, residential heating, forest fires and agricultural activities.
The information reported by facilities is publicly available on Environment Canada’s website at www.ec.gc.ca/inrp-npri/ default.asp?lang=En&n=B85A1846-1.
The compilation of the comprehensive 2012 air pollutant emission summaries was completed in early 2014, and the emission data have been included in this report. The Canadian emission summaries are available on Environment Canada’s website at www.ec.gc.ca/inrp-npri/ default. asp?lang=En&n=F98AFAE7-1.
New emission inventory modelling files for the calendar years 2011 and 2012 are now available, and include updated information on the temporal and the spatial allocation of the emissions for various sources and pollutants.
In the United States, the EPA developed the National Emissions Inventory (NEI) as a comprehensive inventory covering emissions in all U.S. states for point sources, nonpoint sources, on road mobile sources, non-road mobile sources and natural sources (http://www.epa.gov/ttn/chief/ net/2011inventory.html). The NEI includes both criteria pollutants and HAPs. The U.S. regulations require that states report criteria pollutant emissions from large point sources every year and for all sources once every three years; the states voluntarily submit HAP emissions. The 2011 NEI is the most recent comprehensive national compilation of emission sources collected from state, local and tribal air agencies. The NEI includes emission information collected from the EPA emission programs, including the Toxics Release Inventory (www.epa.gov/tri/), emission trading programs such as the ARP (www.epa.gov/airmarkt/quarterlytracking.html and www.epa.gov/ampd), and data collected as part of EPA regulatory development for reducing emissions of air toxics. The next comprehensive NEI, for 2014, is expected to be released in mid-2016.
Table 1 shows 2012 U.S. and Canadian emissions in the PEMA. Figures 16 and 17 show U.S. emission trends in these areas for 1990 through 2012. The trend in the PEMA states is similar to the U.S. national trend. For NOx, most of the emission reductions originate from on-road mobile sources and electric power generation. The sharp decline in EGU NOx after 2008 illustrates the effect of the CAIR NOx ozone season program starting in 2009. The sharp increase for on-road transportation in 2002 is due to a different estimation method beginning with that year and continuing for several subsequent years through 2011, wherein the EPA re-computed the on-road and non-road mobile source emissions using the more recent EPA mobile model MOVES 2010b. Non-road transportation is also a significant source of NOx emissions, but the amount of emissions and the decrease over time is greater for on-road transportation and EGUs.
Similar to the national trends for VOCs, the predominant sectors that contribute VOC emissions for the PEMA are on-road mobile sources, solvent utilization processes, and non-road mobile sources. The reductions in VOC emissions are primarily from on-road mobile sources and solvent utilization. VOC emissions from non-industrial fuel combustion sources increased after 1998 and then returned to a downward trend by 2000, followed by a sharp increase in 2002. The increase in non-industrial fuel combustion VOC emissions for 2002 is due to improved emission characterization methods applied in the 2002 NEI for non-industrial fuel combustion sources, which include commercial and institutional sources such as office buildings, schools and hospitals, as well as residential wood combustion.
The U.S. PEMA 2012 emissions are estimated by applying the same methods used to develop the national trends (http:// www.epa.gov/ttn/chief/trends/index.html). The state emissions were held constant from the 2011 NEI for all pollutants and tiers, with the following exceptions: the 2012 NOx and SO2 emissions for EGUs are from the EPA’s database of continuous emissions monitoring (CEM) data for regulated sources; and the on-road and non-road mobile source emissions are interpolated between the 2011 NEI and projected 2020 inventory. The biogenic and forest wildfire emissions are for the year 2011. Ozone season emissions are approximated as a five-month fraction, e.g., May-September, of the annual emission category totals. Biogenic and forest wildfire emissions for the ozone season are not provided.
Table 1. PEMA Emissions, 2012
|Emissions Category||2012 Annual
1000 Short Tons
1000 Short Tons
1000 Metric Tons
|2012 Ozone Season
|2012 Ozone Season
1000 Metric Tons
|2012 Ozone Season
|2012 Ozone Season
|Non-industrial Fuel Combustion||43||39||98||89||10||9||16||14|
|Electric Power Generation||18||17||0||0||8||7||0||0|
|Other Anthropogenic Sources||7||6||97||88||4||3||57||52|
|TOTALS without Forest Fires and Biogenics||459||417||733||667||195||176||315||286|
|Emissions Category||2012 Annual
1000 Short Tons
1000 Short Tons
1000 Metric Tons
|2012 Ozone Season
|2012 Ozone Season
1000 Metric Tons
|2012 Ozone Season
|2012 Ozone Season
Note: Short tons and metric tons are rounded to the nearest thousand. Totals in rows may not equal the sum of the individual columns due to rounding.
Source: Environment Canada and U.S. EPA, 2014
|Non-industrial Fuel Combustion||317||287||266||241||132||120||111||101|
|Electric Power Generation||616||559||14||13||257||233||6||5|
|Other Anthropogenic Sources||54||49||425||386||22||20||177||161|
|TOTALS without Forest Fires and Biogenics||4201||3811||3581||3249||1752||1589||1493||1355|
Source: U.S. EPA, 2014
Figure 16. U.S. NOx Emission Trends in PEMA States, 1990-2012
Figure 16 depicts U.S. NOx emission trends (in thousand short tons) in the PEMA states from 1990 to 2012. This includes trends for on-road transportation, electric power generation, non-road transportation, industrial sources, non-industrial fuel sources and other anthropogenic sources. For NOx most of the emission reductions come from on-road mobile sources and electric utilities.
Source: U.S. EPA, 2014
Figure 17. U.S. VOC Emission Trends in PEMA States, 1990-2012
Figure 17 depicts U.S. VOC emission trends (in thousand short tons) in the PEMA states from 1990 to 2012. This includes trends for solvent utilization, on-road transportation, non-road transportation, industrial sources, non-industrial fuel sources and other anthropogenic sources. The reduction in VOCemissions are primarily from on-road and nonroad mobile sources and solvent utilization.
Figures 18 and 19 show Canadian NOx and VOC PEMA emission trends for 1990 through 2012. For NOx, most of the reductions originate from on-road mobile sources and electric power generation, with increases in non-industrial fuel combustion and other anthropogenic sources. Similar reductions and increases were observed for VOC emissions. VOC emission reductions were primarily from on-road mobile sources, electric power generation, industrial sources, and solvent utilization, with a slight increase in non-industrial fuel combustion.
Source: Environment Canada, 2014
Figure 18. Canada NOx Emission Trends in the PEMA Region, 1990-2012
Figure 18 depicts Canada NOx emission trends (in thousand metric tons) in the PEMA region from 1990 to 2012. This includes trends for on-road transportation, non-road transportation, industrial sources, electric power generation, non-industrial fuel sources and other anthropogenic sources. For NOx, most of the emission reductions come from on-road mobile sources and electric power generation.
Source: Environment Canada, 2014
Figure 19. Canada VOC Emission Trends in the PEMA Region, 1990 -2012
Figure 19 depicts Canada VOC emission trends (in thousand metric tons) in the PEMA region from 1990 to 2012. This includes trends for solvent utilization, on-road transportation, non-road transportation, industrial sources, non-industrial fuel sources and other anthropogenic sources. VOC emissions reductions are primarily from on-road mobile source, electric power generation, industrial sources and solvent utilization.
Reporting Air Quality for All Relevant Monitors within 500 km of the Border between Canada and the United States
The United States and Canada operate extensive networks to monitor O3 and its precursors. Both federal governments prepare routine reports summarizing measurement levels and trends, with the latest quality-assured complete data set from both countries being from 2012.
Ambient Levels of Ozone in the Border Region
Figure 20 illustrates O3 conditions in the border region in the metrics of national standards; the reference period is 2010 through 2012. Only data from sites within 500 km (310 miles) of the United States-Canada border that met data completeness requirements were used to develop this map. The figure shows that higher O3 levels occur in the Great Lakes and Ohio Valley regions and along the U.S. east coast, and that the lowest values are generally found in the west and Atlantic Canada. Levels are generally higher downwind of urban areas, as can be seen in the western portions of lower Michigan, though the full detail of urban variation is not shown. For O3, the data completeness requirement was that a site’s annual fourth-highest daily maximum 8-hour concentration, in parts per billion (ppb) by volume, be based on 75 percent or more of all possible daily values during the EPA-designated O3 monitoring seasons.
Note: Data are the 2010-2012 averages of annual fourth-highest daily values, where the daily value is the highest running 8-hour average for the day. Sites used had at least 75 percent of possible daily values for the period.
Sources: Environment Canada NAPS Network Canada-wide Air Quality Database, 2012 (www.ec.gc.ca/rnspa-naps/default.asp?lang=En&n=8BA86647-1); U.S. EPA Air Quality System (AQS) Data Mart (www.epa.gov/airdata).
Figure 20. Ozone Concentrations along the United States -Canada Border (Three-Year Average of the Fourth-highest daily Maximum 8-Hour Average), 2010-2012
Figure 20 depicts a map of ozone concentrations along the U.S.-Canada border (three-year average of the fourth-highest daily maximum 8-hour average) in ppb from 2010 to 2012. Higher ozone levels occur in the lower Great Lakes-Ohio Valley region and along the U.S. East Coast. Lowest values are generally found in the West and Atlantic Canada. Levels are generally higher downwind of urban areas, as can be seen in the western portions of lower Michigan, though the full detail of urban variation is not shown.
Ambient Concentrations of O3, NOX and VOCs
Annual O3levels over the 1995-2012 time period are presented in Figure 21, based on information from longer-term eastern monitoring sites within 500 km (310 miles) of the United States-Canada border. Ozone levels have decreased over this period, with a notable decline in O3 levels since 2002. The lower O3 levels shown for 2004 and 2009 were due, in part, to the cool, rainy summers in eastern North America. There is also a complex regional pattern in O3level concentrations, which is not evident from the graph shown in Figure 21. Figures 22 and 23 depict the average ozone season levels of O3 precursors (NOx and VOCs) in the eastern United States and Canada. These measurements represent information from a more limited network of monitoring sites than is available for O3. Figure 24 shows the network of monitoring sites actually used to create the trend graphs in Figures 21 through 23. The data in Figures 22 and 23 represent measurements for the ozone season (i.e. May through September). NOx and VOC concentrations have fluctuated over recent years, most likely due to varying meteorological conditions. Overall, the data indicate a downward trend in the ambient levels of NOx and VOCs. The limited correspondence between composite ozone trends and NOx and VOC trends could reflect the complex regional patterns in ozone concentrations as well as the limited number of NOx and VOC monitoring sites. The NOx and VOC concentration trends shown in Figures 22 and 23 are based on a limited number of U.S. and Canadian monitoring sites with sufficient long-term data availability. Therefore, the number of monitoring sites used to depict the trends in Figures 22 and 23 will vary from previous versions of the Progress Report and will likely show slightly different concentration values in the trends graphics.
Recently in the United States, there has been much investigation into the relationship between NOx emission reductions and observed concentrations of ambient O3 in the PEMA states. Generally, a strong association has been found between areas with the greatest NOx emission reductions and downwind monitoring sites measuring the greatest improvements in O3.
From 2010 to 2012, reductions in NOx emissions during the O3 season from power plants under the NOx SIP Call, ARP and CAIR have continued contributing to significant regional improvements in ambient total nitrate (nitrate (NO3) plus nitric acid (HNO3)) concentrations. For instance, annual mean ambient total NO3 concentrations for 2010-2012 in the mid-Atlantic region were 48 percent less than the annual mean concentration from 1989-1991. These improvements can be partly attributed to added NOx controls installed for compliance with the NOx SIP Call and CAIR. For further information on the changes in O3 concentrations before and after implementation of the NBP and CAIR, and for a comparison of regional and geographic trends in O3 levels to changes in meteorological conditions (such as temperature) and NOx emissions from CAIR sources, consult www.epa.gov/airmarkets/progress/ARPCAIR10_02.html.
Source: U.S. EPA and Environment Canada, 2014
Figure 21. Annual Average Fourth-Highest Maximum 8-Hour Ozone Concentration for Sites within 500 km of the United States-Canada Border, 1995-2012
Figure 21 depicts U.S. and Canada annual fourth-highest maximum 8-hour ozone concentration for sites within 500 km of the U.S.-Canada border in Parts per billion (ppb) from 1995 to 2012. Ozone levels have decreased over this time period. The apparent decreasing trend in ozone levels from 2002 is in part due to the cool, rainy summer of 2004 and 2009 in eastern North America.
Source: U.S. EPA and Environment Canada, 2014
Figure 22. Average Ozone Season (May-September) 1-Hour NOx Concentration for Sites within 500 km of the United States-Canada Border, 1995-2012
Figure 22 depicts Canada and U.S. ozone season 1-hour NOx concentration for sites within 500 km of the Canada-U.S. border in ppb from 1995 to 2012. The NOx data shown in Figure 22 represent measurements for the “ozone season” (i.e., May through September) and indicate a decline in the ambient level of NOx.
Source: U.S. EPA and Environment Canada, 2014
Figure 23. Average Ozone Season (May-September) 24-Hour VOC Concentrations for Sites within 500 km of the United States-Canada Border, 1997-2012
Figure 23 depicts Canada and U.S. annual average 24-hour VOC concentration for sites with 500 km of the Canada-U.S. border in ppb from 1997 to 2012. The VOC data shown in Figure 23 represent measurements for the “ozone season” (i.e., May through September) and indicate a decline in the ambient level of VOCs.
Source: U.S. EPA and Environment Canada, 2012
Figure 24. Network of Monitoring sites Used to Create Graphs of Ambient Ozone, NOx, and VOC Levels
Figure 24 depicts a map of the network of monitoring sites in eastern Canada and the eastern U.S. that were used to create the ambient levels of ozone, NOx and VOC graphs presented in Figures 21, 22 and 23.
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