International Air Quality Advisory Board
SPECIAL REPORT ON
November 1998
8. SURVEILLANCE ISSUES 8.1 Eastern PM2.5 Quantification The promulgation of the U.S. EPA standard for fine particulates (PM2.5) included a requirement for ambient sampling of PM2.5 at 1,500 sites distributed throughout the United States. The criteria for siting monitors will include high population density, since one of the U.S. EPA's objectives is to determine the locations that do not meet the daily or annual PM2.5 standards. Such sites would frequently be large urban centers. Given this criterion, the Board could determine whether or not sufficient population-based or urban monitors are placed in the border regions. It could also ascertain if there is an adequate number of PM2.5 transport monitoring sites in or adjacent to the border regions to allow determination of the seasonal and temporal concentration patterns of PM2.5. This would allow the Board and the Commission to identify the temporal trends in PM2.5 concentrations and assess the implications of the measured levels for future control strategies. Achieving a coherent understanding of PM2.5 releases and transport is essential to establishing the most appropriate strategies to reduce daily and annual average concentrations. In this particular instance, however, since PM2.5 is a physicalchemical mixture of ultra-fine and fine particles and inorganic and organic chemicals, surveillance must go beyond simple mass measurements. Thus, the Commission should review the information acquired by the major PM2.5 research programs implemented by the United States over the next three to five years to determine the specific chemicals of concern, the particle size of concern for human health, and the sources requiring control. Obviously, because it is not limited to a single pollutant and a single type of risk, this undertaking will require consideration of a vast amount of data and information. Furthermore, this assessment must be done in concert with current programs examining the control options for tropospheric ozone, since some PM2.5 is formed as a consequence of photochemical processes that produce ozone. PM2.5 can exist in the atmosphere concurrently with gases such as ozone, SO2, and NO2. 8.2 Focus on Endpoints (Biota/Human Impacts) Monitoring air quality and deposition in the border region is not enough. The status and trends in sensitive receptors of air pollution must also be periodically monitored. Certain receptors are particularly vulnerable to certain pollutants, including:
Both the United States and Canada have programs to assess these important endpoints through human epidemiological and ecosystem studies, such as the U.S. Environmental Monitoring and Assessment Program (EMAP) and the Canadian Ecological Monitoring and Assessment Network (EMAN). Presently, there is considerable interest in charting the recovery of fresh waters in the eastern region of North America in response to decreases in sulfate deposition. Lack of sustained funding and shifting priorities, however, currently make it difficult for agencies to maintain long-term monitoring and assessment studies of human health and ecosystems. 8.3 Emissions Trading and Environmental Integrity Programs that rely upon free-market principles for air pollution abatement strategies are increasingly being offered as an alternative to traditional command-and-control programs. The first large-scale implementation of such a program was under Title IV of the U.S. CAA, a program designed to respond to the environmental damage caused by acidifying emissions. Title IV focused primarily on reducing sulfur-bearing emissions from utilities and other sources. The success or failure of this program depends on the perspective from which it is viewed. As a program to produce the least-cost reductions of SO2 emissions, it has been judged highly successful: SO2 allowance costs fell from a projected $330 U.S. per tonne ($300 per ton) to an actual cost on the order of $83 U.S. per tonne ($75 per ton). As a program aimed at solving an environmental concern, however, the outcome is less clear: acidifying emissions remain a concern, and further reductions are needed. Under a cap-and-trade program, benefits are often presented in terms of total tons of emission reductions, a value that can easily be calculated. When trading is turned over to the free market, however, there is no environmental integrity test that considers geographic or other factors important in determining the total environmental impact of the emission reductions. Under a cap-and-trade program, overall emissions may be reduced, but emissions that adversely affect critical or sensitive areas may actually increase and damage in such areas may be exacerbated. Because market instruments are increasingly considered a primary strategy for abating other air pollution problems, the absence of an environmental integrity test becomes more critical. For example, an emissions trading program is being considered for the ozone precursor pollutant, NOX. In the atmospheric chemical process by which ozone precursors are transformed into the offending pollutant, three factors -- time, distance, and season -- are critical to determining the actual reduction of ozone. It may be that emissions trading should be limited in distance or that a "discount rate" should be established in order for the program to provide meaningful environmental benefits along with overall net emission reductions. Recommendations In conjunction with efforts to assess the release and transport of PM2.5, the Commission should ensure that any monitoring network established by the United States over the next five years is at least compatible with, or can be compared to, PM2.5 monitoring done in Canada. This does not necessarily mean that both countries need identical monitoring equipment. There should, however, be a program to encourage collocation of monitoring equipment so that collected data can be used to determine flux and distribution of PM2.5 throughout the entire transboundary region. This program should be consistent with the seamless border approach for the airshed shared by the United States and Canada. The Commission should urge governments to determine appropriate endpoints and indicators of air quality (such as hospital admissions and alterations in fisheries) and to conduct periodic surveys of air pollution receptors (such as sensitive vegetative species) to determine the effects of cleaner air in the border region. This indicator monitoring should include a research component to ensure that all the significant health and ecosystem linkages (e.g. air quality effects on forests) are determined and understood. |