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Southwest Lake Michigan Pilot Study
Developing an Inventory of Toxic Air Emissions from Area Sources in the Chicago, Milwaukee and Gary Urban Areas, 1993
Illinois, Indiana and Wisconsin, working together through the Great Lakes Commission, have completed the first multistate inventory of emissions of toxic air contaminants that are identified as being potentially harmful to the Great Lakes ecosystem or human health.
Specifically, these states created an inventory of small point and area sources of toxic air emissions from the combined 12-county urban areas of Chicago, Gary and Milwaukee. The study identified small point and area source categories that contribute the most to the total emissions of 49 hazardous air pollutants, including arsenic, chromium, mercury and lead.
The project was the first test of the regional protocol, the Air Toxics Emissions Inventory Protocol for the Great Lakes States, and provided an opportunity to develop and test state-of-the-art inventory software, the Regional Air Pollutant Inventory Development System (RAPIDS).
The Great Lakes region had an additional incentive to undertake the SWLM project. The development of multistate client/server toxic air emission inventory software and procedures goes a long way toward meeting provisions of the Great Lakes Governors' Toxic Substances Control Agreement of 1986, which called on the states to jointly identify sources of persistent toxic substances contaminating the Great Lakes.
The SWLM pilot study is part of a larger initiative to develop a Great Lakes regional database of airborne toxic pollutant emissions. Once a quality controlled/quality assured data inventory has been established, the states and the U.S. Environmental Protection Agency can begin to work separately and in concert to define and regulate sources; evaluate control technology; establish guidelines for siting new facilities; and reduce airborne deposition of persistent toxic chemicals to the Great Lakes.
Relevance to Mission
The Basin Compact directs the Commission "To promote the orderly, integrated, and comprehensive development, use, and conservation of the water resources of the Great Lakes Basin; (Article I.1) and, "To plan for the welfare and development of the water resources of the Basin as a whole as well as for those portions of the Basin which may have problems of special concern. (Article I.2)
The deposition of airborne toxic substances on the Great Lakes is an issue that must be addressed on a multijursidictional basis and is clearly a problem of special concern to all basin jurisidictions. Successfully meeting this challenge will require the states, federal governments and provinces to share large amounts of data and information.
The Strategic Plan of the Great Lakes Commission direct the Commission to "coordinate and contribute to the development of databases that permit broad access to comprehensive and consistent Basinwide data and information." The RAPIDS database designed and tested during this study directly addresses this goal.
Background / History
To implement effective air pollution control strategies, it is vital to understand how these pollutants enter the atmosphere. Wind can widely disperse the pollutants; thus, identification and quantification of emission sources throughout the Great Lakes region is mandatory.
The 1986 Toxic Substances Control Agreement signed by the Governors of the eight Great Lakes states contains a provision ensuring cooperation toward "quantifying the loadings of toxic substances originating from all sources, with the purpose of developing the most environmentally and economically sound control programs."
To pursue this goal, in 1987 state environmental administrators recommended development of a computerized air toxics database to better understand the nature and sources of toxic air emissions, and their migration, dispersion and resulting impact upon the Great Lakes Basin. They also agreed that such a database was necessary not just for evaluating impacts, but for identifying potential problems and developing appropriate control strategies. The Great Lakes Commission has coordinated the development of this database.
As recommended during the July 1987 workshop, a list of 30 priority pollutants/pollutant classes was constructed based on potential threat to aquatic and human life. Recognizing the need for a consistent level of quality information on emissions of these pollutants across the region, the eight Great Lakes states developed a protocol for inventorying toxic air emissions from point, area and mobile sources. The states also worked with U.S. EPA to identify the best available emission factors for use in estimating emissions of compounds of interest under differing operating conditions.
The states expanded the list of toxic compounds of interest from 30 to 49 during 1994. The states of Illinois, Indiana and Wisconsin then led an effort to test the protocol and develop a relational database system to inventory emissions for these 49 compounds from point and area sources. The inventory software, the Regional Air Pollutant Inventory Development System, was developed with U.S. EPA funds during FY 1994. The Southwest Lake Michigan Pilot Study began in FY 1994 to test the the regional protocol, and provided an opportunity to develop and test RAPIDS. The pilot study's final report was released in December 1995.
In the News
Milestone dates include the following:
Ongoing efforts for 1996 include state, provincial, federal and academic review of the inventory content and methodology; discussion with U.S. EPA of proposed addition of mobile and large point source inventory to the study; and collective work by the eight Great Lakes states and province of Ontario to follow the methodology developed by the SWLM study in compiling an inventory of point and area sources for the region.
Emission inventory specialists from the pilot study states, as well as staff from the other Great Lakes states, U.S. EPA and the province of Ontario, worked together closely, making the study a team effort.