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 RESEARCH TRIANGLE PARK, N.C., June 29 /PRNewswire/ -- A 2-week study that ended late last week at Fort McHenry Tunnel in Baltimore promises to help answer a controversial question: Are motor vehicles producing more air pollution -- in particular, carbon monoxide and materials that contribute to the formation of smog (ozone) -- than was previously thought? The answer to this question could reshape actions States take to clean up the air and to comply with the Clean Air Act Amendments of 1990.
 The primary research is based on straightforward arithmetic. Measure the carbon monoxide and materials that contribute to ozone formation at the start of the tunnel and at the end as vehicles exit. Subtract levels at the start of the tunnel from those at the end and the result is the amount of air pollutants vehicles emit. The science becomes more complicated as researchers take into account clean air piped into the tunnel to improve ventilation and other variables.
 The research is being jointly funded by the U.S. Government and industry, with the U.S. Environmental Protection Agency contributing $500,000; the Coordinating Research Council, an automobile and petroleum industry research group, $400,000; and the National Renewable Energy Laboratory, U.S. Department of Energy, $200,000. Co-chairs for the study are Dr. Kenneth T. Knapp, Branch Chief at EPA's Atmospheric Research and Exposure Assessment Laboratory in the Research Triangle Park, N.C., and Professor Ellis Cowling of North Carolina State University, representing the Southern Oxidant Study, a consortium of State and Federal government agencies and academia.
 With this unique test site available to them, researchers have been running as many tests and gaining as much data as possible.
 In addition to gross measurements of the number of vehicles that move through the tunnel in a given timeframe and the pollutants they emit, researchers have been gathering data from individual vehicles using four remote sensors that measure tailpipe emissions from the vehicles as they drive by.
 The remote sensors are connected to a video camera. As each car goes by, it is filmed and the amount of its emissions imprinted at the top of the video screen. Later, emissions can be analyzed by car make and model.
 The remote sensors have been moved around to collect a variety of data. They have been measuring the emissions of an idling car waiting to pay the toll and the emissions of the same car as it accelerates from the toll booth. The sensors have been measuring the effect of road grade on emissions, showing the effect when a car goes downhill at the start of the tunnel and when it goes uphill as it exits the tunnel.
 At certain times, drivers have been asked their cars' odometer readings. With enough of these data, researchers can extrapolate the effect of mileage on vehicle emissions.
 Tunnels are a good place to study emissions since, unlike the outdoor environment, variables are limited. The tunnel is self- contained.
 The 1.7-mile Fort McHenry Tunnel, operated by the Maryland Transportation Authority, offers a particularly interesting research setting. Two of the four tubes carry cars and pickups, while the other two carry mainly heavy duty trucks. (Each tube is two lanes wide.) Researchers can compare emissions from cars and pickups versus heavy duty trucks.
 The tunnel administration was able to accommodate the research project without adversely affecting traffic by carefully coordinating the study team's activities so as not to interfere with routine operations.
 Preliminary data from this study will be available in approximately 6 months. It is expected that researchers will use this vast data base for years to come.
 -- For some years, policymakers, researchers and others have wondered why carbon monoxide and smog levels in the air outdoors have not dropped proportionately as governments required emission control devices on motor vehcles.
 -- In 1988, a groundbreaking report on vehicle emissions was issued, based on 21 tests run in a tunnel in Van Nuys, Calif. The study measured vehicle emissions (carbon monoxide, oxides of nitrogen, and total hydrocarbons) in the tunnel; compared the levels to estimates from emssion models; and found that the models, on average, underestimated emissions by a factor of 3 to 4, and in one test, underestimated hydrocarbons by a factor of 7. Participants in the "Southern California Air Quality Study" included the State of California, the Coordinating Research Council (an automobile and petroleum industry research group), the U.S. Environmental Protection Agency, General Motors, Ford and academia.
 -- On the East Coast, the Southern Oxidant Study, a consortium of State and Federal government agencies and academia, was looking at air pollution too. The Southern Oxidant Study questioned whether air pollution inventories were correct. They suspected figures for the amount of pollutants from various sources were incorrect. If the inventories were wrong, then models predicting air pollution could not be right. Determining proper inventories became a priority for the Southern Oxidant Study.
 -- In October 1990, the Coordinating Research Council sponsored a workshop on mobile source modelling. The group concluded that models were estimating vehicle emissions too low. Most workshop participants felt incorrect estimates were due to the lack of real-world, in-use vehicle data. One recommendation was to conduct additional, well-planned tunnel studies.
 -- In February 1991, the U.S. Environmental Protection Agency brought together 40 world experts to discuss ways of improving vehicle emission data and modelling. The group recommended a test be conducted in Baltimore's Fort McHenry Tunnel to measure actual emissions and see if they matched modelling assumptions. A tunnel that goes under a body of water, like the Fort McHenry Tunnel, offers researchers the opportunity to examine the effect of changes in road grade on vehicle emissions. In subsequent discussions, experts suggested tests also be conducted in a tunnel where the road grade was flat, that is, where the road did not go uphill or downhill.
 -- In November 1991, the National Academy of Sciences completed its study, "Rethinking the Ozone Problem in Urban and Regional Air Pollution." The study, mandated by the Clean Air Act Amendments of 1990, concluded current models underestimate vehicle emissions.
 -- A 2-week study of vehicle emissions was conducted at the Fort McHenry Tunnel, Baltimore, Md., in June 1992. The test was jointly funded by the U.S. Government and industry, with the U.S. Environmental Protection Agency contributing $500,000; the Coordinating Research Council, $400,000; and the National Renewable Energy Laboratory, U.S. Department of Energy, $200,000. Co-chairs for the study were Dr. Kenneth T. Knapp of the U.S. EPA and Professor Ellis Cowling representing the Southern Oxidant Study. A test will be conducted later this summer in the Tuscarora mountain tunnel on the Pennsylvania Turnpike, a flat tunnel.
 -- The Clean Air Act Amendments of 1990 state that the U.S. Environmental Protection Agency must study remote sensing devices as a means of measuring vehicle emissions. Remote sensors measure emissions as cars drive by versus measuring emissions directly from the tailpipe. The Fort McHenry Tunnel study was another step in the continuing evaluation of this equipment.
 -0- 6/29/92
 /CONTACT: Rhoda Ritzenberg, United States Environmental Protection Agency, 919-541-2615/ CO: U.S. Environmental Protection Agency ST: North Carolina, Maryland IN: SU:

JZ -- CH002 -- 4518 06/29/92 08:46 EDT
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Date:Jun 29, 1992

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