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NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
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How the Representation of Emissions Inventories in Air Quality Regulatory Modeling in the Presence of High Temporal Variability Effects the Choice of Control Strategies
Mort Webster, Mike Symons, Harvey Jeffries
University of North Carolina
Tom Tesche and Dennis McNally
Alpine Geophysics
Conventional wisdom is that “bad ozone” days are mostly caused by “bad meteorology”, because the emissions inventory is “about the same” every weekday. This has resulted in the regulatory efforts to lower the average emission rates during these “bad meteorology” days and thereby achieve the National Ambient Air Quality Standards. In situations like those in cities with very large industrial complexes, like Houston, Texas, however, new data suggests that there are more days with “ozone forming” meteorology than there are bad days, and that instead, “bad ozone days” are actually associated with “bad emissions” days. That is, with world-class industrial facilities densely packed along the ship channel and with a large shipping port, and with very large gasoline production, the industrial point source emissions inventory can not be well characterized by current State and EPA emissions inventory preparation methods. New industrial measurements and the results of the Texas Air Quality Study in August of 2000 clearly show that modeling inventories can not capture the complexity of the actually emissions. This case has important implications for both regulatory support tools and for the design of efficient regulation itself.
Using a process described in another abstract (The Development of a Stochastic Emissions Inventory for Industrial Emissions in Houston/Galveston Texas and Its Use in Photochemical Modeling, Jeffries, et al.), we have produced an alternative analysis tool, a stochastic emissions inventory generator, and have applied it to the Houston case.
Using this tool and a detailed air quality model, we evaluate alternative policy designs for achieving attainment. In particular, we will show that policies that focus on incentives to reduce the high non-standard emission events (i.e., that “clip the tail” of the distribution) promise to be much more cost-effective approaches to reaching attainment. The possible design of a cap-and-trade system, particularly of the appropriate time-interval for allowances, is also explored.