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ESTIMATE OZONE FROM FUEL REFORMULATION
Project No. A-67
Leaders:
R. S. MacArthur
A. M. Dunker
Scope and Objective
The objective of this project is to estimate
ambient O3 changes due to the prospective use of biofuel blends. An
emissions-processing scheme is to be developed which quickly applies on-road and
nonroad emissions changes due to transportation fuel reformulation to result in
a grid-model-ready emissions inventory. A "companion" CAMx grid model O3
application (e.g., a SIP episode) will serve to predict the results from the
emissions inventory changes, thus a "model suite."
Current Status and Future Program
Biofuel blends in transportation fuel are being
required by many states--as well as by the federal renewable fuel standard (RFS)--consequently
requiring regulatory decision-makers to demonstrate National Ambient Air Quality
Standards (NAAQS) compliance with these measures in place. There is concern
since vehicle emissions tests have indicated some increase in permeation HC
emissions due to ethanol, and some increase in NOx emissions from
both biodiesel and ethanol.
Although generalizations about VOC- or NOx
-limitation in the airshed may be helpful, mixed blends, the market penetration
of the blends, and spatial and temporal variation of both mobile source HC and
NOx increases render the predictability less certain. Since "sound
science" grid modeling applications of the simplest of control strategies are
time consumptive and burdensome, and since the release timing of vehicle
emissions testing results is highly uncertain, it seems prudent to develop a
flexible modeling methodology which enables the timely grid modeling
investigation of how the vehicle emissions testing results may be represented in
the mobile source fleet and the consequent response of ambient ozone.
Through close
coordination with Lake Michigan Air Directors Consortium (LADCO), the
Consolidated Community Emissions Processing Tool (CONCEPT) will be modified to
enable flexibility in changes in on-road (link-based) and nonroad temporal and
spatial speciated- process- vehicle-specific ozone precursor emissions external
from the grass-roots emissions development process. The emissions inventory can
then be used as input to CAMx to show the effects of fuel reformulation in the
airshed. The "model suite" is intended for decision-makers' and consultants'
use to speed up delivery of results and reduce costs. The project deliverables
include a journal article, a model user's guide, public domain-resident code,
models and model inputs. CRC issued a request for proposal for this study, and
a project start is anticipated later in 2007.
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