Modeling Mobile-Source Emissions (2000) / Chapter Skim
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6 A Toolkit of Future Emissions Inventory Models
6 A Toolkit of Future Emissions Inventory Models
Pages 197-209
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From page 197... ...
The motivation for this recommendation is that MOBILE is currently applied in situations for which it was not designed and is poorly suited. A "toolkit" of models is required, and here we lay out the structure for this proposed emissions modeling toolkit.
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From page 198... ...
Some of the individual issues associated with the use of MOBILE include the following: No protocol exists on the calibration of MOBILE model components. No protocol exists for standardizing emissions tests and ambient measurements made by the public and private sectors.
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From page 199... ...
for estimating emissions using aggregate vehicle activity data; a new-generation mesoscale emissions modeling component that integrates detailed transportation and emissions components to estimate regional and subregional (corridor) emissions and air quality through the coupling of vehicle operating conditions with appropriate link-based or trip-based emissions factors; a microscale instantaneous emissions modeling component that uses instantaneous operating conditions of individual vehicles to estimate continuous vehicle emissions and can be used for a variety of applications, including generating emissions factors for microscale traff~c-simulation models, mesoscale emissions models, traffic data sets, and dispersion models.
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From page 200... ...
MOBILE should remain as the aggregated regional emissions-factor component in the new suite of emissions models. This type of modeling component is required for comparisons of some control strategies and for comparing emissions from mobile sources with other source categories.
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From page 201... ...
The mesoscale emissions modeling component would have a corresponding set of vehicle types and a set of emissions factors that correspond to different types of roadway facilities at different levels of congestion that can be applied on a link-by-link or trip-by-trip basis. These emissions factors can be established through comprehensive testing and the application of the microscale instantaneous emissions modeling component, described in the next section.
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From page 202... ...
It cannot be overemphasized, though, that any model intended to fulfill such a regulatory role must undergo extensive peer review and validation, and provide in-depth documentation to any potential users. Data bleeds for Mesoscale Transporlation and Emissions Modeling Component To estimate emissions inventories more accurately using the integrated mesoscale modeling component described above, will require a greater array of input data.
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From page 203... ...
This module will also require more detail on the vehicle fleet, such as registration distributions by vehicle class, fuel type, and emitter-level category. Microscale Transportation and Emissions Modeling Component A critical component to the emissions modeling toolkit is a microscale instantaneous emissions model.
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From page 204... ...
used in the regional aggregate emissions-factor component can be improved with an accurate instantaneous emissions model. Some of the applications that require an accurate coupling of transportation and emissions modeling components can be performed using a combined microscale transportation and emissions model set.
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From page 205... ...
However, the instantaneous emissions modeling component can also be used to derive the mesoscale emissions factors. The microscale emissions model could
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From page 206... ...
A prominent example of how things should be consistent is that an instantaneous emissions model should generate the same integrated emissions numbers as an aggregate model for a specific driving cycle. Further, link-based or trip-based emissions factors can be generated directly from an instantaneous component, insuring consistency between those two layers.
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From page 207... ...
The microscale components in this case would consist of a traffic simulation model (and/or off-model statistical evaluations of modal activity changes) tightly coupled with the instantaneous emissions model component.
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From page 208... ...
The development of a modeling toolkit approach will require a major initiative championed by a broad constituency. The committee feels strongly that such an effort is warranted, given the significance of mobile-source regulation.
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From page 209... ...
A final issue involves the need for support for a modeling toolkit initiative from the legislative community that is involved in setting mobilesource regulations but not in implementing and evaluating these regulations. There is a constant demand *
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