 |
NARSTO Workshop on Innovative Methods for Emission Inventory Development and Evaluation University of Texas, Austin October 14-17, 2003 |
 |
OPen Emissions Models (OPEM)—Re-Thinking The Emissions Modeling Paradigm
Mark Janssen
LADCO
Zion Wang
UC Riverside
This approach is intended to propose a new construct for emissions modeling. The authors intend to have a balanced review of the state of the science as well as a forward thinking design of a new system that would meet those needs. A public domain relational database management system (RDBMS) will be used as a backbone for emissions processing system while all functionalities in currently available emissions processing system are retained.
Emissions modeling is the act of calculating complex emissions inventories of air pollutants from raw data. The usual form of this calculation is emission factor times activity equaling emissions estimates. The reality of emissions modeling is much more complex than this simple equations. The most common use of emissions modeling is to prepare emissions estimates for photochemical or chemical transport modeling. The estimates required for this modeling must match those of a specific real day or an artificial day in the future. The estimates must also reflect the spatial resolution of the modeling system, and finally they must characterize the chemical species required by the chemical mechanism in the chemical transport model.
It is important to distinguish between emissions models and emissions processors. Emissions processors use spatial, temporal, and speciation processors to modify pre-existing emissions estimates to create pseudo-day specific emissions estimates. Emissions models create new emissions estimates based on a variety of factors. Often the two terms are used interchangeably but the distinction can be important when describing building new tools. Common examples of Emissions models are modern Mobile sources models, Biogenics, and Nonroad. Examples of emissions processors are Point and Area source models that generate model ready estimates based on SIP like annual countywide emissions inventories. SMOKE and EMS-2002 are combinations of emissions models and emissions processors.
The development of a high quality regional emissions model has traditionally been an expensive undertaking. Models like EMS and SMOKE can cost millions to develop and implement. These older development structures have revolved around a single contractor hiring high cost experts to code the model in a relatively insulated environment. These models did not rely on the expertise inherent in the community. This community based development structure has been critical to the development of the Linux operating system has been proven to work effectively for models like MM5. This proposal is not seeking a large initial outlay of resources to build this new tool instead we are looking for community supporters that are interested in development of some aspect of the model with in-kind resources.