The State of Utah developed a state implementation plan (SIP) for PM10 encompassing Salt Lake and Utah counties in the early 1990s. It was approved by the U.S. EPA in 1994. This SIP targeted Utah's historical problem with secondary particulate formation during wintertime inversions along the Wasatch Front. Although there have been no violations of the National Ambient Air Quality Standards (NAAQS) in the nonattainment areas since the SIP was implemented, Utah's Department of Transportation expects that the 2000-2001 transportation plans will be unable to show conformity to the PM10 SIP. Much of this nonconformity is the result of U.S. EPA changes to mobile emissions models used to establish emission budgets in the current SIP. For this reason, and to fix elements of the current SIP that have created ongoing difficulties in implementation, the Utah Division of Air Quality has decided to create an entirely new PM10 SIP.
The U.S. EPA requires that SIPs include a modeled attainment demonstration. STI's assistance to the State of Utah includes the following tasks:
|
|
A major study comparing regional air quality modeling systems used for regulatory purposes in the U.S. and Canada is being conducted under the auspices of the North American Research Strategy for Tropospheric Ozone (NARSTO). The opportunity for such a study arose when, stimulated by the need to meet regulatory milestones for attainment of national standards and objectives for ozone in the two countries, many public and private groups modeled time periods in July 1995 in overlapping domains covering most of eastern North America. The study began taking shape at a workshop for interested parties in May 1998. Work groups focusing on emissions, meteorological, and air quality modeling were formed and charged with developing comparison and evaluation protocols for models in their respective areas.
The study was conceived to take place in two phases. In the first phase, the models were to be compared in their "native" mode, i.e., using the same input files and model configurations that each group used in their individual assessments, based on modeling a 12- to 14-day period in July 1995. The planners believed that, with a minimal amount of extra effort, existing model output files could readily be used for the comparison and valuable information would be gained on the relative performance of these disparate models, each of which was used in exercises having significant policy implications.
STI is carrying out the first phase of the study by comparing "native" mode model results with observations and with results from each of the other models. STI is comparing the following models:
| Participant/Sponsor | Meteorological Model | Air Quality Model | Grid-cell Size, km | Period Simulated |
| Meteorological Service of Canada | MC2 | CHRONOS | 40 and 10 | 7-18 July, 1995 |
| US EPA | MM5 | CMAQ | 36 and 12 | 7-18 July, 1995 |
| New York State Dept. of Environmental Conservation | RAMS3b | UAM-V | 36 and 12 | 7-18 July, 1995 |
| MCNC - Environmental Programs | MM5 | MAQSIP | 36 | 7-18 July, 1995 |
| Environ/Coordinating Research Council | MM5 | CAMx | 36 and 12 | 7-15 July, 1995 |
| ICF Consulting/Southern Co. | MM5 | UAM-V | 36 and 12 | 7-15 July, 1995 |
Model performance is being summarized for the northeastern U.S., southeastern U.S., and U.S.-Canada border subdomains shown in this figure. Model performance is also being summarized for major urban and suburban areas.
STI developed a Modeling Support System (MSS) for a commercial company in the United States and delivered it to 11 cities in the People's Republic of China. The MSS is a complete meteorological and air quality modeling system that runs on an Intel Pentium class computer under the Windows operating system. The MSS was integrated with the customer's Data Acquisition System (DAS) so that the MSS modeling and analysis tools could use data collected by the DAS directly. STI designed the MSS to be expandable so that new models and analysis tools can be easily added.
The core model for the MSS is the CALPUFF air quality model. The system includes the CALMET diagnostic meteorological model, which is required to use CALPUFF. The system also includes the standard CALMET and CALPUFF pre-processors and post-processors.
The MSS has a graphical user interface that provides access to all models, analysis tools, pre-processors and help files that have been integrated into the system. In addition, the MSS interface allows users to organize model runs and analyses into "studies". The MSS also maintains a log of system actions, program executions, and diagnostic messages.
The MSS uses the concept of a "study" to organize data, streamline model execution, and ensure that all models and tools use consistent inputs. A study defines the location and time period to be modeled or analyzed. When a study is created, changed, or reused, all program control files are modified in the study directory to include the same domain definition (location and grid specifications), dates, and times. The MSS also allows the user to define a series of programs to run as part of a study. For example, a study might first extract data from the DAS database, then use that data to run CALMET, then use the results from CALMET to run CALPUFF. If the user desires to modify a model input, the entire study can be rerun with a click of the mouse.
The MSS includes two visual analysis tools that enhance the user's ability to use the modeling system and the data provided by the DAS. These are the CalDESK 2.0 analysis tool, developed by EnviroModeling Ltd., and the map generator (MapGen), developed for the United States Environmental Protection Agency's AIRNow program (http://www.airnow.gov). CalDESK 2.0 is a copyrighted commercial software product, and STI provides licenses to each end user. MapGen is freely available and no license is required to use it.
In addition, the MSS includes the PRTMET and CALPOST post-processing utilities for extracting and manipulating data from CALMET and CALPUFF, respectively. The CALPOST program also allows the user to estimate visibility from modeled particulate matter concentrations.
