STI collects, processes, and quality assures emissions data. STI staff are proficient with the use of common emissions processing tools, such as EPS and SMOKE, and with Geographic Information Systems used to generate modeling inputs. As part of inventory development, STI offers technology transfer services and training. Thus, our clients have true ownership and control over their emissions and air quality modeling systems.
STI and its subcontractors provided technical support to the State of Utah for the development of the 2001 PM10 State Implementation Plan (SIP) revisions. The STI team provided support for emissions modeling, air quality modeling, and control strategy evaluation. STI staff performed an initial study to identify the important sources of PM10 and phenomena contributing to the PM10 problem in Salt Lake and Utah counties. We provided detailed recommendations for improvements to the emission inventories and modeling protocols. We estimated emissions rates for previously omitted categories and improved the accuracy of the distribution of emissions by developing new spatial and temporal allocation factors as well as new PM chemical speciation factors. The new approaches and data for the emission inventory were documented for the SIP. STI staff provided technical support and guidance on the application of the UAM-AERO photochemical model to five-day winter PM10 episodes in the region. This support involved developing model performance evaluation criteria, assisting with meteorological modeling, training Utah technical staff on emissions modeling and air quality modeling, performing diagnostic evaluations of simulations, reviewing all model inputs and outputs, and preparing documentation. STI staff continues to assist the Utah Division of Air Quality in developing new emission inventories and model applications for PM episodes.
STI developed a gridded mobile source emission inventory and gridded spatial allocation fields for the 1997 Southern California Ozone Study (SCOS97) modeling domain. STI analysts used innovative approaches to develop more precise spatial allocation fields for numerous area sources, such as construction activities, gasoline service stations, and dry cleaners. We gathered activity data for mobile and area sources from several participating local air districts and transportation planning agencies and set up base-year and future-year DTIM3 model runs. The California Air Resources Board used the inventories as part of the modeled attainment demonstration for California’s State Implementation Plan.
STI staff compiled a first-ever gridded emission inventory for the Paso del Norte air basin (El Paso, Texas and Juarez, Mexico) for use in photochemical air quality modeling. We used newly developed high resolution electronic databases of source locations and socioeconomic statistics to spatially allocate county-wide area source emissions. The product of this project was a spatially and temporally resolved, speciated emission inventory. STI staff evaluated the inventory by comparing the emission inventory data to ambient data. Specifically, the ratios of non-methane hydrocarbons and carbon monoxide to nitrogen oxides (NMHC:NOx and CO:NOx) in the emission inventory and in 1996 ambient air quality data were compared. During this evaluation, STI staff identified several areas of potential improvement for the inventory.
STI prepared a 1993 emission inventory for central and eastern Texas and surrounding states. This project included preparation of emission inputs for point, area, and mobile sources; onshore biogenic emissions; and offshore anthropogenic emissions from oil production/exploration and commercial/recreational boating as well as all necessary spatial allocation factors for gridding the emission inventory. STI analysts projected this inventory to the year 2007. In addition, we assisted in the development and testing of various conceptual models of ozone formation processes during the month-long modeling episode and compared model-developed boundary conditions with ambient data. This work was performed for the Texas Commission on Environmental Quality.
STI and its subcontractor developed three methodologies for independently corroborating mobile source emissions model inputs to (1) generate locality-specific auto registration and mileage accumulation distributions by vehicle age for input to the MOBILE5a model; (2) develop guidance to gather local remote-sensing data and create inputs to MOBILE5a that better reflect emissions patterns; and (3) develop guidance to gather and use tax revenue data for estimating mobile source fuel consumption in a locality. The final report, "Preferred and Alternate Methods for Gathering and Locating Specific Emission Inventory Data", is published in Volume IV of the Emission Inventory Improvement Program’s (EIIP) Guidance Documents series (http://www.epa.gov/ttn/chief/eiip/techreport/volume04/index.html). This work was performed for the U.S. EPA.
STI contributed to the development of the California Energy Commission's annual California emission inventories of greenhouse gases for 1990-1999. STI gathered, processed, and provided guidance on the use of activity data for mobile, stationary, and area emissions source categories. STI’s work was incorporated into the California Energy Commission’s "Staff Report: Inventory of California Greenhouse Gas Emissions and Sinks: 1990-1999," Publication Numbers 600-02-001F and 600-02-001F-ES (available at http://www.energy.ca.gov/2005publications/CEC-600-2005-025/index.html).
STI staff acquired population, census, and housing data for Texas, Louisiana, Arkansas, and Oklahoma. Using these data, we developed spatial surrogates for area source emissions at a variety of grid resolutions for the study domain. The Texas Commission on Environmental Quality is using these surrogates to disaggregate county-wide emissions estimates to individual grid cells for use as input to photochemical air quality simulation models.