In 2014, H-GAC contracted with Eastern Research Group, Inc. and Cambridge Systematics, Inc. to develop a modeling framework called the Spatial Emissions Estimator for estimating regional on-road emission inventories of criteria air pollutants, air toxics and greenhouse gases emissions for each hour of a day with highly detailed spatial resolution. This framework, at the project scale and county scale, includes all needed emission processes in accordance with U.S. Environmental Protection Agency modeling guidance.

On January 7, 2021, U.S. Environmental Protection Agency released major updates to the previous model versions which require source code updates to the Spatial Emissions Estimator.

A summary of the key changes affecting on-road emissions inventories and/or the operation of the Spatial Emissions Estimator includes:

• Updated on-road vehicle exhaust emission rates, including heavy-duty greenhouse gases Phase 2 and Safer Affordable Fuel Efficiency  rules
• Updated on-road activity, vehicle populations, and fuels
• New combinations of source types and fuel types; mostly heavy duty operating on compressed natural gas
• New regulatory vehicle class: gliders
• New emission process: off-network idle
• Revised inputs for hoteling and starts
• Removal of ramps as a separate road type
• Use of MariaDB instead of MySQL programming language
• Additional calendar years for modeling 2051-2060

2022 Unified Planning Work Program

Request authorization to negotiate a one year contract in the amount of $75,000 with Eastern Research Group, Inc. to update the Air Quality Spatial Emissions Estimator.  (Staff Contact: Graciela Lubertino)