Greenhouse Gas (GHG) Emissions Modeling

FREY can assist clients with Greenhouse Gas (GHG) emissions modeling for future projects. FREY utilizes California Emissions Estimator Model (CalEEMod) a state wide land use emissions computer model developed by ENVIRON International Corporation, the South Coast Air Quality Management District (SCAQMD) and other air districts for use in California.


The CalEEMod software uses the CalEEMod land use emissions inventory model to estimate greenhouse gas and criteria pollutant emissions under particular scenarios involving construction, land area, and other sources. It has been designed specifically for California, and uses California-specific road and construction emissions factors. The model estimates emissions from the property resulting from demolition and construction activities, area source emissions (emissions from the property), and operational (vehicle) emissions (emissions from vehicular traffic). CalEEMod can be used for air quality analyses for California Environmental Quality Act (CEQA) documents, National Environmental Policy Act (NEPA) documents, compliance with local air quality rules and regulations, and early project planning.


CalEEMod calculates the estimated direct and indirect GHG emissions generated during project construction and the estimated yearly direct and indirect GHG emissions generated through Site use. Indirect emissions result from actions at the Site that cause GHG emissions at a source that is owned and controlled by another entity, such as a power plant. The indirect GHG emissions were calculated for electricity use, natural gas use, water use, and solid waste disposal.

Emission Mitigation

When the estimated emissions results reported in screening analysis mode do not meet regulatory thresholds, then the next tier of modeling can be performed utilizing mitigation factors and additional Site data to reduce estimated emissions. The CalEEMod model allows the use of a wide range of emission mitigation measures, from simple input values to detailed Site-specific project data. Detailed project data is typically more complex and requires the collection of additional Site data including: phased-construction use, specific emission source data, construction equipment exhaust data, fugitive dust mitigation, equipment to be used during Site development, traffic study data, temperature data, and other factors.

Professional Environmental Consulting