SWAPE was retained to evaluate potentially significant health impacts associated with the Los Cerritos Wetlands Oil Consolidation and Restoration Project in Long Beach, California.  The objective of the Project is to consolidate petroleum operations on existing oil fields, restore existing wetlands, and create new wetlands for public access.  For the project, SWAPE worked alongside several environmental consulting firms to create a Health Risk Assessment (HRA) using an innovative approach that integrated several modeling programs, including CalEEMod, AERMOD, and HARP 2 RAST. The results of this HRA were presented in the Draft Environmental Impact Report (EIR) for the Project.

CalEEMod (the California Emissions Estimator Model) is a land use emissions modeling software that is used to quantify criteria air pollutant and greenhouse gas emissions associated with construction and operational emissions from proposed projects. Estimated emissions generated by CalEEMod are often compared to significance thresholds outlined by CEQA (the California Environmental Quality Act). The model calculates emissions using a combination of default values and project-specific values such as land use type, construction timeline, and equipment usage. For the purposes of SWAPE’S HRA, CalEEMod results were used to develop source terms for AERMOD.

AERMOD is the U.S. EPA’s preferred/recommended regulatory dispersion model. AERMOD is a steady-state Gaussian plume model that generates ambient air concentrations of contaminants based on pollution-source input parameters, meteorological data, and topographical data. SWAPE developed source terms and modeled Project emissions of diesel particulate matter (DPM) and volatile organic compounds (VOCs) at potential sensitive receptor locations surrounding the Project site.

HARP 2 RAST (the Hotspots Analysis and Reporting Program Version 2 Risk Assessment Standalone Tool) was developed by the California Air Resources Board (CARB) in order to conduct HRAs. SWAPE used concentration results from AERMOD as inputs into HARP to calculate the unmitigated and mitigated cancer risk, non-cancer acute risk, and non-cancer chronic risk in the community surrounding the Project site. Infant, Child, and Adult risks were added together in order to compare cumulative risk levels with appropriate significance thresholds set by the South Coast Air Quality Management District (SCAQMD).

Throughout this complex modeling process, SWAPE made the most conservative assumptions possible in order to benefit both the environment and human health.  SWAPE’s innovative approach for the Los Cerritos Wetlands HRA for the Draft EIR resulted in a mitigated cumulative health risk that was well below significance thresholds.