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Air Dispersion Modeling

One of our favorite areas of work here at ZMassociates is air dispersion modeling.

ZMassociates tackles the industry’s toughest air dispersion modeling projects primarily utilizing Lakes AERMOD software. We research meteorological and historic emissions data to produce the most accurate and reliable air dispersion models. Working with engineers and government officials, we make sure that our models are accurate and comply with regulations.


Examples of our Air Dispersion Modeling work:

Caltrans – High Desert Corridor PM10 & PM2.5 Highway Project Emissions Inventory, AERMOD Modeling, and Conformity Analysis.

ZMassociates set precedence when performing the nation’s first federal EPA conformity analysis modeling. Modeling was determined for a 65-mile long proposed highway project spanning from Palmdale to Victorville, California.  Though the PM10 & PM2.5 EPA conformity analysis rule was not scheduled to be implemented at the beginning of the project, EPA and Caltrans required conformity analysis for this project due to its relevance and precedence-setting character.

ZMassociates performed the emissions inventory for mobile and stationary sources, obtained relevant MET data suitable for AERMOD analysis, evaluated terrain and downwash characteristics of the project, and set up and ran AERMOD in modular sections representative of the project route.  We ran and modeled several alternative routings using EMFAC2007 and EMFAC2011 for traffic data sets covering all of the segments and intersections of the project.  High-speed rail analysis was included into the project analysis.  AERMOD was set up using line-volume for the mobile sources and point and area sources for stationary sources within a two mile distance of the project route.  Due to the length of the proposed highway, the project was split into four sections and analyzed accordingly.

STV Inc., High Speed Rail Burbank to Los Angeles to Anaheim – Prepare EIR/EIS Analysis for two segments of the High Speed Rail from Burbank to Los Angeles and from Los Angeles to Anaheim. 

The EIR/EIS technical reports will include a summary of environmental impacts and mitigation measures, methodology, affected environment, environmental consequences (operational and construction), cumulative impacts analysis, and appendices, as necessary. Some outlines for the technical studies may vary due to specific requirements of a particular environmental topic. The methodology will include a discussion of the methods used to conduct the analysis, measures used to define the study area, regulatory requirements, and any NEPA or CEQA significance criteria specific to the environmental topic. Both the potential operational and construction impacts will be discussed as part of the environmental consequences. Potential mitigation measures will also be identified. All technical reports will be based on the Environmental Methodology Guidelines Version 5.