Practices > Air Quality

We possess extensive air quality analysis and regulatory experience in both the public and private sectors coupled with an advanced educational background and on-going training.

We emphasize the importance of using cutting-edge analysis tools and methodologies for the clear presentation of modeling results along with the development of effective, feasible solutions. Ascent’s air quality services range from dispersion modeling and health risk assessments to quantification of mass emissions for analyzing plan- and project-level impacts. We offer additional expertise in guidance for assessing impacts and development of legally defensible thresholds of significance and analytical methods, as well as emission reduction measures.

A comprehensive summary of our air quality-related services includes:

CEQA/NEPA/SEPA Analyses and Documentation
Development of Analytical Methods, Thresholds of Significance, Emission Reduction Strategies
Technical Analyses (Mobile, Stationary, and Area Source Mass Emissions and Dispersion Modeling; Contour/Isopleth Development; Health Risk and Odor Assessments)
Construction (Dust/Asbestos) and Operational Mitigation Plans and Fee Assessments
Permitting and Emission Inventories
Constraints and Design-Stage Analyses
Federal Clean Air Act Conformity, Applicability Analyses, and Conformity Determinations
Development of Guidance for Assessing Air Quality Impacts for Regulatory Agencies, including CEQA Guidelines

Our analyses are conducted in accordance with rules, regulations, and guidance from federal, regional, state, and local agencies, including the U.S. Environmental Protection Agency (EPA), the Office of Environmental Health Hazard Assessment (OEHHA), California Air Resources Board (ARB), CalTrans, and air quality management and pollution control districts. This includes the use of the following models: Urban Emissions Model (URBEMIS), Emissions Factor Models (e.g., EMFAC, MOBILE, MOVES), Road Construction Emissions Model, Direct Traffic Impact Model (DTIM), American Meteorological Society (AMS)/EPA Regulatory Model (AERMOD), Industrial Source Complex (ISC), Line Source Dispersion Models (e.g., CALINE/Cal3QHC), and Hot Spots Analysis and Reporting Program (HARP), and many more.