Air Quality Modeling and Analysis
Air quality is regulated by both Federal and California laws (the Clean Air Act and California Clean Air Act) and by regional air quality management districts. CEQA and NEPA also require developers to perform air quality modeling and associated analysis to receive permits for the construction and operations of a new facility or piece of equipment. The results of these assessments are used to ensure that all new sources of air emissions remain below legal thresholds.
ECORP has completed hundreds of air quality reports to help our clients receive the needed approvals and permits from air quality management districts and lead agencies throughout California as part of our Air Quality Modeling and Analysis Services.

Air Quality Modeling and Analysis Services for New Facilities
Before a new facility can be built, project proponents must prepare an Air Quality Impact Assessment (AQIA) to estimate emissions of air pollutants (criteria air pollutants) and compare them to thresholds set by the local air quality management districts. ECORP creates AQIAs by using air emissions modeling software to estimate the criteria air pollutants that would be generated from the project’s construction and operations.
Air Quality and Toxic Air Contaminants
Some types of development, such as gas stations, industrial operations, and development with heavy truck traffic, emit Toxic Air Contaminants (TACs) that also require additional evaluation. If a project has the potential to emit TACs, we perform a health risk assessment to determine whether they will pose a danger to human health at or around the project site.
If emissions exceed legal limits or health risks are identified, we recommend mitigation measures to reduce air emissions to meet the thresholds established by the local air quality management district, if possible.

NSR Permitting for New Stationary Sources Added to an Existing Facility
After the facility is constructed, any new equipment must be permitted for use before installation. There are two types of permits that may be required. The first is for stationary sources of air emissions such as a boiler, incinerator, generator, or smelter. These permits are granted by the local agencies through the New Source Review (NSR) process.
NSR permits differ based on the number of pollutants a stationary source creates and whether or not mitigation measures have been taken to reduce those levels.

There are three primary types of NSR permits, including:
- Title V Major Source Permits are required for a stationary source or group of stationary sources which produce 10 tons of a single hazardous air contaminant or 25 tons of several contaminants annually
- Minor Source Permits are required for stationary sources that produce minor levels of toxic air emissions
- Synthetic Minor Source Permits are required for new stationary sources which are expected to produce toxic air emissions above major source levels but which have implemented restrictions to reduce emissions.

Mobile Source Air Modeling, Analysis, and Permitting
Mobile sources of air emissions are those which move around a facility, such as diesel trucks or gas-powered vehicles. The California Air Resources Board (CARB) oversees the approval of these permits, which include:
- Large Spark Ignition (LSI) permits: Required for engine fleets, such as forklifts, sweeper/scrubbers, and industrial tow tractors
- In-Use Off-Road Diesel-Fueled Fleets Regulation (DOORS) permits: Required for mobile diesel equipment.
- Portable Equipment Regulation Program (PERP) permits: Required for portable engines
Contact ECORP to Learn More About Air Quality Modeling and Analysis
Whether you need a permit to begin new construction or expand on existing facilities, ECORP’s air quality experts provide air quality analysis and modeling services designed to help builders, developers, and facility operators complete the legally required reports needed for CEQA, NEPA, and other permitting purposes.
Contact ECORP today to learn more about how our air quality modeling and analysis services can help you get the permits needed to move forward on your next project.