Air quality models use mathematical and numerical techniques to simulate the physical and chemical processes that affect air pollutants as they disperse and react in the atmosphere. Based on inputs of meteorological data and source parameter information like emission rates and stack height, these models are designed to characterize primary pollutants that are emitted directly into the atmosphere. These models are important to our air quality management process because they assist in determining compliance with National / State Ambient Air Quality Standards (NAAQS /SAAQS) and other regulatory requirements such as New Source Review (NSR), evaluate projects subject to California Environmental Quality Act (CEQA) review, and assist in the design of effective strategies to reduce harmful air pollutants. For example, air quality models can be used during the permitting process to verify that a new source will not exceed ambient air quality standards and will not have a negative impact on public health.
In addition, air quality models can also be used to predict future pollutant concentrations from multiple sources after the implementation of a new regulatory program in order to estimate the effectiveness of the program in reducing harmful exposures to humans and the environment.