Air Quality Measurement

Learn about the Air District’s air quality measurement activities, including the air monitoring network and special studies, laboratory support, data quality assurance, and pollutant source testing.

Ambient Air Monitoring

The  Air District conducts ambient air monitoring, both through a fixed-station network and special, short-term studies.

The ambient air monitoring network consists of over 30 stations that collect local air quality data, including measurements of significant air pollutants.

The data from the network and special studies are used for many important purposes, including:

  • Determining compliance with state and federal air quality standards.
  • Preparing air quality forecasts.
  • Clean Air Plan modeling.
  • Prevention of Significant Deterioration permit modeling.
  • Preparing environmental impact reports.
  • Providing information about regional and local air quality and air quality trends.
  • Developing air quality rules and regulations.

Special sampling projects, such as fine particulate matter speciation and short-term studies in specific communities, provide data for use in developing air quality plans, updating regulations, and furthering our understanding of air quality in the Bay Area.


The Laboratory provides a variety of monitoring related services and support to Air District departments and activities, including:

  • Analyzing samples for potential enforcement action and during and after episodic events (laboratory methods are available in the Manual of Procedures).
  • Evaluating, developing, and updating analytical methods.
  • Providing technical information for evaluating permits and developing regulatory standards.
  • Performing PM2.5 and PM10 gravimetric analysis.
  • Performing anion/cation speciation and organic carbon/elemental carbon analysis on PM10 filters.
  • Analyzing ambient air for volatile organic compounds and ozone precursor compounds.

Quality Assurance

To ensure the accuracy of data collected through the laboratory, air monitoring and meteorological networks, the Air District validates the data through quality assurance audits. Data generated by the laboratory also require quality assurance review to meet U.S. EPA validation requirements.

Source Testing

The Air District performs source testing to determine whether a pollution source is in compliance with air quality regulations and to provide further information about emission sources. Source test functions include:

  • Conducting analytical source tests.
  • Conducting performance audits on continuous emissions monitoring and predictive emissions monitoring systems.
  • Reviewing and determining suitability of third-party source tests.
  • Researching and developing new analytical source test procedures.
  • Producing source test data-based engineering studies.

Additional Resources

Contact Us

General Information


Meteorology & Measurements
Air Monitoring


Contact Us

Spare the Air Status

Last Updated: 9/27/2016