The District has three particulate matter (PM-10) and one ozone  (O3) site. The PM-10 sites are located in Healdsburg, Cloverdale, and Guerneville.  The ozone site is located in Healdsburg.  

EPA has assigned a specific color to each AQI category to make it easier for people to understand quickly whether air pollution is reaching unhealthy levels in their communities. On the local map:  hover over the AQI legend for more information on each color code/category.  Click on a site for expanded information.  Select the link below the map for a daily graph report of all 4 sites.

State-wide Air Monitoring

AQI for PM and Ozone by AirNow

Visit EPA's AQI site for more information:

District Monitoring Sites

The District provides air quality information from its sites and simple report tools for public information with the map tools, above.  This data is displayed by default as the r Air Quality Index format on the map.  The AQI value is different than the measured value which is used to calculate attainment of air quality standards.  Please note that because this data is displayed in real time it has not undergone QA/QC.  During monitor maintenance or calibration, the values may drop, spike, or be absent.

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The District performs ambient air monitoring for planning and regulatory purposes. Federal regulations require state and local agencies that conduct ambient air monitoring to use specific federal reference analyzers, to meet specific siting criteria, and to certify data quality to meet the federal regulatory requirements set forth in 40CFR Part58.  Specific information regarding the monitoring sites is included in the state's Annual Network Monitoring Report, which is reviewed annually by the District and the California Air Resource Board, and approved by EPA.

​​Air Quality

Air Quality Data

Local Air Monitoring​ ​​- AQI for PM and Ozone by Northern Sonoma County APCD

The Air Quality Index (AQI)