Ground level ozone impacts public health. Ozone is not emitted directly into the air, but is created by chemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOC) in the presence of heat and sunlight. The Valley experiences its highest ozone levels in the summer. EPA has established ozone standards based on 1-hour averaging periods, and for 8-hour averaging periods. More information is available on EPA’s website.
For the first time in recorded history, in 2013, the Valley had zero violations of the 1-hour ozone standard established by EPA under the federal Clean Air Act. The Valley now meets the 1-hour ozone standard based on air monitoring data. As such, the District submitted an attainment request to EPA in May 2014.
On July 18, 2016, EPA published in the Federal Register a final action determining that the San Joaquin Valley has attained the 1-hour ozone national ambient air quality standard. This determination is based on the most recent three-year period (2012-2014) of sufficient, quality-assured, and certified data.