1-Hour Ozone Attainment Request

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 the most recent three year period air monitoring data (2011-2013).

On May 6, 2014, the District submitted a formal request that EPA determine that the Valley has attained the federal 1-hour ozone standard. Per federal requirements, the District’s submittal includes a clean data finding and a finding that attainment is due to permanent and enforceable emissions reductions.

As part of the clean data finding, the District requested EPA concurrence that an exceedance at Fresno-Drummond on August 10, 2012 was due to an exceptional event. Alternatively, the District also provided compelling evidence that the Valley would attain the 1-hour ozone standard but for the influence of international air pollutant transport, allowing nonattainment penalties to be lifted under federal Clean Air Act section 179B.

The 2014 submittal to EPA included the following:


On July 13, 2015, the District submitted a second formal request that EPA determine that the Valley has attained the federal 1-hour ozone standard.

The 2015 submittal to EPA included the following:

On July 18, 2016, the EPA published in the Federal Register the final action to determine that the San Joaquin Valley has attained the 1-hour ozone standard. This determination is based on sufficient, quality-assured, and certified data for the period 2012-2014. The EPA determination is available here.