Data and Records

Since the start of the Spare the Air program in 1991, the Air District has kept records for the number of alerts issued each year.

The table below lists the number of Spare the Air days issued for the Bay Area each year, as well as the number of days on which ozone concentrations exceeded the state and federal health-based air quality standards.

Year
Spare the Air Days
National 1 Hour Excess Days
National 8 Hour Excess Days
CA 1 Hour Excess Days
CA 8 Hour Excess Days
2019 19 * 7 4 7
2018 13 * 3**** 2 3
2017 18 * 6**** 6 6
2016 27 * 15 5 15
2015 9 * 5 4 11
2014 10 * 5 3 10
2013 6 * 3 3 3
2012 10 * 4 3 8
2011 8 * 4 5 10
2010 10 * 9 8 11
2009 14 * 8 11 13
2008 13 * 12**** 9 20
2007 2 * 1 4 9
2006 11 * 12 18 22
2005 1 * 1 9 9
2004 4 0 0 7 ***
2003 9 1 7 19 ***
2002 7 2 7 16 ***
2001 5 1 7 15 ***
2000 5 3 4 12 ***
1999 11 3 9 20 ***
1998 23 8 16 29 ***
1997 3 0 ** 8 ***
1996 25 8 ** 34 ***
1995 24 11 ** 28 ***
1994 12 2 ** 13 ***
1993 19 3 ** 19 ***
1992 7 2 ** 23 ***
1991 11 2 ** 23 ***

 

Record keeping for the historical ozone data reflects updates to the EPA standards.

* The national 1-hour ozone standard was revoked on June 15, 2005.
** The national 8-hour ozone standard of 0.08 ppm was implemented in 1998. On May 27, 2008, the U.S. EPA implemented a more stringent national 8-hour ozone standard of 0.075 ppm. In December 2015, the U.S. EPA implemented an even more stringent national 8-hour ozone standard of 0.070 ppm.
*** The California 8-hour ozone standard became effective May 17, 2006. The Air District began keeping records for the standard in 2005. The standard is set at 70 parts per billion of ozone in the ambient air, averaged over 8 hours.
**** On these exceedance days ozone concentrations were exacerbated due to wildfire emissions. This does not necessarily mean that these ozone exceedances were solely caused by wildfire emissions.