For more information about National Park Service air resources, please visit http://www.nature.nps.gov/air/.
Ozone Standard Exceedances in National Parks
The National Park Service (NPS) actively monitors ozone at its parks from April to October. Ozone measurements are compared with the National Ambient Air Quality Standard (NAAQS) for ozone. The Environmental Protection Agency (EPA) sets this standard as the level at which the ozone in the air becomes unhealthy.
The NPS tracks the days when the standard is exceeded in the parks. The table below displays the parks and the ozone values along with the number of days when the daily maximum 8-hour average ozone concentration exceeded the standard of 75 parts per billion (ppb)†. The fourth highest ozone column has been color-coded for easier viewing. The thumbnail on the right links to a map of parks with 2015 ozone exceedances.
Annual Exceedance Summaries2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004
Compiled Exceedance Summaries
- Exceedance days in parks; 1989–2010 (pdf, 273 KB) (csv, 7 KB)
- Annual maximum ozone concentrations; 1989–2010 (pdf, 314 KB) (csv, 10 KB)
- 3-year average maximum ozone concentrations; 1991–2010 (pdf, 301 KB) (csv, 9 KB)
Last Updated: November 13, 2015