For more information about National Park Service air resources, please visit http://www.nature.nps.gov/air/.
2004 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 level of the National Ambient Air Quality Standard (NAAQS) for ozone in 2004 was 80 part per billion (ppb), daily maximum 8-hour average. The ozone standard was exceeded at an ambient air quality monitoring site when the 3-year average of the annual fourth-highest daily maximum 8-hour average ozone concentration was greater than 85 ppb, which occurred when the 3-year average equaled or exceeded 85 ppb. The table below counts the number of days when the daily maximum 8-hour average ozone concentration equaled or exceeded 85 ppb in 2004.2003–2005 Average Annual 4th Highest Daily Maximum for
NPS Units (pdf, 130 KB) »
Annual Exceedance Summaries2014 | 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: June 20, 2012