For more information about National Park Service air resources, please visit http://www.nature.nps.gov/air/.


Ozone Standard Exceedances in National Parks

Map of 2015 Ozone Exceedances - Season to Date
Map of 2015 Ozone Exceedances (Click photo to enlarge)

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.

2015 Ozone Standard Exceedances

National Park April May June July Aug. Sept. Oct. 2015 Season
Total Count Max 8-hr O3 (ppb) 4th highest max.
8-hr O3 (ppb)
Great Basin National Park– Maintenance Yard 0 0 1 1 76 66
Great Smoky Mountains National Park– Clingmans Dome 0 0 0 0 75 66
Great Smoky Mountains National Park– Cove Mountain 0 0 0 0 69 68
Great Smoky Mountains National Park– Look Rock 0 0 0 0 72 68
Joshua Tree National Park– Black Rock 6 5 8 19 92 83
Joshua Tree National Park– Cottonwood Canyon 0 0 2 2 85 72
Joshua Tree National Park– Pinto Wells 2 1 2 5 84 77
Mammoth Cave National Park-Houchin Meadow– Houchin Meadow 0 0 0 0 67 63
Mojave National Preserve– Kelso Mountains 0 0 7 7 83 78
Pinnacles National Monument– Entrance Station 0 0 0 0 69 67
Rocky Mountain National Park– Long's Peak 0 0 0 0 75 69
Sequoia and Kings Canyon National Parks– Ash Mountain 1 4 16 21 88 87
Sequoia and Kings Canyon National Parks– Lower Kaweah 0 1 10 11 83 82
Yosemite National Park– Turtleback Dome 0 0 0 0 73 70

Validation Level *

2

2

2

 

 

 

 

 

 

 


Annual Exceedance Summaries

2015 | 2014 | 2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 2004

2003 (pdf, 137 KB) | 2002 (pdf, 146 KB) | 2001 (pdf, 136 KB) | 2000 (pdf, 133 KB)


Compiled Exceedance Summaries


Last Updated: July 21, 2015