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


2009 Ozone Standard Exceedances in National Parks

Map of 2009 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 2009 ozone exceedances.

2009 Ozone Standard Exceedances

National Park April May June July Aug. Sept. Oct. 2009 Season
Total Count Max 8-hr O3 (ppb) 4th highest max.
8-hr O3 (ppb)
Acadia– McFarland Hill 0 1 0 0 1 0 0 1 86 73
Acadia– Cadillac Mountain 0 0 0 0 1 0 0 1 77 61
Cape Cod– State Site 0 0 0 0 2 0 0 2 82 72
Death Valley– Park Village 0 0 0 0 2 0 0 2 86 70
Great Smoky Mountains– Cade's Cove 0 0 0 0 0 0 0 0 67 62
Great Smoky Mountains– Clingman's Dome 0 0 0 0 0 0 0 0 72 71
Great Smoky Mountains– Cove Mountain 0 0 0 0 0 0 0 0 74 70
Great Smoky Mountains– Look Rock 0 0 1 0 0 0 0 1 84 69
Joshua Tree– Black Rock 3 10 10 15 18 3 0 59 104 93
Joshua Tree– Cottonwood Canyon 1 4 2 3 1 0 0 11 85 81
Joshua Tree– Pinto Wells 2 1 0 0 1 0 0 4 82 78
Mammoth Cave– Houchin Meadow 0 0 0 0 0 0 0 0 69 65
Mojave– Kelso Mountains 1 0 1 2 7 2 0 13 85 80
Pinnacles– SW of East Entrance Stn. 0 0 0 0 0 0 0 0 73 71
Rocky Mountain– Long's Peak 0 0 0 0 0 0 0 0 75 68
Sequoia and Kings Canyon– Ash Mountain 0 4 9 26 15 16 2 72 100 98
Sequoia and Kings Canyon– Lower Kaweah 0 0 0 12 5 1 0 18 85 80
Yellowstone– Water Tank 0 0 0 0 0 1 0 1 93 63
Yosemite– Glacier Point 0 0 0 0 0 1 0 1 76 72
Yosemite– Turtleback Dome 1 0 0 0 6 2 0 9 86 79
Zion National Park– Dalton's Wash 1 0 0 0 0 0 0 1 78 68

Validation Level *

2

2

2

2

2

2

2

 

 

 


Annual Exceedance Summaries

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: October 23, 2013