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 2011 ozone exceedances.
2013 Ozone Standard Exceedances |
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|---|---|---|---|---|---|---|---|---|---|---|
| National Park | April | May | June | July | Aug. | Sept. | Oct. | 2013 Season | ||
| Total Count | Max 8-hr O3 (ppb) | 4th highest max. 8-hr O3 (ppb) |
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| Great Smoky Mountains– Cove Mountain | 0 | – | – | – | – | – | – | 0 | 66 | 59 |
| Great Smoky Mountains– Look Rock | 0 | – | – | – | – | – | – | 0 | 66 | 62 |
| Joshua Tree– Black Rock | 2 | – | – | – | – | – | – | 2 | 80 | 72 |
| Mammoth Cave– Houchin Meadow | 0 | – | – | – | – | – | – | 0 | 69 | 57 |
| Rocky Mountain– Long's Peak | 0 | – | – | – | – | – | – | 0 | 64 | 61 |
| Sequoia and Kings Canyon– Ash Mountain | 3 | – | – | – | – | – | – | 3 | 79 | 73 |
| Sequoia and Kings Canyon– Lower Kaweah | 1 | – | – | – | – | – | – | 1 | 76 | 69 |
| Yosemite– Turtleback Dome | 0 | – | – | – | – | – | – | 0 | 67 | 55 |
Validation Level * |
1 |
0 |
0 |
0 |
0 |
0 |
0 |
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*Validation level 0 indicates raw data. Validation level 1 indicates preliminary data. Validation level 2 indicates final, validated data. Counts of days with 8-hr average ozone greater than 75 ppb may change after the data is fully validated. The ozone season runs from April to October for the detailed current ozone conditions. During the winter, more limited numbers of locations and web products are available. |
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Annual Exceedance Summaries
2013 | 2012 | 2011 | 2010 | 2009 | 2008 | 2007 | 2006 | 2005 | 20042003 (pdf, 137 KB) | 2002 (pdf, 146 KB) | 2001 (pdf, 136 KB) | 2000 (pdf, 133 KB)
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: May 09, 2013
