Denali National Park and Preserve Data Timelines
Ozone Data Collected at the Headquarters Monitoring Site
Ozone -- 1-hour and 8-hour average concentrations
These data are raw and have not yet been validated using the standard procedures to guarantee their quality prior to their release for scientific and regulatory purposes. These data may be revised at a later time.
The background of the chart is color coded and relates to the EPA National Ambient Air Quality Standard for ozone, which is designed to protect human health. The chart plots both the 1-hour and running 8-hour average ozone concentration, but only the 8-hour average should be used to compare with the standard. The standard is exceeded when the 8-hour concentrations reach or go above 76 parts per billion, as denoted by the line with the label NAT'L AMBIENT AIR QUALITY STANDARD. Compare the background color behind the data concentration values with the colors in the table below to determine the levels of health concern and caution associated with that concentration.
| Good | No cautionary statement. |
| Moderate | Unusually sensitive people should consider reducing prolonged or heavy exertion outdoors. |
| Unhealthy For Sensitive People | Active children and adults, and people with lung disease, such as asthma, should reduce prolonged or heavy exertion outdoors. |
| Unhealthy | Active children and adults, and people with lung disease, such as asthma, should avoid prolonged or heavy exertion outdoors. Everyone else, especially children, should reduce prolonged or heavy exertion outdoors. |
| Very Unhealthy | Active children and adults, and people with lung disease, such as asthma, should avoid all outdoor exertion. Everyone else, especially children, should avoid prolonged or heavy exertion outdoors. |