Theodore Roosevelt National Park Data Timelines
Ozone, Particulate Matter (PM2.5), and Sulfur Dioxide (SO2) Data
Collected at the Visitor Center Monitoring Site
Ozone -- 1-hour and 8-hour average concentrations
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 85 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. |
PM2.5 -- Particulate Matter Less Than 2.5 Micrometers in Diameter -- 1-hour and 24-hour average concentrations
The background of the chart is color coded and relates to the EPA National Ambient Air Quality Standard for particulate matter, which is designed to protect human health. The chart plots both the 1-hour and running 24-hour average pm2.5 concentration, but only the 24-hour average should be used to compare with the standard. The standard is exceeded when the 24-hour concentrations go above 65 micrograms per cubic meter, 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. |
| Unhealthy For Sensitive People | People with heart or lung disease, older adults, and children should reduce prolonged or heavy exertion. |
| Unhealthy | People with heart or lung disease, older adults, and children should avoid prolonged or heavy exertion. Everyone else should reduce prolonged or heavy exertion. |
| Very Unhealthy | People with heart or lung disease, older adults, and children should avoid all physical activity outdoors. Everyone else should avoid prolonged or heavy exertion. |
| Hazardous | Everyone should avoid all physical activity outdoors; people with heart or lung disease, older adults, and children should remain indoors and keep activity levels low. |
Sulfur Dioxide -- 1-hour average concentrations
