Point Reyes National Seashore Data Timelines
Particulate Matter (PM2.5) Data
PM2.5 -- Particulate Matter Less Than 2.5 Micrometers in Diameter -- 1-hour and 24-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 particulate matter, which is designed to protect human health. The chart plots both the 1-hour and running 24-hour average pm2.5 concentration. 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. |