Grand County—3 Day Forecast
Last Updated: June 3, 2023 6:24 AM
The Division of Air Quality does not forecast for Grand at this time.
The forecast indicates the highest pollution level of the day. During the summer, Ozone pollution levels are generally low during the morning, evening and night. During the winter, particulate matter (i.e., PM 2.5) pollution levels build up until a storm or weather system moves the air out of the valley.
The health forecast helps to determine how the highest pollution level of the day will affect people with various health conditions. Click on the “Health Forecast” legend to plan your physical activity to help minimize the effects of pollution on your health.
The action forecast notifies the public of the voluntary or mandatory actions (e.g., carpooling, wood burning) they need to adhere to for the current pollution levels. Click on the “Action Forecast” legend for a description of the action regulations.
|Air Quality Index (AQI)||PM 2.5||Ozone|
|Good||0 - 12.0 µg/m3||0 - 0.054 ppm|
|Moderate||12.1 - 35.4 µg/m3||0.055 - 0.070 ppm|
|Unhealthy for Sensitive Groups||35.5 - 55.4 µg/m3||0.071 - 0.085 ppm|
|Unhealthy||55.5 - 150.4 µg/m3||0.086 - 0.105 ppm|
|Very Unhealthy||150.5 - 250.4 µg/m3||0.106 - 0.200 ppm|
|Hazardous||Above 250.5 µg/m3||Above 0.201 ppm|
|Based on a 24-hour average.||Based on an 8-hour average.|