Weather and Air Quality Index Thresholds

The University considers multiple factors depending on the weather situation.  The following categories are broad guidelines used in decisionmaking.

Low Temperature

1. Low air temperatures or windchill

   When the immediate forecast calls for air temperatures or sustained windchill at or below -35ºF for more than three consecutive hours, between the hours of 6:00 am and 10:00 pm, the campus will consider the need for reduced operations.

2. Low air temperatures or windchill, combined with other hazardous conditions

   When the immediate forecast calls for air temperatures or sustained windchill at or below -25ºF for more than three consecutive hours combined with a significant snowfall between the hours of 6:00 am and 10:00 pm, the campus will consider the need for reduced operations.

Snow and Ice

Even with modern forecasting technology, the track of snow and ice storms and their resulting accumulation can be highly unpredictable.  Senior leaders consider the following factors in determining whether to cancel classes or reduce operations:

• rate of snowfall
• anticipated total accumulation
• impact of winds
• status of public transit operations and area roadways
• ability of facilities management to keep campus roads and sidewalks passable

Air Quality Index Thresholds

Air Quality Index (AQI): The Environmental Protection Agency’s AQI measures the amount of pollution in the air on a scale of 0 (least hazardous) to 500 (most hazardous), and tracks the following five pollutants: fine particles, ground-level ozone, sulfur dioxide, nitrogen dioxide, and carbon monoxide. The most relevant pollutants of concern in Minnesota are fine particles and ground-level ozone. The AQI categories for fine particles and ground-level ozone pollution include:

• Good (0-50): Air quality is satisfactory, and air pollution poses little or no risk.
• Moderate (51-100): Air quality is acceptable. However, there may be a risk for some people, particularly those who are unusually sensitive to air pollution.
• Unhealthy for Sensitive Groups (101-150): Members of sensitive groups may experience health effects. The general public is less likely to be affected.
• Unhealthy (151-200): Some members of the general public may experience health effects; members of sensitive groups may experience more serious health effects.
• Very Unhealthy (201-300): The risk of health effects is increased for everyone.
• Hazardous (301-500): Everyone is more likely to be affected. 

The University considers multiple factors when determining the appropriate actions to take when the AQI is poor. When the AQI is Very Unhealthy (201-300) or Hazardous (301-500), the campus will consider the need to alter campus operations, which could include reducing or cancelling outdoor activities, moving to reduced operations, or recommending additional protective measures.