In addition to bringing cold temperatures, Utah winters can also bring increased levels of smog, particularly in the Salt Lake Valley and Cache Valley. This smog can lower temperatures even further and increase health problems for people who have asthma or other respiratory difficulties.
One of the leading contributing factors to Utah’s winter air quality is inversion. An inversion occurs when cold air is trapped in the valley under a layer of warm air. The cold air traps pollutants from car, industry, and wood stoves. The pollutants continue to build until wind or storm pushes the polluted air out. The longer that the inversion stays, the more pollutions gather in the air, and the more unhealthy the air quality becomes. During this time, the air in lower elevations is actually colder than the air in the mountains because the inversion traps the cold air down low.
Utah’s Division of Air Quality monitors the quality of the air. For the past two decades, the division has labeled the air quality through a simple three-color guide: red (unhealthy), Yellow (moderately unhealthy), and green (healthy). When the state’s Division of Air Quality declares the air quality “unhealthy,” there are several restrictions that come into play. Residents are required to shut down any wood-burning stoves and are encouraged to drive less in order to decrease smog output. It is also advised to avoid outdoor exercise or activities. The restrictions and advisements are in place to help reduce the health risks that can occur when you are exposed to unhealthy air.
In January 2013, the Division of Air Quality released a new six-color guide to determine Utah’s air quality. Under this new code, green is healthy, yellow is moderate, orange is unhealthy for sensitive people, red is unhealthy, purple is very unhealthy, and brown is hazardous. It is hoped that the new system will help reduce inversion by providing a warning system that encourages the reduction of polluting activities earlier. You can check the daily air quality online or listen for updates on TV and radio weather reports.