You might feel like holding your breath the next few days! Unfortunately, a prolonged inversion is expected to last until later this week.
During an inversion, cold air is trapped in the valleys by a layer of warmer air above it. Pollution will continue to build in that cold air and result poor air quality as well as increasing valley haze. Overnight fog will become increasingly likely as well especially near bodies of water like the Great Salt Lake.
Air quality will get worse until a storm approaches and either brings cold air or enough wind to break up the inversion. A storm brushing by Friday might bring relief.
SALT LAKE CITY
Monday: Sunny with increasing valley haze. Highs: Near 40.
Monday Night: Partly cloudy, cold, & hazy. Lows: Mid 20s.
ST. GEORGE
Monday: Sunny. Highs: Mid 50s.
Monday Night: Clear & cold. Lows: Lower 30s.