Smoggy skies in the valley, what we can expect for air quality this week
Nov 27, 2023, 11:01 AM
SALT LAKE CITY — Utahns along the Wasatch Front were greeted on their Monday morning commute with thick smog.
According to a tweet from the National Weather Service in Salt Lake City, building pressure and accumulating pollutants have created an inversion in the valley.
An inversion is when the air is colder near the ground, and clear skies begin to warm up the upper atmosphere. When a high-pressure system moves in, that warmer air sinks and acts as a lid over the valley bowl. The Utah Department of Environmental Quality explains, “The longer a high-pressure system lasts, the longer and stronger the inversion.”
So what can we expect this week?
NWS expects the air quality will continue to decrease as more pollutants gather in the valleys of northern Utah along with reduced visibility and areas of low clouds. This should last through at least the middle of the week.
⚠Building high pressure will create the conditions necessary for inversions to occur. This will allow pollutants to accumulate, reducing air quality. A storm system that will impact Utah toward the end of the week may improve the conditions and clear out the inversions. #utwx pic.twitter.com/swx7KSZjzl
— NWS Salt Lake City (@NWSSaltLakeCity) November 26, 2023
A storm system is expected to move in towards the end of the week, but it’s not clear yet how strong this system will be and how much of the inversion it will push out.
Health forecast and action forecast
The Utah Department of Environmental Quality releases a three-day forecast for air quality including a health forecast and action forecast.
The health forecast is based on the Air Quality Index shown below and helps determine how the pollution of the day will impact the public’s health.
As of Monday, the first three days of the week were ranked as a moderate health risk, meaning it’s only unhealthy for extremely sensitive groups.
The full guide for the health forecast can be found here.
The action forecast outlines “voluntary or mandatory actions (e.g., carpooling, wood burning) they need to adhere to for the current pollution levels.”
Monday’s mandatory actions include:
- no use of solid fuel-burning devices
- no open burning
According to a Salt Lake County Health regulation, you may not burn solid fuel in fireplaces, wood wood-burning stoves on days that the State of Utah designates as mandatory or voluntary air action days. (also called no burn days.)
The regulation also prohibits outdoor fires including bonfires, patio pits, and charcoal grill fires on no-burn days.