Inversions and pollution: what’s the difference?

Dec 4, 2023, 12:11 PM | Updated: 1:37 pm

air quality...

FILE -- With the Wasatch Mountains to the left, a layer of haze and smog covers the Salt Lake Valley on Wednesday, Dec. 13, 2017. (Stuart Johnson/Deseret News)

(Stuart Johnson/Deseret News)

SALT LAKE CITY — According to the Utah Department of Air Quality, the average Utah winter brings about five to six multi-day inversions. 

Similar to pollution, inversions can lead to unhealthy air quality. Chronic exposure can lead to diseases such as stroke, ischaemic heart disease, and lung cancer, according to the World Health Organization

Air pollution is defined by the World Health Organization as contamination of the air by “any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere.” 

Inversions and pollution

An inversion, on the other hand, is a phenomenon that can trap pollution close to the valley floor. The Utah Division of Air Quality said that “surface temperature inversions play a major role in air quality, especially during the winter.”

KSL Meteorologist Matt Johnson said that “inversions have existed since the beginning of time.” He added that “inversion[s] trap pollution. Pollution does not cause inversion.” 

According to the DEQ, warmer air normally sits closer to the ground. But when an inversion happens colder air gets trapped closer to the ground. 

When that happens, pollutants are also trapped closer to the valley floor. Pollutants can be vehicle or factory emissions, or other compounds such as sulfur dioxide and lead, according to the DEQ

They cause that thick fog that appears to erase the mountains. 

The science behind reversed air temperatures

According to the DEQ, air temperatures get reversed for a few different reasons. First, longer winter nights allow the ground more time to cool. The longer cooling period results in a lower surface temperature. The lower position of the sun also impacts the cool temperatures. 

Second, calm winter winds reduce the mixing of cold and warm air. When cold and warm air aren’t mixed, pollutants aren’t dispersed

The DEQ said that it is common for Utah to see inversions following snowstorms. Additionally, mountains can make inversions stronger. The Wasatch and Oquirrh mountains, as well as Traverse Mountain, all form a basin that traps cold air. According to the DEQ, the basin formed by the mountains shields it from wind that might otherwise clear inversions out of the Salt Lake Valley. 


We want to hear from you.

Have a story idea or tip? Send it to the KSL NewsRadio team here.


school bus is snowy, cache county school district apologized for not having a snow day...

Jessica Lowell

Cache County School District apologizes for not holding a snow day

The Cache County School District decided to hold a regular school day on Tuesday despite weather conditions. 

1 day ago

Motorists drive in the rain in Millcreek on Wednesday, Feb. 7, 2024....

Adam Small

Utah expected to get more rain and snow this week

An atmospheric river making its way to Utah will bring rain to the valley and snow to the mountains throughout this week.

3 days ago

three skiers on lift shown, snow in utah expected today...

Peter Johnston

Skiers rejoice! A foot of snow is coming to the northern Wasatch Mountains

Brighton, Park City and Solitude will see more than a foot of snow drop today, according to Ski Utah.

6 days ago

Motorists drive in the rain in Millcreek on Feb. 7. Mountain snow and valley rain are back in Utah'...

Carter Williams

Advisory issued as rain and snow return to Utah

The advisory states that some high-elevation locations may end up with another foot of snow or more over the next few days.

8 days ago


Adam Small

Avalanche conditions remain considerably dangerous in some areas

According to the Utah Avalanche Center, the danger for people to trigger avalanches is 'considerable' in the mountains from Salt Lake to Provo, and in the Uintahs.

11 days ago

Vehicles in Big Cottonwood Canyon Jan. 15, While utah snow levels have gone down in February, rain ...

Tammy Kikuchi

Utah’s February snow levels are below normal, but it’s no cause for concern

While Utah snow levels have been low early on in February, the extreme amount of rain has been making up the majority of the snowfall.

13 days ago

Sponsored Articles

Mother and cute toddler child in a little fancy wooden cottage, reading a book, drinking tea and en...

Visit Bear Lake

How to find the best winter lodging in Bear Lake, Utah

Winter lodging in Bear Lake can be more limited than in the summer, but with some careful planning you can easily book your next winter trip.

Happy family in winter clothing at the ski resort, winter time, watching at mountains in front of t...

Visit Bear Lake

Ski more for less: Affordable ski resorts near Bear Lake, Utah

Plan your perfect ski getaway in Bear Lake this winter, with pristine slopes, affordable tickets, and breathtaking scenery.

front of the Butch Cassidy museum with a man in a cowboy hat standing in the doorway...

Bear Lake Convention and Visitors Bureau

Looking Back: The History of Bear Lake

The history of Bear Lake is full of fascinating stories. At over 250,000 years old, the lake has seen generations of people visit its shores.

silhouette of a family looking over a lake with a bird in the top corner flying...

Bear Lake Convention and Visitors Bureau

8 Fun Activities To Do in Bear Lake Without Getting in the Water

Bear Lake offers plenty of activities for the whole family to enjoy without having to get in the water. Catch 8 of our favorite activities.

Wellsville Mountains in the spring with a pond in the foreground...

Wasatch Property Management

Advantages of Renting Over Owning a Home

Renting allows you to enjoy luxury amenities and low maintenance without the long-term commitment and responsibilities of owning a home.

Clouds over a red rock vista in Hurricane, Utah...

Wasatch Property Management

Why Southern Utah is a Retirement Paradise

Retirement in southern Utah offers plenty of cultural and recreational opportunities. Find out all that this region has to offer.

Inversions and pollution: what’s the difference?