SmogRank / Episodes / United States

Utah, United States, June 2026

For 2 days, from 23 to 24 June 2026, 9 cities in the United States had PM2.5 at least twice their usual for the time of year. The worst reading was Herriman, Utah, United States: 34.4 µg/m³ on 23 June, about 5.0× its usual 6.9.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 1 country
Days223 to 24 June 2026
Worst day23 June7 cities counted
Furthest above usual6.7×Grand Junction

Day by day

23 June 7 cities at twice their usual or more
HighlandRock SpringsMagnaTooeleNorth OgdenBrigham CityLoganCedar CityLaramieBoulderGoldenLongmontKen CarylArvadaLakewoodFort CollinsWestminsterCañon CityNorthglennDenverThorntonSpanish ForkMillcreekOremWest Valley CityWest JordanSalt Lake CityBountifulHerrimanGrand Junction
20 Jun21222324252627
Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.

How it spread

HerrimanHerriman, 20 June: 17.2 µg/m³, 2.5× usualHerriman, 21 June: 6.9 µg/m³, 1.0× usualHerriman, 22 June: 20.5 µg/m³, 3.0× usualHerriman, 23 June: 34.4 µg/m³, 5.0× usualHerriman, 24 June: 25.7 µg/m³, 3.7× usualHerriman, 25 June: 10.1 µg/m³, 1.5× usualHerriman, 26 June: 12.7 µg/m³, 1.8× usualHerriman, 27 June: 11.2 µg/m³, 1.6× usualMillcreekMillcreek, 20 June: 12.5 µg/m³, 1.3× usualMillcreek, 21 June: 8.9 µg/m³, 0.9× usualMillcreek, 22 June: 21.1 µg/m³, 2.2× usualMillcreek, 23 June: 32.1 µg/m³, 3.3× usualMillcreek, 24 June: 30.4 µg/m³, 3.1× usualMillcreek, 25 June: 7.4 µg/m³, 0.8× usualMillcreek, 26 June: 6.8 µg/m³, 0.7× usualMillcreek, 27 June: 7.9 µg/m³, 0.8× usualWest JordanWest Jordan, 20 June: 10.8 µg/m³, 1.3× usualWest Jordan, 21 June: 9.8 µg/m³, 1.2× usualWest Jordan, 22 June: 19.1 µg/m³, 2.4× usualWest Jordan, 23 June: 30.8 µg/m³, 3.8× usualWest Jordan, 24 June: 23.7 µg/m³, 2.9× usualWest Jordan, 25 June: 14.4 µg/m³, 1.8× usualWest Jordan, 26 June: 14.9 µg/m³, 1.8× usualWest Jordan, 27 June: 9.3 µg/m³, 1.1× usualOremOrem, 20 June: 12.9 µg/m³, 1.6× usualOrem, 21 June: 6.6 µg/m³, 0.8× usualOrem, 22 June: 18.7 µg/m³, 2.3× usualOrem, 23 June: 29.9 µg/m³, 3.6× usualOrem, 24 June: 20.4 µg/m³, 2.5× usualOrem, 25 June: 7.6 µg/m³, 0.9× usualOrem, 26 June: 9.8 µg/m³, 1.2× usualOrem, 27 June: 7.6 µg/m³, 0.9× usualSpanish ForkSpanish Fork, 20 June: 16.2 µg/m³, 2.0× usualSpanish Fork, 21 June: 6.7 µg/m³, 0.8× usualSpanish Fork, 22 June: 18.7 µg/m³, 2.3× usualSpanish Fork, 23 June: 26.9 µg/m³, 3.3× usualSpanish Fork, 24 June: 24.3 µg/m³, 3.0× usualSpanish Fork, 25 June: 13.0 µg/m³, 1.6× usualSpanish Fork, 26 June: 13.6 µg/m³, 1.7× usualSpanish Fork, 27 June: 8.9 µg/m³, 1.1× usualSalt Lake CitySalt Lake City, 20 June: 11.8 µg/m³, 1.6× usualSalt Lake City, 21 June: 10.7 µg/m³, 1.4× usualSalt Lake City, 22 June: 16.0 µg/m³, 2.2× usualSalt Lake City, 23 June: 25.6 µg/m³, 3.5× usualSalt Lake City, 24 June: 29.8 µg/m³, 4.0× usualSalt Lake City, 25 June: 8.6 µg/m³, 1.2× usualSalt Lake City, 26 June: 6.7 µg/m³, 0.9× usualSalt Lake City, 27 June: 7.5 µg/m³, 1.0× usualWest Valley CityWest Valley City, 20 June: 14.8 µg/m³, 2.0× usualWest Valley City, 21 June: 5.6 µg/m³, 0.8× usualWest Valley City, 22 June: 17.2 µg/m³, 2.3× usualWest Valley City, 23 June: 25.2 µg/m³, 3.4× usualWest Valley City, 24 June: 27.7 µg/m³, 3.7× usualWest Valley City, 25 June: 9.9 µg/m³, 1.3× usualWest Valley City, 26 June: 7.6 µg/m³, 1.0× usualWest Valley City, 27 June: 6.1 µg/m³, 0.8× usualGrand JunctionGrand Junction, 20 June: 3.3 µg/m³, 0.7× usualGrand Junction, 21 June: 6.8 µg/m³, 1.4× usualGrand Junction, 22 June: 6.2 µg/m³, 1.2× usualGrand Junction, 23 June: 18.5 µg/m³, 3.7× usualGrand Junction, 24 June: 33.7 µg/m³, 6.7× usualGrand Junction, 25 June: 7.1 µg/m³, 1.4× usualGrand Junction, 26 June: 3.3 µg/m³, 0.7× usualGrand Junction, 27 June: 3.3 µg/m³, 0.7× usualBountifulBountiful, 20 June: 12.6 µg/m³, 1.8× usualBountiful, 21 June: 5.4 µg/m³, 0.8× usualBountiful, 22 June: 15.3 µg/m³, 2.2× usualBountiful, 23 June: 22.2 µg/m³, 3.2× usualBountiful, 24 June: 30.4 µg/m³, 4.3× usualBountiful, 25 June: 9.2 µg/m³, 1.3× usualBountiful, 26 June: 7.5 µg/m³, 1.1× usualBountiful, 27 June: 6.9 µg/m³, 1.0× usual20 Jun21222324252627
Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
Grand JunctionColorado, United States1 33.724 June3.56.7×
HerrimanUtah, United States2 34.423 June6.95.0×
BountifulUtah, United States1 30.424 June7.04.3×
Salt Lake CityUtah, United States2 29.824 June7.44.0×
West JordanUtah, United States1 30.823 June8.13.8×
West Valley CityUtah, United States2 27.724 June7.43.7×
OremUtah, United States1 29.923 June8.33.6×
Spanish ForkUtah, United States1 26.923 June8.13.3×
MillcreekUtah, United States2 32.123 June9.73.3×

Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.

Against other episodes in the United States

Number 72 of 98 episodes in the United States since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 98.

Use this page

SmogRank, Utah, United States, June 2026: 9 cities with PM2.5 at twice their usual or more, 23 to 24 June 2026, smogrank.com/episodes/2026-06-utah-united-states (accessed 2 October 2026).

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You're welcome to reuse a single chart, image or figure with this citation and a link. Terms.

An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes. Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.