SmogRank / United States / Utah / Herriman
Herriman, month by month
Herriman has a measured daily mean on 1,353 days since 1 January 2023. Its worst month was July 2024, at 55 US AQI (11.1 µg/m³), 550th of 2,566 cities on that month's world ranking. Its cleanest was February 2024, at 13 US AQI (2.4 µg/m³). 2025 averaged 32 US AQI (5.7 µg/m³), against 32 US AQI (5.8 µg/m³) in 2024.
Every month since 2023
The US EPA's Air Quality Index for PM2.5 (2024 breakpoints). Show values as: µg/m³ · US AQI · India AQI · China AQI · European AQI · UK DAQI · Canada AQHI+. About the scales
Herriman's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2024 | 5511.1 µg/m³ | 550thof 2,566 | North-western United States and Canada, July 2024 |
| June 2026 | 519.1 µg/m³ | 790thof 2,497 | Utah and Colorado, United States, June 2026 |
| August 2026 | 498.8 µg/m³ | 1,258thof 2,896 | – |
| February 2023 | 468.2 µg/m³ | 803rdof 1,129 | Utah and Idaho, United States, February 2023 |
| August 2025 | 468.2 µg/m³ | 1,750thof 2,901 | – |
| July 2023 | 458.1 µg/m³ | 845thof 1,432 | – |
Monthly means over the days measured; finished months only. World rank: its place on that month's world ranking of every city with enough days. Each month opens that ranking.
Herriman's worst days
| Day | US AQI | Episode |
|---|---|---|
| 11 Sept 2024 | 10537.2 µg/m³ | North-western United States and Canada, 4 to 11 September 2024 |
| 23 Jun 2026 | 9834.4 µg/m³ | Utah and Colorado, United States, June 2026 |
| 30 Nov 2023 | 9231.0 µg/m³ | Utah and Idaho, United States, November 2023 |
| 30 Aug 2023 | 8829.0 µg/m³ | – |
| 29 Nov 2023 | 8728.3 µg/m³ | Utah and Idaho, United States, November 2023 |
| 4 Feb 2023 | 8627.9 µg/m³ | Utah and Idaho, United States, February 2023 |
| 31 Jul 2024 | 8527.1 µg/m³ | North-western United States and Canada, July 2024 |
| 24 Jun 2026 | 8225.7 µg/m³ | Utah and Colorado, United States, June 2026 |
| 28 Mar 2025 | 8125.0 µg/m³ | – |
| 8 Aug 2024 | 8024.5 µg/m³ | – |
Daily means, the highest since 1 Jan 2023; the WHO's daily guideline is 15 µg/m³. Each date opens that day's world ranking, and each episode the bad-air spell it was part of.
Use this history
SmogRank, PM2.5 monthly and daily means, Herriman, United States, 1 Jan 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/herriman/history (accessed 12 Oct 2026).
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms. Raw monitor readings in bulk are published by OpenAQ, under each provider's licence.
Herriman now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 20:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index. Some low-cost readings: Sensor.Community, ODbL (data and licence). Some readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); RMCAB (Secretaría Distrital de Ambiente, Bogotá); Love My Air (City and County of Denver), no reuse terms published (why we use them).