SmogRank / Brighton / Thornton
Brighton vs Thornton: PM2.5 compared
Over the last year, Brighton and Thornton had about the same air: PM2.5 averaged 5.9 and 5.8 µg/m³, on the 161 days both cities were measured. Brighton had the dirtier air on 85 of those days, Thornton on 72. Brighton was over the WHO's daily guideline of 15 µg/m³ on 1 of them, Thornton on 2.
Right now
The last year, day by day
Month by month
Year by year
| Year | Brighton | Thornton | Days Brighton was worse |
|---|---|---|---|
| 2026 so far | 32 | 31 | 62 |
| 2025 | 43 | 43 | 104 |
| 2024 | 41 | 43 | 60 |
Means in US AQI over the days both cities were measured that year; a year shows once they share 30 such days.
Each city's worst days
Brighton
- 1 Jul 20266215.1 µg/m³
- 28 Jun 20265913.4 µg/m³
- 20 Jan 20265813.0 µg/m³
Thornton
- 1 Jul 20267019.4 µg/m³
- 28 Jun 20266617.0 µg/m³
- 28 Nov 20255812.8 µg/m³
Daily means in US AQI, with µg/m³ beside them, since the index stops at its top value, over the days both cities were measured in the last year. Each date opens that day's world board.
Compare either city with another
Brighton
Side by side with Mecca (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Thornton
Side by side with Commerce City (the nearest), Mecca (United States's worst on 30 days), Gujranwala (the world's worst on 30 days).
Use this page
SmogRank, PM2.5 daily means compared, Brighton and Thornton, 8 Oct 2025 – 7 Oct 2026, smogrank.com/compare/us-brighton-colorado/us-thornton (accessed 8 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.
The same rules as every SmogRank figure: reference monitors first, and a day counts with 18 measured hours. How we measure.
Updated 2026-10-08 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 readings: Uzhydromet (Uzbekistan's Hydrometeorological Service); Department of Environment, Nepal; Vietnam's government monitors; Aurassure; Umhverfisstofnun (Environment Agency of Iceland); Love My Air (City and County of Denver), no reuse terms published (why we use them).