SmogRank / United States / Arkansas / Marion
Marion, month by month
Marion has a measured daily mean on 1,150 days since 1 January 2023. Its worst month was August 2024, at 64 US AQI (16.0 µg/m³), 152nd of 2,010 cities on that month's world ranking. Its cleanest was January 2024, at 36 US AQI (6.4 µg/m³). 2024 averaged 52 US AQI (9.4 µg/m³), against 52 US AQI (9.7 µg/m³) in 2023.
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
Months without a mean, and why
7 months
| Month | Why |
|---|---|
| May 2025 | 2 of 31 days measured; a month needs 22. The others: 29 with under 18 hours of readings or readings that failed our checks. |
| Apr 2025 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | 8 of 28 days measured; a month needs 20. The others: 20 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 1 with under 18 hours of readings or readings that failed our checks. |
| Jan 2023 | 2 of 31 days measured; a month needs 22. The others: 7 missing from OpenAQ's archive, 22 with under 18 hours of readings or readings that failed our checks. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Marion's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2024 | 6416.0 µg/m³ | 152ndof 2,010 | Southern and eastern United States and Mexico, July and August 2024 |
| July 2025 | 6315.7 µg/m³ | 354thof 2,889 | North-eastern United States, July 2025 |
| June 2023 | 6114.7 µg/m³ | 395thof 1,603 | – |
| October 2024 | 5913.5 µg/m³ | 316thof 2,020 | – |
| September 2025 | 5812.7 µg/m³ | 421stof 3,104 | – |
| July 2026 | 5812.7 µg/m³ | 775thof 2,784 | – |
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.
Marion's worst days
| Day | US AQI | Episode |
|---|---|---|
| 1 Aug 2024 | 12846.6 µg/m³ | Southern and eastern United States and Mexico, July and August 2024 |
| 5 Jul 2025 | 12645.6 µg/m³ | North-eastern United States, July 2025 |
| 28 Jul 2023 | 9532.9 µg/m³ | – |
| 23 Jul 2025 | 9432.1 µg/m³ | – |
| 22 Jul 2025 | 9230.9 µg/m³ | – |
| 23 Sept 2024 | 9029.8 µg/m³ | – |
| 2 Aug 2024 | 8426.7 µg/m³ | Southern and eastern United States and Mexico, July and August 2024 |
| 4 Oct 2023 | 8326.5 µg/m³ | South-eastern United States, October 2023 |
| 23 Oct 2024 | 8225.9 µg/m³ | – |
| 28 Aug 2024 | 8225.5 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, Marion, 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/marion-arkansas/history (accessed 13 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.
Marion now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 04:07 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).