SmogRank / United States / Virginia / Ashburn
Ashburn, month by month
Ashburn has a measured daily mean on 1,026 days since 1 December 2023. Its worst month was July 2026, at 66 US AQI (17.3 µg/m³), 412th of 2,784 cities on that month's world ranking. Its cleanest was October 2025, at 27 US AQI (4.9 µg/m³). 2025 averaged 38 US AQI (6.8 µg/m³), against 41 US AQI (7.3 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
Ashburn's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| July 2026 | 6617.3 µg/m³ | 412thof 2,784 | Northern United States and Canada, July 2026 |
| June 2025 | 529.8 µg/m³ | 1,357thof 2,508 | – |
| July 2025 | 529.7 µg/m³ | 1,338thof 2,889 | North-eastern United States, July 2025 |
| February 2026 | 529.5 µg/m³ | 1,532ndof 2,866 | – |
| December 2023 | 519.2 µg/m³ | 894thof 2,247 | – |
| August 2024 | 519.2 µg/m³ | 804thof 2,010 | – |
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.
Ashburn's worst days
| Day | US AQI | Episode |
|---|---|---|
| 17 Jul 2026 | 247172.0 µg/m³ | Northern United States and Canada, July 2026 |
| 18 Jul 2026 | 15662.8 µg/m³ | Northern United States and Canada, July 2026 |
| 4 Jul 2025 | 10336.5 µg/m³ | North-eastern United States, July 2025 |
| 5 Jul 2025 | 10035.2 µg/m³ | North-eastern United States, July 2025 |
| 7 Aug 2025 | 7923.9 µg/m³ | – |
| 18 Feb 2026 | 7823.6 µg/m³ | – |
| 5 Mar 2026 | 7723.2 µg/m³ | – |
| 19 Jul 2026 | 7522.2 µg/m³ | Northern United States and Canada, July 2026 |
| 24 Jan 2024 | 7522.0 µg/m³ | – |
| 13 Jun 2025 | 7522.0 µg/m³ | – |
Daily means, the highest since 1 Dec 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, Ashburn, United States, 1 Dec 2023 – 11 Oct 2026. Monitor data from AirNow, via OpenAQ and from the publisher directly; sources listed at smogrank.com/sources. smogrank.com/us/ashburn/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.
Ashburn 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).