SmogRank / United States / Maryland / Rockville
Rockville, month by month
Rockville has a measured daily mean on 1,295 days since 1 January 2023. Its worst month was June 2023, at 65 US AQI (16.4 µg/m³), 348th of 1,603 cities on that month's world ranking. Its cleanest was September 2026, at 13 US AQI (2.4 µg/m³). 2025 averaged 33 US AQI (5.9 µg/m³), against 33 US AQI (6.0 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
Rockville's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| June 2023 | 6516.4 µg/m³ | 348thof 1,603 | Eastern United States and Canada, June and July 2023 Eastern United States and Canada, May and June 2023 |
| July 2026 | 5913.4 µg/m³ | 669thof 2,784 | Northern United States and Canada, July 2026 |
| February 2026 | 488.6 µg/m³ | 1,795thof 2,866 | – |
| July 2024 | 478.5 µg/m³ | 1,174thof 2,566 | – |
| August 2024 | 468.3 µg/m³ | 1,135thof 2,010 | – |
| January 2025 | 458.1 µg/m³ | 1,379thof 2,474 | – |
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.
Rockville's worst days
| Day | US AQI | Episode |
|---|---|---|
| 17 Jul 2026 | 191113.0 µg/m³ | Northern United States and Canada, July 2026 |
| 29 Jun 2023 | 16474.7 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 8 Jun 2023 | 16372.8 µg/m³ | Eastern United States and Canada, May and June 2023 |
| 7 Jun 2023 | 15256.5 µg/m³ | Eastern United States and Canada, May and June 2023 |
| 18 Jul 2026 | 12344.5 µg/m³ | Northern United States and Canada, July 2026 |
| 30 Jun 2023 | 9834.2 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 28 Jun 2023 | 9130.7 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 17 Jul 2023 | 8024.5 µg/m³ | – |
| 1 Jul 2023 | 8024.4 µg/m³ | Eastern United States and Canada, June and July 2023 |
| 2 Jul 2026 | 7924.0 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, Rockville, 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/rockville/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.
Rockville now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 22:07 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).