SmogRank / United States / California / Richmond
Richmond, month by month
Richmond, California has a measured daily mean on 1,064 days since 1 January 2023. Its worst month was September 2023, at 61 US AQI (14.6 µg/m³), 187th of 2,176 cities on that month's world ranking. Its cleanest was July 2025, at 31 US AQI (5.5 µg/m³). 2025 averaged 48 US AQI (8.6 µg/m³), against 53 US AQI (10.0 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
10 months
| Month | Why |
|---|---|
| Oct 2026 | 6 of 11 days measured; a month needs 8. The others: 2 with no readings from the monitor, 3 with readings for part of the day (a day needs 18 hours). |
| May 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Apr 2026 | 6 of 30 days measured; a month needs 21. The others: 24 with under 18 hours of readings or readings that failed our checks. |
| May 2025 | 13 of 31 days measured; a month needs 22. The others: 18 with under 18 hours of readings or readings that failed our checks. |
| Mar 2025 | 15 of 31 days measured; a month needs 22. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| Feb 2025 | No day measured. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Jan 2025 | 10 of 31 days measured; a month needs 22. The others: 21 with under 18 hours of readings or readings that failed our checks. |
| May 2024 | 4 of 31 days measured; a month needs 22. The others: 27 with under 18 hours of readings or readings that failed our checks. |
| Apr 2024 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | No day measured. The others: 1 missing from OpenAQ's archive, 30 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.
Richmond's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| September 2023 | 6114.6 µg/m³ | 187thof 2,176 | California and Oregon, United States, September 2023 |
| June 2024 | 6013.7 µg/m³ | 251stof 2,563 | – |
| December 2024 | 5712.5 µg/m³ | 629thof 2,616 | California and Oregon, United States, December 2024 |
| May 2023 | 5611.7 µg/m³ | 287thof 1,600 | – |
| August 2023 | 5511.5 µg/m³ | 393rdof 1,980 | – |
| July 2024 | 5511.2 µg/m³ | 540thof 2,566 | – |
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.
Richmond's worst days
| Day | US AQI | Episode |
|---|---|---|
| 20 Sept 2023 | 11340.3 µg/m³ | California and Oregon, United States, September 2023 |
| 21 Sept 2023 | 10336.2 µg/m³ | California and Oregon, United States, September 2023 |
| 22 Sept 2023 | 10235.9 µg/m³ | California and Oregon, United States, September 2023 |
| 7 Dec 2024 | 9432.3 µg/m³ | California and Oregon, United States, December 2024 |
| 19 Sept 2023 | 8829.0 µg/m³ | California and Oregon, United States, September 2023 |
| 8 Dec 2024 | 8125.1 µg/m³ | California and Oregon, United States, December 2024 |
| 23 Sept 2023 | 8125.0 µg/m³ | California and Oregon, United States, September 2023 |
| 30 Aug 2023 | 8024.7 µg/m³ | – |
| 23 May 2023 | 7823.8 µg/m³ | – |
| 6 Jun 2024 | 7823.4 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, Richmond, California, 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/richmond-california/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.
Richmond now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-13 02:07 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).