SmogRank / Brazil / São Paulo / Santos
Santos, month by month
Santos has a measured daily mean on 1,222 days since 1 January 2023. Its worst month was August 2024, at 68 US AQI (18.2 µg/m³), 118th of 2,010 cities on that month's world ranking. Its cleanest was October 2023, at 47 US AQI (8.4 µg/m³). 2025 averaged 55 US AQI (11.1 µg/m³), against 58 US AQI (13.0 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
Months without a mean, and why
7 months
| Month | Why |
|---|---|
| Oct 2026 | No day measured. The others: 11 with no readings from the monitor. |
| Sep 2026 | No day measured. The others: 30 with no readings from the monitor. |
| Aug 2026 | No day measured. The others: 31 with no readings from the monitor. |
| Jul 2026 | 19 of 31 days measured; a month needs 22. The others: 11 with no readings from the monitor, 1 with readings for part of the day (a day needs 18 hours). |
| Mar 2023 | 11 of 31 days measured; a month needs 22. The others: 20 missing from OpenAQ's archive. |
| Feb 2023 | 3 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive. |
| Jan 2023 | 20 of 31 days measured; a month needs 22. The others: 3 with no readings from the monitor, 2 with readings for part of the day (a day needs 18 hours), 6 missing from OpenAQ's archive. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Santos's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| August 2024 | 6818.2 µg/m³ | 118thof 2,010 | Southern Brazil, 30 August to 5 September 2024 Southern Brazil, 22 to 25 August 2024and 1 more |
| June 2024 | 6717.7 µg/m³ | 126thof 2,563 | Southern Brazil, 11 to 13 June 2024 |
| June 2023 | 6617.1 µg/m³ | 333rdof 1,603 | – |
| September 2024 | 6416.3 µg/m³ | 141stof 2,010 | Southern Brazil, 7 to 17 September 2024 Southern Brazil, 30 August to 5 September 2024 |
| December 2023 | 6114.6 µg/m³ | 295thof 2,247 | – |
| July 2023 | 6114.4 µg/m³ | 174thof 1,432 | – |
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.
Santos's worst days
| Day | US AQI | Episode |
|---|---|---|
| 25 Jun 2023 | 11943.0 µg/m³ | – |
| 19 Aug 2024 | 11440.7 µg/m³ | Southern Brazil, 15 to 22 August 2024 |
| 12 Sept 2024 | 11240.1 µg/m³ | Southern Brazil, 7 to 17 September 2024 |
| 11 Sept 2024 | 11239.9 µg/m³ | Southern Brazil, 7 to 17 September 2024 |
| 26 Jul 2024 | 9934.8 µg/m³ | Southern Brazil, 25 to 28 July 2024 |
| 22 Aug 2024 | 9733.8 µg/m³ | Southern Brazil, 22 to 25 August 2024 Southern Brazil, 15 to 22 August 2024 |
| 19 Jul 2026 | 9432.2 µg/m³ | – |
| 16 Aug 2024 | 9432.1 µg/m³ | Southern Brazil, 15 to 22 August 2024 |
| 7 Aug 2023 | 9231.3 µg/m³ | – |
| 28 Jul 2024 | 9231.1 µg/m³ | Southern Brazil, 25 to 28 July 2024 |
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, Santos, Brazil, 1 Jan 2023 – 19 Jul 2026. Monitor data from CETESB, read from the publisher; sources listed at smogrank.com/sources. smogrank.com/br/santos/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.
Santos 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).