SmogRank / Brazil / Rio de Janeiro / Duque de Caxias
Duque de Caxias, month by month
Duque de Caxias has a measured daily mean on 740 days since 25 August 2023. Its worst month was June 2026, at 68 US AQI (18.3 µg/m³), 269th of 2,497 cities on that month's world ranking. Its cleanest was March 2025, at 33 US AQI (6.0 µg/m³).
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
17 months
| Month | Why |
|---|---|
| Nov 2025 | No day measured. The others: 30 with no readings from the monitors. |
| Oct 2025 | 13 of 31 days measured; a month needs 22. The others: 10 with no readings from the monitors, 8 with readings for part of the day (a day needs 18 hours). |
| Jun 2025 | 11 of 30 days measured; a month needs 21. The others: 12 with no readings from the monitors, 7 with readings for part of the day (a day needs 18 hours). |
| May 2025 | 20 of 31 days measured; a month needs 22. The others: 3 with no readings from the monitors, 8 with readings for part of the day (a day needs 18 hours). |
| Apr 2025 | 18 of 30 days measured; a month needs 21. The others: 2 with no readings from the monitors, 9 with readings for part of the day (a day needs 18 hours), 1 with readings left out by our checks. |
| Dec 2024 | No day measured. The others: 31 with readings for part of the day (a day needs 18 hours). |
| Nov 2024 | 2 of 30 days measured; a month needs 21. The others: 1 with no readings from the monitors, 27 with readings for part of the day (a day needs 18 hours). |
| Oct 2024 | 8 of 31 days measured; a month needs 22. The others: 23 with readings for part of the day (a day needs 18 hours). |
| Sep 2024 | 4 of 30 days measured; a month needs 21. The others: 26 with readings for part of the day (a day needs 18 hours). |
| Aug 2024 | 3 of 31 days measured; a month needs 22. The others: 28 with readings for part of the day (a day needs 18 hours). |
| Jul 2024 | 4 of 31 days measured; a month needs 22. The others: 27 with readings for part of the day (a day needs 18 hours). |
| Jun 2024 | 7 of 30 days measured; a month needs 21. The others: 23 with readings for part of the day (a day needs 18 hours). |
| May 2024 | 5 of 31 days measured; a month needs 22. The others: 3 with no readings from the monitors, 23 with readings for part of the day (a day needs 18 hours). |
| Apr 2024 | 7 of 30 days measured; a month needs 21. The others: 23 with readings for part of the day (a day needs 18 hours). |
| Mar 2024 | 10 of 31 days measured; a month needs 22. The others: 5 with no readings from the monitors, 16 with readings for part of the day (a day needs 18 hours). |
| Oct 2023 | 17 of 31 days measured; a month needs 22. The others: 14 with readings for part of the day (a day needs 18 hours). |
| Aug 2023 | 7 of 31 days measured; a month needs 22. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Duque de Caxias's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| June 2026 | 6818.3 µg/m³ | 269thof 2,497 | Rio de Janeiro and São Paulo, Brazil, June 2026 |
| July 2026 | 6315.7 µg/m³ | 480thof 2,784 | – |
| August 2026 | 6214.9 µg/m³ | 390thof 2,896 | – |
| July 2025 | 6013.8 µg/m³ | 521stof 2,889 | Southern Brazil, July 2025 |
| May 2026 | 5511.5 µg/m³ | 613thof 2,874 | São Paulo and Rio de Janeiro, Brazil, May 2026 |
| December 2023 | 5511.4 µg/m³ | 483rdof 2,247 | – |
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.
Duque de Caxias's worst days
| Day | US AQI | Episode |
|---|---|---|
| 17 Aug 2024 | 11440.9 µg/m³ | Southern Brazil, 15 to 22 August 2024 |
| 24 Sept 2023 | 11340.5 µg/m³ | – |
| 11 Jun 2026 | 11139.4 µg/m³ | Rio de Janeiro and São Paulo, Brazil, June 2026 |
| 17 Jul 2025 | 10838.2 µg/m³ | Southern Brazil, July 2025 |
| 3 Jul 2026 | 10637.5 µg/m³ | – |
| 9 Jun 2026 | 10537.3 µg/m³ | Rio de Janeiro and São Paulo, Brazil, June 2026 |
| 2 Jul 2026 | 10436.6 µg/m³ | – |
| 4 Aug 2026 | 10336.4 µg/m³ | – |
| 21 Aug 2026 | 10336.4 µg/m³ | – |
| 27 Jun 2026 | 10336.2 µg/m³ | – |
Daily means, the highest since 25 Aug 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, Duque de Caxias, Brazil, 25 Aug 2023 – 11 Oct 2026. Monitor data from Rio City Hall via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/br/duque-de-caxias/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.
Duque de Caxias 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).