SmogRank / Thailand / Bangkok / Bangkok
Bangkok, month by month
Bangkok has a measured daily mean on 1,177 days since 1 January 2023. Its worst month was January 2025, at 124 US AQI (45.0 µg/m³), 42nd of 2,474 cities on that month's world ranking. Its cleanest was August 2026, at 55 US AQI (11.4 µg/m³). 2025 averaged 80 US AQI (24.8 µg/m³), against 77 US AQI (23.2 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 |
|---|---|
| Jul 2026 | 3 of 31 days measured; a month needs 22. The others: 28 with under 18 hours of readings or readings that failed our checks. |
| Nov 2025 | 12 of 30 days measured; a month needs 21. The others: 18 with under 18 hours of readings or readings that failed our checks. |
| Oct 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. |
| Aug 2025 | 6 of 31 days measured; a month needs 22. The others: 25 with under 18 hours of readings or readings that failed our checks. |
| Jul 2025 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Mar 2023 | 9 of 31 days measured; a month needs 22. The others: 19 missing from OpenAQ's archive, 3 with under 18 hours of readings or readings that failed our checks. |
| Feb 2023 | 2 of 28 days measured; a month needs 20. The others: 25 missing from OpenAQ's archive, 1 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.
Bangkok's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| January 2025 | 12445.0 µg/m³ | 42ndof 2,474 | Northern Thailand, January 2025 |
| January 2024 | 11240.0 µg/m³ | 65thof 2,385 | – |
| April 2023 | 10436.7 µg/m³ | 24thof 1,622 | Thailand, April 2023 Northern Thailand and Laos around Bangkok, 5 to 8 April 2023 |
| February 2025 | 10135.7 µg/m³ | 143rdof 2,633 | – |
| January 2026 | 9834.5 µg/m³ | 129thof 2,617 | – |
| January 2023 | 9633.2 µg/m³ | 57thof 1,261 | Northern Thailand and Laos, January and February 2023 |
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.
Bangkok's worst days
| Day | US AQI | Episode |
|---|---|---|
| 24 Jan 2025 | 16981.4 µg/m³ | Northern Thailand, January 2025 |
| 1 Feb 2023 | 16778.4 µg/m³ | Northern Thailand and Laos, January and February 2023 |
| 23 Jan 2025 | 16373.3 µg/m³ | Northern Thailand, January 2025 |
| 14 Feb 2024 | 16270.5 µg/m³ | Thailand, February 2024 |
| 24 Mar 2025 | 15967.1 µg/m³ | Thailand and Laos, March 2025 |
| 23 Mar 2025 | 15865.6 µg/m³ | Thailand and Laos, March 2025 |
| 25 Jan 2025 | 15764.7 µg/m³ | Northern Thailand, January 2025 |
| 22 Jan 2025 | 15764.3 µg/m³ | – |
| 15 Feb 2024 | 15763.7 µg/m³ | Thailand, February 2024 |
| 31 Jan 2024 | 15560.7 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, Bangkok, Thailand, 1 Jan 2023 – 12 Oct 2026. Monitor data from Air4Thai via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/th/bangkok/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.
Bangkok now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 23:07 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).