SmogRank / Taiwan / Taiwan / Toufen
Toufen, month by month
Toufen has a measured daily mean on 830 days since 28 February 2024. Its worst month was March 2024, at 71 US AQI (20.0 µg/m³), 163rd of 1,698 cities on that month's world ranking. Its cleanest was July 2026, at 35 US AQI (6.3 µg/m³). 2025 averaged 59 US AQI (13.3 µg/m³), against 57 US AQI (12.4 µg/m³) in 2024.
Every month since 2024
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
5 months
| Month | Why |
|---|---|
| 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. |
| Feb 2024 | 2 of 29 days measured; a month needs 21. |
A day counts once 18 hours of it are measured; a month needs 70% of its days.
Toufen's worst months
| Month | US AQI | World rank | Episode |
|---|---|---|---|
| March 2024 | 7120.0 µg/m³ | 163rdof 1,698 | Taiwan, March 2024 |
| April 2025 | 7019.2 µg/m³ | 382ndof 2,951 | – |
| April 2024 | 6918.5 µg/m³ | 276thof 2,520 | – |
| February 2026 | 6516.7 µg/m³ | 701stof 2,866 | Taiwan, February 2026 |
| March 2025 | 6516.6 µg/m³ | 809thof 2,862 | Taiwan, March 2025 |
| January 2025 | 6416.1 µg/m³ | 433rdof 2,474 | Taiwan, 21 to 22 January 2025 |
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.
Toufen's worst days
| Day | US AQI | Episode |
|---|---|---|
| 14 Dec 2024 | 12043.4 µg/m³ | Taiwan, December 2024 |
| 16 Mar 2024 | 11139.5 µg/m³ | Taiwan, March 2024 |
| 15 Nov 2024 | 10537.3 µg/m³ | Taiwan, November 2024 |
| 27 Feb 2025 | 10236.0 µg/m³ | Taiwan, 26 to 28 February 2025 |
| 11 Mar 2025 | 10135.5 µg/m³ | Taiwan, March 2025 |
| 29 Mar 2026 | 9331.9 µg/m³ | – |
| 22 Jan 2025 | 9331.4 µg/m³ | Taiwan, 21 to 22 January 2025 |
| 14 Feb 2025 | 9130.7 µg/m³ | – |
| 12 Apr 2024 | 9030.2 µg/m³ | – |
| 17 Mar 2024 | 9029.8 µg/m³ | Taiwan, March 2024 |
Daily means, the highest since 28 Feb 2024; 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, Toufen, Taiwan, 28 Feb 2024 – 12 Oct 2026. Monitor data from Taiwan's Ministry of Environment via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/tw/toufen/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.
Toufen 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).