SmogRank / Hong Kong / Tuen Mun / Tuen Mun
Tuen Mun, month by month
Tuen Mun has a measured daily mean on 955 days since 11 May 2023. Its worst month was December 2024, at 110 US AQI (39.1 µg/m³), 44th of 2,616 cities on that month's world ranking. Its cleanest was September 2025, at 41 US AQI (7.3 µg/m³). 2025 averaged 70 US AQI (19.2 µg/m³), against 73 US AQI (21.0 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
11 months
| Month | Why |
|---|---|
| Sep 2026 | 2 of 30 days measured; a month needs 21. The others: 1 with readings for part of the day (a day needs 18 hours), 27 with under 18 hours of readings or readings that failed our checks. |
| Aug 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jul 2026 | No day measured. The others: 31 with under 18 hours of readings or readings that failed our checks. |
| Jun 2026 | No day measured. The others: 30 with under 18 hours of readings or readings that failed our checks. |
| Mar 2024 | 17 of 31 days measured; a month needs 22. The others: 14 with under 18 hours of readings or readings that failed our checks. |
| Oct 2023 | 18 of 31 days measured; a month needs 22. The others: 13 with under 18 hours of readings or readings that failed our checks. |
| Sep 2023 | 19 of 30 days measured; a month needs 21. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Aug 2023 | 20 of 31 days measured; a month needs 22. The others: 11 with under 18 hours of readings or readings that failed our checks. |
| Jul 2023 | 9 of 31 days measured; a month needs 22. The others: 1 missing from OpenAQ's archive, 21 with under 18 hours of readings or readings that failed our checks. |
| Jun 2023 | 14 of 30 days measured; a month needs 21. The others: 16 with under 18 hours of readings or readings that failed our checks. |
| May 2023 | 9 of 31 days measured; a month needs 22. The others: 12 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.
Tuen Mun's worst months
| Month | US AQI | World rank |
|---|---|---|
| December 2024 | 11039.1 µg/m³ | 44thof 2,616 |
| January 2025 | 9633.0 µg/m³ | 72ndof 2,474 |
| December 2025 | 9532.9 µg/m³ | 275thof 3,006 |
| January 2026 | 9432.4 µg/m³ | 152ndof 2,617 |
| January 2024 | 9432.0 µg/m³ | 104thof 2,385 |
| December 2023 | 9130.8 µg/m³ | 62ndof 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.
Tuen Mun's worst days
| Day | US AQI |
|---|---|
| 14 Apr 2025 | 16981.6 µg/m³ |
| 13 Apr 2025 | 16676.6 µg/m³ |
| 31 Dec 2023 | 15966.3 µg/m³ |
| 30 Dec 2025 | 15560.6 µg/m³ |
| 6 Jan 2024 | 15560.5 µg/m³ |
| 30 Dec 2024 | 15358.8 µg/m³ |
| 15 Apr 2025 | 15358.8 µg/m³ |
| 29 Dec 2024 | 15358.6 µg/m³ |
| 13 Jan 2026 | 15256.3 µg/m³ |
| 31 Dec 2024 | 14754.3 µg/m³ |
Daily means, the highest since 11 May 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, Tuen Mun, Hong Kong, 11 May 2023 – 10 Oct 2026. Monitor data from Hong Kong's Environmental Protection Department via OpenAQ; sources listed at smogrank.com/sources. smogrank.com/hk/tuen-mun/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.
Tuen Mun now: the last 24 hours, its ranks today and the last 12 months day by day.
Updated 2026-10-12 17:07 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).