SmogRank / Thailand / Bangkok

Air quality in Sai Mai

Bangkok, Thailand. PM2.5 from 7 low-cost sensors, updated hourly.

9.6 µg/m³
Moderate

Latest hour (05:00 UTC), 0.6× the WHO 24-hour guideline.

Rank

24 h
–
not enough data
7 days
#1,293
of 2,330 · 6.8 µg/m³
30 days
#466
of 2,327 · 9.2 µg/m³
Year
#214
of 2,160 · 21.4 µg/m³

Why it ranks here

Cleaner than usual. The last 7 days averaged 6.8 µg/m³, well below its typical 21.7; rain or wind often clears the air for a while.

Seasonal. Over the past year its worst months were January, February, averaging up to 48.9 µg/m³ against 3.3 in its cleanest month. Seasonal peaks usually come from heating, crop burning, fire or dust seasons.

Based on Sai Mai's own measurements; causes are the usual kinds for a pattern like this, not a confirmed source.

Last 4 days, hour by hour

15302026-10-01 00:00 UTC: 21.4 µg/m³2026-10-01 01:00 UTC: 23.0 µg/m³2026-10-01 02:00 UTC: 23.9 µg/m³2026-10-01 03:00 UTC: 16.1 µg/m³2026-10-01 04:00 UTC: 14.6 µg/m³2026-10-01 05:00 UTC: 9.6 µg/m³Sep 28Sep 29Sep 30Oct 1

Times in UTC. Dashed line: WHO 24-hour guideline (15 µg/m³).

Every day for a year

SepNovDecJanFebMarAprMayJunJulAugSepMonWedFri2025-09-29: 4.1 µg/m³2025-09-30: 3.1 µg/m³2025-10-01: 13.2 µg/m³2025-10-02: 16.7 µg/m³2025-10-03: 15.4 µg/m³2025-10-04: 21.6 µg/m³2025-10-05: 34.2 µg/m³2025-10-06: 8.3 µg/m³2025-10-07: 4.1 µg/m³2025-10-08: 15.4 µg/m³2025-10-09: 17.8 µg/m³2025-10-10: 19.0 µg/m³2025-10-11: 20.2 µg/m³2025-10-12: 22.5 µg/m³2025-10-13: 22.7 µg/m³2025-10-14: 15.0 µg/m³2025-10-15: 10.4 µg/m³2025-10-16: 13.3 µg/m³2025-10-17: 13.7 µg/m³2025-10-18: 16.4 µg/m³2025-10-19: 13.2 µg/m³2025-10-20: 17.1 µg/m³2025-10-21: 28.6 µg/m³2025-10-22: 23.9 µg/m³2025-10-23: 14.1 µg/m³2025-10-24: 9.1 µg/m³2025-10-25: 13.1 µg/m³2025-10-26: 19.3 µg/m³2025-10-27: 26.2 µg/m³2025-10-28: 20.7 µg/m³2025-10-29: 21.7 µg/m³2025-10-30: 18.3 µg/m³2025-10-31: 15.6 µg/m³2025-11-01: 12.0 µg/m³2025-11-02: 6.6 µg/m³2025-11-03: 4.9 µg/m³2025-11-04: 11.8 µg/m³2025-11-05: 17.6 µg/m³2025-11-06: 18.4 µg/m³2025-11-07: 25.8 µg/m³2025-11-08: 11.7 µg/m³2025-11-09: 38.9 µg/m³2025-11-10: 26.9 µg/m³2025-11-11: 23.4 µg/m³2025-11-12: 40.6 µg/m³2025-11-13: 23.0 µg/m³2025-11-14: no data2025-11-15: 25.5 µg/m³2025-11-16: 21.6 µg/m³2025-11-17: 18.7 µg/m³2025-11-18: 18.6 µg/m³2025-11-19: 15.5 µg/m³2025-11-20: 15.6 µg/m³2025-11-21: 20.6 µg/m³2025-11-22: 24.7 µg/m³2025-11-23: 29.4 µg/m³2025-11-24: 24.7 µg/m³2025-11-25: 35.1 µg/m³2025-11-26: 39.2 µg/m³2025-11-27: 36.4 µg/m³2025-11-28: 29.3 µg/m³2025-11-29: 40.5 µg/m³2025-11-30: 46.1 µg/m³2025-12-01: 49.5 µg/m³2025-12-02: 52.6 µg/m³2025-12-03: 49.9 µg/m³2025-12-04: 24.6 µg/m³2025-12-05: 25.0 µg/m³2025-12-06: 26.7 µg/m³2025-12-07: 32.0 µg/m³2025-12-08: 25.8 µg/m³2025-12-09: 37.9 µg/m³2025-12-10: 35.5 µg/m³2025-12-11: 34.3 µg/m³2025-12-12: 32.3 µg/m³2025-12-13: 30.1 µg/m³2025-12-14: 26.8 µg/m³2025-12-15: 19.6 µg/m³2025-12-16: 26.3 µg/m³2025-12-17: 27.5 µg/m³2025-12-18: 19.3 µg/m³2025-12-19: 34.6 µg/m³2025-12-20: 41.8 µg/m³2025-12-21: 31.4 µg/m³2025-12-22: 29.5 µg/m³2025-12-23: 28.1 µg/m³2025-12-24: 37.7 µg/m³2025-12-25: 37.4 µg/m³2025-12-26: 23.4 µg/m³2025-12-27: 26.0 µg/m³2025-12-28: 31.7 µg/m³2025-12-29: 43.0 µg/m³2025-12-30: 47.1 µg/m³2025-12-31: 56.3 µg/m³2026-01-01: 68.1 µg/m³2026-01-02: 38.8 µg/m³2026-01-03: 33.1 µg/m³2026-01-04: 35.2 µg/m³2026-01-05: 35.8 µg/m³2026-01-06: 30.2 µg/m³2026-01-07: 27.7 µg/m³2026-01-08: 35.1 µg/m³2026-01-09: 41.9 µg/m³2026-01-10: 45.9 µg/m³2026-01-11: 46.1 µg/m³2026-01-12: 46.0 µg/m³2026-01-13: 56.4 µg/m³2026-01-14: 67.8 µg/m³2026-01-15: 71.9 µg/m³2026-01-16: 62.9 µg/m³2026-01-17: 52.2 µg/m³2026-01-18: 48.2 µg/m³2026-01-19: 55.3 µg/m³2026-01-20: 43.5 µg/m³2026-01-21: 45.3 µg/m³2026-01-22: 43.7 µg/m³2026-01-23: 36.9 µg/m³2026-01-24: 39.2 µg/m³2026-01-25: 46.1 µg/m³2026-01-26: 59.1 µg/m³2026-01-27: 65.7 µg/m³2026-01-28: 72.2 µg/m³2026-01-29: 41.5 µg/m³2026-01-30: 65.9 µg/m³2026-01-31: 59.0 µg/m³2026-02-01: 49.5 µg/m³2026-02-02: 35.3 µg/m³2026-02-03: 24.0 µg/m³2026-02-04: 35.6 µg/m³2026-02-05: 48.7 µg/m³2026-02-06: 42.6 µg/m³2026-02-07: 35.6 µg/m³2026-02-08: 36.1 µg/m³2026-02-09: 40.5 µg/m³2026-02-10: 40.4 µg/m³2026-02-11: 51.7 µg/m³2026-02-12: 65.1 µg/m³2026-02-13: 43.7 µg/m³2026-02-14: 38.9 µg/m³2026-02-15: 39.8 µg/m³2026-02-16: 45.2 µg/m³2026-02-17: 43.3 µg/m³2026-02-18: 39.8 µg/m³2026-02-19: 49.0 µg/m³2026-02-20: 46.1 µg/m³2026-02-21: 45.5 µg/m³2026-02-22: 41.2 µg/m³2026-02-23: 39.5 µg/m³2026-02-24: 36.4 µg/m³2026-02-25: 40.8 µg/m³2026-02-26: 38.9 µg/m³2026-02-27: 24.8 µg/m³2026-02-28: 10.8 µg/m³2026-03-01: 19.0 µg/m³2026-03-02: 19.8 µg/m³2026-03-03: 36.6 µg/m³2026-03-04: 42.3 µg/m³2026-03-05: 44.1 µg/m³2026-03-06: 27.5 µg/m³2026-03-07: 26.5 µg/m³2026-03-08: 34.8 µg/m³2026-03-09: 41.8 µg/m³2026-03-10: 28.4 µg/m³2026-03-11: 28.5 µg/m³2026-03-12: 44.3 µg/m³2026-03-13: 44.0 µg/m³2026-03-14: 37.1 µg/m³2026-03-15: 38.2 µg/m³2026-03-16: 43.3 µg/m³2026-03-17: 28.9 µg/m³2026-03-18: 30.7 µg/m³2026-03-19: 26.8 µg/m³2026-03-20: 27.4 µg/m³2026-03-21: 37.4 µg/m³2026-03-22: 33.0 µg/m³2026-03-23: 28.9 µg/m³2026-03-24: 30.2 µg/m³2026-03-25: 29.9 µg/m³2026-03-26: 36.2 µg/m³2026-03-27: 35.4 µg/m³2026-03-28: 37.7 µg/m³2026-03-29: 30.1 µg/m³2026-03-30: 27.3 µg/m³2026-03-31: 24.8 µg/m³2026-04-01: 34.8 µg/m³2026-04-02: 29.2 µg/m³2026-04-03: 31.7 µg/m³2026-04-04: 39.8 µg/m³2026-04-05: 43.0 µg/m³2026-04-06: 40.4 µg/m³2026-04-07: 43.6 µg/m³2026-04-08: 41.9 µg/m³2026-04-09: 38.1 µg/m³2026-04-10: 32.9 µg/m³2026-04-11: 35.9 µg/m³2026-04-12: 36.3 µg/m³2026-04-13: 28.9 µg/m³2026-04-14: 37.9 µg/m³2026-04-15: 35.6 µg/m³2026-04-16: 35.4 µg/m³2026-04-17: 36.4 µg/m³2026-04-18: 37.5 µg/m³2026-04-19: 32.0 µg/m³2026-04-20: 30.8 µg/m³2026-04-21: 36.7 µg/m³2026-04-22: 35.5 µg/m³2026-04-23: 32.1 µg/m³2026-04-24: 26.9 µg/m³2026-04-25: 31.1 µg/m³2026-04-26: 35.9 µg/m³2026-04-27: 29.4 µg/m³2026-04-28: 17.0 µg/m³2026-04-29: 29.2 µg/m³2026-04-30: 36.0 µg/m³2026-05-01: 27.0 µg/m³2026-05-02: 26.9 µg/m³2026-05-03: 18.2 µg/m³2026-05-04: 20.1 µg/m³2026-05-05: 10.8 µg/m³2026-05-06: 32.6 µg/m³2026-05-07: 26.3 µg/m³2026-05-08: 25.0 µg/m³2026-05-09: 39.4 µg/m³2026-05-10: 35.4 µg/m³2026-05-11: 22.7 µg/m³2026-05-12: 19.9 µg/m³2026-05-13: 11.7 µg/m³2026-05-14: 1.7 µg/m³2026-05-15: 3.2 µg/m³2026-05-16: 2.9 µg/m³2026-05-17: 0.2 µg/m³2026-05-18: 4.9 µg/m³2026-05-19: 4.6 µg/m³2026-05-20: 11.0 µg/m³2026-05-21: 18.8 µg/m³2026-05-22: 11.4 µg/m³2026-05-23: 5.2 µg/m³2026-05-24: 1.3 µg/m³2026-05-25: 2.7 µg/m³2026-05-26: 4.9 µg/m³2026-05-27: 3.2 µg/m³2026-05-28: 7.2 µg/m³2026-05-29: 13.0 µg/m³2026-05-30: 15.5 µg/m³2026-05-31: 18.8 µg/m³2026-06-01: 10.9 µg/m³2026-06-02: 22.0 µg/m³2026-06-03: 8.9 µg/m³2026-06-04: 3.0 µg/m³2026-06-05: 1.2 µg/m³2026-06-06: 0.9 µg/m³2026-06-07: 0.2 µg/m³2026-06-08: 2.8 µg/m³2026-06-09: 6.3 µg/m³2026-06-10: 4.7 µg/m³2026-06-11: 4.7 µg/m³2026-06-12: 2.2 µg/m³2026-06-13: 2.5 µg/m³2026-06-14: 1.8 µg/m³2026-06-15: 2.0 µg/m³2026-06-16: 3.9 µg/m³2026-06-17: 3.1 µg/m³2026-06-18: 3.5 µg/m³2026-06-19: 5.2 µg/m³2026-06-20: 5.2 µg/m³2026-06-21: 2.5 µg/m³2026-06-22: 6.2 µg/m³2026-06-23: 2.1 µg/m³2026-06-24: 0.3 µg/m³2026-06-25: 2.0 µg/m³2026-06-26: 4.8 µg/m³2026-06-27: 8.6 µg/m³2026-06-28: 3.1 µg/m³2026-06-29: 0.2 µg/m³2026-06-30: 0.2 µg/m³2026-07-01: 1.2 µg/m³2026-07-02: 2.8 µg/m³2026-07-03: 3.7 µg/m³2026-07-04: 2.3 µg/m³2026-07-05: 4.7 µg/m³2026-07-06: 3.4 µg/m³2026-07-07: 5.8 µg/m³2026-07-08: 4.0 µg/m³2026-07-09: 12.5 µg/m³2026-07-10: 8.0 µg/m³2026-07-11: 4.8 µg/m³2026-07-12: 2.2 µg/m³2026-07-13: 1.7 µg/m³2026-07-14: 8.0 µg/m³2026-07-15: 9.0 µg/m³2026-07-16: 6.0 µg/m³2026-07-17: 14.5 µg/m³2026-07-18: 14.6 µg/m³2026-07-19: 12.1 µg/m³2026-07-20: 7.5 µg/m³2026-07-21: 7.8 µg/m³2026-07-22: 6.6 µg/m³2026-07-23: 6.8 µg/m³2026-07-24: 5.5 µg/m³2026-07-25: 5.3 µg/m³2026-07-26: 4.9 µg/m³2026-07-27: 3.0 µg/m³2026-07-28: 4.7 µg/m³2026-07-29: 6.1 µg/m³2026-07-30: 10.3 µg/m³2026-07-31: 2.8 µg/m³2026-08-01: 2.4 µg/m³2026-08-02: 3.7 µg/m³2026-08-03: 2.8 µg/m³2026-08-04: 7.5 µg/m³2026-08-05: 1.4 µg/m³2026-08-06: 3.0 µg/m³2026-08-07: 2.4 µg/m³2026-08-08: 3.3 µg/m³2026-08-09: 3.8 µg/m³2026-08-10: 2.0 µg/m³2026-08-11: 2.4 µg/m³2026-08-12: 4.9 µg/m³2026-08-13: 1.6 µg/m³2026-08-14: 1.4 µg/m³2026-08-15: 7.0 µg/m³2026-08-16: 4.0 µg/m³2026-08-17: 4.0 µg/m³2026-08-18: 7.0 µg/m³2026-08-19: 3.5 µg/m³2026-08-20: 1.7 µg/m³2026-08-21: 2.1 µg/m³2026-08-22: 1.0 µg/m³2026-08-23: 2.4 µg/m³2026-08-24: 3.2 µg/m³2026-08-25: 1.4 µg/m³2026-08-26: 0.5 µg/m³2026-08-27: 0.3 µg/m³2026-08-28: 2.3 µg/m³2026-08-29: 4.5 µg/m³2026-08-30: 7.7 µg/m³2026-08-31: 7.3 µg/m³2026-09-01: 6.9 µg/m³2026-09-02: 7.4 µg/m³2026-09-03: 9.8 µg/m³2026-09-04: 6.1 µg/m³2026-09-05: 9.0 µg/m³2026-09-06: 7.1 µg/m³2026-09-07: 2.5 µg/m³2026-09-08: 3.7 µg/m³2026-09-09: 5.8 µg/m³2026-09-10: 17.5 µg/m³2026-09-11: 3.8 µg/m³2026-09-12: 19.2 µg/m³2026-09-13: 26.8 µg/m³2026-09-14: 26.5 µg/m³2026-09-15: 18.2 µg/m³2026-09-16: 8.1 µg/m³2026-09-17: 3.6 µg/m³2026-09-18: 7.5 µg/m³2026-09-19: 4.7 µg/m³2026-09-20: 2.2 µg/m³2026-09-21: 7.4 µg/m³2026-09-22: 8.6 µg/m³2026-09-23: 16.3 µg/m³2026-09-24: 4.5 µg/m³2026-09-25: 1.5 µg/m³2026-09-26: 1.4 µg/m³2026-09-27: 0.8 µg/m³2026-09-28: 1.5 µg/m³2026-09-29: 12.8 µg/m³2026-09-30: 25.2 µg/m³
Good 0–9.0Moderate 9.1+Unhealthy for sensitive groups 35.5+Unhealthy 55.5+Very unhealthy 125.5+Hazardous 225.5+No data

216 of 364 measured days were over the WHO 24-hour guideline.

Daily world rank

#1#2363OctNovDecJanFebMarAprMayJunJulAugSep

Rank on each day's board (1 = most polluted city that day).

2026 against 2025, month by month

15Jan 2026: 48.9 µg/m³JanFeb 2025: 48.2 µg/m³Feb 2026: 40.3 µg/m³FebMar 2025: 41.9 µg/m³Mar 2026: 32.9 µg/m³MarApr 2025: 26.4 µg/m³Apr 2026: 34.4 µg/m³AprMay 2025: 18.4 µg/m³May 2026: 14.4 µg/m³MayJun 2025: 9.2 µg/m³Jun 2026: 4.2 µg/m³JunJul 2025: 11.1 µg/m³Jul 2026: 6.2 µg/m³JulAug 2025: 8.2 µg/m³Aug 2026: 3.3 µg/m³AugSep 2025: 11.0 µg/m³Sep 2026: 9.2 µg/m³SepOct 2025: 17.4 µg/m³OctNov 2025: 24.2 µg/m³NovDec 2025: 33.7 µg/m³Dec

Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 6.8 µg/m³6.820252025: 8.1 µg/m³8.1

Mean PM2.5 for 24 Sept to 30 Sept in each year. Dashed line: WHO 24-hour guideline.

Monitors

StationOperatorType
Rangsit - Nakhon Nayok 25CC BY 4.0WitLow-cost
Khlong 3 - Lat SawaiCC BY 4.0TDLow-cost
Neighbour HomeCC BY 4.0Brad FordLow-cost
Britania KhuKhotCC BY 4.0AirGradientLow-cost
OatState Home - Baan Klang Muang Phaholyothin 50CC BY 4.0AirGradientLow-cost
Meow-nitoring Station, Thoet Rachan, Don mueang, BangkokCC BY 4.0AirGradientLow-cost
Rangsit - Nakhon Nayok 50CC BY 4.0AirGradientLow-cost

No reference monitor here, so the value is the median of low-cost sensors (at least two reporting each hour). Low-cost sensors can read high in humid air. Data via OpenAQ; licences as listed. How we rank. Embed this on your site.

Other cities in Thailand

Khlong Luang 11.2Chiang Mai 11.1Bangkok 10.4Bang Pakong 10.0Ban Khlong Prawet 9.5Uttaradit 8.0

30-day averages, µg/m³. All of Thailand →

Updated 2026-10-01 06:07 UTC. Values are PM2.5 in µg/m³ (fine particles), the median of each city's monitors.