SmogRank / South Korea / Chungcheongnam-do

Air quality in Seosan

Chungcheongnam-do, South Korea. PM2.5 from 3 reference monitors, updated hourly. Only 1 of them reported in the last 24 hours.

6US AQI
Good

Latest hour (03:00 UTC), 0.1× the WHO 24-hour guideline. PM2.5 1.0 µg/m³.

Rank, worst first

24 hours–not enough data
7 days#842of 2,605, at 52 US AQI (9.6 µg/m³)
30 days#4of 2,626, at 299 US AQI (224.6 µg/m³)
This year#7of 2,447, at 206 US AQI (130.2 µg/m³)

Why it ranks here

Seasonal. Over the past year its worst months were July, August, September, averaging up to 266.1 µg/m³ against 9.0 in its cleanest month. Seasonal peaks usually come from heating, crop burning, fire or dust seasons.

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

The last 12 months, day by day

1102031Nov 2025DecJan 2026FebMarAprMayJunJulAugSepOct2025-11-01: 9.6 µg/m³2025-11-02: 6.4 µg/m³2025-11-03: 13.5 µg/m³2025-11-04: 16.5 µg/m³2025-11-05: 26.2 µg/m³2025-11-06: 29.3 µg/m³2025-11-07: 45.9 µg/m³2025-11-08: 22.2 µg/m³2025-11-09: 22.2 µg/m³2025-11-10: 5.5 µg/m³2025-11-11: 10.4 µg/m³2025-11-12: 14.8 µg/m³2025-11-13: 16.6 µg/m³2025-11-14: 11.7 µg/m³2025-11-15: 18.7 µg/m³2025-11-16: 23.5 µg/m³2025-11-17: 8.7 µg/m³2025-11-18: 11.2 µg/m³2025-11-19: 13.5 µg/m³2025-11-20: 17.1 µg/m³2025-11-21: 215.3 µg/m³2025-11-22: no data2025-11-23: 19.0 µg/m³2025-11-24: 48.1 µg/m³2025-11-25: 455.0 µg/m³2025-11-26: 12.9 µg/m³2025-11-27: 12.2 µg/m³2025-11-28: 213.5 µg/m³2025-11-29: 8.3 µg/m³2025-11-30: 15.8 µg/m³2025-12-01: 221.6 µg/m³2025-12-02: 1,044.0 µg/m³2025-12-03: 3.9 µg/m³2025-12-04: 9.9 µg/m³2025-12-05: 7.7 µg/m³2025-12-06: 12.2 µg/m³2025-12-07: 44.9 µg/m³2025-12-08: 633.0 µg/m³2025-12-09: 13.6 µg/m³2025-12-10: 14.8 µg/m³2025-12-11: 19.5 µg/m³2025-12-12: 15.6 µg/m³2025-12-13: 10.9 µg/m³2025-12-14: 8.9 µg/m³2025-12-15: 15.0 µg/m³2025-12-16: 17.0 µg/m³2025-12-17: 24.2 µg/m³2025-12-18: 15.5 µg/m³2025-12-19: 16.0 µg/m³2025-12-20: 18.1 µg/m³2025-12-21: 5.4 µg/m³2025-12-22: 14.6 µg/m³2025-12-23: 19.7 µg/m³2025-12-24: 14.0 µg/m³2025-12-25: 7.1 µg/m³2025-12-26: 8.4 µg/m³2025-12-27: 18.7 µg/m³2025-12-28: 14.1 µg/m³2025-12-29: 38.5 µg/m³2025-12-30: 7.3 µg/m³2025-12-31: 4.6 µg/m³2026-01-01: 5.4 µg/m³2026-01-02: 6.8 µg/m³2026-01-03: 14.7 µg/m³2026-01-04: 24.7 µg/m³2026-01-05: 10.7 µg/m³2026-01-06: 14.1 µg/m³2026-01-07: 15.5 µg/m³2026-01-08: 7.0 µg/m³2026-01-09: 12.7 µg/m³2026-01-10: 18.8 µg/m³2026-01-11: 6.6 µg/m³2026-01-12: 11.7 µg/m³2026-01-13: 12.9 µg/m³2026-01-14: 10.6 µg/m³2026-01-15: 48.3 µg/m³2026-01-16: 42.5 µg/m³2026-01-17: 29.7 µg/m³2026-01-18: 31.1 µg/m³2026-01-19: 10.8 µg/m³2026-01-20: 8.3 µg/m³2026-01-21: 5.5 µg/m³2026-01-22: 6.7 µg/m³2026-01-23: 19.2 µg/m³2026-01-24: 13.0 µg/m³2026-01-25: 5.3 µg/m³2026-01-26: 12.1 µg/m³2026-01-27: 14.4 µg/m³2026-01-28: 9.1 µg/m³2026-01-29: 13.5 µg/m³2026-01-30: 13.9 µg/m³2026-01-31: 21.0 µg/m³2026-02-01: 28.0 µg/m³2026-02-02: 17.8 µg/m³2026-02-03: 17.7 µg/m³2026-02-04: 28.7 µg/m³2026-02-05: 37.8 µg/m³2026-02-06: 8.4 µg/m³2026-02-07: 7.9 µg/m³2026-02-08: 9.2 µg/m³2026-02-09: 11.9 µg/m³2026-02-10: 21.8 µg/m³2026-02-11: 39.0 µg/m³2026-02-12: 31.1 µg/m³2026-02-13: 40.5 µg/m³2026-02-14: 46.0 µg/m³2026-02-15: 25.5 µg/m³2026-02-16: 11.1 µg/m³2026-02-17: 13.1 µg/m³2026-02-18: 17.8 µg/m³2026-02-19: 12.5 µg/m³2026-02-20: 31.3 µg/m³2026-02-21: 28.9 µg/m³2026-02-22: 14.1 µg/m³2026-02-23: 11.4 µg/m³2026-02-24: 12.6 µg/m³2026-02-25: 17.3 µg/m³2026-02-26: 13.2 µg/m³2026-02-27: 11.3 µg/m³2026-02-28: 16.1 µg/m³2026-03-01: 13.1 µg/m³2026-03-02: 4.6 µg/m³2026-03-03: 4.0 µg/m³2026-03-04: 14.0 µg/m³2026-03-05: 30.5 µg/m³2026-03-06: 16.9 µg/m³2026-03-07: 14.3 µg/m³2026-03-08: 16.0 µg/m³2026-03-09: 33.3 µg/m³2026-03-10: 22.6 µg/m³2026-03-11: 24.5 µg/m³2026-03-12: 34.3 µg/m³2026-03-13: 19.4 µg/m³2026-03-14: 24.0 µg/m³2026-03-15: 32.6 µg/m³2026-03-16: 55.9 µg/m³2026-03-17: 53.3 µg/m³2026-03-18: 33.0 µg/m³2026-03-19: 9.3 µg/m³2026-03-20: 16.4 µg/m³2026-03-21: 23.0 µg/m³2026-03-22: 28.7 µg/m³2026-03-23: 34.1 µg/m³2026-03-24: 35.3 µg/m³2026-03-25: 25.8 µg/m³2026-03-26: 22.5 µg/m³2026-03-27: 19.3 µg/m³2026-03-28: 28.5 µg/m³2026-03-29: 22.4 µg/m³2026-03-30: 29.1 µg/m³2026-03-31: 24.5 µg/m³2026-04-01: 22.4 µg/m³2026-04-02: 36.1 µg/m³2026-04-03: 39.2 µg/m³2026-04-04: 17.0 µg/m³2026-04-05: 20.4 µg/m³2026-04-06: 14.1 µg/m³2026-04-07: 6.3 µg/m³2026-04-08: 10.7 µg/m³2026-04-09: 9.4 µg/m³2026-04-10: 9.5 µg/m³2026-04-11: 24.7 µg/m³2026-04-12: 17.7 µg/m³2026-04-13: 20.9 µg/m³2026-04-14: 24.1 µg/m³2026-04-15: 27.4 µg/m³2026-04-16: 22.8 µg/m³2026-04-17: 12.6 µg/m³2026-04-18: 13.4 µg/m³2026-04-19: 17.6 µg/m³2026-04-20: 15.8 µg/m³2026-04-21: 14.3 µg/m³2026-04-22: 12.5 µg/m³2026-04-23: 16.9 µg/m³2026-04-24: 12.0 µg/m³2026-04-25: 15.4 µg/m³2026-04-26: 13.4 µg/m³2026-04-27: 13.3 µg/m³2026-04-28: 9.1 µg/m³2026-04-29: 12.4 µg/m³2026-04-30: 12.5 µg/m³2026-05-01: 18.3 µg/m³2026-05-02: 33.1 µg/m³2026-05-03: 12.7 µg/m³2026-05-04: 217.0 µg/m³2026-05-05: 216.4 µg/m³2026-05-06: 841.5 µg/m³2026-05-07: 425.8 µg/m³2026-05-08: 7.6 µg/m³2026-05-09: 8.7 µg/m³2026-05-10: 8.0 µg/m³2026-05-11: 425.7 µg/m³2026-05-12: 6.5 µg/m³2026-05-13: 217.4 µg/m³2026-05-14: 440.5 µg/m³2026-05-15: 15.9 µg/m³2026-05-16: 222.0 µg/m³2026-05-17: 15.9 µg/m³2026-05-18: 432.0 µg/m³2026-05-19: 23.1 µg/m³2026-05-20: 640.0 µg/m³2026-05-21: 221.5 µg/m³2026-05-22: 422.3 µg/m³2026-05-23: 15.6 µg/m³2026-05-24: 22.0 µg/m³2026-05-25: 24.3 µg/m³2026-05-26: 16.1 µg/m³2026-05-27: 217.0 µg/m³2026-05-28: 8.0 µg/m³2026-05-29: 228.2 µg/m³2026-05-30: 15.0 µg/m³2026-05-31: 13.4 µg/m³2026-06-01: 431.4 µg/m³2026-06-02: 24.4 µg/m³2026-06-03: 22.4 µg/m³2026-06-04: 434.5 µg/m³2026-06-05: 213.9 µg/m³2026-06-06: 12.9 µg/m³2026-06-07: 11.5 µg/m³2026-06-08: 426.9 µg/m³2026-06-09: 7.3 µg/m³2026-06-10: 637.0 µg/m³2026-06-11: 11.6 µg/m³2026-06-12: 13.8 µg/m³2026-06-13: 14.1 µg/m³2026-06-14: 10.1 µg/m³2026-06-15: 431.0 µg/m³2026-06-16: 19.3 µg/m³2026-06-17: 22.1 µg/m³2026-06-18: 12.5 µg/m³2026-06-19: 229.3 µg/m³2026-06-20: 3.8 µg/m³2026-06-21: 212.1 µg/m³2026-06-22: 217.6 µg/m³2026-06-23: 8.6 µg/m³2026-06-24: 627.2 µg/m³2026-06-25: 7.1 µg/m³2026-06-26: 424.3 µg/m³2026-06-27: 13.1 µg/m³2026-06-28: 12.3 µg/m³2026-06-29: 428.9 µg/m³2026-06-30: 428.1 µg/m³2026-07-01: 221.8 µg/m³2026-07-02: 429.7 µg/m³2026-07-03: 6.5 µg/m³2026-07-04: 217.2 µg/m³2026-07-05: 7.0 µg/m³2026-07-06: 425.5 µg/m³2026-07-07: 215.0 µg/m³2026-07-08: 4.5 µg/m³2026-07-09: 4.4 µg/m³2026-07-10: 7.1 µg/m³2026-07-11: 216.8 µg/m³2026-07-12: 12.1 µg/m³2026-07-13: 633.6 µg/m³2026-07-14: 840.0 µg/m³2026-07-15: 9.0 µg/m³2026-07-16: 217.4 µg/m³2026-07-17: 15.5 µg/m³2026-07-18: 8.1 µg/m³2026-07-19: 7.1 µg/m³2026-07-20: 8.8 µg/m³2026-07-21: 629.5 µg/m³2026-07-22: 6.3 µg/m³2026-07-23: 426.5 µg/m³2026-07-24: 6.9 µg/m³2026-07-25: 5.3 µg/m³2026-07-26: 3.9 µg/m³2026-07-27: 628.0 µg/m³2026-07-28: 424.3 µg/m³2026-07-29: 211.7 µg/m³2026-07-30: 1,260.0 µg/m³2026-07-31: 8.8 µg/m³2026-08-01: 16.2 µg/m³2026-08-02: 422.3 µg/m³2026-08-03: 843.0 µg/m³2026-08-04: 228.3 µg/m³2026-08-05: 430.3 µg/m³2026-08-06: 227.8 µg/m³2026-08-07: 16.4 µg/m³2026-08-08: 428.0 µg/m³2026-08-09: 4.7 µg/m³2026-08-10: no data2026-08-11: no data2026-08-12: 1,045.0 µg/m³2026-08-13: 214.0 µg/m³2026-08-14: 218.6 µg/m³2026-08-15: 226.0 µg/m³2026-08-16: 7.2 µg/m³2026-08-17: 213.2 µg/m³2026-08-18: 9.1 µg/m³2026-08-19: 425.0 µg/m³2026-08-20: 217.2 µg/m³2026-08-21: 9.5 µg/m³2026-08-22: 215.6 µg/m³2026-08-23: 7.0 µg/m³2026-08-24: 429.3 µg/m³2026-08-25: 213.5 µg/m³2026-08-26: 5.2 µg/m³2026-08-27: 215.2 µg/m³2026-08-28: 429.6 µg/m³2026-08-29: 425.2 µg/m³2026-08-30: 10.9 µg/m³2026-08-31: 5.3 µg/m³2026-09-01: 1,250.0 µg/m³2026-09-02: 422.0 µg/m³2026-09-03: 427.0 µg/m³2026-09-04: 212.4 µg/m³2026-09-05: 835.5 µg/m³2026-09-06: 420.7 µg/m³2026-09-07: 632.0 µg/m³2026-09-08: 9.7 µg/m³2026-09-09: 1,250.0 µg/m³2026-09-10: 421.0 µg/m³2026-09-11: 10.2 µg/m³2026-09-12: 15.2 µg/m³2026-09-13: 19.0 µg/m³2026-09-14: 636.0 µg/m³2026-09-15: 7.4 µg/m³2026-09-16: 13.0 µg/m³2026-09-17: 632.9 µg/m³2026-09-18: 215.1 µg/m³2026-09-19: 215.5 µg/m³2026-09-20: 217.2 µg/m³2026-09-21: 13.8 µg/m³2026-09-22: 14.9 µg/m³2026-09-23: 16.3 µg/m³2026-09-24: 13.1 µg/m³2026-09-25: 13.7 µg/m³2026-09-26: 7.5 µg/m³2026-09-27: 10.7 µg/m³2026-09-28: 10.2 µg/m³2026-09-29: 10.0 µg/m³2026-09-30: 11.2 µg/m³2026-10-01: 4.1 µg/m³
193 of 362 measured days were over the WHO 24-hour guideline (15 µg/m³). One row per month, one square per local day.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

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

Last 4 days, hour by hour

15302026-10-02 00:00 UTC: 23.0 µg/m³2026-10-02 01:00 UTC: 20.0 µg/m³2026-10-02 02:00 UTC: 4.0 µg/m³2026-10-02 03:00 UTC: 1.0 µg/m³Sep 29Sep 30Oct 1
Times in UTC. Dashed line: WHO 24-hour guideline (15 µg/m³).

Where it stood each day

Top 10Top 100#1#10#100#1,000#2,835NovDecJanFebMarAprMayJunJulAugSep#614
Its rank on each day's world board, #1 being the most polluted city that day. The scale is logarithmic: each step down is ten times as many cities. See it among every city.

2026 against 2025, month by month

15Jan 2025: 21.6 µg/m³Jan 2026: 15.4 µg/m³JanFeb 2025: 17.1 µg/m³Feb 2026: 20.8 µg/m³FebMar 2025: 25.4 µg/m³Mar 2026: 24.7 µg/m³MarApr 2025: 17.6 µg/m³Apr 2026: 17.1 µg/m³AprMay 2025: 15.7 µg/m³May 2026: 175.2 µg/m³MayJun 2025: 12.7 µg/m³Jun 2026: 179.0 µg/m³JunJul 2025: 12.8 µg/m³Jul 2026: 229.6 µg/m³JulAug 2025: 9.2 µg/m³Aug 2026: 246.8 µg/m³AugSep 2025: 8.6 µg/m³Sep 2026: 266.1 µg/m³SepOct 2025: 9.4 µg/m³OctNov 2025: 46.3 µg/m³NovDec 2025: 74.8 µg/m³Dec
Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 9.6 µg/m³9.620252025: 11.9 µg/m³11.9
Mean PM2.5 for 25 Sept to 1 Oct in each year. Dashed line: WHO 24-hour guideline.

Monitors

StationOperatorType
성연면Permission requested (AirKorea, 2026-10-01)Korea Air Ministry of EnvironmentReference
동문동Permission requested (AirKorea, 2026-10-01)Korea Air Ministry of EnvironmentReference
동문동Permission requested (AirKorea, 2026-10-01)Korea Air Ministry of EnvironmentReference

The city's value is the median of its reference monitors each hour, when at least a third of them report (three are always enough); low-cost sensors are listed but not counted when reference monitors exist. Data via OpenAQ; licences as listed. How we rank. Embed this on your site.

Use this page

SmogRank, PM2.5 daily means, Seosan, South Korea, 2 Oct 2025 – 1 Oct 2026, smogrank.com/kr/seosan (accessed 2 Oct 2026).

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Other cities in South Korea

30-day averages, US AQI. All of South Korea.

Updated 2026-10-02 04:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.