SmogRank / South Korea / Daejeon

Air quality in Sintansin

Daejeon, South Korea. Over the last 24 hours its air rated Good, the 527th most polluted of 1,340 cities measured.

24-hour average47US AQI
Good

PM2.5 8.4 µg/m³, 0.6× the WHO 24-hour guideline. The figure the 24-hour ranking uses.

Latest hour: 6 US AQI (1.0 µg/m³), local time

About 1.3× its usual for early October (6.7 µg/m³).

Where Sintansin ranks

24 hours#527of 1,340, at 47 US AQI (8.4 µg/m³)
7 days#729of 2,680, at 52 US AQI (9.4 µg/m³)
30 days#699of 2,888, at 52 US AQI (9.6 µg/m³)
This year#505of 2,734, at 64 US AQI (16.0 µg/m³)

Why it ranks here

Seasonal. Over the past year its worst months were February, March, November, averaging up to 26.3 µg/m³ against 8.6 in its cleanest month. Seasonal peaks usually come from heating, crop burning, fire or dust seasons.

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

Bad-air episodes that reached Sintansin

Times when Sintansin and many cities around it had PM2.5 at twice their usual or more on the same days. Latest 8 of 23. All episodes.

The last 12 months, day by day

1102031Nov 2025DecJan 2026FebMarAprMayJunJulAugSepOct2025-11-01: 15.7 µg/m³2025-11-02: 7.4 µg/m³2025-11-03: 14.5 µg/m³2025-11-04: 22.2 µg/m³2025-11-05: 44.4 µg/m³2025-11-06: 47.8 µg/m³2025-11-07: 31.2 µg/m³2025-11-08: 19.1 µg/m³2025-11-09: 18.5 µg/m³2025-11-10: 6.9 µg/m³2025-11-11: 17.4 µg/m³2025-11-12: 28.8 µg/m³2025-11-13: 28.8 µg/m³2025-11-14: 19.8 µg/m³2025-11-15: 25.4 µg/m³2025-11-16: 23.9 µg/m³2025-11-17: 11.4 µg/m³2025-11-18: 11.2 µg/m³2025-11-19: 17.8 µg/m³2025-11-20: 30.8 µg/m³2025-11-21: 8.5 µg/m³2025-11-22: 19.5 µg/m³2025-11-23: 28.7 µg/m³2025-11-24: 49.3 µg/m³2025-11-25: 40.4 µg/m³2025-11-26: 27.3 µg/m³2025-11-27: 17.6 µg/m³2025-11-28: no daily value, under 18 hours of readings, or readings that failed our checks2025-11-29: 12.6 µg/m³2025-11-30: 21.8 µg/m³2025-12-01: 17.8 µg/m³2025-12-02: 11.2 µg/m³2025-12-03: 7.9 µg/m³2025-12-04: 11.0 µg/m³2025-12-05: 11.8 µg/m³2025-12-06: 12.9 µg/m³2025-12-07: 44.3 µg/m³2025-12-08: 16.5 µg/m³2025-12-09: 15.0 µg/m³2025-12-10: 22.1 µg/m³2025-12-11: 25.3 µg/m³2025-12-12: 12.2 µg/m³2025-12-13: 4.2 µg/m³2025-12-14: 11.5 µg/m³2025-12-15: 17.0 µg/m³2025-12-16: 21.7 µg/m³2025-12-17: 26.5 µg/m³2025-12-18: 23.1 µg/m³2025-12-19: 27.5 µg/m³2025-12-20: 35.9 µg/m³2025-12-21: 8.1 µg/m³2025-12-22: 15.4 µg/m³2025-12-23: 19.4 µg/m³2025-12-24: 17.1 µg/m³2025-12-25: 13.6 µg/m³2025-12-26: 6.5 µg/m³2025-12-27: 16.4 µg/m³2025-12-28: 20.6 µg/m³2025-12-29: 39.2 µg/m³2025-12-30: 14.0 µg/m³2025-12-31: 9.5 µg/m³2026-01-01: 7.3 µg/m³2026-01-02: 11.1 µg/m³2026-01-03: 17.3 µg/m³2026-01-04: 28.2 µg/m³2026-01-05: 20.0 µg/m³2026-01-06: 18.0 µg/m³2026-01-07: 15.9 µg/m³2026-01-08: 8.6 µg/m³2026-01-09: 12.8 µg/m³2026-01-10: 17.3 µg/m³2026-01-11: 8.8 µg/m³2026-01-12: 13.7 µg/m³2026-01-13: 15.8 µg/m³2026-01-14: 11.3 µg/m³2026-01-15: 55.7 µg/m³2026-01-16: 60.1 µg/m³2026-01-17: 45.4 µg/m³2026-01-18: 44.1 µg/m³2026-01-19: 20.8 µg/m³2026-01-20: 12.7 µg/m³2026-01-21: 10.6 µg/m³2026-01-22: 10.3 µg/m³2026-01-23: 23.0 µg/m³2026-01-24: 17.2 µg/m³2026-01-25: 10.1 µg/m³2026-01-26: 17.1 µg/m³2026-01-27: 17.2 µg/m³2026-01-28: 16.0 µg/m³2026-01-29: 15.7 µg/m³2026-01-30: 15.6 µg/m³2026-01-31: 23.6 µg/m³2026-02-01: 25.7 µg/m³2026-02-02: 21.1 µg/m³2026-02-03: 22.7 µg/m³2026-02-04: 40.7 µg/m³2026-02-05: 53.2 µg/m³2026-02-06: 12.6 µg/m³2026-02-07: 9.8 µg/m³2026-02-08: 12.3 µg/m³2026-02-09: 14.3 µg/m³2026-02-10: 25.6 µg/m³2026-02-11: 41.9 µg/m³2026-02-12: 43.8 µg/m³2026-02-13: 53.7 µg/m³2026-02-14: 58.0 µg/m³2026-02-15: 34.0 µg/m³2026-02-16: 14.8 µg/m³2026-02-17: 16.5 µg/m³2026-02-18: 15.7 µg/m³2026-02-19: 13.2 µg/m³2026-02-20: 28.9 µg/m³2026-02-21: 32.5 µg/m³2026-02-22: 18.4 µg/m³2026-02-23: 8.1 µg/m³2026-02-24: 15.4 µg/m³2026-02-25: 12.5 µg/m³2026-02-26: 7.0 µg/m³2026-02-27: 7.2 µg/m³2026-02-28: 11.0 µg/m³2026-03-01: 8.9 µg/m³2026-03-02: 4.6 µg/m³2026-03-03: 3.8 µg/m³2026-03-04: 13.6 µg/m³2026-03-05: 22.8 µg/m³2026-03-06: 18.2 µg/m³2026-03-07: 14.7 µg/m³2026-03-08: 17.2 µg/m³2026-03-09: 34.4 µg/m³2026-03-10: 41.9 µg/m³2026-03-11: 34.3 µg/m³2026-03-12: 34.3 µg/m³2026-03-13: 11.9 µg/m³2026-03-14: 15.2 µg/m³2026-03-15: 33.7 µg/m³2026-03-16: 37.8 µg/m³2026-03-17: 43.8 µg/m³2026-03-18: 38.7 µg/m³2026-03-19: 18.2 µg/m³2026-03-20: 19.7 µg/m³2026-03-21: 27.0 µg/m³2026-03-22: 30.4 µg/m³2026-03-23: 32.4 µg/m³2026-03-24: 41.3 µg/m³2026-03-25: 36.5 µg/m³2026-03-26: 32.1 µg/m³2026-03-27: 43.2 µg/m³2026-03-28: 33.7 µg/m³2026-03-29: 28.6 µg/m³2026-03-30: 30.6 µg/m³2026-03-31: 11.9 µg/m³2026-04-01: 13.5 µg/m³2026-04-02: 26.4 µg/m³2026-04-03: 38.6 µg/m³2026-04-04: 10.3 µg/m³2026-04-05: 15.9 µg/m³2026-04-06: 15.1 µg/m³2026-04-07: 6.9 µg/m³2026-04-08: 10.4 µg/m³2026-04-09: 13.1 µg/m³2026-04-10: 12.0 µg/m³2026-04-11: 19.4 µg/m³2026-04-12: 18.0 µg/m³2026-04-13: 13.8 µg/m³2026-04-14: 13.5 µg/m³2026-04-15: 19.1 µg/m³2026-04-16: 13.2 µg/m³2026-04-17: 10.4 µg/m³2026-04-18: 15.3 µg/m³2026-04-19: 14.8 µg/m³2026-04-20: 17.3 µg/m³2026-04-21: 13.5 µg/m³2026-04-22: 10.7 µg/m³2026-04-23: 11.9 µg/m³2026-04-24: 8.8 µg/m³2026-04-25: 11.5 µg/m³2026-04-26: 13.8 µg/m³2026-04-27: 15.3 µg/m³2026-04-28: 10.8 µg/m³2026-04-29: 14.2 µg/m³2026-04-30: 15.8 µg/m³2026-05-01: 11.1 µg/m³2026-05-02: 25.7 µg/m³2026-05-03: 19.5 µg/m³2026-05-04: 8.6 µg/m³2026-05-05: 11.0 µg/m³2026-05-06: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-07: 14.1 µg/m³2026-05-08: 8.8 µg/m³2026-05-09: 9.7 µg/m³2026-05-10: 10.8 µg/m³2026-05-11: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-12: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-13: 12.0 µg/m³2026-05-14: 23.3 µg/m³2026-05-15: 16.3 µg/m³2026-05-16: 19.9 µg/m³2026-05-17: 20.0 µg/m³2026-05-18: 18.8 µg/m³2026-05-19: 28.0 µg/m³2026-05-20: 11.5 µg/m³2026-05-21: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-22: 6.6 µg/m³2026-05-23: 11.3 µg/m³2026-05-24: 12.6 µg/m³2026-05-25: 14.5 µg/m³2026-05-26: no daily value, under 18 hours of readings, or readings that failed our checks2026-05-27: 9.5 µg/m³2026-05-28: 9.0 µg/m³2026-05-29: 14.0 µg/m³2026-05-30: 10.5 µg/m³2026-05-31: 12.9 µg/m³2026-06-01: 22.2 µg/m³2026-06-02: 18.0 µg/m³2026-06-03: 21.4 µg/m³2026-06-04: 15.8 µg/m³2026-06-05: 4.5 µg/m³2026-06-06: 10.9 µg/m³2026-06-07: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-08: 14.9 µg/m³2026-06-09: 11.0 µg/m³2026-06-10: 11.9 µg/m³2026-06-11: 13.3 µg/m³2026-06-12: 13.3 µg/m³2026-06-13: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-14: 11.6 µg/m³2026-06-15: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-16: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-17: 12.0 µg/m³2026-06-18: 18.4 µg/m³2026-06-19: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-20: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-21: 4.8 µg/m³2026-06-22: 10.2 µg/m³2026-06-23: 5.6 µg/m³2026-06-24: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-25: no daily value, under 18 hours of readings, or readings that failed our checks2026-06-26: 10.6 µg/m³2026-06-27: 15.0 µg/m³2026-06-28: 14.9 µg/m³2026-06-29: 15.0 µg/m³2026-06-30: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-01: 12.3 µg/m³2026-07-02: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-03: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-04: 13.1 µg/m³2026-07-05: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-06: 8.4 µg/m³2026-07-07: 10.5 µg/m³2026-07-08: 7.8 µg/m³2026-07-09: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-10: 7.9 µg/m³2026-07-11: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-12: 10.1 µg/m³2026-07-13: 6.8 µg/m³2026-07-14: 6.7 µg/m³2026-07-15: 7.7 µg/m³2026-07-16: 17.5 µg/m³2026-07-17: 10.7 µg/m³2026-07-18: 8.1 µg/m³2026-07-19: 5.9 µg/m³2026-07-20: 9.1 µg/m³2026-07-21: 8.8 µg/m³2026-07-22: 11.1 µg/m³2026-07-23: 10.0 µg/m³2026-07-24: 8.7 µg/m³2026-07-25: 4.8 µg/m³2026-07-26: 3.7 µg/m³2026-07-27: 5.5 µg/m³2026-07-28: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-29: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-30: no daily value, under 18 hours of readings, or readings that failed our checks2026-07-31: 12.9 µg/m³2026-08-01: 15.6 µg/m³2026-08-02: 14.4 µg/m³2026-08-03: 15.4 µg/m³2026-08-04: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-05: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-06: 5.7 µg/m³2026-08-07: 6.4 µg/m³2026-08-08: 6.8 µg/m³2026-08-09: 2.2 µg/m³2026-08-10: 3.0 µg/m³2026-08-11: 3.3 µg/m³2026-08-12: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-13: 5.4 µg/m³2026-08-14: 9.1 µg/m³2026-08-15: 11.0 µg/m³2026-08-16: 6.3 µg/m³2026-08-17: 4.2 µg/m³2026-08-18: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-19: 14.2 µg/m³2026-08-20: 8.9 µg/m³2026-08-21: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-22: 6.4 µg/m³2026-08-23: 8.9 µg/m³2026-08-24: 11.1 µg/m³2026-08-25: 10.9 µg/m³2026-08-26: 12.1 µg/m³2026-08-27: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-28: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-29: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-30: no daily value, under 18 hours of readings, or readings that failed our checks2026-08-31: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-01: 4.3 µg/m³2026-09-02: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-03: 7.7 µg/m³2026-09-04: 3.0 µg/m³2026-09-05: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-06: 6.1 µg/m³2026-09-07: 8.0 µg/m³2026-09-08: 8.4 µg/m³2026-09-09: 4.3 µg/m³2026-09-10: 6.7 µg/m³2026-09-11: 7.8 µg/m³2026-09-12: 12.0 µg/m³2026-09-13: 17.1 µg/m³2026-09-14: 19.4 µg/m³2026-09-15: 11.8 µg/m³2026-09-16: 13.5 µg/m³2026-09-17: 5.8 µg/m³2026-09-18: 6.0 µg/m³2026-09-19: 7.0 µg/m³2026-09-20: 7.0 µg/m³2026-09-21: no daily value, under 18 hours of readings, or readings that failed our checks2026-09-22: 7.8 µg/m³2026-09-23: 10.0 µg/m³2026-09-24: 16.5 µg/m³2026-09-25: 13.9 µg/m³2026-09-26: 6.5 µg/m³2026-09-27: 7.4 µg/m³2026-09-28: 13.1 µg/m³2026-09-29: 8.8 µg/m³2026-09-30: 9.4 µg/m³2026-10-01: 5.9 µg/m³2026-10-02: 9.0 µg/m³2026-10-03: 10.2 µg/m³2026-10-04: no daily value, only 14 of the 18 hours a day needs
136 of 328 measured days were over the WHO 24-hour guideline (15 µg/m³). 37 days without a value: 1 with readings for part of the day (a day needs 18 hours), 36 with under 18 hours of readings or readings that failed our checks; point at a grey square for its reason (why days go blank). 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

15304 Oct 10:00 local, 2026-10-04 01:00 UTC: 8.0 µg/m³4 Oct 11:00 local, 2026-10-04 02:00 UTC: 3.0 µg/m³4 Oct 12:00 local, 2026-10-04 03:00 UTC: 1.0 µg/m³4 Oct 13:00 local, 2026-10-04 04:00 UTC: 1.0 µg/m³4 Oct 14:00 local, 2026-10-04 05:00 UTC: 1.0 µg/m³4 Oct 15:00 local, 2026-10-04 06:00 UTC: 1.0 µg/m³4 Oct 16:00 local, 2026-10-04 07:00 UTC: 5.0 µg/m³4 Oct 17:00 local, 2026-10-04 08:00 UTC: 1.0 µg/m³4 Oct 18:00 local, 2026-10-04 09:00 UTC: 2.0 µg/m³4 Oct 19:00 local, 2026-10-04 10:00 UTC: 10.0 µg/m³4 Oct 20:00 local, 2026-10-04 11:00 UTC: 15.0 µg/m³4 Oct 21:00 local, 2026-10-04 12:00 UTC: 20.0 µg/m³4 Oct 22:00 local, 2026-10-04 13:00 UTC: 19.0 µg/m³4 Oct 23:00 local, 2026-10-04 14:00 UTC: 17.0 µg/m³5 Oct 00:00 local, 2026-10-04 15:00 UTC: 10.0 µg/m³5 Oct 01:00 local, 2026-10-04 16:00 UTC: 4.0 µg/m³5 Oct 02:00 local, 2026-10-04 17:00 UTC: 8.0 µg/m³5 Oct 03:00 local, 2026-10-04 18:00 UTC: 16.0 µg/m³5 Oct 04:00 local, 2026-10-04 19:00 UTC: 13.0 µg/m³5 Oct 05:00 local, 2026-10-04 20:00 UTC: 11.0 µg/m³5 Oct 06:00 local, 2026-10-04 21:00 UTC: 9.0 µg/m³5 Oct 07:00 local, 2026-10-04 22:00 UTC: 4.0 µg/m³5 Oct 08:00 local, 2026-10-04 23:00 UTC: 6.0 µg/m³5 Oct 09:00 local, 2026-10-05 00:00 UTC: 13.0 µg/m³5 Oct 10:00 local, 2026-10-05 01:00 UTC: 7.0 µg/m³5 Oct 11:00 local, 2026-10-05 02:00 UTC: 1.0 µg/m³Oct 2Oct 3Oct 4Oct 5
Sintansin's local time; hover a bar for UTC. Dashed line: WHO 24-hour guideline (15 µg/m³).

Where it stood each day

Top 10Top 100#1#10#100#1,000#3,193NovDecJanFebMarAprMayJunJulAugSep#563
Its rank on each day's world board, #1 being the most polluted city that day. Higher is worse. Each gridline down is ten times the rank above it (#1, #10, #100, #1,000), so the top places get the most room. See it among every city.

2026 against 2025, month by month

15Jan 2025: 23.6 µg/m³Jan 2026: 20.0 µg/m³JanFeb 2025: 17.3 µg/m³Feb 2026: 24.0 µg/m³FebMar 2025: 25.1 µg/m³Mar 2026: 26.3 µg/m³MarApr 2025: 20.9 µg/m³Apr 2026: 14.8 µg/m³AprMay 2025: 18.0 µg/m³May 2026: 14.2 µg/m³MayJun 2025: 16.7 µg/m³Jun 2026: 13.1 µg/m³JunJul 2025: 12.7 µg/m³Jul 2026: 9.0 µg/m³JulAug 2025: 11.1 µg/m³Aug 2026: 8.6 µg/m³AugSep 2025: 8.8 µg/m³Sep 2026: 9.2 µg/m³SepOct 2025: 10.2 µg/m³OctNov 2025: 23.1 µg/m³NovDec 2025: 17.9 µg/m³Dec
Faded bars: 2025. A month shows once it has 10 measured days.

This week against past years

This weekThis week: 9.4 µg/m³9.420252025: 12.5 µg/m³12.520242024: 6.3 µg/m³6.3
Mean PM2.5 for 28 Sept to 4 Oct in each year. Dashed line: WHO 24-hour guideline.

Monitors

PM2.5 from 2 reference monitors, updated hourly. Only 1 of them reported in the last 24 hours.

StationOperatorType
문평동Permission requested (AirKorea, 2026-10-01)Korea Air Ministry of EnvironmentReference
부강면Permission 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, Sintansin, South Korea, 5 Oct 2025 – 3 Oct 2026, smogrank.com/kr/sintansin (accessed 5 Oct 2026).

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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.

Other cities in South Korea

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

Updated 2026-10-05 03:07 UTC. Values are PM2.5 (fine particles), the median of each city's monitors, as the US AQI PM2.5 sub-index.