What is the air quality trend in Koesan?

Over the past 8 days, Koesan had an average AQI of 42 based on station measurements. The worst day was 2026-10-21 with AQI 55.

How is Koesan air quality measured?

Air quality in Koesan is measured by ground-level monitoring stations that report PM2.5 and PM10 concentrations hourly. CERNS.IO aggregates readings from nearby stations and converts PM2.5 to the US EPA Air Quality Index (AQI) scale.

Air Quality History for Koesan, South Korea

Name: Koesan Air Quality History
Creator: CERNS.IO
License: https://creativecommons.org/licenses/by/4.0/

Historical PM2.5 and AQI trend from monitoring stations near Koesan, South Korea.

Current AQI
Moderate Station

48 Hours 7 Days 14 Days 20 Days

CSV JSON

Air Quality Index Station

166h

PM2.5 Station

166h · 16 stations

Temperature GFS model

28pt

Precipitation GFS model

mm/day

Daily Summary Station

Date	AQI	Range	PM2.5 avg	Hours	Stations
2026-10-21	55	45–61	14.6 µg/m³	3h	9
2026-10-20	40	15–58	9.8 µg/m³	24h	12
2026-10-19	37	9–55	9.0 µg/m³	24h	21
2026-10-18	36	14–59	8.7 µg/m³	24h	16
2026-10-17	47	23–101	12.3 µg/m³	24h	12
2026-10-16	50	6–74	13.2 µg/m³	24h	18
2026-10-15	40	18–177	12.3 µg/m³	24h	14
2026-10-14	37	21–76	9.2 µg/m³	19h	18

Back to Koesan Air Quality