SmogRank / Episodes / South Korea
South Korea, October 2025
For 2 days, from 30 to 31 October 2025, 25 cities in South Korea had PM2.5 at least twice their usual for the time of year. The worst reading was Seonghwan, Chungcheongnam-do, South Korea: 51.2 µg/m³ on 31 October, about 2.9× its usual 17.5.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 25 in 1 country
Days 2 30 to 31 October 2025
Worst day 31 October 25 cities counted
Furthest above usual 3.1× Hongseong
Day by day
Play 31 October 25 cities at twice their usual or more
Gongju Sejong Buyeo Nonsan Chinch'ŏn Cheongju-si Anyang-si Daejeon Yŏnmu Jungpyong Gwangmyeong Seongnam-si Bucheon-si Gwangju Icheon-si Seoul Namsa Okcheon Pubal Hanam Gimpo-si Kinzan Guri-si Goyang-si Wabu Koesan Yeoju Namyangju Jeonju Yangp'yŏng Hwado Ganghwa-gun Yeongdong Chungju Jinan-gun Yangju Munsan Jeongeup Imsil Wŏnju Gapyeong Changsu Sangju Mungyeong Hongch’ŏn Gimcheon Chuncheon Damyang Nangen Jangseong Gwangju Yecheon Gumi Hwacheon Masan Kurye Neietsu Hwasun Waegwan Naju Yanggu Yeongju Kunwi Muan Andong Hwawŏn Hadong Suncheon Kwangyang Daegu Yeongam Beolgyo Chinju Boseong Gwangyang Mokpo Changnyeong Sinan Jangheung Gyeongsan-si Hayang Yeosu T’aebaek Haenam Eisen Cheongsong gun Naesŏ Gangneung Miryang Sokcho Jumunjin Kosong Goseong Changwon Donghae City Santyoku Tongyeong Gyeongju Kimhae Sinhyeon Yeonil Yangsan Pohang Ungsang Geoje Busan Ulsan Gijang Nagato Wanju Yeonggwang Incheon Iksan Kimje Gunsan Uijeongbu-si Koch'ang Osan Suwon Cheorwon Cheonan Buan Ansan-si Seosan Asan Taesal-li Hwaseong-si Boryeong Pyeongtaek Seonghwan Tangjin Yesan Anseong Hongseong 27 Oct 28 29 30 31 1 Nov 2 3 Every measured city in the area, coloured by its PM2.5 that day; a dark ring marks a city at twice its usual or more. Bars: cities counted each day, coloured by their median level. Choose a day or press play; without JavaScript, the days link to that day's world ranking.
How it spread
Seonghwan Seonghwan, 27 October: 14.5 µg/m³, 0.8× usual Seonghwan, 28 October: 14.7 µg/m³, 0.8× usual Seonghwan, 29 October: 26.8 µg/m³, 1.5× usual Seonghwan, 30 October: 39.9 µg/m³, 2.3× usual Seonghwan, 31 October: 51.2 µg/m³, 2.9× usual Seonghwan, 1 November: 21.0 µg/m³, 1.2× usual Seonghwan, 2 November: 10.8 µg/m³, 0.6× usual Seonghwan, 3 November: 17.7 µg/m³, 1.0× usual Hwaseong-si Hwaseong-si, 27 October: 7.9 µg/m³, 0.5× usual Hwaseong-si, 28 October: 10.7 µg/m³, 0.7× usual Hwaseong-si, 29 October: 20.3 µg/m³, 1.4× usual Hwaseong-si, 30 October: 32.6 µg/m³, 2.2× usual Hwaseong-si, 31 October: 39.6 µg/m³, 2.7× usual Hwaseong-si, 1 November: 11.4 µg/m³, 0.8× usual Hwaseong-si, 2 November: 6.9 µg/m³, 0.5× usual Hwaseong-si, 3 November: 14.6 µg/m³, 1.0× usual Anseong Anseong, 27 October: 12.8 µg/m³, 1.1× usual Anseong, 28 October: 7.5 µg/m³, 0.6× usual Anseong, 29 October: 18.5 µg/m³, 1.5× usual Anseong, 30 October: 32.0 µg/m³, 2.7× usual Anseong, 31 October: 36.5 µg/m³, 3.0× usual Anseong, 1 November: 17.7 µg/m³, 1.5× usual Anseong, 2 November: 7.0 µg/m³, 0.6× usual Anseong, 3 November: 10.8 µg/m³, 0.9× usual Pyeongtaek Pyeongtaek, 27 October: 11.2 µg/m³, 0.8× usual Pyeongtaek, 28 October: 9.5 µg/m³, 0.7× usual Pyeongtaek, 29 October: 20.0 µg/m³, 1.4× usual Pyeongtaek, 30 October: 29.1 µg/m³, 2.1× usual Pyeongtaek, 31 October: 41.4 µg/m³, 2.9× usual Pyeongtaek, 1 November: 15.2 µg/m³, 1.1× usual Pyeongtaek, 2 November: 8.6 µg/m³, 0.6× usual Pyeongtaek, 3 November: 12.6 µg/m³, 0.9× usual Cheorwon Cheorwon, 27 October: 15.8 µg/m³, 1.2× usual Cheorwon, 28 October: 14.0 µg/m³, 1.1× usual Cheorwon, 29 October: 19.0 µg/m³, 1.4× usual Cheorwon, 30 October: 28.3 µg/m³, 2.1× usual Cheorwon, 31 October: 30.9 µg/m³, 2.3× usual Cheorwon, 1 November: 15.8 µg/m³, 1.2× usual Cheorwon, 2 November: 13.8 µg/m³, 1.0× usual Cheorwon, 3 November: 15.1 µg/m³, 1.1× usual Tangjin Tangjin, 27 October: 13.5 µg/m³, 0.8× usual Tangjin, 28 October: 12.7 µg/m³, 0.8× usual Tangjin, 29 October: 23.2 µg/m³, 1.4× usual Tangjin, 30 October: 34.6 µg/m³, 2.1× usual Tangjin, 31 October: 51.1 µg/m³, 3.0× usual Tangjin, 1 November: 16.5 µg/m³, 1.0× usual Tangjin, 2 November: 15.8 µg/m³, 0.9× usual Tangjin, 3 November: 14.0 µg/m³, 0.8× usual Yesan Yesan, 27 October: 11.0 µg/m³, 0.7× usual Yesan, 28 October: 13.3 µg/m³, 0.8× usual Yesan, 29 October: 19.8 µg/m³, 1.2× usual Yesan, 30 October: 26.0 µg/m³, 1.6× usual Yesan, 31 October: 48.2 µg/m³, 3.0× usual Yesan, 1 November: 19.2 µg/m³, 1.2× usual Yesan, 2 November: 9.0 µg/m³, 0.6× usual Yesan, 3 November: 15.0 µg/m³, 0.9× usual Hongseong Hongseong, 27 October: 8.6 µg/m³, 0.6× usual Hongseong, 28 October: 13.4 µg/m³, 0.9× usual Hongseong, 29 October: 21.2 µg/m³, 1.4× usual Hongseong, 30 October: 28.7 µg/m³, 1.9× usual Hongseong, 31 October: 45.3 µg/m³, 3.1× usual Hongseong, 1 November: 17.6 µg/m³, 1.2× usual Hongseong, 2 November: 8.1 µg/m³, 0.5× usual Hongseong, 3 November: 13.4 µg/m³, 0.9× usual Asan Asan, 27 October: 14.3 µg/m³, 0.9× usual Asan, 28 October: 11.8 µg/m³, 0.7× usual Asan, 29 October: 22.9 µg/m³, 1.4× usual Asan, 30 October: 27.4 µg/m³, 1.7× usual Asan, 31 October: 43.1 µg/m³, 2.7× usual Asan, 1 November: 22.4 µg/m³, 1.4× usual Asan, 2 November: 12.0 µg/m³, 0.8× usual Asan, 3 November: 14.9 µg/m³, 0.9× usual Kimje Kimje, 27 October: 16.0 µg/m³, 0.9× usual Kimje, 28 October: 18.8 µg/m³, 1.0× usual Kimje, 29 October: 22.8 µg/m³, 1.3× usual Kimje, 30 October: 24.9 µg/m³, 1.4× usual Kimje, 31 October: 38.3 µg/m³, 2.1× usual Kimje, 1 November: 24.4 µg/m³, 1.4× usual Kimje, 2 November: 11.5 µg/m³, 0.6× usual Kimje, 3 November: 17.8 µg/m³, 1.0× usual Boryeong Boryeong, 27 October: 8.6 µg/m³, 0.6× usual Boryeong, 28 October: 11.3 µg/m³, 0.8× usual Boryeong, 29 October: 14.3 µg/m³, 1.0× usual Boryeong, 30 October: 22.7 µg/m³, 1.6× usual Boryeong, 31 October: 38.0 µg/m³, 2.8× usual Boryeong, 1 November: 14.5 µg/m³, 1.1× usual Boryeong, 2 November: 8.6 µg/m³, 0.6× usual Boryeong, 3 November: 13.5 µg/m³, 1.0× usual Buan Buan, 27 October: 9.6 µg/m³, 0.6× usual Buan, 28 October: 13.8 µg/m³, 0.9× usual Buan, 29 October: 24.8 µg/m³, 1.6× usual Buan, 30 October: 29.5 µg/m³, 1.9× usual Buan, 31 October: 37.3 µg/m³, 2.4× usual Buan, 1 November: 16.6 µg/m³, 1.1× usual Buan, 2 November: 6.8 µg/m³, 0.4× usual Buan, 3 November: 11.5 µg/m³, 0.7× usual Iksan Iksan, 27 October: 11.4 µg/m³, 0.7× usual Iksan, 28 October: 12.9 µg/m³, 0.7× usual Iksan, 29 October: 20.2 µg/m³, 1.2× usual Iksan, 30 October: 22.2 µg/m³, 1.3× usual Iksan, 31 October: 36.8 µg/m³, 2.1× usual Iksan, 1 November: 22.5 µg/m³, 1.3× usual Iksan, 2 November: 10.8 µg/m³, 0.6× usual Iksan, 3 November: 12.2 µg/m³, 0.7× usual Gunsan Gunsan, 27 October: 8.3 µg/m³, 0.5× usual Gunsan, 28 October: 10.6 µg/m³, 0.7× usual Gunsan, 29 October: 21.2 µg/m³, 1.3× usual Gunsan, 30 October: 23.9 µg/m³, 1.5× usual Gunsan, 31 October: 34.1 µg/m³, 2.1× usual Gunsan, 1 November: 15.4 µg/m³, 1.0× usual Gunsan, 2 November: 10.7 µg/m³, 0.7× usual Gunsan, 3 November: 14.0 µg/m³, 0.9× usual Ansan-si Ansan-si, 27 October: 9.4 µg/m³, 0.7× usual Ansan-si, 28 October: 10.7 µg/m³, 0.8× usual Ansan-si, 29 October: 16.4 µg/m³, 1.2× usual Ansan-si, 30 October: 26.8 µg/m³, 2.0× usual Ansan-si, 31 October: 33.6 µg/m³, 2.5× usual Ansan-si, 1 November: 11.4 µg/m³, 0.8× usual Ansan-si, 2 November: 7.9 µg/m³, 0.6× usual Ansan-si, 3 November: 13.7 µg/m³, 1.0× usual Cheonan Cheonan, 27 October: 12.4 µg/m³, 0.9× usual Cheonan, 28 October: 10.7 µg/m³, 0.8× usual Cheonan, 29 October: 18.9 µg/m³, 1.3× usual Cheonan, 30 October: 22.7 µg/m³, 1.6× usual Cheonan, 31 October: 33.5 µg/m³, 2.4× usual Cheonan, 1 November: 16.5 µg/m³, 1.2× usual Cheonan, 2 November: 9.9 µg/m³, 0.7× usual Cheonan, 3 November: 13.2 µg/m³, 0.9× usual Taesal-li Taesal-li, 27 October: 7.6 µg/m³, 0.6× usual Taesal-li, 28 October: 10.9 µg/m³, 0.9× usual Taesal-li, 29 October: 15.3 µg/m³, 1.3× usual Taesal-li, 30 October: 21.8 µg/m³, 1.9× usual Taesal-li, 31 October: 32.1 µg/m³, 2.7× usual Taesal-li, 1 November: 10.9 µg/m³, 0.9× usual Taesal-li, 2 November: 10.9 µg/m³, 0.9× usual Taesal-li, 3 November: 15.0 µg/m³, 1.3× usual Wanju Wanju, 27 October: 14.3 µg/m³, 0.9× usual Wanju, 28 October: 12.2 µg/m³, 0.8× usual Wanju, 29 October: 14.4 µg/m³, 0.9× usual Wanju, 30 October: 18.0 µg/m³, 1.2× usual Wanju, 31 October: 30.9 µg/m³, 2.0× usual Wanju, 1 November: 22.5 µg/m³, 1.5× usual Wanju, 2 November: 12.4 µg/m³, 0.8× usual Wanju, 3 November: 13.8 µg/m³, 0.9× usual Incheon Incheon, 27 October: 11.0 µg/m³, 0.8× usual Incheon, 28 October: 11.4 µg/m³, 0.8× usual Incheon, 29 October: 15.7 µg/m³, 1.1× usual Incheon, 30 October: 26.6 µg/m³, 1.8× usual Incheon, 31 October: 30.3 µg/m³, 2.1× usual Incheon, 1 November: 12.2 µg/m³, 0.8× usual Incheon, 2 November: 9.3 µg/m³, 0.6× usual Incheon, 3 November: 13.7 µg/m³, 0.9× usual Osan Osan, 27 October: 11.8 µg/m³, 0.9× usual Osan, 28 October: 8.8 µg/m³, 0.7× usual Osan, 29 October: 15.4 µg/m³, 1.2× usual Osan, 30 October: 23.3 µg/m³, 1.8× usual Osan, 31 October: 29.7 µg/m³, 2.3× usual Osan, 1 November: 13.4 µg/m³, 1.0× usual Osan, 2 November: 8.3 µg/m³, 0.6× usual Osan, 3 November: 10.9 µg/m³, 0.8× usual Suwon Suwon, 27 October: 11.9 µg/m³, 0.9× usual Suwon, 28 October: 9.9 µg/m³, 0.8× usual Suwon, 29 October: 16.1 µg/m³, 1.2× usual Suwon, 30 October: 25.2 µg/m³, 1.9× usual Suwon, 31 October: 29.5 µg/m³, 2.3× usual Suwon, 1 November: 12.8 µg/m³, 1.0× usual Suwon, 2 November: 9.7 µg/m³, 0.7× usual Suwon, 3 November: 12.7 µg/m³, 1.0× usual Seosan Seosan, 27 October: 5.5 µg/m³, 0.5× usual Seosan, 28 October: 10.1 µg/m³, 0.9× usual Seosan, 29 October: 15.6 µg/m³, 1.4× usual Seosan, 30 October: 23.1 µg/m³, 2.0× usual Seosan, 31 October: 28.5 µg/m³, 2.5× usual Seosan, 1 November: 9.6 µg/m³, 0.8× usual Seosan, 2 November: 6.4 µg/m³, 0.6× usual Seosan, 3 November: 13.5 µg/m³, 1.2× usual Uijeongbu-si Uijeongbu-si, 27 October: 11.9 µg/m³, 0.9× usual Uijeongbu-si, 28 October: 10.4 µg/m³, 0.8× usual Uijeongbu-si, 29 October: 14.8 µg/m³, 1.1× usual Uijeongbu-si, 30 October: 25.5 µg/m³, 1.9× usual Uijeongbu-si, 31 October: 27.2 µg/m³, 2.1× usual Uijeongbu-si, 1 November: 12.9 µg/m³, 1.0× usual Uijeongbu-si, 2 November: 7.9 µg/m³, 0.6× usual Uijeongbu-si, 3 November: 10.5 µg/m³, 0.8× usual Koch'ang Koch'ang, 27 October: 8.6 µg/m³, 0.7× usual Koch'ang, 28 October: 8.0 µg/m³, 0.7× usual Koch'ang, 29 October: 10.9 µg/m³, 0.9× usual Koch'ang, 30 October: 10.4 µg/m³, 0.8× usual Koch'ang, 31 October: 26.8 µg/m³, 2.2× usual Koch'ang, 1 November: 13.3 µg/m³, 1.1× usual Koch'ang, 2 November: 7.6 µg/m³, 0.6× usual Koch'ang, 3 November: 10.5 µg/m³, 0.9× usual Yeonggwang Yeonggwang, 27 October: 6.4 µg/m³, 0.5× usual Yeonggwang, 28 October: 7.8 µg/m³, 0.6× usual Yeonggwang, 29 October: 14.6 µg/m³, 1.2× usual Yeonggwang, 30 October: 15.6 µg/m³, 1.2× usual Yeonggwang, 31 October: 25.2 µg/m³, 2.0× usual Yeonggwang, 1 November: 10.7 µg/m³, 0.8× usual Yeonggwang, 2 November: 5.8 µg/m³, 0.5× usual Yeonggwang, 3 November: 8.1 µg/m³, 0.6× usual 27 Oct 28 29 30 31 1 Nov 2 3 Every counted city, in the order the episode reached them, 3 days before to 3 after. Each square is a day, coloured by that day's PM2.5; outlined: at twice the city's usual or more. Good 0–50
Moderate 51–100
Sensitive groups 101–150
Unhealthy 151–200
Very unhealthy 201–300
Hazardous 301+
Every city it reached
City Days Highest Usual Above usual
Hongseong Chungcheongnam-do, South Korea 1 31 October 14.8 3.1× Anseong Gyeonggi-do, South Korea 2 31 October 12.0 3.0× Tangjin Chungcheongnam-do, South Korea 1 31 October 16.8 3.0× Yesan Chungcheongnam-do, South Korea 1 31 October 16.3 3.0× Pyeongtaek Gyeonggi-do, South Korea 2 31 October 14.1 2.9× Seonghwan Chungcheongnam-do, South Korea 2 31 October 17.5 2.9× Boryeong Chungcheongnam-do, South Korea 1 31 October 13.8 2.8× Taesal-li Chungcheongnam-do, South Korea 1 31 October 11.7 2.7× Hwaseong-si Gyeonggi-do, South Korea 2 31 October 14.6 2.7× Asan Chungcheongnam-do, South Korea 1 31 October 16.0 2.7× Seosan Chungcheongnam-do, South Korea 1 31 October 11.4 2.5× Ansan-si Gyeonggi-do, South Korea 1 31 October 13.5 2.5× Buan Jeollabuk-do, South Korea 1 31 October 15.6 2.4× Cheonan Chungcheongnam-do, South Korea 1 31 October 14.2 2.4× Cheorwon Gangwon-do, South Korea 2 31 October 13.3 2.3× Osan Gyeonggi-do, South Korea 1 31 October 13.0 2.3× Suwon Gyeonggi-do, South Korea 1 31 October 13.1 2.3× Koch'ang Jeollabuk-do, South Korea 1 31 October 12.3 2.2× Gunsan Jeollabuk-do, South Korea 1 31 October 16.0 2.1× Kimje Jeollabuk-do, South Korea 1 31 October 18.0 2.1× Iksan Jeollabuk-do, South Korea 1 31 October 17.4 2.1× Incheon Incheon, South Korea 1 31 October 14.5 2.1× Uijeongbu-si Gyeonggi-do, South Korea 1 31 October 13.2 2.1× Wanju Jeollabuk-do, South Korea 1 31 October 15.4 2.0× Yeonggwang Jeollanam-do, South Korea 1 31 October 12.6 2.0×
Daily means in µg/m³. Usual: the city's median for this time of year (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that.
Against other episodes in South Korea
Number 30 of 43 episodes in South Korea since our records began, by cities reached.
Japan and South Korea, March 2025 454 Japan and South Korea, March 2026 305 Japan and South Korea, January 2025 274 Japan and South Korea, February and March 2025 192 South Korea and Japan, January 2026 169 South Korea and Japan, February 2026 147 South Korea, February 2025 132 South Korea, November 2025 128 South Korea, February 2026 121 South Korea, December 2025 113 South Korea, January 2025 113 South Korea, December 2025 107 South Korea, October 2025 25 Bars: cities reached; colour: the level of the episode's highest daily reading. All 43 .
Use this page SmogRank, South Korea, October 2025: 25 cities with PM2.5 at twice their usual or more, 30 to 31 October 2025, smogrank.com/episodes/2025-10-south-korea (accessed 2 October 2026).
Copy citation Download top 10 (PNG)
You're welcome to reuse a single chart, image or figure with this citation and a link. Terms .
An episode is a run of days when many cities close to each other (four or more within 350 km on a day, 8 or more in all) each had a daily PM2.5 mean of at least 25 µg/m³ and at least 2 times their usual for that time of year. Found in our own measurements, not picked by hand. How we find episodes . Values are each city's daily mean of its own monitors; causes are the usual kinds for a pattern like this, not a confirmed source.
