SmogRank / Episodes / South Korea
South Korea and Japan, December 2025
For 1 day, on 11 December 2025, 20 cities in South Korea and Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Hayang, Gyeongsangbuk-do, South Korea: 40.2 µg/m³ on 11 December, about 2.5× its usual 15.8.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 20 in 2 countries
Days 1 11 December 2025
Worst day 11 December 20 cities counted
Furthest above usual 3.2× Kurye
Day by day
Play 11 December 20 cities at twice their usual or more
Busan Geoje Sinhyeon Yangsan Naesŏ Gijang Tongyeong Miryang Ungsang Changnyeong Ulsan Hwawŏn Tsushima Daegu Gyeongju Yeonil Hadong Pohang Gwangyang Gumi Kwangyang Gimcheon Cheongsong gun Iki Changsu Beolgyo Nangen Andong Sangju Yeongdong Jinan-gun Kinzan Boseong Matsuura Yeongju Hwasun Karatsu Jeonju Wanju Gwangju Maebaru-chūō Itoshima Jangheung Imarichō-kō Daejeon Sasebo Koga Jeongeup Namsa Munakata Fukuoka Yŏnmu Koesan Taku Iksan Kimje Takeo Koga Cheongju-si Naju Nonsan Wakasugi Saikai Kasuga Yeongam Nakama T’aebaek Ureshinomachi-shimojuku Chungju Higashigō Jungpyong Koch'ang Neietsu Nōgata Sejong Kashima Buan Kanzakimachi-kanzaki Saga Iizuka Gongju Kitakyushu Haenam Gotō Tosu Shimonoseki Ogōri Ōmura Buyeo Chinch'ŏn Tagawa Gunsan Yeonggwang Togitsu Muan Yanagawa Obita Nagato Chikugo Kanda Tanushimarumachi-toyoki Isahaya Nagasaki Yukuhashi Santyoku Mokpo Mine Ukiha Cheonan Yame Ōmuta Onoda Wŏnju Arao Anseong Asan Seonghwan Ube Yeoju Hagi Yesan Boryeong Buzen Tamana Pubal Pyeongtaek Icheon-si Nakatsu Hongseong Yamaguchi Sinan Jeju City Uekimachi-mōno Kikuchi Osan Kumamoto Hōfu Ōyanomachi-noboritate Seogwipo Kotō Gwangju Ōzu Uto Tangjin Suwon Gaigeturi Seongnam-si Mifune Seosan Masuda Hwaseong-si Aso Anyang-si Yufu Shūnan Ansan-si Taesal-li Beppu Kudamatsu Kunisaki Hamada Ōita Hikari Tsurusaki Gōtsuchō Mie Yanai Ōtake Iwakuni Tsukumiura Hiroshima Gion Ōdachō-ōda Saiki Yae Nobeoka Kure Yawatahama Higashihiroshima Izumo Miyoshi Iyo Unnan Matsuyama Uwajima Takehara Matsue Imabari Mihara Shinagawa Onomichi Yasugichō Sakaiminato Shin’ichi Saijō Yonago Fukuyama Nakamura Niihama Niimi Kasaoka Susaki Takahashi Asakuchi Ino Shikokuchūō Kan’onjichō Kochi Sōja Kurashiki Marugame Kurayoshi Zentsujichó Nankoku Ikedachō Kunwi Hita Gyeongsan-si Goseong Changwon Jangseong Damyang Waegwan Masan Chinju Kimhae Mungyeong Okcheon Eisen Yeosu Suncheon Yecheon Imsil Hayang Kurye 8 Dec 9 10 11 12 13 14 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
Hayang Hayang, 8 December: 19.8 µg/m³ Hayang, 9 December: 11.4 µg/m³ Hayang, 10 December: 33.6 µg/m³ Hayang, 11 December: 40.2 µg/m³, 2.5× its usual 15.8 Hayang, 12 December: 13.3 µg/m³ Hayang, 13 December: 14.2 µg/m³ Hayang, 14 December: 8.9 µg/m³ Okcheon Okcheon, 8 December: 26.5 µg/m³ Okcheon, 9 December: 18.5 µg/m³ Okcheon, 10 December: 33.0 µg/m³ Okcheon, 11 December: 37.9 µg/m³, 2.2× its usual 17.3 Okcheon, 12 December: 17.0 µg/m³ Okcheon, 13 December: 12.1 µg/m³ Okcheon, 14 December: 20.0 µg/m³ Masan Masan, 8 December: 18.8 µg/m³ Masan, 9 December: 12.6 µg/m³ Masan, 10 December: 28.9 µg/m³ Masan, 11 December: 33.8 µg/m³, 2.1× its usual 16.1 Masan, 12 December: 16.1 µg/m³ Masan, 13 December: 9.0 µg/m³ Masan, 14 December: 8.7 µg/m³ Imsil Imsil, 8 December: 16.8 µg/m³ Imsil, 9 December: 10.0 µg/m³ Imsil, 10 December: 21.9 µg/m³ Imsil, 11 December: 33.3 µg/m³, 2.4× its usual 14.1 Imsil, 12 December: 10.5 µg/m³ Imsil, 13 December: 7.0 µg/m³ Imsil, 14 December: 13.2 µg/m³ Waegwan Waegwan, 8 December: 19.6 µg/m³ Waegwan, 9 December: 12.0 µg/m³ Waegwan, 10 December: 26.3 µg/m³ Waegwan, 11 December: 33.3 µg/m³, 2.1× its usual 15.6 Waegwan, 12 December: 11.8 µg/m³ Waegwan, 13 December: 11.0 µg/m³ Waegwan, 14 December: 11.9 µg/m³ Gyeongsan-si Gyeongsan-si, 8 December: 20.5 µg/m³ Gyeongsan-si, 9 December: 11.3 µg/m³ Gyeongsan-si, 10 December: 31.3 µg/m³ Gyeongsan-si, 11 December: 32.3 µg/m³, 2.0× its usual 16.0 Gyeongsan-si, 12 December: 12.9 µg/m³ Gyeongsan-si, 13 December: 15.2 µg/m³ Gyeongsan-si, 14 December: 12.3 µg/m³ Yecheon Yecheon, 8 December: 18.3 µg/m³ Yecheon, 9 December: 10.3 µg/m³ Yecheon, 10 December: 21.5 µg/m³ Yecheon, 11 December: 31.8 µg/m³, 2.4× its usual 13.4 Yecheon, 12 December: 13.2 µg/m³ Yecheon, 13 December: 6.7 µg/m³ Yecheon, 14 December: 13.1 µg/m³ Eisen Eisen, 8 December: no reading Eisen, 9 December: no reading Eisen, 10 December: 29.0 µg/m³ Eisen, 11 December: 30.9 µg/m³, 2.3× its usual 13.6 Eisen, 12 December: 11.4 µg/m³ Eisen, 13 December: 6.3 µg/m³ Eisen, 14 December: 9.7 µg/m³ Mungyeong Mungyeong, 8 December: 17.0 µg/m³ Mungyeong, 9 December: no reading Mungyeong, 10 December: 23.0 µg/m³ Mungyeong, 11 December: 29.7 µg/m³, 2.2× its usual 13.8 Mungyeong, 12 December: 10.2 µg/m³ Mungyeong, 13 December: 4.9 µg/m³ Mungyeong, 14 December: 10.3 µg/m³ Kimhae Kimhae, 8 December: 23.3 µg/m³ Kimhae, 9 December: 11.6 µg/m³ Kimhae, 10 December: 24.6 µg/m³ Kimhae, 11 December: 29.5 µg/m³, 2.2× its usual 13.5 Kimhae, 12 December: 8.8 µg/m³ Kimhae, 13 December: 6.3 µg/m³ Kimhae, 14 December: 9.1 µg/m³ Hita Hita, 8 December: 17.8 µg/m³ Hita, 9 December: 17.0 µg/m³ Hita, 10 December: 17.1 µg/m³ Hita, 11 December: 29.5 µg/m³, 2.0× its usual 14.4 Hita, 12 December: 13.1 µg/m³ Hita, 13 December: 8.7 µg/m³ Hita, 14 December: 7.4 µg/m³ Kurye Kurye, 8 December: 16.3 µg/m³ Kurye, 9 December: 8.1 µg/m³ Kurye, 10 December: no reading Kurye, 11 December: 29.2 µg/m³, 3.2× its usual 9.2 Kurye, 12 December: no reading Kurye, 13 December: no reading Kurye, 14 December: 9.6 µg/m³ Chinju Chinju, 8 December: 21.8 µg/m³ Chinju, 9 December: 10.8 µg/m³ Chinju, 10 December: 22.8 µg/m³ Chinju, 11 December: 29.1 µg/m³, 2.2× its usual 13.4 Chinju, 12 December: 11.9 µg/m³ Chinju, 13 December: 6.3 µg/m³ Chinju, 14 December: 7.5 µg/m³ Damyang Damyang, 8 December: 15.5 µg/m³ Damyang, 9 December: no reading Damyang, 10 December: 22.8 µg/m³ Damyang, 11 December: 27.3 µg/m³, 2.1× its usual 13.2 Damyang, 12 December: 7.7 µg/m³ Damyang, 13 December: 3.9 µg/m³ Damyang, 14 December: 5.8 µg/m³ Jangseong Jangseong, 8 December: no reading Jangseong, 9 December: 8.8 µg/m³ Jangseong, 10 December: 20.1 µg/m³ Jangseong, 11 December: 27.3 µg/m³, 2.1× its usual 12.8 Jangseong, 12 December: 11.5 µg/m³ Jangseong, 13 December: 6.8 µg/m³ Jangseong, 14 December: 7.4 µg/m³ Suncheon Suncheon, 8 December: 18.8 µg/m³ Suncheon, 9 December: 7.3 µg/m³ Suncheon, 10 December: 23.5 µg/m³ Suncheon, 11 December: 26.8 µg/m³, 2.4× its usual 11.3 Suncheon, 12 December: 11.2 µg/m³ Suncheon, 13 December: 4.6 µg/m³ Suncheon, 14 December: 7.1 µg/m³ Yeosu Yeosu, 8 December: 18.7 µg/m³ Yeosu, 9 December: 11.7 µg/m³ Yeosu, 10 December: 17.8 µg/m³ Yeosu, 11 December: 26.6 µg/m³, 2.4× its usual 11.1 Yeosu, 12 December: 10.3 µg/m³ Yeosu, 13 December: 4.9 µg/m³ Yeosu, 14 December: 6.5 µg/m³ Changwon Changwon, 8 December: 19.9 µg/m³ Changwon, 9 December: 9.3 µg/m³ Changwon, 10 December: 21.3 µg/m³ Changwon, 11 December: 25.8 µg/m³, 2.1× its usual 12.4 Changwon, 12 December: 9.7 µg/m³ Changwon, 13 December: 7.5 µg/m³ Changwon, 14 December: 7.8 µg/m³ Kunwi Kunwi, 8 December: 18.0 µg/m³ Kunwi, 9 December: 11.0 µg/m³ Kunwi, 10 December: no reading Kunwi, 11 December: 25.8 µg/m³, 2.0× its usual 12.9 Kunwi, 12 December: 10.0 µg/m³ Kunwi, 13 December: 5.6 µg/m³ Kunwi, 14 December: 11.8 µg/m³ Goseong Goseong, 8 December: 23.5 µg/m³ Goseong, 9 December: no reading Goseong, 10 December: 22.7 µg/m³ Goseong, 11 December: 25.5 µg/m³, 2.1× its usual 12.2 Goseong, 12 December: 10.3 µg/m³ Goseong, 13 December: 5.3 µg/m³ Goseong, 14 December: 9.1 µg/m³ 8 Dec 9 10 11 12 13 14 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
Kurye Jeollanam-do, South Korea 1 11 December 9.2 3.2× Hayang Gyeongsangbuk-do, South Korea 1 11 December 15.8 2.5× Imsil Jeollabuk-do, South Korea 1 11 December 14.1 2.4× Yecheon Gyeongsangbuk-do, South Korea 1 11 December 13.4 2.4× Suncheon Jeollanam-do, South Korea 1 11 December 11.3 2.4× Yeosu Jeollanam-do, South Korea 1 11 December 11.1 2.4× Eisen Gyeongsangbuk-do, South Korea 1 11 December 13.6 2.3× Okcheon North Chungcheong, South Korea 1 11 December 17.3 2.2× Mungyeong Gyeongsangbuk-do, South Korea 1 11 December 13.8 2.2× Kimhae Gyeongsangnam-do, South Korea 1 11 December 13.5 2.2× Chinju Gyeongsangnam-do, South Korea 1 11 December 13.4 2.2× Masan Gwangju, South Korea 1 11 December 16.1 2.1× Waegwan Gyeongsangbuk-do, South Korea 1 11 December 15.6 2.1× Damyang Jeollanam-do, South Korea 1 11 December 13.2 2.1× Jangseong Jeollanam-do, South Korea 1 11 December 12.8 2.1× Changwon Gyeongsangnam-do, South Korea 1 11 December 12.4 2.1× Goseong Gyeongsangnam-do, South Korea 1 11 December 12.2 2.1× Gyeongsan-si Gyeongsangbuk-do, South Korea 1 11 December 16.0 2.0× Hita Oita, Japan 1 11 December 14.4 2.0× Kunwi Gyeongsangbuk-do, South Korea 1 11 December 12.9 2.0×
Daily means in µg/m³, over the days each city counted in this episode. Highest: its highest of those days. Usual: the city's median for the time of year of that day (its days within 21 days of the date, every year, leaving out the week around it). Above usual: its highest day against that, with a usual under 5 µg/m³ taken as 5.
Against other episodes in South Korea and Japan
Number 66 of 94 episodes in South Korea and Japan since our records began, by cities reached.
Japan and South Korea, June and July 2025 508 Japan and South Korea, April 2024 499 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 Japan, 21 to 25 July 2026 172 South Korea and Japan, January 2026 169 South Korea and Japan, 10 to 15 February 2026 147 South Korea, 14 to 16 February 2025 132 Japan, November 2023 131 South Korea and Japan, November 2025 128 South Korea and Japan, December 2025 20 Bars: cities reached; colour: the level of the episode's highest daily reading. All 94 .
Use this page SmogRank, South Korea and Japan, December 2025: 20 cities with PM2.5 at twice their usual or more, 11 December 2025, smogrank.com/episodes/2025-12-south-korea-and-japan (accessed 4 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.
