SmogRank / Episodes / Japan
Japan, February 2024
For 2 days, from 14 to 15 February 2024, 21 cities in Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Kasaoka, Okayama, Japan: 46.9 µg/m³ on 14 February, about 5.7× its usual 8.3.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 21 in 1 country
Days 2 14 to 15 February 2024
Worst day 15 February 19 cities counted
Furthest above usual 5.7× Kasaoka
Day by day
Play 15 February 19 cities at twice their usual or more
Kobe Akashi Minato Sumoto Iwade Nishinomiya Kainan Higashinozoe Kinokawa Amagasaki Takarazuka Arida Sandachō Ono Kakogawachō-honmachi Toyonaka Hashimoto Nishiwaki Himeji Narutochō-mitsuishi Ikoma Gobō Hōryūji Kashiwara Ikaruga Kashihara-shi Tanba Kameoka Tatsuno Yawata Nara-shi Tokushima Tenri Sugai Kōtari Nantan Aioi Anan Kizugawa Jōyō Uji Tanabe Kariya Fukuchiyama Kyoto Ayabe Kamojimachō-jōgejima Ōtsu Bizen Yoshinogawa Nabari Shido Maizuru Kusatsu Ueno-ebisumachi Kitahama Miyazu Mima Takamatsu Toyooka Kyōtango Shingū Kōka Owase Kumano Ōmihachiman Tamano Okayama Takinomiya Youkaichi Takashima Hikone Tottori-shi Zentsujichó Ikedachō Tsu Nagahama Takahashi Yokkaichi Ise Inabe Aki Kurayoshi Kuwana Kaizu Shima Toba Yatomi Ōgaki Niimi Nankoku Ibi Hashima Mizuho Ama Motosu Handa Kochi Tōkai Ichinomiya Shin’ichi Gifu Minamichita Hekinan Nagoya Kariya Onomichi Ino Nishio Kakamigahara Chiryū Anjō Inuyama Nisshin Owariasahi Yonago Sekimachi Mihara Okazaki Toyota Seto Yasugichō Gamagōri Kani Minokamo Susaki Tajimi Sakaiminato Kaga Takehara Toki Toyohashi Shinagawa Miyoshi Matsue Komatsu Unnan Higashihiroshima Kosai Shinshiro Matsuyama Gero Matsutō Izumo Nonoichi Iyo Kure Kanazawa Yae Hamamatsu Nakamura Gion Hamakita Takayama Hiroshima Tsubata Ōdachō-ōda Iwata Oyabe Fukuroi Tonami Uwajima Iida Yawatahama Kakegawa Hakui Ōtake Iwakuni Takaoka Gōtsuchō Kikugawa Himimachi Imizu Toyama Yanai Shimada Hamada Ina Fujieda Namerikawa Hikari Uozu Shizuoka Masuda Kudamatsu Matsumoto Shūnan Suwa Nyūzen Minami-Alps Kunisaki Tsukumiura Saiki Chikuma Hōfu Usuki Fuji Kofu Tsurusaki Yamaguchi Ueda Hagi Nagano Ōita Yamanashi Saku Numazu Fujiyoshida Shimoda Beppu Susono Suzaka Izunokuni Mie Gotemba Ube Mine Nagato Nobeoka Atami Yufu Onoda Ōtsuki Nakatsu Hyūga Minamiashigara Buzen Odawara Tomioka Hadano Kanda Yukuhashi Chichibu Shimonoseki Nakanojō Hiratsuka Takasaki Ōme Minawa Takanabe Aihara Kitakyushu Atsugi Kodamachō-kodamaminami Hachiōji Hita Shibukawa Chigasaki Ebina Yorii Shintomi Ayase Morohongō Tagawa Honjō Ogawamachi Akishima Minamirinkan Fujisawa Yamato Yokota Iruma Machida Numata Nōgata Nakama Sakai-nakajima Koga Kamakura Sayama Sakado Fuchū Higashimurayama Kodaira Ukiha Iizuka Tokorozawa Miura Azamino Higashi-Matsuyama Higashikurume Kumagaya Noborito Kawagoe Igusa Menuma Tanushimarumachi-toyoki Yokosuka Ōta Yokohama Kiryū Niiza Munakata Kurihama Gyōda Yame Asaka Kōnosu Wakasugi Ashikaga Hanyū Ogōri Tokyo Ageo Koga Tatebayashi Saitama Tosu Kazo Tateyama Kurume Kawaguchi Kasuga Fukuoka Kukichūō Sano Chikugo Kimitsu Kasukabe Sōka Koshigaya Kisarazu Koga Kanzakimachi-kanzaki Ōmuta Urayasu Yanagawa Misato, Saitama Matsudo Noda Sodegaura Tochigi Bandō Saga Oyama Maebaru-chūō Kamagaya Kashiwa Itoshima Kanuma Narashino Ichihara Imaichi Jōsō Shimo-tsuma Toride Kaminokawa Chikusei Utsunomiya Mooka Yaita Izumi Kurashiki Asakuchi Tahara Imabari Sōja Marugame Tokoname Kameyama Iga Tsuyama Hiragi Kan’onjichō Saijō Suzuka Saikū Fukuyama Matsusaka Shikokuchūō Kaminoma Niihama Kasaoka 11 Feb 12 13 14 15 16 17 18 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
Shikokuchūō Shikokuchūō, 11 February: 29.1 µg/m³, 3.1× usual Shikokuchūō, 12 February: 21.5 µg/m³, 2.3× usual Shikokuchūō, 13 February: 25.3 µg/m³, 2.7× usual Shikokuchūō, 14 February: 36.4 µg/m³, 3.9× usual Shikokuchūō, 15 February: 43.5 µg/m³, 4.6× usual Shikokuchūō, 16 February: 4.8 µg/m³, 0.5× usual Shikokuchūō, 17 February: 10.2 µg/m³, 1.1× usual Shikokuchūō, 18 February: 25.9 µg/m³, 2.8× usual Kan’onjichō Kan’onjichō, 11 February: 28.6 µg/m³, 3.1× usual Kan’onjichō, 12 February: 16.6 µg/m³, 1.8× usual Kan’onjichō, 13 February: 21.2 µg/m³, 2.3× usual Kan’onjichō, 14 February: 33.6 µg/m³, 3.7× usual Kan’onjichō, 15 February: 34.7 µg/m³, 3.8× usual Kan’onjichō, 16 February: 2.8 µg/m³, 0.3× usual Kan’onjichō, 17 February: 10.1 µg/m³, 1.1× usual Kan’onjichō, 18 February: 25.0 µg/m³, 2.7× usual Marugame Marugame, 11 February: 28.5 µg/m³, 3.6× usual Marugame, 12 February: 16.5 µg/m³, 2.1× usual Marugame, 13 February: 16.9 µg/m³, 2.1× usual Marugame, 14 February: 24.1 µg/m³, 3.0× usual Marugame, 15 February: 27.1 µg/m³, 3.4× usual Marugame, 16 February: 2.8 µg/m³, 0.4× usual Marugame, 17 February: 7.1 µg/m³, 0.9× usual Marugame, 18 February: 11.3 µg/m³, 1.4× usual Kasaoka Kasaoka, 11 February: 28.3 µg/m³, 3.4× usual Kasaoka, 12 February: 19.6 µg/m³, 2.4× usual Kasaoka, 13 February: 21.9 µg/m³, 2.6× usual Kasaoka, 14 February: 46.9 µg/m³, 5.7× usual Kasaoka, 15 February: 31.4 µg/m³, 3.8× usual Kasaoka, 16 February: 4.1 µg/m³, 0.5× usual Kasaoka, 17 February: 10.5 µg/m³, 1.3× usual Kasaoka, 18 February: 20.9 µg/m³, 2.5× usual Niihama Niihama, 11 February: 28.0 µg/m³, 3.0× usual Niihama, 12 February: 22.0 µg/m³, 2.4× usual Niihama, 13 February: 20.3 µg/m³, 2.2× usual Niihama, 14 February: 34.8 µg/m³, 3.7× usual Niihama, 15 February: 43.6 µg/m³, 4.7× usual Niihama, 16 February: 5.0 µg/m³, 0.5× usual Niihama, 17 February: 10.5 µg/m³, 1.1× usual Niihama, 18 February: 17.7 µg/m³, 1.9× usual Fukuyama Fukuyama, 11 February: 26.0 µg/m³, 2.7× usual Fukuyama, 12 February: 17.1 µg/m³, 1.8× usual Fukuyama, 13 February: 24.1 µg/m³, 2.5× usual Fukuyama, 14 February: 40.6 µg/m³, 4.3× usual Fukuyama, 15 February: 32.6 µg/m³, 3.4× usual Fukuyama, 16 February: 4.2 µg/m³, 0.4× usual Fukuyama, 17 February: 14.0 µg/m³, 1.5× usual Fukuyama, 18 February: 21.9 µg/m³, 2.3× usual Saijō Saijō, 11 February: 21.3 µg/m³, 2.2× usual Saijō, 12 February: no reading Saijō, 13 February: no reading Saijō, 14 February: 35.6 µg/m³, 3.6× usual Saijō, 15 February: 38.4 µg/m³, 3.9× usual Saijō, 16 February: 5.3 µg/m³, 0.5× usual Saijō, 17 February: 11.8 µg/m³, 1.2× usual Saijō, 18 February: 16.1 µg/m³, 1.6× usual Imabari Imabari, 11 February: 24.1 µg/m³, 2.7× usual Imabari, 12 February: 18.6 µg/m³, 2.1× usual Imabari, 13 February: 17.6 µg/m³, 2.0× usual Imabari, 14 February: 29.6 µg/m³, 3.3× usual Imabari, 15 February: 27.5 µg/m³, 3.1× usual Imabari, 16 February: no reading Imabari, 17 February: 8.8 µg/m³, 1.0× usual Imabari, 18 February: 13.5 µg/m³, 1.5× usual Kurashiki Kurashiki, 11 February: 24.3 µg/m³, 2.7× usual Kurashiki, 12 February: 18.2 µg/m³, 2.0× usual Kurashiki, 13 February: 19.6 µg/m³, 2.2× usual Kurashiki, 14 February: 28.1 µg/m³, 3.1× usual Kurashiki, 15 February: 27.1 µg/m³, 3.0× usual Kurashiki, 16 February: 3.4 µg/m³, 0.4× usual Kurashiki, 17 February: 8.5 µg/m³, 0.9× usual Kurashiki, 18 February: 12.5 µg/m³, 1.4× usual Asakuchi Asakuchi, 11 February: 23.9 µg/m³, 2.6× usual Asakuchi, 12 February: 17.0 µg/m³, 1.9× usual Asakuchi, 13 February: 17.4 µg/m³, 1.9× usual Asakuchi, 14 February: 28.0 µg/m³, 3.1× usual Asakuchi, 15 February: 28.9 µg/m³, 3.2× usual Asakuchi, 16 February: 3.6 µg/m³, 0.4× usual Asakuchi, 17 February: 8.5 µg/m³, 0.9× usual Asakuchi, 18 February: 12.0 µg/m³, 1.3× usual Sōja Sōja, 11 February: 22.6 µg/m³, 2.8× usual Sōja, 12 February: 17.3 µg/m³, 2.1× usual Sōja, 13 February: 17.8 µg/m³, 2.2× usual Sōja, 14 February: 26.4 µg/m³, 3.3× usual Sōja, 15 February: 22.2 µg/m³, 2.7× usual Sōja, 16 February: 3.3 µg/m³, 0.4× usual Sōja, 17 February: 8.3 µg/m³, 1.0× usual Sōja, 18 February: 10.4 µg/m³, 1.3× usual Tahara Tahara, 11 February: 9.4 µg/m³, 1.2× usual Tahara, 12 February: 11.0 µg/m³, 1.4× usual Tahara, 13 February: 10.9 µg/m³, 1.3× usual Tahara, 14 February: 26.1 µg/m³, 3.2× usual Tahara, 15 February: 17.9 µg/m³, 2.2× usual Tahara, 16 February: 5.3 µg/m³, 0.7× usual Tahara, 17 February: 12.4 µg/m³, 1.5× usual Tahara, 18 February: 7.9 µg/m³, 1.0× usual Matsusaka Matsusaka, 11 February: 15.6 µg/m³, 2.3× usual Matsusaka, 12 February: 11.6 µg/m³, 1.7× usual Matsusaka, 13 February: 11.7 µg/m³, 1.7× usual Matsusaka, 14 February: 21.5 µg/m³, 3.2× usual Matsusaka, 15 February: 29.6 µg/m³, 4.4× usual Matsusaka, 16 February: 3.7 µg/m³, 0.6× usual Matsusaka, 17 February: 8.4 µg/m³, 1.3× usual Matsusaka, 18 February: 10.8 µg/m³, 1.6× usual Saikū Saikū, 11 February: 12.9 µg/m³, 1.9× usual Saikū, 12 February: 9.8 µg/m³, 1.5× usual Saikū, 13 February: 10.0 µg/m³, 1.5× usual Saikū, 14 February: 16.7 µg/m³, 2.5× usual Saikū, 15 February: 28.0 µg/m³, 4.2× usual Saikū, 16 February: 3.4 µg/m³, 0.5× usual Saikū, 17 February: 7.6 µg/m³, 1.1× usual Saikū, 18 February: 9.8 µg/m³, 1.5× usual Suzuka Suzuka, 11 February: 11.9 µg/m³, 1.8× usual Suzuka, 12 February: 9.0 µg/m³, 1.3× usual Suzuka, 13 February: 11.7 µg/m³, 1.7× usual Suzuka, 14 February: 21.1 µg/m³, 3.1× usual Suzuka, 15 February: 28.0 µg/m³, 4.1× usual Suzuka, 16 February: 3.6 µg/m³, 0.5× usual Suzuka, 17 February: 7.3 µg/m³, 1.1× usual Suzuka, 18 February: 9.5 µg/m³, 1.4× usual Tsuyama Tsuyama, 11 February: 19.0 µg/m³, 2.6× usual Tsuyama, 12 February: 10.0 µg/m³, 1.4× usual Tsuyama, 13 February: 14.2 µg/m³, 1.9× usual Tsuyama, 14 February: 21.9 µg/m³, 3.0× usual Tsuyama, 15 February: 27.0 µg/m³, 3.7× usual Tsuyama, 16 February: 3.4 µg/m³, 0.5× usual Tsuyama, 17 February: 5.8 µg/m³, 0.8× usual Tsuyama, 18 February: 8.1 µg/m³, 1.1× usual Hiragi Hiragi, 11 February: 24.7 µg/m³, 3.5× usual Hiragi, 12 February: 16.0 µg/m³, 2.3× usual Hiragi, 13 February: 11.9 µg/m³, 1.7× usual Hiragi, 14 February: 20.2 µg/m³, 2.9× usual Hiragi, 15 February: 26.7 µg/m³, 3.8× usual Hiragi, 16 February: 2.3 µg/m³, 0.3× usual Hiragi, 17 February: 4.6 µg/m³, 0.7× usual Hiragi, 18 February: 10.2 µg/m³, 1.5× usual Kameyama Kameyama, 11 February: 12.5 µg/m³, 1.7× usual Kameyama, 12 February: 9.7 µg/m³, 1.3× usual Kameyama, 13 February: 10.6 µg/m³, 1.4× usual Kameyama, 14 February: 19.2 µg/m³, 2.6× usual Kameyama, 15 February: 26.7 µg/m³, 3.6× usual Kameyama, 16 February: 3.7 µg/m³, 0.5× usual Kameyama, 17 February: 6.2 µg/m³, 0.8× usual Kameyama, 18 February: 10.0 µg/m³, 1.4× usual Kaminoma Kaminoma, 11 February: 7.1 µg/m³, 1.3× usual Kaminoma, 12 February: 7.1 µg/m³, 1.3× usual Kaminoma, 13 February: 10.7 µg/m³, 1.9× usual Kaminoma, 14 February: 18.0 µg/m³, 3.3× usual Kaminoma, 15 February: 26.0 µg/m³, 4.7× usual Kaminoma, 16 February: 2.7 µg/m³, 0.5× usual Kaminoma, 17 February: 5.1 µg/m³, 0.9× usual Kaminoma, 18 February: 7.2 µg/m³, 1.3× usual Tokoname Tokoname, 11 February: 6.5 µg/m³, 0.9× usual Tokoname, 12 February: 6.1 µg/m³, 0.8× usual Tokoname, 13 February: 8.8 µg/m³, 1.2× usual Tokoname, 14 February: 19.3 µg/m³, 2.6× usual Tokoname, 15 February: 25.9 µg/m³, 3.5× usual Tokoname, 16 February: no reading Tokoname, 17 February: 4.7 µg/m³, 0.6× usual Tokoname, 18 February: 7.3 µg/m³, 1.0× usual Iga Iga, 11 February: 13.6 µg/m³, 1.9× usual Iga, 12 February: 9.1 µg/m³, 1.3× usual Iga, 13 February: 11.4 µg/m³, 1.6× usual Iga, 14 February: 16.2 µg/m³, 2.3× usual Iga, 15 February: 25.8 µg/m³, 3.7× usual Iga, 16 February: 3.2 µg/m³, 0.5× usual Iga, 17 February: 6.1 µg/m³, 0.9× usual Iga, 18 February: 6.7 µg/m³, 1.0× usual 11 Feb 12 13 14 15 16 17 18 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
Kasaoka Okayama, Japan 2 14 February 8.3 5.7× Kaminoma Aichi, Japan 1 15 February 5.5 4.7× Niihama Ehime, Japan 2 15 February 9.3 4.7× Shikokuchūō Ehime, Japan 2 15 February 9.4 4.6× Matsusaka Mie, Japan 1 15 February 6.7 4.4× Fukuyama Hiroshima, Japan 2 14 February 9.5 4.3× Saikū Mie, Japan 1 15 February 6.7 4.2× Suzuka Mie, Japan 1 15 February 6.8 4.1× Saijō Ehime, Japan 2 15 February 9.9 3.9× Hiragi Kagawa, Japan 1 15 February 7.0 3.8× Kan’onjichō Kagawa, Japan 2 15 February 9.2 3.8× Tsuyama Okayama, Japan 1 15 February 7.3 3.7× Iga Mie, Japan 1 15 February 7.0 3.7× Kameyama Mie, Japan 1 15 February 7.4 3.6× Marugame Kagawa, Japan 1 11 February 8.0 3.6× Tokoname Aichi, Japan 1 15 February 7.5 3.5× Imabari Ehime, Japan 2 14 February 8.9 3.3× Sōja Okayama, Japan 1 14 February 8.1 3.3× Tahara Aichi, Japan 1 14 February 8.1 3.2× Asakuchi Okayama, Japan 2 15 February 9.1 3.2× Kurashiki Okayama, Japan 2 14 February 9.1 3.1×
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 Japan
Number 26 of 39 episodes in Japan since our records began, by cities reached.
Japan, 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, July 2026 172 Japan, November 2023 131 Japan, August 2025 126 Japan, January and February 2025 110 Japan, May 2025 103 Japan, March 2025 92 Japan, February 2024 21 Bars: cities reached; colour: the level of the episode's highest daily reading. All 39 .
Use this page SmogRank, Japan, February 2024: 21 cities with PM2.5 at twice their usual or more, 14 to 15 February 2024, smogrank.com/episodes/2024-02-japan-2 (accessed 3 October 2026).
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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.
