SmogRank / Episodes / Japan
Japan, April 2025
For 1 day, on 30 April 2025, 8 cities in Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Arida, Wakayama, Japan: 27.6 µg/m³ on 30 April, about 2.7× its usual 10.2.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 8 in 1 country
Days 1 30 April 2025
Worst day 30 April 8 cities counted
Furthest above usual 2.7× Arida
Day by day
Play 30 April 8 cities at twice their usual or more
Ueno-ebisumachi Iga Nabari Kizugawa Sugai Kōka Jōyō Tenri Kusatsu Uji Ōtsu Hōryūji Kashihara-shi Ikoma Ōmihachiman Kōtari Youkaichi Kyoto Hirakata Kashiwara Kameyama Kitahama Takatsuki Tsu Yao Habikino Tondabayashichō Matsusaka Kameoka Sayama Hikone Suzuka Osaka Kawachi-Nagano Yono Toyonaka Sakai Hashimoto Saikū Amagasaki Inabe Nantan Nagahama Izumi Takarazuka Owase Ise Nishinomiya Kishiwada Kinokawa Izumisano Obama Tokoname Kaminoma Toba Sandachō Kumano Ama Kobe Sennan Shima Handa Tōkai Tsuruga Ichinomiya Hekinan Minamichita Nagoya Ayabe Maizuru Nishio Chiryū Shingū Kainan Minato Akashi Anjō Nisshin Owariasahi Fukuchiyama Tanba Inuyama Nishiwaki Ono Okazaki Toyota Seto Miyazu Higashinozoe Gamagōri Sabae Tahara Kakogawachō-honmachi Tanabe Sumoto Gobō Ono Kyōtango Fukui-shi Toyohashi Himeji Shinshiro Toyooka Mikuni Kosai Ikaruga Tatsuno Narutochō-mitsuishi Kaga Aioi Anan Tokushima Kariya Hamamatsu Komatsu Hamakita Iwata Bizen Kamojimachō-jōgejima Matsutō Fukuroi Nonoichi Yoshinogawa Shido Iida Kanazawa Kakegawa Tottori-shi Hiragi Mima Tsubata Takamatsu Kikugawa Tsuyama Tonami Oyabe Tamano Okayama Shimada Takinomiya Ina Fujieda Takaoka Hakui Toyama Imizu Kurashiki Sōja Himimachi Marugame Zentsujichó Kurayoshi Shizuoka Ikedachō Okaya Namerikawa Matsumoto Suwa Takahashi Uozu Asakuchi Nanao Kan’onjichō Aki Kasaoka Minami-Alps Niimi Fujinomiya Shikokuchūō Nyūzen Fuji Nankoku Kofu Fukuyama Chikuma Ueda Shin’ichi Kochi Yonago Yamanashi Fujiyoshida Numazu Saku Niihama Nagano Onomichi Ino Susono Yasugichō Shimoda Itoigawa Izunokuni Sakaiminato Gotemba Suzaka Saijō Mihara Atami Ōtsuki Susaki Matsue Minamiashigara Imabari Odawara Takehara Unnan Miyoshi Tomioka Hadano Shinagawa Jōetsu Chichibu Higashihiroshima Hiratsuka Nakanojō Izumo Ōme Minawa Aihara Atsugi Hachiōji Kodamachō-kodamaminami Chigasaki Ebina Matsuyama Shibukawa Yorii Ayase Hannō Morohongō Akishima Ogawamachi Minamirinkan Honjō Yamato Fujisawa Yokota Iruma Machida Iyo Yae Kure Sayama Kamakura Sakai-nakajima Numata Sakado Fuchū Higashimurayama Ōdachō-ōda Kodaira Tokorozawa Nakamura Azamino Miura Gion Higashi-Matsuyama Higashikurume Kumagaya Noborito Hiroshima Kawagoe Igusa Menuma Yokosuka Ōta Yokohama Minamiuonuma Niiza Kiryū Kurihama Gyōda Asaka Kōnosu Ashikaga Hanyū Tokyo Ageo Saitama Tatebayashi Kazo Uwajima Kawaguchi Tateyama Gōtsuchō Yawatahama Kukichūō Sano Kimitsu Ōtake Iwakuni Minamibōsō Kasukabe Sōka Koshigaya Kisarazu Koga Urayasu Hamada Misato, Saitama Matsudo Noda Yanai Sodegaura Tochigi Bandō Oyama Kashiwa Kamagaya Narashino Kanuma Ichihara Jōsō Imaichi Chiba Shimo-tsuma Hikari Yachiyo Toride Masuda Yotsukaidō Kaminokawa Chikusei Utsunomiya Kudamatsu Inzai Shūnan Katsuura Sakura Mobara Mooka Naka Ajiki Ōami Yachimata Ōhara Tsuchiura Narita Tōgane Yaita Inashiki Ishioka Kunisaki Tsukumiura Kasama Yokoshiba Saiki Nasukarasuyama Hōfu Usuki Sawara Nasushiobara Sōsa Tsurusaki Yamaguchi Hagi Hokota Mito Omigawa Ōita Hitachiomiya Kashima-shi Kamisu Hitachi-Naka Beppu Mie Shirakawa Nagato Ube Mine Choshi Nobeoka Yufu Onoda Hitachi Hyūga Nakatsu Buzen Kitaibaraki Iwaki Yawata Yokkaichi Higashiosaka Takashima Iwade Kariya Arida Kuwana 27 Apr 28 29 30 1 May 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
Arida Arida, 27 April: 18.9 µg/m³, 1.9× usual Arida, 28 April: 11.2 µg/m³, 1.1× usual Arida, 29 April: 14.5 µg/m³, 1.4× usual Arida, 30 April: 27.6 µg/m³, 2.7× usual Arida, 1 May: 17.2 µg/m³, 1.7× usual Arida, 2 May: 8.7 µg/m³, 0.9× usual Arida, 3 May: 12.5 µg/m³, 1.2× usual Kuwana Kuwana, 27 April: 17.5 µg/m³, 1.8× usual Kuwana, 28 April: 15.0 µg/m³, 1.6× usual Kuwana, 29 April: 15.4 µg/m³, 1.6× usual Kuwana, 30 April: 25.8 µg/m³, 2.7× usual Kuwana, 1 May: 16.0 µg/m³, 1.7× usual Kuwana, 2 May: 7.2 µg/m³, 0.8× usual Kuwana, 3 May: 9.2 µg/m³, 1.0× usual Yawata Yawata, 27 April: 18.8 µg/m³, 1.6× usual Yawata, 28 April: 13.5 µg/m³, 1.2× usual Yawata, 29 April: 16.7 µg/m³, 1.4× usual Yawata, 30 April: 25.6 µg/m³, 2.2× usual Yawata, 1 May: 19.0 µg/m³, 1.6× usual Yawata, 2 May: 8.5 µg/m³, 0.7× usual Yawata, 3 May: 12.0 µg/m³, 1.0× usual Iwade Iwade, 27 April: 16.2 µg/m³, 1.6× usual Iwade, 28 April: 10.0 µg/m³, 1.0× usual Iwade, 29 April: 10.2 µg/m³, 1.0× usual Iwade, 30 April: 25.4 µg/m³, 2.5× usual Iwade, 1 May: 16.6 µg/m³, 1.7× usual Iwade, 2 May: 7.6 µg/m³, 0.8× usual Iwade, 3 May: 10.8 µg/m³, 1.1× usual Takashima Takashima, 27 April: 19.4 µg/m³, 1.9× usual Takashima, 28 April: 11.4 µg/m³, 1.1× usual Takashima, 29 April: 16.5 µg/m³, 1.6× usual Takashima, 30 April: 25.4 µg/m³, 2.5× usual Takashima, 1 May: 16.0 µg/m³, 1.6× usual Takashima, 2 May: 8.1 µg/m³, 0.8× usual Takashima, 3 May: 10.7 µg/m³, 1.0× usual Higashiosaka Higashiosaka, 27 April: 20.0 µg/m³, 1.8× usual Higashiosaka, 28 April: 13.3 µg/m³, 1.2× usual Higashiosaka, 29 April: 15.2 µg/m³, 1.4× usual Higashiosaka, 30 April: 25.3 µg/m³, 2.3× usual Higashiosaka, 1 May: 21.3 µg/m³, 2.0× usual Higashiosaka, 2 May: 9.8 µg/m³, 0.9× usual Higashiosaka, 3 May: 12.9 µg/m³, 1.2× usual Yokkaichi Yokkaichi, 27 April: 20.9 µg/m³, 1.8× usual Yokkaichi, 28 April: 16.4 µg/m³, 1.4× usual Yokkaichi, 29 April: 16.7 µg/m³, 1.4× usual Yokkaichi, 30 April: 25.3 µg/m³, 2.2× usual Yokkaichi, 1 May: 16.8 µg/m³, 1.4× usual Yokkaichi, 2 May: 9.2 µg/m³, 0.8× usual Yokkaichi, 3 May: 10.7 µg/m³, 0.9× usual Kariya Kariya, 27 April: 19.7 µg/m³, 2.1× usual Kariya, 28 April: 14.9 µg/m³, 1.6× usual Kariya, 29 April: 15.6 µg/m³, 1.6× usual Kariya, 30 April: 25.0 µg/m³, 2.6× usual Kariya, 1 May: 15.4 µg/m³, 1.6× usual Kariya, 2 May: 6.5 µg/m³, 0.7× usual Kariya, 3 May: 10.2 µg/m³, 1.1× usual 27 Apr 28 29 30 1 May 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
Arida Wakayama, Japan 1 30 April 10.2 2.7× Kuwana Mie, Japan 1 30 April 9.6 2.7× Kariya Aichi, Japan 1 30 April 9.5 2.6× Iwade Wakayama, Japan 1 30 April 10.0 2.5× Takashima Shiga, Japan 1 30 April 10.3 2.5× Higashiosaka Osaka, Japan 1 30 April 10.9 2.3× Yawata Kyoto, Japan 1 30 April 11.6 2.2× Yokkaichi Mie, Japan 1 30 April 11.6 2.2×
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 27 episodes in Japan since our records began, by cities reached.
Japan, June and July 2025 508 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 and South Korea, April 2025 86 Japan, April 2025 8 Bars: cities reached; colour: the level of the episode's highest daily reading. All 27 .
Use this page SmogRank, Japan, April 2025: 8 cities with PM2.5 at twice their usual or more, 30 April 2025, smogrank.com/episodes/2025-04-japan-2 (accessed 2 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.
