SmogRank / Episodes / Japan
Japan, 19 to 20 April 2025
For 2 days, from 19 to 20 April 2025, 34 cities in Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Hiratsuka, Kanagawa, Japan: 51.2 µg/m³ on 20 April, about 6.1× its usual 8.4.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 34 in 1 country
Days 2 19 to 20 April 2025
Worst day 19 April 33 cities counted
Furthest above usual 6.1× Hiratsuka
Day by day
Play 19 April 33 cities at twice their usual or more
Kiryū Numata Ōta Ashikaga Shibukawa Honjō Tatebayashi Imaichi Nakanojō Hanyū Tochigi Tomioka Ogawamachi Koga Chichibu Utsunomiya Kaminokawa Kawagoe Minamiuonuma Sayama Kasukabe Iruma Chikusei Saitama Mooka Bandō Ōme Tokorozawa Shimo-tsuma Niiza Yokota Asaka Higashimurayama Higashikurume Koshigaya Akishima Kodaira Jōsō Kawaguchi Saku Sōka Nasukarasuyama Hachiōji Fuchū Nasushiobara Aihara Tokyo Noborito Kashiwa Suzaka Ōtsuki Matsudo Kasama Nagaoka Azamino Naka Machida Toride Tsuchiura Ishioka Kamagaya Minamirinkan Urayasu Yamato Atsugi Nagano Ayase Hitachiomiya Inzai Shirakawa Narashino Aizu-Wakamatsu Yachiyo Ebina Yokohama Hadano Mito Ajiki Inashiki Chikuma Fujiyoshida Fujisawa Jōetsu Chigasaki Minamiashigara Minami-Alps Shirone Yotsukaidō Chiba Sakura Kamakura Hitachi-Naka Niitsu-honchō Gotemba Maki Narita Odawara Hokota Ichihara Yokosuka Kisarazu Kimitsu Okaya Kameda-honchō Sodegaura Matsumoto Yachimata Hitachi Kurihama Sawara Kōriyama Niigata Shibata Susono Miura Ōami Tōgane Atami Kashima-shi Kitaibaraki Yokoshiba Fuji Numazu Omigawa Mobara Ina Sōsa Itoigawa Kamisu Yonezawa Minamibōsō Tateyama Ōhara Nagai Katsuura Sado Choshi Iida Shizuoka Nyūzen Shimoda Uozu Namerikawa Fujieda Shiroishi Yamagata Minami-Sōma Shimada Kakuda Sōma Toyama Sagae Imizu Kikugawa Kakegawa Higashine Tsuruoka Fukuroi Takaoka Natori-shi Hamakita Himimachi Iwata Sendai Tonami Nanao Shonai Hamamatsu Shinshiro Oyabe Shinjō Sakata Tagajō-shi Yoshioka Anamizu Hakui Seto Tsubata Kosai Matsushima Toyota Toyohashi Inuyama Owariasahi Nisshin Okazaki Ōsaki Higashimatsushima Nonoichi Kanazawa Gamagōri Anjō Matsutō Wakuya Chiryū Nagoya Ichinomiya Kariya Nishio Kurihara Tōkai Ama Komatsu Hekinan Ono Tome Handa Minamichita Tokoname Kaga Kaminoma Kuwana Ichinoseki Inabe Yokkaichi Fukui-shi Mikuni Sabae Suzuka Toba Nagahama Kesennuma Hikone Shima Kameyama Ise Tsu Saikū Tsuruga Matsusaka Youkaichi Takashima Ōmihachiman Kōka Iga Ueno-ebisumachi Kitahama Kusatsu Obama Nabari Ōtsu Kyoto Uji Jōyō Kizugawa Sugai Kōtari Yawata Tenri Kameoka Hirakata Ikoma Hōryūji Takatsuki Kashihara-shi Nantan Kashiwara Maizuru Yono Higashiosaka Yao Habikino Toyonaka Miyazu Tondabayashichō Osaka Ayabe Sayama Kawachi-Nagano Amagasaki Hashimoto Sakai Takarazuka Kyōtango Fukuchiyama Nishinomiya Izumi Sandachō Kishiwada Tanba Kinokawa Kobe Izumisano Toyooka Sennan Iwade Nishiwaki Ono Akashi Kainan Minato Higashinozoe Kakogawachō-honmachi Himeji Sumoto Ikaruga Tatsuno Aioi Tottori-shi Kariya Narutochō-mitsuishi Bizen Fukushima Tahara Gyōda Iwanuma Kofu Yorii Igusa Kodamachō-kodamaminami Sakado Ageo Kazo Ishinomaki Hannō Kōnosu Kukichūō Misato, Saitama Morohongō Higashi-Matsuyama Kumagaya Sakai-nakajima Menuma Sano Minawa Noda Iwaki Oyama Yaita Kanuma Fujinomiya Ueda Suwa Yamanashi Izunokuni Hiratsuka 16 Apr 17 18 19 20 21 22 23 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
Yamanashi Yamanashi, 16 April: no reading Yamanashi, 17 April: no reading Yamanashi, 18 April: 32.3 µg/m³ Yamanashi, 19 April: 30.3 µg/m³, 3.2× its usual 9.6 Yamanashi, 20 April: 25.5 µg/m³, 2.7× its usual 9.5 Yamanashi, 21 April: no reading Yamanashi, 22 April: no reading Yamanashi, 23 April: no reading Ishinomaki Ishinomaki, 16 April: 6.8 µg/m³ Ishinomaki, 17 April: 19.4 µg/m³ Ishinomaki, 18 April: 25.6 µg/m³ Ishinomaki, 19 April: 29.0 µg/m³, 2.5× its usual 11.8 Ishinomaki, 20 April: 17.2 µg/m³ Ishinomaki, 21 April: 10.8 µg/m³ Ishinomaki, 22 April: 13.4 µg/m³ Ishinomaki, 23 April: 12.7 µg/m³ Menuma Menuma, 16 April: 6.3 µg/m³ Menuma, 17 April: 14.6 µg/m³ Menuma, 18 April: 21.2 µg/m³ Menuma, 19 April: 28.0 µg/m³, 2.7× its usual 10.3 Menuma, 20 April: 26.0 µg/m³, 2.5× its usual 10.3 Menuma, 21 April: 8.9 µg/m³ Menuma, 22 April: 14.0 µg/m³ Menuma, 23 April: 8.5 µg/m³ Minawa Minawa, 16 April: 7.0 µg/m³ Minawa, 17 April: 14.5 µg/m³ Minawa, 18 April: 20.5 µg/m³ Minawa, 19 April: 27.6 µg/m³, 2.8× its usual 9.7 Minawa, 20 April: 17.7 µg/m³ Minawa, 21 April: 8.5 µg/m³ Minawa, 22 April: 10.9 µg/m³ Minawa, 23 April: 4.7 µg/m³ Kodamachō-kodamamin… Kodamachō-kodamaminami, 16 April: 5.9 µg/m³ Kodamachō-kodamaminami, 17 April: 14.0 µg/m³ Kodamachō-kodamaminami, 18 April: 24.2 µg/m³ Kodamachō-kodamaminami, 19 April: 27.1 µg/m³, 2.4× its usual 11.2 Kodamachō-kodamaminami, 20 April: 26.0 µg/m³, 2.3× its usual 11.2 Kodamachō-kodamaminami, 21 April: 7.8 µg/m³ Kodamachō-kodamaminami, 22 April: 14.5 µg/m³ Kodamachō-kodamaminami, 23 April: 9.7 µg/m³ Oyama Oyama, 16 April: 4.8 µg/m³ Oyama, 17 April: 14.8 µg/m³ Oyama, 18 April: 19.9 µg/m³ Oyama, 19 April: 27.0 µg/m³, 2.9× its usual 9.3 Oyama, 20 April: 20.5 µg/m³ Oyama, 21 April: 8.0 µg/m³ Oyama, 22 April: 13.4 µg/m³ Oyama, 23 April: 5.0 µg/m³ Iwaki Iwaki, 16 April: 6.1 µg/m³ Iwaki, 17 April: 11.4 µg/m³ Iwaki, 18 April: 21.6 µg/m³ Iwaki, 19 April: 26.7 µg/m³, 2.9× its usual 9.2 Iwaki, 20 April: 20.8 µg/m³ Iwaki, 21 April: 8.8 µg/m³ Iwaki, 22 April: 12.7 µg/m³ Iwaki, 23 April: 9.3 µg/m³ Kumagaya Kumagaya, 16 April: 6.1 µg/m³ Kumagaya, 17 April: 14.0 µg/m³ Kumagaya, 18 April: 19.7 µg/m³ Kumagaya, 19 April: 26.6 µg/m³, 2.7× its usual 10.0 Kumagaya, 20 April: 25.5 µg/m³, 2.6× its usual 10.0 Kumagaya, 21 April: 8.1 µg/m³ Kumagaya, 22 April: 13.2 µg/m³ Kumagaya, 23 April: 7.1 µg/m³ Gyōda Gyōda, 16 April: 7.4 µg/m³ Gyōda, 17 April: 15.7 µg/m³ Gyōda, 18 April: 21.2 µg/m³ Gyōda, 19 April: 26.6 µg/m³, 2.3× its usual 11.5 Gyōda, 20 April: 24.9 µg/m³ Gyōda, 21 April: 9.4 µg/m³ Gyōda, 22 April: 14.8 µg/m³ Gyōda, 23 April: 8.7 µg/m³ Sano Sano, 16 April: 6.8 µg/m³ Sano, 17 April: 16.1 µg/m³ Sano, 18 April: 21.9 µg/m³ Sano, 19 April: 26.4 µg/m³, 2.8× its usual 9.4 Sano, 20 April: 22.2 µg/m³ Sano, 21 April: 9.1 µg/m³ Sano, 22 April: 13.9 µg/m³ Sano, 23 April: 5.7 µg/m³ Igusa Igusa, 16 April: 5.8 µg/m³ Igusa, 17 April: 14.0 µg/m³ Igusa, 18 April: 22.9 µg/m³ Igusa, 19 April: 26.4 µg/m³, 2.4× its usual 11.2 Igusa, 20 April: 25.9 µg/m³, 2.3× its usual 11.2 Igusa, 21 April: 8.1 µg/m³ Igusa, 22 April: 13.7 µg/m³ Igusa, 23 April: 7.1 µg/m³ Higashi-Matsuyama Higashi-Matsuyama, 16 April: 6.8 µg/m³ Higashi-Matsuyama, 17 April: 13.9 µg/m³ Higashi-Matsuyama, 18 April: 21.5 µg/m³ Higashi-Matsuyama, 19 April: 26.3 µg/m³, 2.6× its usual 10.1 Higashi-Matsuyama, 20 April: 24.6 µg/m³ Higashi-Matsuyama, 21 April: 8.5 µg/m³ Higashi-Matsuyama, 22 April: 13.6 µg/m³ Higashi-Matsuyama, 23 April: 7.4 µg/m³ Izunokuni Izunokuni, 16 April: 5.2 µg/m³ Izunokuni, 17 April: 14.4 µg/m³ Izunokuni, 18 April: 21.3 µg/m³ Izunokuni, 19 April: 26.2 µg/m³, 3.5× its usual 7.4 Izunokuni, 20 April: 9.1 µg/m³ Izunokuni, 21 April: 8.1 µg/m³ Izunokuni, 22 April: 8.9 µg/m³ Izunokuni, 23 April: 3.1 µg/m³ Ueda Ueda, 16 April: 5.6 µg/m³ Ueda, 17 April: 14.9 µg/m³ Ueda, 18 April: 21.5 µg/m³ Ueda, 19 April: 26.1 µg/m³, 3.0× its usual 8.7 Ueda, 20 April: 19.2 µg/m³ Ueda, 21 April: 7.6 µg/m³ Ueda, 22 April: 12.5 µg/m³ Ueda, 23 April: 6.0 µg/m³ Kazo Kazo, 16 April: 5.7 µg/m³ Kazo, 17 April: 14.6 µg/m³ Kazo, 18 April: 21.0 µg/m³ Kazo, 19 April: 26.1 µg/m³, 2.5× its usual 10.4 Kazo, 20 April: 21.2 µg/m³ Kazo, 21 April: 8.4 µg/m³ Kazo, 22 April: 13.0 µg/m³ Kazo, 23 April: 7.7 µg/m³ Morohongō Morohongō, 16 April: 4.8 µg/m³ Morohongō, 17 April: 13.1 µg/m³ Morohongō, 18 April: 22.4 µg/m³ Morohongō, 19 April: 26.0 µg/m³, 2.6× its usual 9.9 Morohongō, 20 April: 25.0 µg/m³, 2.5× its usual 9.9 Morohongō, 21 April: 7.7 µg/m³ Morohongō, 22 April: 13.9 µg/m³ Morohongō, 23 April: 6.8 µg/m³ Sakai-nakajima Sakai-nakajima, 16 April: 5.8 µg/m³ Sakai-nakajima, 17 April: 14.7 µg/m³ Sakai-nakajima, 18 April: 20.3 µg/m³ Sakai-nakajima, 19 April: 25.8 µg/m³, 2.5× its usual 10.3 Sakai-nakajima, 20 April: 27.6 µg/m³, 2.7× its usual 10.3 Sakai-nakajima, 21 April: 7.4 µg/m³ Sakai-nakajima, 22 April: 14.0 µg/m³ Sakai-nakajima, 23 April: 7.9 µg/m³ Misato, Saitama Misato, Saitama, 16 April: 6.3 µg/m³ Misato, Saitama, 17 April: 14.8 µg/m³ Misato, Saitama, 18 April: 21.3 µg/m³ Misato, Saitama, 19 April: 25.8 µg/m³, 2.6× its usual 10.1 Misato, Saitama, 20 April: 13.6 µg/m³ Misato, Saitama, 21 April: 10.6 µg/m³ Misato, Saitama, 22 April: 14.9 µg/m³ Misato, Saitama, 23 April: 7.3 µg/m³ Kukichūō Kukichūō, 16 April: 6.8 µg/m³ Kukichūō, 17 April: 14.5 µg/m³ Kukichūō, 18 April: 20.4 µg/m³ Kukichūō, 19 April: 25.7 µg/m³, 2.6× its usual 10.0 Kukichūō, 20 April: 20.5 µg/m³ Kukichūō, 21 April: 8.2 µg/m³ Kukichūō, 22 April: 14.5 µg/m³ Kukichūō, 23 April: 7.3 µg/m³ Yorii Yorii, 16 April: 6.2 µg/m³ Yorii, 17 April: 14.2 µg/m³ Yorii, 18 April: 22.7 µg/m³ Yorii, 19 April: 25.7 µg/m³, 2.4× its usual 10.6 Yorii, 20 April: 25.3 µg/m³, 2.4× its usual 10.6 Yorii, 21 April: 7.8 µg/m³ Yorii, 22 April: 13.9 µg/m³ Yorii, 23 April: 9.1 µg/m³ Fujinomiya Fujinomiya, 16 April: 7.6 µg/m³ Fujinomiya, 17 April: 14.4 µg/m³ Fujinomiya, 18 April: 23.7 µg/m³ Fujinomiya, 19 April: 25.6 µg/m³, 3.0× its usual 8.6 Fujinomiya, 20 April: 9.6 µg/m³ Fujinomiya, 21 April: 8.1 µg/m³ Fujinomiya, 22 April: 7.2 µg/m³ Fujinomiya, 23 April: 5.1 µg/m³ Tahara Tahara, 16 April: 10.2 µg/m³ Tahara, 17 April: 15.6 µg/m³ Tahara, 18 April: 20.9 µg/m³ Tahara, 19 April: 25.6 µg/m³, 2.3× its usual 11.2 Tahara, 20 April: 14.6 µg/m³ Tahara, 21 April: 10.1 µg/m³ Tahara, 22 April: 11.0 µg/m³ Tahara, 23 April: 10.1 µg/m³ Kofu Kofu, 16 April: 9.1 µg/m³ Kofu, 17 April: 18.5 µg/m³ Kofu, 18 April: 24.5 µg/m³ Kofu, 19 April: 25.5 µg/m³, 2.4× its usual 10.6 Kofu, 20 April: 19.1 µg/m³ Kofu, 21 April: 8.4 µg/m³ Kofu, 22 April: 10.6 µg/m³ Kofu, 23 April: 3.4 µg/m³ Kanuma Kanuma, 16 April: 6.6 µg/m³ Kanuma, 17 April: 14.2 µg/m³ Kanuma, 18 April: 19.5 µg/m³ Kanuma, 19 April: 25.4 µg/m³, 3.0× its usual 8.5 Kanuma, 20 April: 23.6 µg/m³ Kanuma, 21 April: 8.6 µg/m³ Kanuma, 22 April: 12.6 µg/m³ Kanuma, 23 April: 5.4 µg/m³ Fukushima Fukushima, 16 April: no reading Fukushima, 17 April: 20.7 µg/m³ Fukushima, 18 April: 17.3 µg/m³ Fukushima, 19 April: 25.4 µg/m³, 2.0× its usual 12.4 Fukushima, 20 April: 22.4 µg/m³ Fukushima, 21 April: no reading Fukushima, 22 April: 13.0 µg/m³ Fukushima, 23 April: 9.2 µg/m³ Ageo Ageo, 16 April: 6.1 µg/m³ Ageo, 17 April: 14.9 µg/m³ Ageo, 18 April: 21.1 µg/m³ Ageo, 19 April: 25.3 µg/m³, 2.5× its usual 10.1 Ageo, 20 April: 20.5 µg/m³ Ageo, 21 April: 9.6 µg/m³ Ageo, 22 April: 13.9 µg/m³ Ageo, 23 April: 7.5 µg/m³ Kōnosu Kōnosu, 16 April: 6.0 µg/m³ Kōnosu, 17 April: 14.9 µg/m³ Kōnosu, 18 April: 20.4 µg/m³ Kōnosu, 19 April: 25.2 µg/m³, 2.6× its usual 9.8 Kōnosu, 20 April: 24.4 µg/m³ Kōnosu, 21 April: 8.7 µg/m³ Kōnosu, 22 April: 13.0 µg/m³ Kōnosu, 23 April: 6.6 µg/m³ Yaita Yaita, 16 April: 5.4 µg/m³ Yaita, 17 April: 12.9 µg/m³ Yaita, 18 April: 18.8 µg/m³ Yaita, 19 April: 25.1 µg/m³, 3.0× its usual 8.3 Yaita, 20 April: 23.1 µg/m³ Yaita, 21 April: 9.4 µg/m³ Yaita, 22 April: 12.0 µg/m³ Yaita, 23 April: 5.4 µg/m³ Hannō Hannō, 16 April: 4.8 µg/m³ Hannō, 17 April: 13.1 µg/m³ Hannō, 18 April: 22.1 µg/m³ Hannō, 19 April: 25.1 µg/m³, 2.6× its usual 9.8 Hannō, 20 April: 23.0 µg/m³ Hannō, 21 April: 8.1 µg/m³ Hannō, 22 April: 12.9 µg/m³ Hannō, 23 April: 8.0 µg/m³ Iwanuma Iwanuma, 16 April: 4.9 µg/m³ Iwanuma, 17 April: 15.3 µg/m³ Iwanuma, 18 April: 18.8 µg/m³ Iwanuma, 19 April: 25.1 µg/m³, 2.4× its usual 10.3 Iwanuma, 20 April: 19.9 µg/m³ Iwanuma, 21 April: 10.6 µg/m³ Iwanuma, 22 April: 13.2 µg/m³ Iwanuma, 23 April: 12.6 µg/m³ Suwa Suwa, 16 April: 6.0 µg/m³ Suwa, 17 April: 18.2 µg/m³ Suwa, 18 April: 24.3 µg/m³ Suwa, 19 April: 25.0 µg/m³, 3.1× its usual 8.0 Suwa, 20 April: 16.2 µg/m³ Suwa, 21 April: 7.4 µg/m³ Suwa, 22 April: 10.8 µg/m³ Suwa, 23 April: 3.1 µg/m³ Noda Noda, 16 April: 5.8 µg/m³ Noda, 17 April: 15.2 µg/m³ Noda, 18 April: 21.8 µg/m³ Noda, 19 April: 25.0 µg/m³, 2.9× its usual 8.5 Noda, 20 April: 12.4 µg/m³ Noda, 21 April: 8.2 µg/m³ Noda, 22 April: 13.6 µg/m³ Noda, 23 April: 6.9 µg/m³ Sakado Sakado, 16 April: 6.5 µg/m³ Sakado, 17 April: 14.4 µg/m³ Sakado, 18 April: 21.7 µg/m³ Sakado, 19 April: 25.0 µg/m³, 2.5× its usual 10.1 Sakado, 20 April: 23.5 µg/m³ Sakado, 21 April: 8.3 µg/m³ Sakado, 22 April: 13.3 µg/m³ Sakado, 23 April: 7.2 µg/m³ Hiratsuka Hiratsuka, 16 April: 6.2 µg/m³ Hiratsuka, 17 April: 12.0 µg/m³ Hiratsuka, 18 April: 18.5 µg/m³ Hiratsuka, 19 April: 22.6 µg/m³ Hiratsuka, 20 April: 51.2 µg/m³, 6.1× its usual 8.4 Hiratsuka, 21 April: 8.0 µg/m³ Hiratsuka, 22 April: 11.0 µg/m³ Hiratsuka, 23 April: 5.6 µg/m³ 16 Apr 17 18 19 20 21 22 23 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
Hiratsuka Kanagawa, Japan 1 20 April 8.4 6.1× Izunokuni Shizuoka, Japan 1 19 April 7.4 3.5× Yamanashi Yamanashi, Japan 2 19 April 9.6 3.2× Suwa Nagano, Japan 1 19 April 8.0 3.1× Ueda Nagano, Japan 1 19 April 8.7 3.0× Fujinomiya Shizuoka, Japan 1 19 April 8.6 3.0× Kanuma Tochigi, Japan 1 19 April 8.5 3.0× Yaita Tochigi, Japan 1 19 April 8.3 3.0× Oyama Tochigi, Japan 1 19 April 9.3 2.9× Iwaki Fukushima, Japan 1 19 April 9.2 2.9× Noda Chiba, Japan 1 19 April 8.5 2.9× Minawa Kanagawa, Japan 1 19 April 9.7 2.8× Sano Tochigi, Japan 1 19 April 9.4 2.8× Menuma Saitama, Japan 2 19 April 10.3 2.7× Sakai-nakajima Gunma, Japan 2 20 April 10.3 2.7× Kumagaya Saitama, Japan 2 19 April 10.0 2.7× Higashi-Matsuyama Saitama, Japan 1 19 April 10.1 2.6× Morohongō Saitama, Japan 2 19 April 9.9 2.6× Misato, Saitama Saitama, Japan 1 19 April 10.1 2.6× Kukichūō Saitama, Japan 1 19 April 10.0 2.6× Kōnosu Saitama, Japan 1 19 April 9.8 2.6× Hannō Saitama, Japan 1 19 April 9.8 2.6× Ishinomaki Miyagi, Japan 1 19 April 11.8 2.5× Kazo Saitama, Japan 1 19 April 10.4 2.5× Ageo Saitama, Japan 1 19 April 10.1 2.5× Sakado Saitama, Japan 1 19 April 10.1 2.5× Kodamachō-kodamaminami Saitama, Japan 2 19 April 11.2 2.4× Igusa Saitama, Japan 2 19 April 11.2 2.4× Yorii Saitama, Japan 2 19 April 10.6 2.4× Kofu Yamanashi, Japan 1 19 April 10.6 2.4× Iwanuma Miyagi, Japan 1 19 April 10.3 2.4× Gyōda Saitama, Japan 1 19 April 11.5 2.3× Tahara Aichi, Japan 1 19 April 11.2 2.3× Fukushima Fukushima, Japan 1 19 April 12.4 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 Japan
Number 21 of 39 episodes in 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 Japan, November 2023 131 Japan, 4 to 5 August 2025 126 Japan, January and February 2025 110 Japan, May 2025 103 Japan, March 2025 92 Japan, 19 to 20 April 2025 34 Bars: cities reached; colour: the level of the episode's highest daily reading. All 39 .
Use this page SmogRank, Japan, 19 to 20 April 2025: 34 cities with PM2.5 at twice their usual or more, 19 to 20 April 2025, smogrank.com/episodes/2025-04-19-japan (accessed 4 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.
