SmogRank / Episodes / Japan
Japan, January and February 2025
For 2 days, from 31 January to 1 February 2025, 110 cities in Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Yawata, Kyoto, Japan: 37.5 µg/m³ on 1 February, about 4.0× its usual 9.4.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 110 in 1 country
Days 2 31 January to 1 February 2025
Worst day 1 February 96 cities counted
Furthest above usual 6.4× Kyōtango
Day by day
Play 1 February 96 cities at twice their usual or more
Takatsuki Nishiwaki Tanba Tokushima Owase Kumano Shingū Kamojimachō-jōgejima Nagahama Yoshinogawa Tsuruga Inabe Yokkaichi Mima Kuwana Takinomiya Toba Tokoname Sabae Shima Kaminoma Ichinomiya Tōkai Ikedachō Fukui-shi Nagoya Hekinan Minamichita Chiryū Mikuni Ono Inuyama Anjō Sekimachi Owariasahi Nisshin Aki Seto Okazaki Toyota Niimi Gamagōri Kaga Nankoku Toyohashi Komatsu Kochi Shinshiro Kosai Ino Yasugichō Matsutō Mihara Nonoichi Kanazawa Susaki Hamamatsu Matsue Takehara Tsubata Hamakita Miyoshi Unnan Oyabe Iwata Tonami Shinagawa Iida Hakui Izumo Takaoka Kakegawa Matsuyama Himimachi Imizu Toyama Iyo Kikugawa Yae Kure Shimada Ōdachō-ōda Gion Ina Hiroshima Nanao Namerikawa Nakamura Fujieda Uozu Okaya Matsumoto Shizuoka Suwa Gōtsuchō Uwajima Yawatahama Ōtake Nyūzen Iwakuni Hamada Minami-Alps Yanai Chikuma Fujinomiya Kofu Fuji Ueda Hikari Itoigawa Nagano Masuda Saku Yamanashi Kudamatsu Shūnan Fujiyoshida Numazu Suzaka Susono Shimoda Izunokuni Gotemba Atami Kunisaki Ōtsuki Tsukumiura Hōfu Saiki Minamiashigara Usuki Odawara Yamaguchi Tsurusaki Tomioka Hagi Hadano Chichibu Ōita Nakanojō Takasaki Hiratsuka Ōme Beppu Minawa Kodamachō-kodamaminami Shibukawa Aihara Mie Atsugi Hachiōji Yorii Ebina Chigasaki Nagato Mine Ube Hannō Honjō Ayase Morohongō Ogawamachi Akishima Onoda Yokota Minamirinkan Iruma Yamato Fujisawa Numata Nobeoka Yufu Machida Sakai-nakajima Sayama Sakado Kamakura Nakatsu Fuchū Higashimurayama Minamiuonuma Kodaira Tokorozawa Higashi-Matsuyama Azamino Hyūga Miura Kumagaya Higashikurume Buzen Igusa Kawagoe Noborito Menuma Ōta Kiryū Yokosuka Niiza Gyōda Yokohama Kurihama Kōnosu Asaka Kanda Yukuhashi Ashikaga Shimonoseki Ageo Tokyo Tatebayashi Saitama Kazo Kawaguchi Kitakyushu Tateyama Sano Kukichūō Aso Hita Kimitsu Kasukabe Minamibōsō Sōka Koshigaya Koga Tagawa Kisarazu Urayasu Nakama Nōgata Misato, Saitama Matsudo Koga Noda Tochigi Bandō Sodegaura Iizuka Oyama Ukiha Kanuma Kashiwa Ōzu Kamagaya Imaichi Kikuchi Narashino Tanushimarumachi-toyoki Ichihara Jōsō Munakata Chiba Shimo-tsuma Yame Mifune Toride Yachiyo Wakasugi Kaminokawa Yamaga Utsunomiya Chikusei Yotsukaidō Ogōri Koga Kotō Uekimachi-mōno Inzai Tosu Kumamoto Kurume Kasuga Mooka Sakura Fukuoka Naka Ajiki Chikugo Tamana Uto Yaita Tsuchiura Kanzakimachi-kanzaki Ōmuta Yanagawa Arao Ishioka Hitoyoshi Honmachi Nasukarasuyama Kasama Nasushiobara Ōyanomachi-noboritate Minamata Shirakawa Shikokuchūō Higashihiroshima Saijō Fukuyama Onomichi Niihama Tahara Bizen Hashimoto Kan’onjichō Kasaoka Sakai Tamano Imabari Kurashiki Marugame Higashiosaka Zentsujichó Asakuchi Hōryūji Osaka Sandachō Shin’ichi Tondabayashichō Yao Hiragi Anan Higashinozoe Shido Minato Sayama Kawachi-Nagano Habikino Kariya Amagasaki Hirakata Izumi Sōja Suzuka Takahashi Tenri Akashi Handa Kinokawa Aioi Kakogawachō-honmachi Narutochō-mitsuishi Ono Saikū Takamatsu Kariya Nishio Gobō Ikaruga Iwade Izumisano Kashiwara Kishiwada Kobe Okayama Tanabe Sugai Kameyama Nishinomiya Kizugawa Matsusaka Ayabe Takarazuka Nantan Tatsuno Sennan Takashima Fukuchiyama Ise Kainan Kashihara-shi Tsuyama Yawata Kyoto Ama Iga Himeji Ikoma Nabari Toyonaka Tsu Uji Kōtari Toyooka Hikone Kusatsu Ueno-ebisumachi Kameoka Maizuru Obama Jōyō Arida Kurayoshi Fukuroi Ōmihachiman Kitahama Kōka Yono Youkaichi Yonago Miyazu Ōtsu Tottori-shi Sakaiminato Kyōtango 28 Jan 29 30 31 1 Feb 2 3 4 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
Yawata Yawata, 28 January: 10.4 µg/m³, 1.1× usual Yawata, 29 January: 6.9 µg/m³, 0.7× usual Yawata, 30 January: 11.0 µg/m³, 1.2× usual Yawata, 31 January: 32.7 µg/m³, 3.5× usual Yawata, 1 February: 37.5 µg/m³, 4.0× usual Yawata, 2 February: 9.9 µg/m³, 1.1× usual Yawata, 3 February: 11.5 µg/m³, 1.2× usual Yawata, 4 February: 9.1 µg/m³, 1.0× usual Tottori-shi Tottori-shi, 28 January: 8.6 µg/m³, 1.3× usual Tottori-shi, 29 January: 9.7 µg/m³, 1.5× usual Tottori-shi, 30 January: 13.9 µg/m³, 2.1× usual Tottori-shi, 31 January: 36.7 µg/m³, 5.6× usual Tottori-shi, 1 February: 19.0 µg/m³, 2.9× usual Tottori-shi, 2 February: 6.6 µg/m³, 1.0× usual Tottori-shi, 3 February: 9.7 µg/m³, 1.5× usual Tottori-shi, 4 February: 6.2 µg/m³, 0.9× usual Sakaiminato Sakaiminato, 28 January: 7.4 µg/m³, 1.2× usual Sakaiminato, 29 January: 8.2 µg/m³, 1.3× usual Sakaiminato, 30 January: 12.0 µg/m³, 1.9× usual Sakaiminato, 31 January: 36.4 µg/m³, 5.8× usual Sakaiminato, 1 February: 18.6 µg/m³, 3.0× usual Sakaiminato, 2 February: 5.4 µg/m³, 0.9× usual Sakaiminato, 3 February: 8.2 µg/m³, 1.3× usual Sakaiminato, 4 February: 6.2 µg/m³, 1.0× usual Nabari Nabari, 28 January: 9.1 µg/m³, 1.1× usual Nabari, 29 January: 6.9 µg/m³, 0.8× usual Nabari, 30 January: 11.8 µg/m³, 1.4× usual Nabari, 31 January: 35.3 µg/m³, 4.2× usual Nabari, 1 February: 29.0 µg/m³, 3.5× usual Nabari, 2 February: 8.2 µg/m³, 1.0× usual Nabari, 3 February: 10.0 µg/m³, 1.2× usual Nabari, 4 February: 10.6 µg/m³, 1.3× usual Kōtari Kōtari, 28 January: 9.8 µg/m³, 1.2× usual Kōtari, 29 January: 7.1 µg/m³, 0.9× usual Kōtari, 30 January: 10.5 µg/m³, 1.3× usual Kōtari, 31 January: 34.2 µg/m³, 4.2× usual Kōtari, 1 February: 35.1 µg/m³, 4.3× usual Kōtari, 2 February: 8.5 µg/m³, 1.0× usual Kōtari, 3 February: 11.6 µg/m³, 1.4× usual Kōtari, 4 February: 7.8 µg/m³, 1.0× usual Jōyō Jōyō, 28 January: 8.9 µg/m³, 1.2× usual Jōyō, 29 January: 6.1 µg/m³, 0.8× usual Jōyō, 30 January: 9.4 µg/m³, 1.2× usual Jōyō, 31 January: 32.2 µg/m³, 4.2× usual Jōyō, 1 February: 35.1 µg/m³, 4.6× usual Jōyō, 2 February: 8.2 µg/m³, 1.1× usual Jōyō, 3 February: 10.6 µg/m³, 1.4× usual Jōyō, 4 February: 8.2 µg/m³, 1.1× usual Uji Uji, 28 January: 10.3 µg/m³, 1.2× usual Uji, 29 January: 6.5 µg/m³, 0.8× usual Uji, 30 January: 9.6 µg/m³, 1.2× usual Uji, 31 January: 31.8 µg/m³, 3.8× usual Uji, 1 February: 35.1 µg/m³, 4.2× usual Uji, 2 February: 8.4 µg/m³, 1.0× usual Uji, 3 February: 10.7 µg/m³, 1.3× usual Uji, 4 February: 9.0 µg/m³, 1.1× usual Arida Arida, 28 January: 10.2 µg/m³, 1.3× usual Arida, 29 January: 7.7 µg/m³, 1.0× usual Arida, 30 January: 13.6 µg/m³, 1.8× usual Arida, 31 January: 33.0 µg/m³, 4.3× usual Arida, 1 February: 34.9 µg/m³, 4.6× usual Arida, 2 February: 8.9 µg/m³, 1.2× usual Arida, 3 February: 12.7 µg/m³, 1.7× usual Arida, 4 February: 11.0 µg/m³, 1.4× usual Osaka Osaka, 28 January: 9.6 µg/m³, 0.9× usual Osaka, 29 January: 6.3 µg/m³, 0.6× usual Osaka, 30 January: 10.7 µg/m³, 1.0× usual Osaka, 31 January: 29.9 µg/m³, 2.9× usual Osaka, 1 February: 34.8 µg/m³, 3.3× usual Osaka, 2 February: 8.7 µg/m³, 0.8× usual Osaka, 3 February: 10.8 µg/m³, 1.0× usual Osaka, 4 February: 8.9 µg/m³, 0.9× usual Higashinozoe Higashinozoe, 28 January: 10.3 µg/m³, 1.0× usual Higashinozoe, 29 January: 7.4 µg/m³, 0.7× usual Higashinozoe, 30 January: 13.3 µg/m³, 1.3× usual Higashinozoe, 31 January: 32.4 µg/m³, 3.1× usual Higashinozoe, 1 February: 34.7 µg/m³, 3.4× usual Higashinozoe, 2 February: 9.9 µg/m³, 1.0× usual Higashinozoe, 3 February: 12.7 µg/m³, 1.2× usual Higashinozoe, 4 February: 9.2 µg/m³, 0.9× usual Youkaichi Youkaichi, 28 January: 9.5 µg/m³, 1.4× usual Youkaichi, 29 January: 6.4 µg/m³, 0.9× usual Youkaichi, 30 January: 10.1 µg/m³, 1.5× usual Youkaichi, 31 January: 30.0 µg/m³, 4.3× usual Youkaichi, 1 February: 34.3 µg/m³, 5.0× usual Youkaichi, 2 February: 9.2 µg/m³, 1.3× usual Youkaichi, 3 February: 10.3 µg/m³, 1.5× usual Youkaichi, 4 February: 6.7 µg/m³, 1.0× usual Sugai Sugai, 28 January: 9.9 µg/m³, 1.1× usual Sugai, 29 January: 6.9 µg/m³, 0.8× usual Sugai, 30 January: 10.3 µg/m³, 1.2× usual Sugai, 31 January: 31.1 µg/m³, 3.5× usual Sugai, 1 February: 34.0 µg/m³, 3.8× usual Sugai, 2 February: 8.8 µg/m³, 1.0× usual Sugai, 3 February: 9.9 µg/m³, 1.1× usual Sugai, 4 February: 8.4 µg/m³, 0.9× usual Kyōtango Kyōtango, 28 January: 6.4 µg/m³, 1.2× usual Kyōtango, 29 January: 8.2 µg/m³, 1.5× usual Kyōtango, 30 January: 8.6 µg/m³, 1.6× usual Kyōtango, 31 January: 33.7 µg/m³, 6.4× usual Kyōtango, 1 February: 20.3 µg/m³, 3.8× usual Kyōtango, 2 February: 8.3 µg/m³, 1.6× usual Kyōtango, 3 February: 8.4 µg/m³, 1.6× usual Kyōtango, 4 February: 3.6 µg/m³, 0.7× usual Tenri Tenri, 28 January: 9.5 µg/m³, 1.0× usual Tenri, 29 January: 6.4 µg/m³, 0.7× usual Tenri, 30 January: 11.0 µg/m³, 1.1× usual Tenri, 31 January: 31.3 µg/m³, 3.2× usual Tenri, 1 February: 33.7 µg/m³, 3.5× usual Tenri, 2 February: 7.2 µg/m³, 0.7× usual Tenri, 3 February: 9.6 µg/m³, 1.0× usual Tenri, 4 February: 8.6 µg/m³, 0.9× usual Higashiosaka Higashiosaka, 28 January: 9.3 µg/m³, 0.9× usual Higashiosaka, 29 January: 5.8 µg/m³, 0.5× usual Higashiosaka, 30 January: 11.0 µg/m³, 1.0× usual Higashiosaka, 31 January: 31.0 µg/m³, 2.9× usual Higashiosaka, 1 February: 33.7 µg/m³, 3.1× usual Higashiosaka, 2 February: 6.7 µg/m³, 0.6× usual Higashiosaka, 3 February: 11.0 µg/m³, 1.0× usual Higashiosaka, 4 February: 9.1 µg/m³, 0.8× usual Kariya Kariya, 28 January: 10.8 µg/m³, 1.1× usual Kariya, 29 January: 8.1 µg/m³, 0.8× usual Kariya, 30 January: 13.3 µg/m³, 1.4× usual Kariya, 31 January: 33.5 µg/m³, 3.5× usual Kariya, 1 February: 33.1 µg/m³, 3.4× usual Kariya, 2 February: 9.9 µg/m³, 1.0× usual Kariya, 3 February: 9.3 µg/m³, 1.0× usual Kariya, 4 February: 10.0 µg/m³, 1.0× usual Kishiwada Kishiwada, 28 January: 7.2 µg/m³, 0.8× usual Kishiwada, 29 January: 6.5 µg/m³, 0.7× usual Kishiwada, 30 January: 10.9 µg/m³, 1.2× usual Kishiwada, 31 January: 29.0 µg/m³, 3.2× usual Kishiwada, 1 February: 33.2 µg/m³, 3.7× usual Kishiwada, 2 February: 8.6 µg/m³, 1.0× usual Kishiwada, 3 February: 10.9 µg/m³, 1.2× usual Kishiwada, 4 February: 8.6 µg/m³, 1.0× usual Yonago Yonago, 28 January: 5.8 µg/m³, 0.9× usual Yonago, 29 January: 9.3 µg/m³, 1.4× usual Yonago, 30 January: 12.1 µg/m³, 1.9× usual Yonago, 31 January: 32.5 µg/m³, 5.0× usual Yonago, 1 February: 17.9 µg/m³, 2.8× usual Yonago, 2 February: 6.1 µg/m³, 0.9× usual Yonago, 3 February: 7.6 µg/m³, 1.2× usual Yonago, 4 February: 5.5 µg/m³, 0.8× usual Kakogawachō-honmachi Kakogawachō-honmachi, 28 January: 9.8 µg/m³, 1.1× usual Kakogawachō-honmachi, 29 January: 6.8 µg/m³, 0.8× usual Kakogawachō-honmachi, 30 January: 11.1 µg/m³, 1.2× usual Kakogawachō-honmachi, 31 January: 28.9 µg/m³, 3.2× usual Kakogawachō-honmachi, 1 February: 32.3 µg/m³, 3.6× usual Kakogawachō-honmachi, 2 February: 8.6 µg/m³, 1.0× usual Kakogawachō-honmachi, 3 February: 9.7 µg/m³, 1.1× usual Kakogawachō-honmachi, 4 February: 8.4 µg/m³, 0.9× usual Amagasaki Amagasaki, 28 January: 9.8 µg/m³, 1.1× usual Amagasaki, 29 January: 6.8 µg/m³, 0.7× usual Amagasaki, 30 January: 10.6 µg/m³, 1.2× usual Amagasaki, 31 January: 30.5 µg/m³, 3.3× usual Amagasaki, 1 February: 32.1 µg/m³, 3.5× usual Amagasaki, 2 February: 8.6 µg/m³, 0.9× usual Amagasaki, 3 February: 12.0 µg/m³, 1.3× usual Amagasaki, 4 February: 8.6 µg/m³, 0.9× usual Miyazu Miyazu, 28 January: 7.0 µg/m³, 1.1× usual Miyazu, 29 January: 9.2 µg/m³, 1.5× usual Miyazu, 30 January: 11.1 µg/m³, 1.8× usual Miyazu, 31 January: 32.0 µg/m³, 5.2× usual Miyazu, 1 February: 19.8 µg/m³, 3.2× usual Miyazu, 2 February: 8.1 µg/m³, 1.3× usual Miyazu, 3 February: 8.7 µg/m³, 1.4× usual Miyazu, 4 February: 5.4 µg/m³, 0.9× usual Aioi Aioi, 28 January: 9.6 µg/m³, 1.1× usual Aioi, 29 January: 7.1 µg/m³, 0.8× usual Aioi, 30 January: 13.0 µg/m³, 1.5× usual Aioi, 31 January: 31.7 µg/m³, 3.6× usual Aioi, 1 February: 31.6 µg/m³, 3.6× usual Aioi, 2 February: 8.6 µg/m³, 1.0× usual Aioi, 3 February: 8.5 µg/m³, 1.0× usual Aioi, 4 February: 9.5 µg/m³, 1.1× usual Asakuchi Asakuchi, 28 January: 10.1 µg/m³, 1.1× usual Asakuchi, 29 January: 6.7 µg/m³, 0.7× usual Asakuchi, 30 January: 13.3 µg/m³, 1.4× usual Asakuchi, 31 January: 26.7 µg/m³, 2.8× usual Asakuchi, 1 February: 31.7 µg/m³, 3.3× usual Asakuchi, 2 February: 12.0 µg/m³, 1.3× usual Asakuchi, 3 February: 13.7 µg/m³, 1.4× usual Asakuchi, 4 February: 6.8 µg/m³, 0.7× usual Iga Iga, 28 January: 8.4 µg/m³, 1.1× usual Iga, 29 January: 6.7 µg/m³, 0.9× usual Iga, 30 January: 9.6 µg/m³, 1.3× usual Iga, 31 January: 30.5 µg/m³, 4.0× usual Iga, 1 February: 31.6 µg/m³, 4.2× usual Iga, 2 February: 7.8 µg/m³, 1.0× usual Iga, 3 February: 10.0 µg/m³, 1.3× usual Iga, 4 February: 9.0 µg/m³, 1.2× usual Habikino Habikino, 28 January: 8.0 µg/m³, 0.9× usual Habikino, 29 January: 5.6 µg/m³, 0.6× usual Habikino, 30 January: 10.6 µg/m³, 1.2× usual Habikino, 31 January: 29.1 µg/m³, 3.2× usual Habikino, 1 February: 31.6 µg/m³, 3.5× usual Habikino, 2 February: 6.2 µg/m³, 0.7× usual Habikino, 3 February: 14.5 µg/m³, 1.6× usual Habikino, 4 February: 7.8 µg/m³, 0.9× usual Kameoka Kameoka, 28 January: 9.5 µg/m³, 1.4× usual Kameoka, 29 January: 5.8 µg/m³, 0.8× usual Kameoka, 30 January: 9.6 µg/m³, 1.4× usual Kameoka, 31 January: 31.4 µg/m³, 4.5× usual Kameoka, 1 February: 28.5 µg/m³, 4.1× usual Kameoka, 2 February: 8.6 µg/m³, 1.2× usual Kameoka, 3 February: 8.1 µg/m³, 1.2× usual Kameoka, 4 February: 7.9 µg/m³, 1.1× usual Tamano Tamano, 28 January: 8.8 µg/m³, 0.8× usual Tamano, 29 January: 7.5 µg/m³, 0.7× usual Tamano, 30 January: 14.6 µg/m³, 1.4× usual Tamano, 31 January: 27.3 µg/m³, 2.6× usual Tamano, 1 February: 31.3 µg/m³, 3.0× usual Tamano, 2 February: 11.0 µg/m³, 1.0× usual Tamano, 3 February: no reading Tamano, 4 February: no reading Kizugawa Kizugawa, 28 January: 7.6 µg/m³, 0.9× usual Kizugawa, 29 January: 5.9 µg/m³, 0.7× usual Kizugawa, 30 January: 9.1 µg/m³, 1.1× usual Kizugawa, 31 January: 31.1 µg/m³, 3.8× usual Kizugawa, 1 February: 31.2 µg/m³, 3.9× usual Kizugawa, 2 February: 6.8 µg/m³, 0.8× usual Kizugawa, 3 February: 9.1 µg/m³, 1.1× usual Kizugawa, 4 February: 8.1 µg/m³, 1.0× usual Ōmihachiman Ōmihachiman, 28 January: 8.9 µg/m³, 1.3× usual Ōmihachiman, 29 January: 5.9 µg/m³, 0.9× usual Ōmihachiman, 30 January: 8.5 µg/m³, 1.3× usual Ōmihachiman, 31 January: 27.9 µg/m³, 4.2× usual Ōmihachiman, 1 February: 31.2 µg/m³, 4.7× usual Ōmihachiman, 2 February: 9.1 µg/m³, 1.4× usual Ōmihachiman, 3 February: 8.9 µg/m³, 1.3× usual Ōmihachiman, 4 February: 6.3 µg/m³, 1.0× usual Takamatsu Takamatsu, 28 January: 8.6 µg/m³, 1.0× usual Takamatsu, 29 January: 5.3 µg/m³, 0.6× usual Takamatsu, 30 January: 12.5 µg/m³, 1.5× usual Takamatsu, 31 January: 26.3 µg/m³, 3.1× usual Takamatsu, 1 February: 31.2 µg/m³, 3.6× usual Takamatsu, 2 February: 12.1 µg/m³, 1.4× usual Takamatsu, 3 February: 14.7 µg/m³, 1.7× usual Takamatsu, 4 February: 8.4 µg/m³, 1.0× usual Kusatsu Kusatsu, 28 January: 9.7 µg/m³, 1.4× usual Kusatsu, 29 January: 6.1 µg/m³, 0.9× usual Kusatsu, 30 January: 9.0 µg/m³, 1.3× usual Kusatsu, 31 January: 31.1 µg/m³, 4.4× usual Kusatsu, 1 February: 30.8 µg/m³, 4.3× usual Kusatsu, 2 February: 9.2 µg/m³, 1.3× usual Kusatsu, 3 February: 10.0 µg/m³, 1.4× usual Kusatsu, 4 February: 7.7 µg/m³, 1.1× usual Kyoto Kyoto, 28 January: 9.7 µg/m³, 1.3× usual Kyoto, 29 January: 5.9 µg/m³, 0.8× usual Kyoto, 30 January: 9.1 µg/m³, 1.2× usual Kyoto, 31 January: 30.2 µg/m³, 4.0× usual Kyoto, 1 February: 31.1 µg/m³, 4.1× usual Kyoto, 2 February: 7.7 µg/m³, 1.0× usual Kyoto, 3 February: 10.0 µg/m³, 1.3× usual Kyoto, 4 February: 7.4 µg/m³, 1.0× usual Kashihara-shi Kashihara-shi, 28 January: 7.3 µg/m³, 0.9× usual Kashihara-shi, 29 January: 5.0 µg/m³, 0.6× usual Kashihara-shi, 30 January: 8.9 µg/m³, 1.1× usual Kashihara-shi, 31 January: 29.0 µg/m³, 3.7× usual Kashihara-shi, 1 February: 31.1 µg/m³, 4.0× usual Kashihara-shi, 2 February: 7.2 µg/m³, 0.9× usual Kashihara-shi, 3 February: 8.1 µg/m³, 1.0× usual Kashihara-shi, 4 February: 6.3 µg/m³, 0.8× usual Yao Yao, 28 January: 8.9 µg/m³, 0.9× usual Yao, 29 January: 5.5 µg/m³, 0.6× usual Yao, 30 January: 10.4 µg/m³, 1.1× usual Yao, 31 January: 31.0 µg/m³, 3.3× usual Yao, 1 February: 30.5 µg/m³, 3.2× usual Yao, 2 February: 6.4 µg/m³, 0.7× usual Yao, 3 February: 10.5 µg/m³, 1.1× usual Yao, 4 February: 8.1 µg/m³, 0.9× usual Hirakata Hirakata, 28 January: 8.6 µg/m³, 1.0× usual Hirakata, 29 January: 5.7 µg/m³, 0.6× usual Hirakata, 30 January: 8.9 µg/m³, 1.0× usual Hirakata, 31 January: 29.9 µg/m³, 3.4× usual Hirakata, 1 February: 31.0 µg/m³, 3.5× usual Hirakata, 2 February: 7.6 µg/m³, 0.9× usual Hirakata, 3 February: 10.1 µg/m³, 1.1× usual Hirakata, 4 February: 7.7 µg/m³, 0.9× usual Sōja Sōja, 28 January: 7.8 µg/m³, 0.9× usual Sōja, 29 January: 5.6 µg/m³, 0.6× usual Sōja, 30 January: 12.7 µg/m³, 1.4× usual Sōja, 31 January: 28.5 µg/m³, 3.2× usual Sōja, 1 February: 31.0 µg/m³, 3.5× usual Sōja, 2 February: 7.1 µg/m³, 0.8× usual Sōja, 3 February: 9.8 µg/m³, 1.1× usual Sōja, 4 February: 8.5 µg/m³, 1.0× usual Ueno-ebisumachi Ueno-ebisumachi, 28 January: 7.6 µg/m³, 1.1× usual Ueno-ebisumachi, 29 January: 5.4 µg/m³, 0.8× usual Ueno-ebisumachi, 30 January: 9.2 µg/m³, 1.3× usual Ueno-ebisumachi, 31 January: 30.9 µg/m³, 4.4× usual Ueno-ebisumachi, 1 February: 28.7 µg/m³, 4.0× usual Ueno-ebisumachi, 2 February: 7.1 µg/m³, 1.0× usual Ueno-ebisumachi, 3 February: 9.6 µg/m³, 1.4× usual Ueno-ebisumachi, 4 February: 8.0 µg/m³, 1.1× usual Sakai Sakai, 28 January: 8.5 µg/m³, 0.8× usual Sakai, 29 January: 5.4 µg/m³, 0.5× usual Sakai, 30 January: 10.1 µg/m³, 1.0× usual Sakai, 31 January: 29.4 µg/m³, 2.9× usual Sakai, 1 February: 30.9 µg/m³, 3.0× usual Sakai, 2 February: 8.8 µg/m³, 0.9× usual Sakai, 3 February: 10.3 µg/m³, 1.0× usual Sakai, 4 February: 8.2 µg/m³, 0.8× usual Sandachō Sandachō, 28 January: 9.7 µg/m³, 1.0× usual Sandachō, 29 January: 6.8 µg/m³, 0.7× usual Sandachō, 30 January: 10.6 µg/m³, 1.1× usual Sandachō, 31 January: 30.8 µg/m³, 3.3× usual Sandachō, 1 February: 30.0 µg/m³, 3.2× usual Sandachō, 2 February: 8.7 µg/m³, 0.9× usual Sandachō, 3 February: 9.9 µg/m³, 1.1× usual Sandachō, 4 February: 8.1 µg/m³, 0.9× usual Tsuyama Tsuyama, 28 January: 8.0 µg/m³, 1.0× usual Tsuyama, 29 January: 6.4 µg/m³, 0.8× usual Tsuyama, 30 January: 11.1 µg/m³, 1.4× usual Tsuyama, 31 January: 27.9 µg/m³, 3.6× usual Tsuyama, 1 February: 30.8 µg/m³, 4.0× usual Tsuyama, 2 February: 9.4 µg/m³, 1.2× usual Tsuyama, 3 February: 8.6 µg/m³, 1.1× usual Tsuyama, 4 February: 6.2 µg/m³, 0.8× usual Iwade Iwade, 28 January: 7.5 µg/m³, 0.9× usual Iwade, 29 January: 5.0 µg/m³, 0.6× usual Iwade, 30 January: 9.3 µg/m³, 1.1× usual Iwade, 31 January: 26.9 µg/m³, 3.2× usual Iwade, 1 February: 30.8 µg/m³, 3.7× usual Iwade, 2 February: 7.4 µg/m³, 0.9× usual Iwade, 3 February: 9.2 µg/m³, 1.1× usual Iwade, 4 February: 7.8 µg/m³, 0.9× usual Shido Shido, 28 January: 8.7 µg/m³, 1.0× usual Shido, 29 January: 5.2 µg/m³, 0.6× usual Shido, 30 January: 12.5 µg/m³, 1.4× usual Shido, 31 January: 27.6 µg/m³, 3.1× usual Shido, 1 February: 30.7 µg/m³, 3.4× usual Shido, 2 February: 11.7 µg/m³, 1.3× usual Shido, 3 February: 13.4 µg/m³, 1.5× usual Shido, 4 February: 8.9 µg/m³, 1.0× usual Nantan Nantan, 28 January: 8.7 µg/m³, 1.1× usual Nantan, 29 January: 8.1 µg/m³, 1.1× usual Nantan, 30 January: 11.7 µg/m³, 1.5× usual Nantan, 31 January: 27.4 µg/m³, 3.6× usual Nantan, 1 February: 30.7 µg/m³, 4.0× usual Nantan, 2 February: no reading Nantan, 3 February: no reading Nantan, 4 February: no reading Akashi Akashi, 28 January: 8.6 µg/m³, 1.0× usual Akashi, 29 January: 6.3 µg/m³, 0.7× usual Akashi, 30 January: 11.1 µg/m³, 1.3× usual Akashi, 31 January: 28.7 µg/m³, 3.3× usual Akashi, 1 February: 30.6 µg/m³, 3.5× usual Akashi, 2 February: 7.8 µg/m³, 0.9× usual Akashi, 3 February: 10.4 µg/m³, 1.2× usual Akashi, 4 February: 7.8 µg/m³, 0.9× usual Fukuyama Fukuyama, 28 January: 9.9 µg/m³, 0.9× usual Fukuyama, 29 January: 6.3 µg/m³, 0.6× usual Fukuyama, 30 January: 13.4 µg/m³, 1.2× usual Fukuyama, 31 January: 27.2 µg/m³, 2.5× usual Fukuyama, 1 February: 30.6 µg/m³, 2.8× usual Fukuyama, 2 February: 10.9 µg/m³, 1.0× usual Fukuyama, 3 February: 13.7 µg/m³, 1.3× usual Fukuyama, 4 February: 9.2 µg/m³, 0.8× usual Tatsuno Tatsuno, 28 January: 8.5 µg/m³, 1.1× usual Tatsuno, 29 January: 5.6 µg/m³, 0.7× usual Tatsuno, 30 January: 11.4 µg/m³, 1.5× usual Tatsuno, 31 January: 29.3 µg/m³, 3.8× usual Tatsuno, 1 February: 30.5 µg/m³, 4.0× usual Tatsuno, 2 February: 6.5 µg/m³, 0.8× usual Tatsuno, 3 February: 7.2 µg/m³, 0.9× usual Tatsuno, 4 February: 7.1 µg/m³, 0.9× usual Yono Yono, 28 January: 8.5 µg/m³, 1.4× usual Yono, 29 January: 7.0 µg/m³, 1.1× usual Yono, 30 January: 9.7 µg/m³, 1.6× usual Yono, 31 January: 30.3 µg/m³, 4.9× usual Yono, 1 February: 25.0 µg/m³, 4.0× usual Yono, 2 February: 6.8 µg/m³, 1.1× usual Yono, 3 February: 9.5 µg/m³, 1.5× usual Yono, 4 February: 8.4 µg/m³, 1.4× usual Kurayoshi Kurayoshi, 28 January: 8.0 µg/m³, 1.2× usual Kurayoshi, 29 January: 8.1 µg/m³, 1.2× usual Kurayoshi, 30 January: 12.5 µg/m³, 1.9× usual Kurayoshi, 31 January: 30.3 µg/m³, 4.6× usual Kurayoshi, 1 February: 13.7 µg/m³, 2.1× usual Kurayoshi, 2 February: 5.1 µg/m³, 0.8× usual Kurayoshi, 3 February: 8.6 µg/m³, 1.3× usual Kurayoshi, 4 February: 7.0 µg/m³, 1.1× usual Takahashi Takahashi, 28 January: 9.1 µg/m³, 1.1× usual Takahashi, 29 January: no reading Takahashi, 30 January: no reading Takahashi, 31 January: 30.3 µg/m³, 3.5× usual Takahashi, 1 February: 29.6 µg/m³, 3.4× usual Takahashi, 2 February: 6.5 µg/m³, 0.8× usual Takahashi, 3 February: 9.3 µg/m³, 1.1× usual Takahashi, 4 February: 9.1 µg/m³, 1.1× usual Sennan Sennan, 28 January: 6.3 µg/m³, 0.8× usual Sennan, 29 January: 4.1 µg/m³, 0.5× usual Sennan, 30 January: 8.7 µg/m³, 1.2× usual Sennan, 31 January: 25.7 µg/m³, 3.4× usual Sennan, 1 February: 30.3 µg/m³, 4.0× usual Sennan, 2 February: 7.0 µg/m³, 0.9× usual Sennan, 3 February: 8.7 µg/m³, 1.2× usual Sennan, 4 February: 7.1 µg/m³, 0.9× usual Ōtsu Ōtsu, 28 January: 7.6 µg/m³, 1.3× usual Ōtsu, 29 January: 5.1 µg/m³, 0.9× usual Ōtsu, 30 January: 8.2 µg/m³, 1.4× usual Ōtsu, 31 January: 28.7 µg/m³, 4.9× usual Ōtsu, 1 February: 30.2 µg/m³, 5.2× usual Ōtsu, 2 February: 7.5 µg/m³, 1.3× usual Ōtsu, 3 February: 8.7 µg/m³, 1.5× usual Ōtsu, 4 February: 6.1 µg/m³, 1.1× usual Minato Minato, 28 January: 8.4 µg/m³, 1.0× usual Minato, 29 January: 5.7 µg/m³, 0.6× usual Minato, 30 January: 11.3 µg/m³, 1.3× usual Minato, 31 January: 27.1 µg/m³, 3.1× usual Minato, 1 February: 30.2 µg/m³, 3.4× usual Minato, 2 February: 7.9 µg/m³, 0.9× usual Minato, 3 February: 10.4 µg/m³, 1.2× usual Minato, 4 February: 9.0 µg/m³, 1.0× usual Izumisano Izumisano, 28 January: 6.5 µg/m³, 0.8× usual Izumisano, 29 January: 5.1 µg/m³, 0.6× usual Izumisano, 30 January: 9.2 µg/m³, 1.1× usual Izumisano, 31 January: 26.7 µg/m³, 3.3× usual Izumisano, 1 February: 30.2 µg/m³, 3.7× usual Izumisano, 2 February: 8.2 µg/m³, 1.0× usual Izumisano, 3 February: 8.9 µg/m³, 1.1× usual Izumisano, 4 February: 7.3 µg/m³, 0.9× usual Onomichi Onomichi, 28 January: 9.1 µg/m³, 0.8× usual Onomichi, 29 January: 6.0 µg/m³, 0.6× usual Onomichi, 30 January: 13.5 µg/m³, 1.2× usual Onomichi, 31 January: 28.2 µg/m³, 2.6× usual Onomichi, 1 February: 30.0 µg/m³, 2.8× usual Onomichi, 2 February: 12.0 µg/m³, 1.1× usual Onomichi, 3 February: 14.0 µg/m³, 1.3× usual Onomichi, 4 February: 8.4 µg/m³, 0.8× usual Kainan Kainan, 28 January: 7.4 µg/m³, 1.0× usual Kainan, 29 January: 5.2 µg/m³, 0.7× usual Kainan, 30 January: 10.7 µg/m³, 1.4× usual Kainan, 31 January: 26.6 µg/m³, 3.5× usual Kainan, 1 February: 30.0 µg/m³, 4.0× usual Kainan, 2 February: 7.7 µg/m³, 1.0× usual Kainan, 3 February: 9.4 µg/m³, 1.3× usual Kainan, 4 February: 8.0 µg/m³, 1.1× usual Kan’onjichō Kan’onjichō, 28 January: 6.6 µg/m³, 0.7× usual Kan’onjichō, 29 January: 4.9 µg/m³, 0.5× usual Kan’onjichō, 30 January: 9.9 µg/m³, 1.0× usual Kan’onjichō, 31 January: 25.7 µg/m³, 2.6× usual Kan’onjichō, 1 February: 30.0 µg/m³, 3.0× usual Kan’onjichō, 2 February: 8.6 µg/m³, 0.9× usual Kan’onjichō, 3 February: 11.3 µg/m³, 1.1× usual Kan’onjichō, 4 February: 5.9 µg/m³, 0.6× usual Shin’ichi Shin’ichi, 28 January: 10.4 µg/m³, 1.1× usual Shin’ichi, 29 January: 7.1 µg/m³, 0.8× usual Shin’ichi, 30 January: 15.1 µg/m³, 1.7× usual Shin’ichi, 31 January: 29.9 µg/m³, 3.3× usual Shin’ichi, 1 February: 28.5 µg/m³, 3.1× usual Shin’ichi, 2 February: 6.9 µg/m³, 0.8× usual Shin’ichi, 3 February: 12.3 µg/m³, 1.4× usual Shin’ichi, 4 February: 10.0 µg/m³, 1.1× usual Hōryūji Hōryūji, 28 January: 9.5 µg/m³, 1.1× usual Hōryūji, 29 January: 6.4 µg/m³, 0.7× usual Hōryūji, 30 January: 10.3 µg/m³, 1.1× usual Hōryūji, 31 January: 29.5 µg/m³, 3.3× usual Hōryūji, 1 February: 29.8 µg/m³, 3.3× usual Hōryūji, 2 February: 8.1 µg/m³, 0.9× usual Hōryūji, 3 February: 10.3 µg/m³, 1.1× usual Hōryūji, 4 February: 9.0 µg/m³, 1.0× usual Kurashiki Kurashiki, 28 January: 9.3 µg/m³, 0.9× usual Kurashiki, 29 January: 6.7 µg/m³, 0.7× usual Kurashiki, 30 January: 12.5 µg/m³, 1.3× usual Kurashiki, 31 January: 23.6 µg/m³, 2.4× usual Kurashiki, 1 February: 31.1 µg/m³, 3.1× usual Kurashiki, 2 February: 9.9 µg/m³, 1.0× usual Kurashiki, 3 February: 12.3 µg/m³, 1.2× usual Kurashiki, 4 February: 9.1 µg/m³, 0.9× usual Nishio Nishio, 28 January: 12.5 µg/m³, 1.5× usual Nishio, 29 January: 7.2 µg/m³, 0.9× usual Nishio, 30 January: 7.8 µg/m³, 1.0× usual Nishio, 31 January: 18.7 µg/m³, 2.3× usual Nishio, 1 February: 29.9 µg/m³, 3.7× usual Nishio, 2 February: 12.0 µg/m³, 1.5× usual Nishio, 3 February: 11.9 µg/m³, 1.5× usual Nishio, 4 February: 8.1 µg/m³, 1.0× usual 28 Jan 29 30 31 1 Feb 2 3 4 The 60 cities with the highest readings of 110, 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
Kyōtango Kyoto, Japan 1 31 January 5.3 6.4× Sakaiminato Tottori, Japan 1 31 January 6.3 5.8× Tottori-shi Tottori, Japan 1 31 January 6.6 5.6× Ōtsu Shiga, Japan 2 1 February 5.8 5.2× Miyazu Kyoto, Japan 1 31 January 6.2 5.2× Yonago Tottori, Japan 1 31 January 6.5 5.0× Youkaichi Shiga, Japan 2 1 February 6.9 5.0× Yono Osaka, Japan 2 31 January 6.2 4.9× Kōka Shiga, Japan 2 1 February 5.6 4.8× Fukuroi Shizuoka, Japan 1 1 February 5.9 4.7× Ōmihachiman Shiga, Japan 2 1 February 6.6 4.7× Kitahama Shiga, Japan 2 31 January 5.7 4.7× Jōyō Kyoto, Japan 2 1 February 7.6 4.6× Arida Wakayama, Japan 2 1 February 7.6 4.6× Kurayoshi Tottori, Japan 1 31 January 6.6 4.6× Obama Fukui, Japan 1 31 January 5.9 4.5× Maizuru Kyoto, Japan 2 1 February 5.9 4.5× Kameoka Kyoto, Japan 2 31 January 7.0 4.5× Kusatsu Shiga, Japan 2 31 January 7.1 4.4× Hikone Shiga, Japan 1 1 February 6.5 4.4× Ueno-ebisumachi Mie, Japan 2 31 January 7.1 4.4× Kōtari Kyoto, Japan 2 1 February 8.2 4.3× Toyooka Hyōgo, Japan 1 31 January 6.5 4.3× Uji Kyoto, Japan 2 1 February 8.3 4.2× Tsu Mie, Japan 2 31 January 6.9 4.2× Nabari Mie, Japan 2 31 January 8.4 4.2× Toyonaka Osaka, Japan 2 31 January 6.6 4.2× Ama Aichi, Japan 1 1 February 6.1 4.2× Ikoma Nara, Japan 2 1 February 7.1 4.2× Iga Mie, Japan 2 1 February 7.6 4.2× Himeji Hyōgo, Japan 2 1 February 7.0 4.2× Kyoto Kyoto, Japan 2 1 February 7.6 4.1× Sennan Osaka, Japan 2 1 February 7.5 4.0× Nantan Kyoto, Japan 2 1 February 7.6 4.0× Takashima Shiga, Japan 1 31 January 6.6 4.0× Fukuchiyama Kyoto, Japan 2 31 January 6.9 4.0× Tsuyama Okayama, Japan 2 1 February 7.7 4.0× Kainan Wakayama, Japan 2 1 February 7.5 4.0× Yawata Kyoto, Japan 2 1 February 9.4 4.0× Kashihara-shi Nara, Japan 2 1 February 7.8 4.0× Ise Mie, Japan 1 31 January 6.9 4.0× Tatsuno Hyōgo, Japan 2 1 February 7.7 4.0× Takarazuka Hyōgo, Japan 2 31 January 7.1 3.9× Ayabe Kyoto, Japan 2 31 January 7.2 3.9× Matsusaka Mie, Japan 1 31 January 7.4 3.9× Kizugawa Kyoto, Japan 2 1 February 8.1 3.9× Nishinomiya Hyōgo, Japan 2 1 February 7.7 3.8× Sugai Kyoto, Japan 2 1 February 8.9 3.8× Kameyama Mie, Japan 2 31 January 7.6 3.8× Kariya Aichi, Japan 1 1 February 7.5 3.7× Tanabe Wakayama, Japan 2 31 January 7.4 3.7× Okayama Okayama, Japan 2 1 February 7.9 3.7× Ikaruga Hyōgo, Japan 2 1 February 7.4 3.7× Iwade Wakayama, Japan 2 1 February 8.3 3.7× Kashiwara Nara, Japan 2 1 February 7.6 3.7× Kobe Hyōgo, Japan 2 1 February 7.7 3.7× Gobō Wakayama, Japan 1 31 January 7.3 3.7× Nishio Aichi, Japan 1 1 February 8.1 3.7× Kishiwada Osaka, Japan 2 1 February 9.0 3.7× Izumisano Osaka, Japan 2 1 February 8.2 3.7× Narutochō-mitsuishi Tokushima, Japan 2 1 February 7.7 3.6× Kinokawa Wakayama, Japan 2 1 February 7.4 3.6× Kakogawachō-honmachi Hyōgo, Japan 2 1 February 8.9 3.6× Takamatsu Kagawa, Japan 2 1 February 8.6 3.6× Aioi Hyōgo, Japan 2 31 January 8.8 3.6× Handa Aichi, Japan 1 1 February 7.2 3.6× Saikū Mie, Japan 1 31 January 7.3 3.6× Ono Hyōgo, Japan 2 1 February 8.0 3.6× Kawachi-Nagano Osaka, Japan 1 31 January 7.1 3.5× Suzuka Mie, Japan 2 1 February 7.6 3.5× Takahashi Okayama, Japan 2 31 January 8.6 3.5× Hirakata Osaka, Japan 2 1 February 8.8 3.5× Sayama Osaka, Japan 2 1 February 7.6 3.5× Izumi Osaka, Japan 2 1 February 7.3 3.5× Kariya Hyōgo, Japan 2 31 January 9.6 3.5× Amagasaki Hyōgo, Japan 2 1 February 9.2 3.5× Sōja Okayama, Japan 2 1 February 8.9 3.5× Akashi Hyōgo, Japan 2 1 February 8.8 3.5× Tenri Nara, Japan 2 1 February 9.7 3.5× Habikino Osaka, Japan 2 1 February 9.1 3.5× Minato Wakayama, Japan 2 1 February 8.8 3.4× Hiragi Kagawa, Japan 1 1 February 7.9 3.4× Shido Kagawa, Japan 2 1 February 9.0 3.4× Anan Tokushima, Japan 2 31 January 7.9 3.4× Higashinozoe Hyōgo, Japan 2 1 February 10.3 3.4× Osaka Osaka, Japan 2 1 February 10.4 3.3× Hōryūji Nara, Japan 2 1 February 9.0 3.3× Asakuchi Okayama, Japan 2 1 February 9.6 3.3× Shin’ichi Hiroshima, Japan 2 31 January 9.1 3.3× Zentsujichó Kagawa, Japan 1 1 February 8.1 3.3× Sandachō Hyōgo, Japan 2 31 January 9.4 3.3× Tondabayashichō Osaka, Japan 2 1 February 7.9 3.3× Yao Osaka, Japan 2 31 January 9.5 3.3× Imabari Ehime, Japan 1 1 February 9.0 3.1× Higashiosaka Osaka, Japan 2 1 February 10.8 3.1× Kurashiki Okayama, Japan 1 1 February 10.0 3.1× Marugame Kagawa, Japan 1 1 February 8.7 3.1× Sakai Osaka, Japan 2 1 February 10.2 3.0× Kan’onjichō Kagawa, Japan 2 1 February 10.0 3.0× Kasaoka Okayama, Japan 2 1 February 9.6 3.0× Tamano Okayama, Japan 2 1 February 10.5 3.0× Hashimoto Wakayama, Japan 2 31 January 9.1 3.0× Tahara Aichi, Japan 1 1 February 9.0 3.0× Bizen Okayama, Japan 2 1 February 9.3 3.0× Niihama Ehime, Japan 1 1 February 9.3 2.9× Fukuyama Hiroshima, Japan 2 1 February 10.9 2.8× Saijō Ehime, Japan 1 1 February 9.9 2.8× Onomichi Hiroshima, Japan 2 1 February 10.9 2.8× Higashihiroshima Hiroshima, Japan 1 1 February 9.9 2.7× Shikokuchūō Ehime, Japan 1 1 February 10.5 2.4×
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 9 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 Bars: cities reached; colour: the level of the episode's highest daily reading. All 27 .
Use this page SmogRank, Japan, January and February 2025: 110 cities with PM2.5 at twice their usual or more, 31 January to 1 February 2025, smogrank.com/episodes/2025-01-japan (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.
