SmogRank / Episodes / Japan
Japan, December 2023
For 3 days, from 29 to 31 December 2023, 20 cities in Japan had PM2.5 at least twice their usual for the time of year. The worst reading was Tsushima, Nagasaki, Japan: 30.7 µg/m³ on 29 December, about 4.4× its usual 7.0.
Likely New Year fireworks It came on the night of 31 December, when smoke from fireworks often fills the air over many cities at once.
Cities reached 20 in 1 country
Days 3 29 to 31 December 2023
Worst day 30 December 14 cities counted
Furthest above usual 4.4× Tsushima
Day by day
Play 30 December 14 cities at twice their usual or more
Yufu Aso Beppu Hita Mie Ōita Ōzu Tsurusaki Nakatsu Buzen Ukiha Yamaga Mifune Uekimachi-mōno Usuki Kotō Yame Kumamoto Tsukumiura Kunisaki Tamana Tagawa Nobeoka Saiki Kanda Iizuka Tosu Arao Hyūga Nōgata Ube Wakasugi Honmachi Kasuga Nakama Onoda Shimonoseki Koga Ōyanomachi-noboritate Fukuoka Munakata Koga Hōfu Hitoyoshi Takanabe Shintomi Mine Yamaguchi Kudamatsu Itoshima Taku Kashima Shūnan Kobayashi Miyazaki Takeo Isahaya Minamata Ureshinomachi-shimojuku Yanai Hondomachi-hondo Yawatahama Nagato Ōmura Karatsu Hagi Izumi Uwajima Imarichō-kō Obita Nagasaki Togitsu Kirishima Iwakuni Ōtake Sasebo Nichinan Matsuura Saikai Sendai Iyo Masuda Kagoshima Kushikino Matsuyama Nakamura Kure Kanoya Hiroshima Gion Shinagawa Kaseda-shirakame Minamikyushu Hamada Higashihiroshima Imabari Yae Susaki Takehara Saijō Gōtsuchō Niihama Ino Mihara Miyoshi Kochi Onomichi Ōdachō-ōda Nankoku Shin’ichi Aki Unnan Izumo Ikedachō Zentsujichó Marugame Takinomiya Matsue Mima Yasugichō Takamatsu Hiragi Yonago Sakaiminato Shido Yoshinogawa Kamojimachō-jōgejima Tokushima Kurayoshi Anan Narutochō-mitsuishi Kariya Aioi Tatsuno Ikaruga Tottori-shi Sumoto Himeji Kakogawachō-honmachi Higashinozoe Arida Gobō Minato Akashi Ono Kainan Tanabe Nishiwaki Iwade Kobe Tanba Toyooka Kinokawa Sandachō Nishinomiya Takarazuka Fukuchiyama Amagasaki Hashimoto Toyonaka Ayabe Miyazu Nantan Maizuru Kashiwara Ikoma Kameoka Hōryūji Kashihara-shi Shingū Yawata Kōtari Tenri Nara-shi Sugai Kizugawa Jōyō Uji Kyoto Ōtsu Nabari Kusatsu Kitahama Takashima Miyakonojō Higashigō Chikugo Ōmuta Tanushimarumachi-toyoki Ogōri Kanzakimachi-kanzaki Saga Kurume Maebaru-chūō Yanagawa Hikari Shikokuchūō Fukuyama Kitakyushu Yukuhashi Kan’onjichō Gotō Iki Tsushima 26 Dec 27 28 29 30 31 1 Jan 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
Tanushimarumachi-to… Tanushimarumachi-toyoki, 26 December: 23.2 µg/m³, 2.1× usual Tanushimarumachi-toyoki, 27 December: 25.8 µg/m³, 2.3× usual Tanushimarumachi-toyoki, 28 December: 19.9 µg/m³, 1.8× usual Tanushimarumachi-toyoki, 29 December: 25.9 µg/m³, 2.3× usual Tanushimarumachi-toyoki, 30 December: 27.1 µg/m³, 2.4× usual Tanushimarumachi-toyoki, 31 December: 21.6 µg/m³, 1.9× usual Tanushimarumachi-toyoki, 1 January: 8.5 µg/m³, 0.8× usual Tanushimarumachi-toyoki, 2 January: 9.5 µg/m³, 0.8× usual Tanushimarumachi-toyoki, 3 January: 10.5 µg/m³, 0.9× usual Tsushima Tsushima, 26 December: 13.2 µg/m³, 1.9× usual Tsushima, 27 December: 10.5 µg/m³, 1.5× usual Tsushima, 28 December: 11.7 µg/m³, 1.7× usual Tsushima, 29 December: 30.7 µg/m³, 4.4× usual Tsushima, 30 December: 21.0 µg/m³, 3.0× usual Tsushima, 31 December: 18.9 µg/m³, 2.7× usual Tsushima, 1 January: 7.0 µg/m³, 1.0× usual Tsushima, 2 January: 10.5 µg/m³, 1.5× usual Tsushima, 3 January: 11.9 µg/m³, 1.7× usual Maebaru-chūō Maebaru-chūō, 26 December: 18.6 µg/m³, 2.0× usual Maebaru-chūō, 27 December: 18.5 µg/m³, 2.0× usual Maebaru-chūō, 28 December: 16.9 µg/m³, 1.8× usual Maebaru-chūō, 29 December: 27.1 µg/m³, 2.9× usual Maebaru-chūō, 30 December: 28.5 µg/m³, 3.1× usual Maebaru-chūō, 31 December: 25.4 µg/m³, 2.8× usual Maebaru-chūō, 1 January: 12.0 µg/m³, 1.3× usual Maebaru-chūō, 2 January: 11.3 µg/m³, 1.2× usual Maebaru-chūō, 3 January: 17.0 µg/m³, 1.8× usual Chikugo Chikugo, 26 December: 17.3 µg/m³, 1.6× usual Chikugo, 27 December: 19.2 µg/m³, 1.8× usual Chikugo, 28 December: 23.1 µg/m³, 2.1× usual Chikugo, 29 December: 25.5 µg/m³, 2.3× usual Chikugo, 30 December: no reading Chikugo, 31 December: 21.7 µg/m³, 2.0× usual Chikugo, 1 January: 8.1 µg/m³, 0.7× usual Chikugo, 2 January: 10.4 µg/m³, 1.0× usual Chikugo, 3 January: 11.9 µg/m³, 1.1× usual Iki Iki, 26 December: 11.2 µg/m³, 1.9× usual Iki, 27 December: 9.0 µg/m³, 1.5× usual Iki, 28 December: 9.1 µg/m³, 1.5× usual Iki, 29 December: 25.0 µg/m³, 4.2× usual Iki, 30 December: 16.9 µg/m³, 2.9× usual Iki, 31 December: 17.5 µg/m³, 3.0× usual Iki, 1 January: 5.5 µg/m³, 0.9× usual Iki, 2 January: 7.4 µg/m³, 1.3× usual Iki, 3 January: 11.2 µg/m³, 1.9× usual Kan’onjichō Kan’onjichō, 26 December: 12.2 µg/m³, 1.6× usual Kan’onjichō, 27 December: 14.3 µg/m³, 1.9× usual Kan’onjichō, 28 December: 19.6 µg/m³, 2.5× usual Kan’onjichō, 29 December: 21.8 µg/m³, 2.8× usual Kan’onjichō, 30 December: 30.2 µg/m³, 3.9× usual Kan’onjichō, 31 December: 26.6 µg/m³, 3.5× usual Kan’onjichō, 1 January: 2.9 µg/m³, 0.4× usual Kan’onjichō, 2 January: 9.2 µg/m³, 1.2× usual Kan’onjichō, 3 January: 14.0 µg/m³, 1.8× usual Fukuyama Fukuyama, 26 December: 13.2 µg/m³, 1.5× usual Fukuyama, 27 December: 14.9 µg/m³, 1.7× usual Fukuyama, 28 December: 19.5 µg/m³, 2.3× usual Fukuyama, 29 December: 20.0 µg/m³, 2.3× usual Fukuyama, 30 December: 29.9 µg/m³, 3.5× usual Fukuyama, 31 December: 24.7 µg/m³, 2.9× usual Fukuyama, 1 January: 3.8 µg/m³, 0.4× usual Fukuyama, 2 January: 8.7 µg/m³, 1.0× usual Fukuyama, 3 January: 14.4 µg/m³, 1.7× usual Kanzakimachi-kanzaki Kanzakimachi-kanzaki, 26 December: 14.3 µg/m³, 1.4× usual Kanzakimachi-kanzaki, 27 December: 17.6 µg/m³, 1.7× usual Kanzakimachi-kanzaki, 28 December: 17.3 µg/m³, 1.7× usual Kanzakimachi-kanzaki, 29 December: 19.9 µg/m³, 1.9× usual Kanzakimachi-kanzaki, 30 December: 29.0 µg/m³, 2.8× usual Kanzakimachi-kanzaki, 31 December: 23.1 µg/m³, 2.2× usual Kanzakimachi-kanzaki, 1 January: 8.8 µg/m³, 0.9× usual Kanzakimachi-kanzaki, 2 January: 10.4 µg/m³, 1.0× usual Kanzakimachi-kanzaki, 3 January: 12.2 µg/m³, 1.2× usual Yanagawa Yanagawa, 26 December: 13.8 µg/m³, 1.6× usual Yanagawa, 27 December: 19.0 µg/m³, 2.2× usual Yanagawa, 28 December: 21.5 µg/m³, 2.4× usual Yanagawa, 29 December: 18.0 µg/m³, 2.0× usual Yanagawa, 30 December: 28.5 µg/m³, 3.2× usual Yanagawa, 31 December: 24.7 µg/m³, 2.8× usual Yanagawa, 1 January: 7.4 µg/m³, 0.8× usual Yanagawa, 2 January: 9.3 µg/m³, 1.1× usual Yanagawa, 3 January: 10.7 µg/m³, 1.2× usual Kurume Kurume, 26 December: 15.7 µg/m³, 1.7× usual Kurume, 27 December: 18.3 µg/m³, 2.0× usual Kurume, 28 December: 18.7 µg/m³, 2.0× usual Kurume, 29 December: 23.3 µg/m³, 2.5× usual Kurume, 30 December: 27.5 µg/m³, 3.0× usual Kurume, 31 December: 21.2 µg/m³, 2.3× usual Kurume, 1 January: 7.5 µg/m³, 0.8× usual Kurume, 2 January: 9.6 µg/m³, 1.0× usual Kurume, 3 January: 9.9 µg/m³, 1.1× usual Saga Saga, 26 December: 14.3 µg/m³, 1.5× usual Saga, 27 December: 15.2 µg/m³, 1.6× usual Saga, 28 December: 13.8 µg/m³, 1.5× usual Saga, 29 December: 19.5 µg/m³, 2.1× usual Saga, 30 December: 26.8 µg/m³, 2.9× usual Saga, 31 December: 24.0 µg/m³, 2.6× usual Saga, 1 January: 8.3 µg/m³, 0.9× usual Saga, 2 January: 9.4 µg/m³, 1.0× usual Saga, 3 January: 11.6 µg/m³, 1.2× usual Kitakyushu Kitakyushu, 26 December: 14.4 µg/m³, 1.9× usual Kitakyushu, 27 December: 15.5 µg/m³, 2.0× usual Kitakyushu, 28 December: 14.1 µg/m³, 1.9× usual Kitakyushu, 29 December: 24.4 µg/m³, 3.2× usual Kitakyushu, 30 December: 26.6 µg/m³, 3.5× usual Kitakyushu, 31 December: 21.9 µg/m³, 2.9× usual Kitakyushu, 1 January: 10.2 µg/m³, 1.3× usual Kitakyushu, 2 January: 7.8 µg/m³, 1.0× usual Kitakyushu, 3 January: 13.5 µg/m³, 1.8× usual Ōmuta Ōmuta, 26 December: 15.0 µg/m³, 1.3× usual Ōmuta, 27 December: 19.2 µg/m³, 1.7× usual Ōmuta, 28 December: 21.3 µg/m³, 1.9× usual Ōmuta, 29 December: 19.9 µg/m³, 1.8× usual Ōmuta, 30 December: 26.4 µg/m³, 2.4× usual Ōmuta, 31 December: 24.0 µg/m³, 2.1× usual Ōmuta, 1 January: 9.5 µg/m³, 0.8× usual Ōmuta, 2 January: 12.6 µg/m³, 1.1× usual Ōmuta, 3 January: 11.7 µg/m³, 1.0× usual Ogōri Ogōri, 26 December: 15.2 µg/m³, 1.6× usual Ogōri, 27 December: 14.8 µg/m³, 1.5× usual Ogōri, 28 December: 19.3 µg/m³, 2.0× usual Ogōri, 29 December: 21.3 µg/m³, 2.2× usual Ogōri, 30 December: 26.1 µg/m³, 2.7× usual Ogōri, 31 December: 19.7 µg/m³, 2.0× usual Ogōri, 1 January: 8.1 µg/m³, 0.8× usual Ogōri, 2 January: 10.1 µg/m³, 1.0× usual Ogōri, 3 January: 10.2 µg/m³, 1.1× usual Yukuhashi Yukuhashi, 26 December: 14.5 µg/m³, 2.0× usual Yukuhashi, 27 December: 17.9 µg/m³, 2.5× usual Yukuhashi, 28 December: 17.0 µg/m³, 2.4× usual Yukuhashi, 29 December: 22.0 µg/m³, 3.1× usual Yukuhashi, 30 December: 26.0 µg/m³, 3.6× usual Yukuhashi, 31 December: 22.8 µg/m³, 3.2× usual Yukuhashi, 1 January: 8.3 µg/m³, 1.2× usual Yukuhashi, 2 January: 7.1 µg/m³, 1.0× usual Yukuhashi, 3 January: 11.3 µg/m³, 1.6× usual Higashigō Higashigō, 26 December: 17.6 µg/m³, 1.6× usual Higashigō, 27 December: 19.9 µg/m³, 1.8× usual Higashigō, 28 December: 21.4 µg/m³, 1.9× usual Higashigō, 29 December: 23.8 µg/m³, 2.2× usual Higashigō, 30 December: 25.7 µg/m³, 2.3× usual Higashigō, 31 December: 24.5 µg/m³, 2.2× usual Higashigō, 1 January: 8.0 µg/m³, 0.7× usual Higashigō, 2 January: 11.1 µg/m³, 1.0× usual Higashigō, 3 January: 13.5 µg/m³, 1.2× usual Hikari Hikari, 26 December: 13.9 µg/m³, 1.8× usual Hikari, 27 December: 12.6 µg/m³, 1.6× usual Hikari, 28 December: 15.5 µg/m³, 2.0× usual Hikari, 29 December: 19.2 µg/m³, 2.5× usual Hikari, 30 December: 25.1 µg/m³, 3.3× usual Hikari, 31 December: 22.4 µg/m³, 2.9× usual Hikari, 1 January: 6.0 µg/m³, 0.8× usual Hikari, 2 January: 7.6 µg/m³, 1.0× usual Hikari, 3 January: 11.8 µg/m³, 1.5× usual Shikokuchūō Shikokuchūō, 26 December: 11.3 µg/m³, 1.4× usual Shikokuchūō, 27 December: no reading Shikokuchūō, 28 December: 15.1 µg/m³, 1.9× usual Shikokuchūō, 29 December: 14.4 µg/m³, 1.8× usual Shikokuchūō, 30 December: 18.1 µg/m³, 2.2× usual Shikokuchūō, 31 December: 27.6 µg/m³, 3.4× usual Shikokuchūō, 1 January: no reading Shikokuchūō, 2 January: no reading Shikokuchūō, 3 January: no reading Miyakonojō Miyakonojō, 26 December: 16.9 µg/m³, 1.4× usual Miyakonojō, 27 December: 20.1 µg/m³, 1.6× usual Miyakonojō, 28 December: 23.9 µg/m³, 1.9× usual Miyakonojō, 29 December: 18.0 µg/m³, 1.4× usual Miyakonojō, 30 December: 24.9 µg/m³, 2.0× usual Miyakonojō, 31 December: 25.5 µg/m³, 2.0× usual Miyakonojō, 1 January: 10.7 µg/m³, 0.9× usual Miyakonojō, 2 January: 8.4 µg/m³, 0.7× usual Miyakonojō, 3 January: 8.3 µg/m³, 0.7× usual Gotō Gotō, 26 December: 11.4 µg/m³, 1.8× usual Gotō, 27 December: 10.3 µg/m³, 1.7× usual Gotō, 28 December: 10.3 µg/m³, 1.7× usual Gotō, 29 December: 18.7 µg/m³, 3.0× usual Gotō, 30 December: 16.8 µg/m³, 2.7× usual Gotō, 31 December: 25.0 µg/m³, 4.0× usual Gotō, 1 January: 6.4 µg/m³, 1.0× usual Gotō, 2 January: 9.9 µg/m³, 1.6× usual Gotō, 3 January: 12.4 µg/m³, 2.0× usual 26 Dec 27 28 29 30 31 1 Jan 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
Tsushima Nagasaki, Japan 1 29 December 7.0 4.4× Iki Nagasaki, Japan 1 29 December 5.9 4.2× Gotō Nagasaki, Japan 1 31 December 6.2 4.0× Kan’onjichō Kagawa, Japan 2 30 December 7.7 3.9× Yukuhashi Fukuoka, Japan 1 30 December 7.2 3.6× Kitakyushu Fukuoka, Japan 1 30 December 7.6 3.5× Fukuyama Hiroshima, Japan 1 30 December 8.6 3.5× Shikokuchūō Ehime, Japan 1 31 December 8.1 3.4× Hikari Yamaguchi, Japan 1 30 December 7.7 3.3× Yanagawa Fukuoka, Japan 1 30 December 8.8 3.2× Maebaru-chūō Fukuoka, Japan 3 30 December 9.2 3.1× Kurume Fukuoka, Japan 1 30 December 9.3 3.0× Saga Saga, Japan 1 30 December 9.4 2.9× Kanzakimachi-kanzaki Saga, Japan 1 30 December 10.3 2.8× Ogōri Fukuoka, Japan 1 30 December 9.7 2.7× Tanushimarumachi-toyoki Fukuoka, Japan 2 30 December 11.3 2.4× Ōmuta Fukuoka, Japan 1 30 December 11.2 2.4× Chikugo Fukuoka, Japan 1 29 December 10.9 2.3× Higashigō Saga, Japan 1 30 December 11.0 2.3× Miyakonojō Miyazaki, Japan 1 31 December 12.5 2.0×
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 3 of 5 episodes in Japan since our records began, by cities reached.
Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Japan, December 2023: 20 cities with PM2.5 at twice their usual or more, 29 to 31 December 2023, smogrank.com/episodes/2023-12-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.
