SmogRank / Episodes / Taiwan
Taiwan, 21 to 22 January 2025
For 2 days, from 21 to 22 January 2025, 22 cities in Taiwan had PM2.5 at least twice their usual for the time of year. The worst reading was Yuanlin, Taiwan: 55.3 µg/m³ on 22 January, about 2.6× its usual 21.0.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 22 in 1 country
Days 2 21 to 22 January 2025
Worst day 22 January 18 cities counted
Furthest above usual 2.8× Buzi
Day by day
Play 22 January 18 cities at twice their usual or more
Erlin Zhushan Erlun Puli Taibao Xinying Zhudong Hualien City Tainan Yilan Taitung Fengshan Kaohsiung Sanzhi Chaozhou Keelung Hengchun Jincheng Ishigaki Nantou Yongkang Xizhi Neili Beigang Chiayi City Taoyuan New Taipei City Toufen Xizhou Miaoli Taipei Shulin Douliu Hsinchu Daxi Zhubei Taichung Yuanlin Changhua Magong Buzi 18 Jan 19 20 21 22 23 24 25 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
Yongkang Yongkang, 18 January: 27.2 µg/m³ Yongkang, 19 January: 23.3 µg/m³ Yongkang, 20 January: 30.8 µg/m³ Yongkang, 21 January: 44.7 µg/m³, 2.0× its usual 22.2 Yongkang, 22 January: 37.9 µg/m³ Yongkang, 23 January: 41.0 µg/m³ Yongkang, 24 January: 25.1 µg/m³ Yongkang, 25 January: 36.8 µg/m³ Magong Magong, 18 January: 17.3 µg/m³ Magong, 19 January: 12.0 µg/m³ Magong, 20 January: 20.7 µg/m³ Magong, 21 January: 38.7 µg/m³, 2.8× its usual 13.6 Magong, 22 January: 25.1 µg/m³ Magong, 23 January: 12.7 µg/m³ Magong, 24 January: 13.8 µg/m³ Magong, 25 January: 20.0 µg/m³ Beigang Beigang, 18 January: 19.7 µg/m³ Beigang, 19 January: 18.3 µg/m³ Beigang, 20 January: 26.7 µg/m³ Beigang, 21 January: 37.6 µg/m³, 2.1× its usual 17.6 Beigang, 22 January: 35.7 µg/m³ Beigang, 23 January: 34.0 µg/m³ Beigang, 24 January: 23.0 µg/m³ Beigang, 25 January: 25.7 µg/m³ Changhua Changhua, 18 January: 15.1 µg/m³ Changhua, 19 January: 14.2 µg/m³ Changhua, 20 January: 20.2 µg/m³ Changhua, 21 January: 31.0 µg/m³, 2.0× its usual 15.3 Changhua, 22 January: 44.1 µg/m³, 2.7× its usual 16.2 Changhua, 23 January: 19.9 µg/m³ Changhua, 24 January: 17.1 µg/m³ Changhua, 25 January: 20.5 µg/m³ Xizhi Xizhi, 18 January: 11.1 µg/m³ Xizhi, 19 January: 17.1 µg/m³ Xizhi, 20 January: 21.4 µg/m³ Xizhi, 21 January: 26.0 µg/m³, 2.1× its usual 12.4 Xizhi, 22 January: 21.0 µg/m³ Xizhi, 23 January: 22.0 µg/m³ Xizhi, 24 January: 13.0 µg/m³ Xizhi, 25 January: 15.1 µg/m³ Taipei Taipei, 18 January: 9.5 µg/m³ Taipei, 19 January: 15.9 µg/m³ Taipei, 20 January: 18.9 µg/m³ Taipei, 21 January: 25.2 µg/m³, 2.2× its usual 11.6 Taipei, 22 January: 28.4 µg/m³, 2.3× its usual 12.1 Taipei, 23 January: 20.6 µg/m³ Taipei, 24 January: 12.1 µg/m³ Taipei, 25 January: 14.8 µg/m³ New Taipei City New Taipei City, 18 January: 9.0 µg/m³ New Taipei City, 19 January: 14.0 µg/m³ New Taipei City, 20 January: 19.4 µg/m³ New Taipei City, 21 January: 25.2 µg/m³, 2.0× its usual 12.4 New Taipei City, 22 January: 27.6 µg/m³, 2.2× its usual 12.5 New Taipei City, 23 January: 18.9 µg/m³ New Taipei City, 24 January: 11.1 µg/m³ New Taipei City, 25 January: 14.7 µg/m³ Yuanlin Yuanlin, 18 January: 21.5 µg/m³ Yuanlin, 19 January: 14.7 µg/m³ Yuanlin, 20 January: 23.3 µg/m³ Yuanlin, 21 January: 35.4 µg/m³ Yuanlin, 22 January: 55.3 µg/m³, 2.6× its usual 21.0 Yuanlin, 23 January: 25.3 µg/m³ Yuanlin, 24 January: 20.9 µg/m³ Yuanlin, 25 January: 22.9 µg/m³ Douliu Douliu, 18 January: 27.5 µg/m³ Douliu, 19 January: 20.9 µg/m³ Douliu, 20 January: 33.6 µg/m³ Douliu, 21 January: 44.3 µg/m³ Douliu, 22 January: 54.9 µg/m³, 2.3× its usual 24.1 Douliu, 23 January: 35.7 µg/m³ Douliu, 24 January: 26.3 µg/m³ Douliu, 25 January: 34.2 µg/m³ Chiayi City Chiayi City, 18 January: 25.5 µg/m³ Chiayi City, 19 January: 19.3 µg/m³ Chiayi City, 20 January: 30.9 µg/m³ Chiayi City, 21 January: no reading Chiayi City, 22 January: 49.4 µg/m³, 2.1× its usual 23.8 Chiayi City, 23 January: 45.6 µg/m³ Chiayi City, 24 January: 32.9 µg/m³ Chiayi City, 25 January: 39.0 µg/m³ Buzi Buzi, 18 January: 15.7 µg/m³ Buzi, 19 January: 13.7 µg/m³ Buzi, 20 January: 18.7 µg/m³ Buzi, 21 January: 31.6 µg/m³ Buzi, 22 January: 47.0 µg/m³, 2.8× its usual 16.6 Buzi, 23 January: 19.3 µg/m³ Buzi, 24 January: 17.3 µg/m³ Buzi, 25 January: 20.4 µg/m³ Taichung Taichung, 18 January: 17.2 µg/m³ Taichung, 19 January: 14.0 µg/m³ Taichung, 20 January: 18.8 µg/m³ Taichung, 21 January: 29.7 µg/m³ Taichung, 22 January: 46.5 µg/m³, 2.6× its usual 18.0 Taichung, 23 January: 22.5 µg/m³ Taichung, 24 January: 17.0 µg/m³ Taichung, 25 January: 18.3 µg/m³ Nantou Nantou, 18 January: 18.8 µg/m³ Nantou, 19 January: 16.3 µg/m³ Nantou, 20 January: 18.3 µg/m³ Nantou, 21 January: 31.8 µg/m³ Nantou, 22 January: 39.3 µg/m³, 2.0× its usual 19.6 Nantou, 23 January: 31.9 µg/m³ Nantou, 24 January: 20.7 µg/m³ Nantou, 25 January: 20.9 µg/m³ Daxi Daxi, 18 January: 13.1 µg/m³ Daxi, 19 January: 15.8 µg/m³ Daxi, 20 January: 17.5 µg/m³ Daxi, 21 January: 23.2 µg/m³ Daxi, 22 January: 34.9 µg/m³, 2.4× its usual 14.3 Daxi, 23 January: 22.7 µg/m³ Daxi, 24 January: 13.8 µg/m³ Daxi, 25 January: 14.8 µg/m³ Miaoli Miaoli, 18 January: 12.9 µg/m³ Miaoli, 19 January: 14.9 µg/m³ Miaoli, 20 January: 17.5 µg/m³ Miaoli, 21 January: 26.7 µg/m³ Miaoli, 22 January: 32.7 µg/m³, 2.2× its usual 14.9 Miaoli, 23 January: 17.9 µg/m³ Miaoli, 24 January: 16.3 µg/m³ Miaoli, 25 January: 17.9 µg/m³ Hsinchu Hsinchu, 18 January: 15.0 µg/m³ Hsinchu, 19 January: 15.3 µg/m³ Hsinchu, 20 January: 20.7 µg/m³ Hsinchu, 21 January: 24.0 µg/m³ Hsinchu, 22 January: 32.5 µg/m³, 2.4× its usual 13.8 Hsinchu, 23 January: 18.4 µg/m³ Hsinchu, 24 January: 14.7 µg/m³ Hsinchu, 25 January: 17.4 µg/m³ Xizhou Xizhou, 18 January: 16.4 µg/m³ Xizhou, 19 January: 12.3 µg/m³ Xizhou, 20 January: 14.1 µg/m³ Xizhou, 21 January: 20.6 µg/m³ Xizhou, 22 January: 32.0 µg/m³, 2.2× its usual 14.5 Xizhou, 23 January: 20.4 µg/m³ Xizhou, 24 January: 16.8 µg/m³ Xizhou, 25 January: 15.3 µg/m³ Neili Neili, 18 January: 13.0 µg/m³ Neili, 19 January: 15.3 µg/m³ Neili, 20 January: 20.3 µg/m³ Neili, 21 January: 25.3 µg/m³ Neili, 22 January: 31.8 µg/m³, 2.1× its usual 14.8 Neili, 23 January: 18.8 µg/m³ Neili, 24 January: 13.4 µg/m³ Neili, 25 January: 18.1 µg/m³ Toufen Toufen, 18 January: 13.7 µg/m³ Toufen, 19 January: 15.5 µg/m³ Toufen, 20 January: 18.9 µg/m³ Toufen, 21 January: 26.3 µg/m³ Toufen, 22 January: 31.4 µg/m³, 2.2× its usual 14.5 Toufen, 23 January: 16.1 µg/m³ Toufen, 24 January: 14.9 µg/m³ Toufen, 25 January: 16.4 µg/m³ Zhubei Zhubei, 18 January: 13.2 µg/m³ Zhubei, 19 January: 13.8 µg/m³ Zhubei, 20 January: 20.9 µg/m³ Zhubei, 21 January: 24.3 µg/m³ Zhubei, 22 January: 31.1 µg/m³, 2.5× its usual 12.4 Zhubei, 23 January: 16.3 µg/m³ Zhubei, 24 January: 13.5 µg/m³ Zhubei, 25 January: 16.6 µg/m³ Shulin Shulin, 18 January: 9.8 µg/m³ Shulin, 19 January: 15.9 µg/m³ Shulin, 20 January: 17.9 µg/m³ Shulin, 21 January: 22.9 µg/m³ Shulin, 22 January: 29.5 µg/m³, 2.3× its usual 12.7 Shulin, 23 January: 21.4 µg/m³ Shulin, 24 January: 11.0 µg/m³ Shulin, 25 January: 14.4 µg/m³ Taoyuan Taoyuan, 18 January: 6.6 µg/m³ Taoyuan, 19 January: 13.0 µg/m³ Taoyuan, 20 January: 15.9 µg/m³ Taoyuan, 21 January: 22.3 µg/m³ Taoyuan, 22 January: 26.5 µg/m³, 2.2× its usual 12.3 Taoyuan, 23 January: 14.8 µg/m³ Taoyuan, 24 January: 9.9 µg/m³ Taoyuan, 25 January: 13.3 µg/m³ 18 Jan 19 20 21 22 23 24 25 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
Buzi Taiwan 1 22 January 16.6 2.8× Magong Taiwan 1 21 January 13.6 2.8× Changhua Taiwan 2 22 January 16.2 2.7× Yuanlin Taiwan 1 22 January 21.0 2.6× Taichung Taiwan 1 22 January 18.0 2.6× Zhubei Taiwan 1 22 January 12.4 2.5× Daxi Taiwan 1 22 January 14.3 2.4× Hsinchu Taiwan 1 22 January 13.8 2.4× Douliu Taiwan 1 22 January 24.1 2.3× Shulin Taipei, Taiwan 1 22 January 12.7 2.3× Taipei Taiwan 2 22 January 12.1 2.3× Miaoli Taiwan 1 22 January 14.9 2.2× Xizhou Taiwan 1 22 January 14.5 2.2× Toufen Taiwan 1 22 January 14.5 2.2× New Taipei City Taipei, Taiwan 2 22 January 12.5 2.2× Taoyuan Taiwan 1 22 January 12.3 2.2× Chiayi City Taiwan 1 22 January 23.8 2.1× Beigang Taiwan 1 21 January 17.6 2.1× Neili Taiwan 1 22 January 14.8 2.1× Xizhi Taipei, Taiwan 1 21 January 12.4 2.1× Yongkang Taiwan 1 21 January 22.2 2.0× Nantou Taiwan 1 22 January 19.6 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 Taiwan
Number 2 of 12 episodes in Taiwan since our records began, by cities reached.
Taiwan, 26 to 28 February 2025 24 Taiwan, 21 to 22 January 2025 22 Taiwan, 17 February 2025 21 Taiwan, November 2024 21 Taiwan, March 2024 20 Taiwan, December 2024 18 Taiwan, 28 November 2025 17 Taiwan, May 2024 16 Taiwan, 14 to 15 January 2025 14 Taiwan, February 2026 13 Taiwan, March 2025 13 Taiwan, 25 November 2025 12 Bars: cities reached; colour: the level of the episode's highest daily reading.
Use this page SmogRank, Taiwan, 21 to 22 January 2025: 22 cities with PM2.5 at twice their usual or more, 21 to 22 January 2025, smogrank.com/episodes/2025-01-21-taiwan (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.
