SmogRank / Episodes / Thailand
North-western Thailand, April and May 2024
For 9 days, from 29 April to 7 May 2024, 45 cities in Thailand and Laos had PM2.5 at least twice their usual for the time of year. The worst reading was Ban Houakhoua, Bokeo, Laos: 237.0 µg/m³ on 2 May, about 7.0× its usual 33.7.
No cause named We have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached 45 in 2 countries
Days 9 29 April to 7 May 2024
Worst day 2 May 34 cities counted
Furthest above usual 7.2× Chiang Rai
Day by day
Play 2 May 34 cities at twice their usual or more
Si Maha Phot Nong Chok Bang Bo District Lat Krabang Ban Talat Bueng Aranyaprathet Khlong Sam Wa Khan Na Yao Bang Na Bang Kapi Sai Mai Rayong Khlong Luang Lak Si Ban Chang Phra Pradaeng Saraburi Chanthaburi Bang Khun Thian Samut Sakhon Nakhon Ratchasima Lop Buri Trat Suphan Buri Sing Buri Buri Ram Kanchanaburi Chai Nat Khon Kaen Yasothon Tha Bo Mae Sot Surat Thani Nakhon Si Thammarat Trang Hat Yai Yala Satun Narathiwat Betong Ban Khlong Prawet Nong Khaem Roi Et Surin Ban Samae Dam Bangkok Nakhon Sawan Vientiane Phra Nakhon Si Ayutthaya Amnat Charoen Chaiyaphum Mukdahan Mueang Nonthaburi Laem Chabang Ratchaburi Nakhon Nayok Phichit Nakhon Pathom Nan Sukhothai Kalasin Phuket Hua Hin Kamphaeng Phet Samut Prakan Si Sa Ket Sakon Nakhon Ubon Ratchathani Phetchabun Udon Thani Pattani Phetchaburi Loei Lampang Phrae Lamphun Pakxan Nong Bua Lamphu Chiang Mai Ranong Phayao Uttaradit Mae Sai Ban Houakhoua Chiang Rai 26 Apr 27 28 29 30 1 May 2 3 4 5 6 7 8 9 10 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
Chiang Mai Chiang Mai, 26 April: 79.9 µg/m³, 3.2× usual Chiang Mai, 27 April: 71.3 µg/m³, 2.8× usual Chiang Mai, 28 April: 68.2 µg/m³, 2.7× usual Chiang Mai, 29 April: 70.2 µg/m³, 2.8× usual Chiang Mai, 30 April: 79.1 µg/m³, 3.1× usual Chiang Mai, 1 May: 73.2 µg/m³, 2.9× usual Chiang Mai, 2 May: 81.2 µg/m³, 3.2× usual Chiang Mai, 3 May: 65.1 µg/m³, 2.6× usual Chiang Mai, 4 May: 75.7 µg/m³, 3.0× usual Chiang Mai, 5 May: 73.0 µg/m³, 2.9× usual Chiang Mai, 6 May: 79.7 µg/m³, 3.2× usual Chiang Mai, 7 May: 76.9 µg/m³, 3.0× usual Chiang Mai, 8 May: 41.2 µg/m³, 1.6× usual Chiang Mai, 9 May: 34.3 µg/m³, 1.4× usual Chiang Mai, 10 May: 25.5 µg/m³, 1.0× usual Pakxan Pakxan, 26 April: 50.7 µg/m³, 2.1× usual Pakxan, 27 April: 51.9 µg/m³, 2.2× usual Pakxan, 28 April: 64.2 µg/m³, 2.7× usual Pakxan, 29 April: 71.5 µg/m³, 3.0× usual Pakxan, 30 April: 62.0 µg/m³, 2.6× usual Pakxan, 1 May: 73.4 µg/m³, 3.1× usual Pakxan, 2 May: 61.7 µg/m³, 2.6× usual Pakxan, 3 May: 55.2 µg/m³, 2.3× usual Pakxan, 4 May: 32.3 µg/m³, 1.3× usual Pakxan, 5 May: 39.4 µg/m³, 1.6× usual Pakxan, 6 May: 35.8 µg/m³, 1.5× usual Pakxan, 7 May: 24.5 µg/m³, 1.0× usual Pakxan, 8 May: 22.3 µg/m³, 0.9× usual Pakxan, 9 May: 23.2 µg/m³, 1.0× usual Pakxan, 10 May: 24.9 µg/m³, 1.0× usual Ban Houakhoua Ban Houakhoua, 26 April: no reading Ban Houakhoua, 27 April: 90.3 µg/m³, 2.7× usual Ban Houakhoua, 28 April: 108.0 µg/m³, 3.2× usual Ban Houakhoua, 29 April: 151.0 µg/m³, 4.5× usual Ban Houakhoua, 30 April: 148.0 µg/m³, 4.4× usual Ban Houakhoua, 1 May: 164.0 µg/m³, 4.9× usual Ban Houakhoua, 2 May: 237.0 µg/m³, 7.0× usual Ban Houakhoua, 3 May: 177.0 µg/m³, 5.3× usual Ban Houakhoua, 4 May: 110.0 µg/m³, 3.3× usual Ban Houakhoua, 5 May: 145.0 µg/m³, 4.3× usual Ban Houakhoua, 6 May: 124.0 µg/m³, 3.7× usual Ban Houakhoua, 7 May: 114.0 µg/m³, 3.4× usual Ban Houakhoua, 8 May: 55.2 µg/m³, 1.6× usual Ban Houakhoua, 9 May: 62.9 µg/m³, 1.9× usual Ban Houakhoua, 10 May: 48.8 µg/m³, 1.4× usual Phayao Phayao, 26 April: 55.2 µg/m³, 1.8× usual Phayao, 27 April: 54.9 µg/m³, 1.8× usual Phayao, 28 April: 88.5 µg/m³, 2.9× usual Phayao, 29 April: 87.9 µg/m³, 2.9× usual Phayao, 30 April: 79.3 µg/m³, 2.6× usual Phayao, 1 May: 84.3 µg/m³, 2.8× usual Phayao, 2 May: 105.0 µg/m³, 3.5× usual Phayao, 3 May: 85.2 µg/m³, 2.8× usual Phayao, 4 May: 74.7 µg/m³, 2.5× usual Phayao, 5 May: 66.7 µg/m³, 2.2× usual Phayao, 6 May: 73.8 µg/m³, 2.5× usual Phayao, 7 May: 80.1 µg/m³, 2.7× usual Phayao, 8 May: 44.9 µg/m³, 1.5× usual Phayao, 9 May: no reading Phayao, 10 May: no reading Nan Nan, 26 April: 71.2 µg/m³, 1.8× usual Nan, 27 April: 68.6 µg/m³, 1.8× usual Nan, 28 April: 82.6 µg/m³, 2.1× usual Nan, 29 April: 86.8 µg/m³, 2.3× usual Nan, 30 April: 80.4 µg/m³, 2.1× usual Nan, 1 May: 81.5 µg/m³, 2.1× usual Nan, 2 May: 87.6 µg/m³, 2.3× usual Nan, 3 May: 74.0 µg/m³, 1.9× usual Nan, 4 May: 50.4 µg/m³, 1.3× usual Nan, 5 May: 61.7 µg/m³, 1.6× usual Nan, 6 May: 68.1 µg/m³, 1.8× usual Nan, 7 May: 67.3 µg/m³, 1.7× usual Nan, 8 May: 49.6 µg/m³, 1.3× usual Nan, 9 May: 41.2 µg/m³, 1.1× usual Nan, 10 May: 43.6 µg/m³, 1.1× usual Lampang Lampang, 26 April: 66.3 µg/m³, 1.9× usual Lampang, 27 April: 61.4 µg/m³, 1.8× usual Lampang, 28 April: 71.4 µg/m³, 2.1× usual Lampang, 29 April: 82.3 µg/m³, 2.4× usual Lampang, 30 April: 72.2 µg/m³, 2.1× usual Lampang, 1 May: 62.7 µg/m³, 1.8× usual Lampang, 2 May: 95.3 µg/m³, 2.8× usual Lampang, 3 May: 94.4 µg/m³, 2.8× usual Lampang, 4 May: 64.1 µg/m³, 1.9× usual Lampang, 5 May: 55.9 µg/m³, 1.6× usual Lampang, 6 May: 67.7 µg/m³, 2.0× usual Lampang, 7 May: 78.3 µg/m³, 2.3× usual Lampang, 8 May: 38.5 µg/m³, 1.1× usual Lampang, 9 May: 37.7 µg/m³, 1.1× usual Lampang, 10 May: 31.6 µg/m³, 0.9× usual Mae Sai Mae Sai, 26 April: 46.4 µg/m³, 1.5× usual Mae Sai, 27 April: 50.1 µg/m³, 1.6× usual Mae Sai, 28 April: 64.4 µg/m³, 2.1× usual Mae Sai, 29 April: 75.3 µg/m³, 2.4× usual Mae Sai, 30 April: 79.1 µg/m³, 2.5× usual Mae Sai, 1 May: 87.3 µg/m³, 2.8× usual Mae Sai, 2 May: 121.0 µg/m³, 3.9× usual Mae Sai, 3 May: 92.1 µg/m³, 3.0× usual Mae Sai, 4 May: 66.9 µg/m³, 2.1× usual Mae Sai, 5 May: 84.9 µg/m³, 2.7× usual Mae Sai, 6 May: 78.6 µg/m³, 2.5× usual Mae Sai, 7 May: 77.8 µg/m³, 2.5× usual Mae Sai, 8 May: 54.9 µg/m³, 1.8× usual Mae Sai, 9 May: 44.8 µg/m³, 1.4× usual Mae Sai, 10 May: 31.0 µg/m³, 1.0× usual Chiang Rai Chiang Rai, 26 April: 44.4 µg/m³, 2.1× usual Chiang Rai, 27 April: 42.7 µg/m³, 2.0× usual Chiang Rai, 28 April: 56.4 µg/m³, 2.6× usual Chiang Rai, 29 April: 72.4 µg/m³, 3.4× usual Chiang Rai, 30 April: 68.6 µg/m³, 3.2× usual Chiang Rai, 1 May: 70.4 µg/m³, 3.3× usual Chiang Rai, 2 May: 128.0 µg/m³, 6.0× usual Chiang Rai, 3 May: 104.0 µg/m³, 4.9× usual Chiang Rai, 4 May: 86.6 µg/m³, 4.0× usual Chiang Rai, 5 May: 154.0 µg/m³, 7.2× usual Chiang Rai, 6 May: 130.0 µg/m³, 6.1× usual Chiang Rai, 7 May: 98.4 µg/m³, 4.6× usual Chiang Rai, 8 May: 72.1 µg/m³, 3.4× usual Chiang Rai, 9 May: 33.6 µg/m³, 1.6× usual Chiang Rai, 10 May: 23.3 µg/m³, 1.1× usual Nong Bua Lamphu Nong Bua Lamphu, 26 April: 31.4 µg/m³, 1.8× usual Nong Bua Lamphu, 27 April: 36.0 µg/m³, 2.0× usual Nong Bua Lamphu, 28 April: 38.8 µg/m³, 2.2× usual Nong Bua Lamphu, 29 April: 43.3 µg/m³, 2.4× usual Nong Bua Lamphu, 30 April: 46.5 µg/m³, 2.6× usual Nong Bua Lamphu, 1 May: 54.2 µg/m³, 3.0× usual Nong Bua Lamphu, 2 May: 55.5 µg/m³, 3.1× usual Nong Bua Lamphu, 3 May: 53.2 µg/m³, 3.0× usual Nong Bua Lamphu, 4 May: 44.9 µg/m³, 2.5× usual Nong Bua Lamphu, 5 May: 39.2 µg/m³, 2.2× usual Nong Bua Lamphu, 6 May: 40.3 µg/m³, 2.3× usual Nong Bua Lamphu, 7 May: 28.3 µg/m³, 1.6× usual Nong Bua Lamphu, 8 May: 22.9 µg/m³, 1.3× usual Nong Bua Lamphu, 9 May: 28.3 µg/m³, 1.6× usual Nong Bua Lamphu, 10 May: 20.6 µg/m³, 1.2× usual Vientiane Vientiane, 26 April: 48.9 µg/m³, 1.4× usual Vientiane, 27 April: 63.8 µg/m³, 1.9× usual Vientiane, 28 April: 60.8 µg/m³, 1.8× usual Vientiane, 29 April: 62.3 µg/m³, 1.8× usual Vientiane, 30 April: 70.1 µg/m³, 2.0× usual Vientiane, 1 May: 59.2 µg/m³, 1.7× usual Vientiane, 2 May: 53.1 µg/m³, 1.6× usual Vientiane, 3 May: 43.6 µg/m³, 1.3× usual Vientiane, 4 May: 38.6 µg/m³, 1.1× usual Vientiane, 5 May: 46.7 µg/m³, 1.4× usual Vientiane, 6 May: 29.0 µg/m³, 0.8× usual Vientiane, 7 May: 22.8 µg/m³, 0.7× usual Vientiane, 8 May: 28.6 µg/m³, 0.8× usual Vientiane, 9 May: 17.7 µg/m³, 0.5× usual Vientiane, 10 May: 20.2 µg/m³, 0.6× usual Loei Loei, 26 April: 40.6 µg/m³, 1.8× usual Loei, 27 April: 42.7 µg/m³, 1.9× usual Loei, 28 April: 48.4 µg/m³, 2.1× usual Loei, 29 April: no reading Loei, 30 April: 54.8 µg/m³, 2.4× usual Loei, 1 May: 64.0 µg/m³, 2.8× usual Loei, 2 May: 60.5 µg/m³, 2.7× usual Loei, 3 May: 57.9 µg/m³, 2.6× usual Loei, 4 May: 47.0 µg/m³, 2.1× usual Loei, 5 May: 43.0 µg/m³, 1.9× usual Loei, 6 May: 45.7 µg/m³, 2.0× usual Loei, 7 May: 31.9 µg/m³, 1.4× usual Loei, 8 May: 22.7 µg/m³, 1.0× usual Loei, 9 May: 22.5 µg/m³, 1.0× usual Loei, 10 May: 14.2 µg/m³, 0.6× usual Udon Thani Udon Thani, 26 April: 35.2 µg/m³, 1.7× usual Udon Thani, 27 April: 37.5 µg/m³, 1.8× usual Udon Thani, 28 April: 43.6 µg/m³, 2.1× usual Udon Thani, 29 April: 44.4 µg/m³, 2.1× usual Udon Thani, 30 April: 45.2 µg/m³, 2.1× usual Udon Thani, 1 May: 53.5 µg/m³, 2.5× usual Udon Thani, 2 May: 56.2 µg/m³, 2.7× usual Udon Thani, 3 May: 50.6 µg/m³, 2.4× usual Udon Thani, 4 May: 36.8 µg/m³, 1.7× usual Udon Thani, 5 May: 41.0 µg/m³, 1.9× usual Udon Thani, 6 May: 36.5 µg/m³, 1.7× usual Udon Thani, 7 May: 25.2 µg/m³, 1.2× usual Udon Thani, 8 May: 20.1 µg/m³, 0.9× usual Udon Thani, 9 May: 27.4 µg/m³, 1.3× usual Udon Thani, 10 May: 24.5 µg/m³, 1.2× usual Sakon Nakhon Sakon Nakhon, 26 April: 39.5 µg/m³, 1.9× usual Sakon Nakhon, 27 April: 37.3 µg/m³, 1.8× usual Sakon Nakhon, 28 April: 44.1 µg/m³, 2.1× usual Sakon Nakhon, 29 April: 44.5 µg/m³, 2.2× usual Sakon Nakhon, 30 April: 43.8 µg/m³, 2.1× usual Sakon Nakhon, 1 May: 49.3 µg/m³, 2.4× usual Sakon Nakhon, 2 May: 54.2 µg/m³, 2.6× usual Sakon Nakhon, 3 May: 51.8 µg/m³, 2.5× usual Sakon Nakhon, 4 May: 40.3 µg/m³, 2.0× usual Sakon Nakhon, 5 May: 41.0 µg/m³, 2.0× usual Sakon Nakhon, 6 May: 28.6 µg/m³, 1.4× usual Sakon Nakhon, 7 May: 19.2 µg/m³, 0.9× usual Sakon Nakhon, 8 May: 21.4 µg/m³, 1.0× usual Sakon Nakhon, 9 May: 23.2 µg/m³, 1.1× usual Sakon Nakhon, 10 May: 19.2 µg/m³, 0.9× usual Uttaradit Uttaradit, 26 April: 58.8 µg/m³, 2.1× usual Uttaradit, 27 April: 53.9 µg/m³, 1.9× usual Uttaradit, 28 April: 64.0 µg/m³, 2.3× usual Uttaradit, 29 April: 57.0 µg/m³, 2.1× usual Uttaradit, 30 April: 56.6 µg/m³, 2.0× usual Uttaradit, 1 May: 67.3 µg/m³, 2.4× usual Uttaradit, 2 May: 103.0 µg/m³, 3.7× usual Uttaradit, 3 May: no reading Uttaradit, 4 May: no reading Uttaradit, 5 May: 54.4 µg/m³, 2.0× usual Uttaradit, 6 May: 62.7 µg/m³, 2.3× usual Uttaradit, 7 May: 61.5 µg/m³, 2.2× usual Uttaradit, 8 May: 29.3 µg/m³, 1.1× usual Uttaradit, 9 May: 30.4 µg/m³, 1.1× usual Uttaradit, 10 May: 27.0 µg/m³, 1.0× usual Kalasin Kalasin, 26 April: 45.5 µg/m³, 1.6× usual Kalasin, 27 April: 48.5 µg/m³, 1.7× usual Kalasin, 28 April: 58.0 µg/m³, 2.0× usual Kalasin, 29 April: 50.6 µg/m³, 1.7× usual Kalasin, 30 April: 50.3 µg/m³, 1.7× usual Kalasin, 1 May: 62.0 µg/m³, 2.1× usual Kalasin, 2 May: 64.3 µg/m³, 2.2× usual Kalasin, 3 May: 70.2 µg/m³, 2.4× usual Kalasin, 4 May: 57.7 µg/m³, 2.0× usual Kalasin, 5 May: 56.2 µg/m³, 1.9× usual Kalasin, 6 May: 48.3 µg/m³, 1.6× usual Kalasin, 7 May: 33.9 µg/m³, 1.2× usual Kalasin, 8 May: 35.8 µg/m³, 1.2× usual Kalasin, 9 May: 37.2 µg/m³, 1.3× usual Kalasin, 10 May: 24.9 µg/m³, 0.8× usual Lamphun Lamphun, 26 April: 59.8 µg/m³, 2.6× usual Lamphun, 27 April: 49.6 µg/m³, 2.1× usual Lamphun, 28 April: 57.7 µg/m³, 2.5× usual Lamphun, 29 April: 57.0 µg/m³, 2.4× usual Lamphun, 30 April: 56.2 µg/m³, 2.4× usual Lamphun, 1 May: 58.6 µg/m³, 2.5× usual Lamphun, 2 May: 68.8 µg/m³, 3.0× usual Lamphun, 3 May: 55.8 µg/m³, 2.4× usual Lamphun, 4 May: 57.6 µg/m³, 2.5× usual Lamphun, 5 May: 47.6 µg/m³, 2.0× usual Lamphun, 6 May: 55.9 µg/m³, 2.4× usual Lamphun, 7 May: 69.4 µg/m³, 3.0× usual Lamphun, 8 May: 35.6 µg/m³, 1.5× usual Lamphun, 9 May: 33.2 µg/m³, 1.4× usual Lamphun, 10 May: 22.3 µg/m³, 1.0× usual Kamphaeng Phet Kamphaeng Phet, 26 April: 46.8 µg/m³, 2.0× usual Kamphaeng Phet, 27 April: 42.3 µg/m³, 1.8× usual Kamphaeng Phet, 28 April: 50.8 µg/m³, 2.1× usual Kamphaeng Phet, 29 April: 47.6 µg/m³, 2.0× usual Kamphaeng Phet, 30 April: 51.2 µg/m³, 2.2× usual Kamphaeng Phet, 1 May: 53.4 µg/m³, 2.2× usual Kamphaeng Phet, 2 May: 60.0 µg/m³, 2.5× usual Kamphaeng Phet, 3 May: 43.3 µg/m³, 1.8× usual Kamphaeng Phet, 4 May: 41.3 µg/m³, 1.7× usual Kamphaeng Phet, 5 May: 37.7 µg/m³, 1.6× usual Kamphaeng Phet, 6 May: 52.2 µg/m³, 2.2× usual Kamphaeng Phet, 7 May: 50.4 µg/m³, 2.1× usual Kamphaeng Phet, 8 May: 27.1 µg/m³, 1.1× usual Kamphaeng Phet, 9 May: 31.4 µg/m³, 1.3× usual Kamphaeng Phet, 10 May: no reading Phetchabun Phetchabun, 26 April: 37.4 µg/m³, 1.9× usual Phetchabun, 27 April: 39.6 µg/m³, 2.0× usual Phetchabun, 28 April: 40.7 µg/m³, 2.0× usual Phetchabun, 29 April: 36.7 µg/m³, 1.8× usual Phetchabun, 30 April: 42.4 µg/m³, 2.1× usual Phetchabun, 1 May: 49.7 µg/m³, 2.5× usual Phetchabun, 2 May: 54.7 µg/m³, 2.7× usual Phetchabun, 3 May: 54.4 µg/m³, 2.7× usual Phetchabun, 4 May: 51.0 µg/m³, 2.6× usual Phetchabun, 5 May: 43.1 µg/m³, 2.2× usual Phetchabun, 6 May: 47.6 µg/m³, 2.4× usual Phetchabun, 7 May: 42.3 µg/m³, 2.1× usual Phetchabun, 8 May: 26.9 µg/m³, 1.4× usual Phetchabun, 9 May: 22.3 µg/m³, 1.1× usual Phetchabun, 10 May: 19.2 µg/m³, 1.0× usual Ratchaburi Ratchaburi, 26 April: 22.7 µg/m³, 1.0× usual Ratchaburi, 27 April: 27.0 µg/m³, 1.2× usual Ratchaburi, 28 April: 28.8 µg/m³, 1.3× usual Ratchaburi, 29 April: 28.7 µg/m³, 1.3× usual Ratchaburi, 30 April: 36.1 µg/m³, 1.7× usual Ratchaburi, 1 May: 48.3 µg/m³, 2.2× usual Ratchaburi, 2 May: 48.7 µg/m³, 2.2× usual Ratchaburi, 3 May: 41.4 µg/m³, 1.9× usual Ratchaburi, 4 May: 37.5 µg/m³, 1.7× usual Ratchaburi, 5 May: 42.3 µg/m³, 1.9× usual Ratchaburi, 6 May: 41.3 µg/m³, 1.9× usual Ratchaburi, 7 May: no reading Ratchaburi, 8 May: no reading Ratchaburi, 9 May: 27.3 µg/m³, 1.3× usual Ratchaburi, 10 May: 21.4 µg/m³, 1.0× usual Phetchaburi Phetchaburi, 26 April: 18.2 µg/m³, 1.2× usual Phetchaburi, 27 April: 22.9 µg/m³, 1.4× usual Phetchaburi, 28 April: 22.4 µg/m³, 1.4× usual Phetchaburi, 29 April: 20.5 µg/m³, 1.3× usual Phetchaburi, 30 April: 26.3 µg/m³, 1.7× usual Phetchaburi, 1 May: 44.5 µg/m³, 2.8× usual Phetchaburi, 2 May: 43.3 µg/m³, 2.7× usual Phetchaburi, 3 May: 36.0 µg/m³, 2.3× usual Phetchaburi, 4 May: 32.3 µg/m³, 2.0× usual Phetchaburi, 5 May: 35.9 µg/m³, 2.3× usual Phetchaburi, 6 May: 35.6 µg/m³, 2.3× usual Phetchaburi, 7 May: 26.7 µg/m³, 1.7× usual Phetchaburi, 8 May: 18.7 µg/m³, 1.2× usual Phetchaburi, 9 May: 22.4 µg/m³, 1.4× usual Phetchaburi, 10 May: 15.4 µg/m³, 1.0× usual Nakhon Pathom Nakhon Pathom, 26 April: 16.6 µg/m³, 0.9× usual Nakhon Pathom, 27 April: 20.8 µg/m³, 1.1× usual Nakhon Pathom, 28 April: 22.8 µg/m³, 1.2× usual Nakhon Pathom, 29 April: 27.2 µg/m³, 1.5× usual Nakhon Pathom, 30 April: 32.6 µg/m³, 1.8× usual Nakhon Pathom, 1 May: 41.7 µg/m³, 2.3× usual Nakhon Pathom, 2 May: 42.0 µg/m³, 2.3× usual Nakhon Pathom, 3 May: 38.5 µg/m³, 2.1× usual Nakhon Pathom, 4 May: 33.2 µg/m³, 1.8× usual Nakhon Pathom, 5 May: 35.3 µg/m³, 1.9× usual Nakhon Pathom, 6 May: 34.0 µg/m³, 1.8× usual Nakhon Pathom, 7 May: 32.2 µg/m³, 1.8× usual Nakhon Pathom, 8 May: 21.1 µg/m³, 1.1× usual Nakhon Pathom, 9 May: 20.9 µg/m³, 1.1× usual Nakhon Pathom, 10 May: 18.4 µg/m³, 1.0× usual Hua Hin Hua Hin, 26 April: 16.7 µg/m³, 1.0× usual Hua Hin, 27 April: 23.4 µg/m³, 1.4× usual Hua Hin, 28 April: 25.2 µg/m³, 1.5× usual Hua Hin, 29 April: 17.1 µg/m³, 1.0× usual Hua Hin, 30 April: 24.8 µg/m³, 1.5× usual Hua Hin, 1 May: 40.9 µg/m³, 2.5× usual Hua Hin, 2 May: 39.3 µg/m³, 2.4× usual Hua Hin, 3 May: 36.0 µg/m³, 2.2× usual Hua Hin, 4 May: 36.1 µg/m³, 2.2× usual Hua Hin, 5 May: 33.9 µg/m³, 2.0× usual Hua Hin, 6 May: 40.2 µg/m³, 2.4× usual Hua Hin, 7 May: 31.4 µg/m³, 1.9× usual Hua Hin, 8 May: 17.9 µg/m³, 1.1× usual Hua Hin, 9 May: 22.4 µg/m³, 1.3× usual Hua Hin, 10 May: 13.1 µg/m³, 0.8× usual Ranong Ranong, 26 April: 23.2 µg/m³, 2.4× usual Ranong, 27 April: 22.7 µg/m³, 2.4× usual Ranong, 28 April: 20.3 µg/m³, 2.1× usual Ranong, 29 April: 18.7 µg/m³, 1.9× usual Ranong, 30 April: 20.5 µg/m³, 2.1× usual Ranong, 1 May: 30.0 µg/m³, 3.1× usual Ranong, 2 May: 32.5 µg/m³, 3.4× usual Ranong, 3 May: 30.7 µg/m³, 3.2× usual Ranong, 4 May: 26.0 µg/m³, 2.7× usual Ranong, 5 May: 26.8 µg/m³, 2.8× usual Ranong, 6 May: 25.2 µg/m³, 2.6× usual Ranong, 7 May: 19.5 µg/m³, 2.0× usual Ranong, 8 May: 11.2 µg/m³, 1.2× usual Ranong, 9 May: 10.4 µg/m³, 1.1× usual Ranong, 10 May: 8.5 µg/m³, 0.9× usual Ubon Ratchathani Ubon Ratchathani, 26 April: 82.2 µg/m³, 2.0× usual Ubon Ratchathani, 27 April: 78.7 µg/m³, 1.9× usual Ubon Ratchathani, 28 April: 68.5 µg/m³, 1.6× usual Ubon Ratchathani, 29 April: 79.5 µg/m³, 1.9× usual Ubon Ratchathani, 30 April: 91.3 µg/m³, 2.2× usual Ubon Ratchathani, 1 May: 75.9 µg/m³, 1.8× usual Ubon Ratchathani, 2 May: 110.0 µg/m³, 2.6× usual Ubon Ratchathani, 3 May: 112.0 µg/m³, 2.7× usual Ubon Ratchathani, 4 May: 71.1 µg/m³, 1.7× usual Ubon Ratchathani, 5 May: 54.7 µg/m³, 1.3× usual Ubon Ratchathani, 6 May: no reading Ubon Ratchathani, 7 May: no reading Ubon Ratchathani, 8 May: 33.8 µg/m³, 0.8× usual Ubon Ratchathani, 9 May: 47.2 µg/m³, 1.1× usual Ubon Ratchathani, 10 May: 66.7 µg/m³, 1.6× usual Phrae Phrae, 26 April: 48.8 µg/m³, 1.7× usual Phrae, 27 April: 50.4 µg/m³, 1.8× usual Phrae, 28 April: 56.3 µg/m³, 2.0× usual Phrae, 29 April: 48.4 µg/m³, 1.7× usual Phrae, 30 April: 49.4 µg/m³, 1.8× usual Phrae, 1 May: 55.9 µg/m³, 2.0× usual Phrae, 2 May: 80.5 µg/m³, 2.9× usual Phrae, 3 May: 74.9 µg/m³, 2.7× usual Phrae, 4 May: 49.5 µg/m³, 1.8× usual Phrae, 5 May: 55.1 µg/m³, 2.0× usual Phrae, 6 May: 58.9 µg/m³, 2.1× usual Phrae, 7 May: 53.4 µg/m³, 1.9× usual Phrae, 8 May: 28.2 µg/m³, 1.0× usual Phrae, 9 May: 31.8 µg/m³, 1.1× usual Phrae, 10 May: 28.3 µg/m³, 1.0× usual Sukhothai Sukhothai, 26 April: 47.8 µg/m³, 1.6× usual Sukhothai, 27 April: 40.5 µg/m³, 1.4× usual Sukhothai, 28 April: 52.1 µg/m³, 1.8× usual Sukhothai, 29 April: 49.0 µg/m³, 1.7× usual Sukhothai, 30 April: 48.2 µg/m³, 1.6× usual Sukhothai, 1 May: 52.5 µg/m³, 1.8× usual Sukhothai, 2 May: 69.9 µg/m³, 2.4× usual Sukhothai, 3 May: 60.1 µg/m³, 2.1× usual Sukhothai, 4 May: 47.8 µg/m³, 1.6× usual Sukhothai, 5 May: 51.6 µg/m³, 1.8× usual Sukhothai, 6 May: 67.0 µg/m³, 2.3× usual Sukhothai, 7 May: 60.5 µg/m³, 2.1× usual Sukhothai, 8 May: 39.0 µg/m³, 1.3× usual Sukhothai, 9 May: 36.4 µg/m³, 1.2× usual Sukhothai, 10 May: 25.2 µg/m³, 0.9× usual Mukdahan Mukdahan, 26 April: 59.6 µg/m³, 1.8× usual Mukdahan, 27 April: 53.3 µg/m³, 1.7× usual Mukdahan, 28 April: 51.5 µg/m³, 1.6× usual Mukdahan, 29 April: 52.7 µg/m³, 1.6× usual Mukdahan, 30 April: 50.2 µg/m³, 1.6× usual Mukdahan, 1 May: 49.7 µg/m³, 1.5× usual Mukdahan, 2 May: 66.9 µg/m³, 2.1× usual Mukdahan, 3 May: 62.9 µg/m³, 1.9× usual Mukdahan, 4 May: 52.6 µg/m³, 1.6× usual Mukdahan, 5 May: 51.9 µg/m³, 1.6× usual Mukdahan, 6 May: 47.6 µg/m³, 1.5× usual Mukdahan, 7 May: 37.6 µg/m³, 1.2× usual Mukdahan, 8 May: 34.8 µg/m³, 1.1× usual Mukdahan, 9 May: 36.7 µg/m³, 1.1× usual Mukdahan, 10 May: 36.8 µg/m³, 1.1× usual Phichit Phichit, 26 April: 33.7 µg/m³, 1.4× usual Phichit, 27 April: 34.0 µg/m³, 1.4× usual Phichit, 28 April: 39.8 µg/m³, 1.7× usual Phichit, 29 April: 31.6 µg/m³, 1.3× usual Phichit, 30 April: 31.3 µg/m³, 1.3× usual Phichit, 1 May: 49.0 µg/m³, 2.0× usual Phichit, 2 May: 54.4 µg/m³, 2.3× usual Phichit, 3 May: 54.6 µg/m³, 2.3× usual Phichit, 4 May: 43.2 µg/m³, 1.8× usual Phichit, 5 May: 41.1 µg/m³, 1.7× usual Phichit, 6 May: 44.4 µg/m³, 1.8× usual Phichit, 7 May: 37.9 µg/m³, 1.6× usual Phichit, 8 May: 25.5 µg/m³, 1.1× usual Phichit, 9 May: 21.3 µg/m³, 0.9× usual Phichit, 10 May: 21.2 µg/m³, 0.9× usual Nakhon Sawan Nakhon Sawan, 26 April: 27.0 µg/m³, 1.0× usual Nakhon Sawan, 27 April: 27.3 µg/m³, 1.0× usual Nakhon Sawan, 28 April: 30.8 µg/m³, 1.2× usual Nakhon Sawan, 29 April: 31.6 µg/m³, 1.2× usual Nakhon Sawan, 30 April: 31.5 µg/m³, 1.2× usual Nakhon Sawan, 1 May: 44.2 µg/m³, 1.7× usual Nakhon Sawan, 2 May: 53.2 µg/m³, 2.0× usual Nakhon Sawan, 3 May: 51.2 µg/m³, 1.9× usual Nakhon Sawan, 4 May: 43.2 µg/m³, 1.6× usual Nakhon Sawan, 5 May: 38.6 µg/m³, 1.5× usual Nakhon Sawan, 6 May: 43.6 µg/m³, 1.6× usual Nakhon Sawan, 7 May: 40.7 µg/m³, 1.5× usual Nakhon Sawan, 8 May: 29.7 µg/m³, 1.1× usual Nakhon Sawan, 9 May: 25.5 µg/m³, 1.0× usual Nakhon Sawan, 10 May: 26.2 µg/m³, 1.0× usual Chaiyaphum Chaiyaphum, 26 April: 28.7 µg/m³, 1.3× usual Chaiyaphum, 27 April: 26.1 µg/m³, 1.1× usual Chaiyaphum, 28 April: 36.4 µg/m³, 1.6× usual Chaiyaphum, 29 April: 30.8 µg/m³, 1.3× usual Chaiyaphum, 30 April: 28.2 µg/m³, 1.2× usual Chaiyaphum, 1 May: 43.4 µg/m³, 1.9× usual Chaiyaphum, 2 May: 47.8 µg/m³, 2.1× usual Chaiyaphum, 3 May: 40.0 µg/m³, 1.7× usual Chaiyaphum, 4 May: 35.9 µg/m³, 1.6× usual Chaiyaphum, 5 May: 25.6 µg/m³, 1.1× usual Chaiyaphum, 6 May: 32.9 µg/m³, 1.4× usual Chaiyaphum, 7 May: 23.8 µg/m³, 1.0× usual Chaiyaphum, 8 May: 16.9 µg/m³, 0.7× usual Chaiyaphum, 9 May: 17.2 µg/m³, 0.8× usual Chaiyaphum, 10 May: 18.7 µg/m³, 0.8× usual Bangkok Bangkok, 26 April: 15.0 µg/m³, 0.7× usual Bangkok, 27 April: 18.6 µg/m³, 0.9× usual Bangkok, 28 April: 18.5 µg/m³, 0.9× usual Bangkok, 29 April: 14.4 µg/m³, 0.7× usual Bangkok, 30 April: 21.9 µg/m³, 1.1× usual Bangkok, 1 May: 38.0 µg/m³, 1.8× usual Bangkok, 2 May: 41.7 µg/m³, 2.0× usual Bangkok, 3 May: 36.4 µg/m³, 1.7× usual Bangkok, 4 May: 30.3 µg/m³, 1.5× usual Bangkok, 5 May: 36.5 µg/m³, 1.8× usual Bangkok, 6 May: 38.8 µg/m³, 1.9× usual Bangkok, 7 May: 27.9 µg/m³, 1.3× usual Bangkok, 8 May: 22.0 µg/m³, 1.1× usual Bangkok, 9 May: 21.5 µg/m³, 1.0× usual Bangkok, 10 May: 19.4 µg/m³, 0.9× usual Ban Samae Dam Ban Samae Dam, 26 April: 15.2 µg/m³, 0.7× usual Ban Samae Dam, 27 April: 19.2 µg/m³, 0.9× usual Ban Samae Dam, 28 April: 18.5 µg/m³, 0.9× usual Ban Samae Dam, 29 April: 14.4 µg/m³, 0.7× usual Ban Samae Dam, 30 April: 23.8 µg/m³, 1.1× usual Ban Samae Dam, 1 May: 38.7 µg/m³, 1.9× usual Ban Samae Dam, 2 May: 41.6 µg/m³, 2.0× usual Ban Samae Dam, 3 May: 36.3 µg/m³, 1.8× usual Ban Samae Dam, 4 May: 32.8 µg/m³, 1.6× usual Ban Samae Dam, 5 May: 38.5 µg/m³, 1.9× usual Ban Samae Dam, 6 May: 38.8 µg/m³, 1.9× usual Ban Samae Dam, 7 May: 31.8 µg/m³, 1.5× usual Ban Samae Dam, 8 May: 27.3 µg/m³, 1.3× usual Ban Samae Dam, 9 May: 22.1 µg/m³, 1.1× usual Ban Samae Dam, 10 May: 19.8 µg/m³, 1.0× usual Mueang Nonthaburi Mueang Nonthaburi, 26 April: 13.6 µg/m³, 0.7× usual Mueang Nonthaburi, 27 April: 17.4 µg/m³, 0.9× usual Mueang Nonthaburi, 28 April: 17.9 µg/m³, 1.0× usual Mueang Nonthaburi, 29 April: 13.7 µg/m³, 0.7× usual Mueang Nonthaburi, 30 April: 21.6 µg/m³, 1.2× usual Mueang Nonthaburi, 1 May: 35.9 µg/m³, 2.0× usual Mueang Nonthaburi, 2 May: 39.4 µg/m³, 2.1× usual Mueang Nonthaburi, 3 May: 33.5 µg/m³, 1.8× usual Mueang Nonthaburi, 4 May: 29.3 µg/m³, 1.6× usual Mueang Nonthaburi, 5 May: 33.6 µg/m³, 1.8× usual Mueang Nonthaburi, 6 May: 36.3 µg/m³, 2.0× usual Mueang Nonthaburi, 7 May: 27.6 µg/m³, 1.5× usual Mueang Nonthaburi, 8 May: 20.4 µg/m³, 1.1× usual Mueang Nonthaburi, 9 May: 21.3 µg/m³, 1.2× usual Mueang Nonthaburi, 10 May: 18.7 µg/m³, 1.0× usual Nakhon Nayok Nakhon Nayok, 26 April: 18.7 µg/m³, 1.1× usual Nakhon Nayok, 27 April: 18.1 µg/m³, 1.1× usual Nakhon Nayok, 28 April: 20.5 µg/m³, 1.2× usual Nakhon Nayok, 29 April: 20.1 µg/m³, 1.2× usual Nakhon Nayok, 30 April: 22.9 µg/m³, 1.4× usual Nakhon Nayok, 1 May: 26.9 µg/m³, 1.6× usual Nakhon Nayok, 2 May: 38.1 µg/m³, 2.3× usual Nakhon Nayok, 3 May: 33.8 µg/m³, 2.0× usual Nakhon Nayok, 4 May: 29.5 µg/m³, 1.8× usual Nakhon Nayok, 5 May: 31.2 µg/m³, 1.9× usual Nakhon Nayok, 6 May: 33.0 µg/m³, 2.0× usual Nakhon Nayok, 7 May: 25.5 µg/m³, 1.5× usual Nakhon Nayok, 8 May: 18.2 µg/m³, 1.1× usual Nakhon Nayok, 9 May: 20.5 µg/m³, 1.2× usual Nakhon Nayok, 10 May: 19.8 µg/m³, 1.2× usual Phuket Phuket, 26 April: 25.9 µg/m³, 1.7× usual Phuket, 27 April: 23.4 µg/m³, 1.5× usual Phuket, 28 April: 25.3 µg/m³, 1.7× usual Phuket, 29 April: 24.5 µg/m³, 1.6× usual Phuket, 30 April: 22.0 µg/m³, 1.4× usual Phuket, 1 May: 30.4 µg/m³, 2.0× usual Phuket, 2 May: 37.9 µg/m³, 2.5× usual Phuket, 3 May: 37.8 µg/m³, 2.5× usual Phuket, 4 May: 35.9 µg/m³, 2.3× usual Phuket, 5 May: 33.7 µg/m³, 2.2× usual Phuket, 6 May: no reading Phuket, 7 May: 24.4 µg/m³, 1.6× usual Phuket, 8 May: 16.2 µg/m³, 1.1× usual Phuket, 9 May: 17.6 µg/m³, 1.2× usual Phuket, 10 May: 14.4 µg/m³, 0.9× usual Si Sa Ket Si Sa Ket, 26 April: 34.4 µg/m³, 1.3× usual Si Sa Ket, 27 April: 26.2 µg/m³, 1.0× usual Si Sa Ket, 28 April: 20.1 µg/m³, 0.8× usual Si Sa Ket, 29 April: 33.7 µg/m³, 1.3× usual Si Sa Ket, 30 April: 41.2 µg/m³, 1.6× usual Si Sa Ket, 1 May: 27.5 µg/m³, 1.1× usual Si Sa Ket, 2 May: 49.2 µg/m³, 1.9× usual Si Sa Ket, 3 May: 66.1 µg/m³, 2.6× usual Si Sa Ket, 4 May: no reading Si Sa Ket, 5 May: 34.0 µg/m³, 1.3× usual Si Sa Ket, 6 May: 32.4 µg/m³, 1.3× usual Si Sa Ket, 7 May: 17.8 µg/m³, 0.7× usual Si Sa Ket, 8 May: no reading Si Sa Ket, 9 May: 40.3 µg/m³, 1.6× usual Si Sa Ket, 10 May: no reading Amnat Charoen Amnat Charoen, 26 April: no reading Amnat Charoen, 27 April: no reading Amnat Charoen, 28 April: 37.1 µg/m³, 1.3× usual Amnat Charoen, 29 April: 39.9 µg/m³, 1.4× usual Amnat Charoen, 30 April: 45.2 µg/m³, 1.5× usual Amnat Charoen, 1 May: 41.1 µg/m³, 1.4× usual Amnat Charoen, 2 May: 59.2 µg/m³, 2.0× usual Amnat Charoen, 3 May: 61.2 µg/m³, 2.1× usual Amnat Charoen, 4 May: 47.4 µg/m³, 1.6× usual Amnat Charoen, 5 May: 42.8 µg/m³, 1.5× usual Amnat Charoen, 6 May: 36.2 µg/m³, 1.2× usual Amnat Charoen, 7 May: 20.5 µg/m³, 0.7× usual Amnat Charoen, 8 May: 25.7 µg/m³, 0.9× usual Amnat Charoen, 9 May: 35.5 µg/m³, 1.2× usual Amnat Charoen, 10 May: 34.1 µg/m³, 1.2× usual Pattani Pattani, 26 April: 16.2 µg/m³, 1.6× usual Pattani, 27 April: 16.8 µg/m³, 1.6× usual Pattani, 28 April: 18.4 µg/m³, 1.8× usual Pattani, 29 April: 18.1 µg/m³, 1.7× usual Pattani, 30 April: 19.8 µg/m³, 1.9× usual Pattani, 1 May: 22.3 µg/m³, 2.1× usual Pattani, 2 May: 18.9 µg/m³, 1.8× usual Pattani, 3 May: 28.6 µg/m³, 2.8× usual Pattani, 4 May: 18.1 µg/m³, 1.7× usual Pattani, 5 May: 21.6 µg/m³, 2.1× usual Pattani, 6 May: 21.4 µg/m³, 2.1× usual Pattani, 7 May: 18.2 µg/m³, 1.7× usual Pattani, 8 May: 15.4 µg/m³, 1.5× usual Pattani, 9 May: 18.5 µg/m³, 1.8× usual Pattani, 10 May: 11.9 µg/m³, 1.1× usual Surin Surin, 26 April: 26.6 µg/m³, 1.5× usual Surin, 27 April: 18.7 µg/m³, 1.1× usual Surin, 28 April: 14.1 µg/m³, 0.8× usual Surin, 29 April: 16.4 µg/m³, 0.9× usual Surin, 30 April: 19.2 µg/m³, 1.1× usual Surin, 1 May: 19.2 µg/m³, 1.1× usual Surin, 2 May: 26.3 µg/m³, 1.5× usual Surin, 3 May: 32.2 µg/m³, 1.9× usual Surin, 4 May: 34.8 µg/m³, 2.0× usual Surin, 5 May: 24.7 µg/m³, 1.4× usual Surin, 6 May: 28.8 µg/m³, 1.7× usual Surin, 7 May: no reading Surin, 8 May: no reading Surin, 9 May: 26.9 µg/m³, 1.6× usual Surin, 10 May: 26.6 µg/m³, 1.5× usual Roi Et Roi Et, 26 April: 29.7 µg/m³, 1.1× usual Roi Et, 27 April: 27.5 µg/m³, 1.0× usual Roi Et, 28 April: 32.5 µg/m³, 1.2× usual Roi Et, 29 April: 30.5 µg/m³, 1.1× usual Roi Et, 30 April: 31.3 µg/m³, 1.1× usual Roi Et, 1 May: 36.3 µg/m³, 1.3× usual Roi Et, 2 May: 46.1 µg/m³, 1.7× usual Roi Et, 3 May: 44.4 µg/m³, 1.6× usual Roi Et, 4 May: 53.0 µg/m³, 1.9× usual Roi Et, 5 May: 55.2 µg/m³, 2.0× usual Roi Et, 6 May: 44.5 µg/m³, 1.6× usual Roi Et, 7 May: 27.6 µg/m³, 1.0× usual Roi Et, 8 May: 33.2 µg/m³, 1.2× usual Roi Et, 9 May: 33.9 µg/m³, 1.2× usual Roi Et, 10 May: 24.7 µg/m³, 0.9× usual Samut Prakan Samut Prakan, 26 April: 11.1 µg/m³, 0.8× usual Samut Prakan, 27 April: 14.1 µg/m³, 1.0× usual Samut Prakan, 28 April: 14.7 µg/m³, 1.0× usual Samut Prakan, 29 April: 10.1 µg/m³, 0.7× usual Samut Prakan, 30 April: 15.0 µg/m³, 1.0× usual Samut Prakan, 1 May: 31.9 µg/m³, 2.2× usual Samut Prakan, 2 May: no reading Samut Prakan, 3 May: no reading Samut Prakan, 4 May: no reading Samut Prakan, 5 May: 33.1 µg/m³, 2.3× usual Samut Prakan, 6 May: 37.8 µg/m³, 2.6× usual Samut Prakan, 7 May: 28.1 µg/m³, 1.9× usual Samut Prakan, 8 May: 20.5 µg/m³, 1.4× usual Samut Prakan, 9 May: 17.7 µg/m³, 1.2× usual Samut Prakan, 10 May: 13.5 µg/m³, 0.9× usual Nong Khaem Nong Khaem, 26 April: 16.0 µg/m³, 0.8× usual Nong Khaem, 27 April: 19.7 µg/m³, 1.0× usual Nong Khaem, 28 April: 21.8 µg/m³, 1.1× usual Nong Khaem, 29 April: 16.0 µg/m³, 0.8× usual Nong Khaem, 30 April: 26.6 µg/m³, 1.4× usual Nong Khaem, 1 May: 38.4 µg/m³, 1.9× usual Nong Khaem, 2 May: 43.1 µg/m³, 2.2× usual Nong Khaem, 3 May: 37.4 µg/m³, 1.9× usual Nong Khaem, 4 May: 35.2 µg/m³, 1.8× usual Nong Khaem, 5 May: 40.3 µg/m³, 2.0× usual Nong Khaem, 6 May: 40.3 µg/m³, 2.0× usual Nong Khaem, 7 May: 33.3 µg/m³, 1.7× usual Nong Khaem, 8 May: 25.9 µg/m³, 1.3× usual Nong Khaem, 9 May: 28.6 µg/m³, 1.5× usual Nong Khaem, 10 May: 22.1 µg/m³, 1.1× usual Phra Nakhon Si Ayut… Phra Nakhon Si Ayutthaya, 26 April: 18.9 µg/m³, 1.0× usual Phra Nakhon Si Ayutthaya, 27 April: 18.4 µg/m³, 1.0× usual Phra Nakhon Si Ayutthaya, 28 April: 19.2 µg/m³, 1.0× usual Phra Nakhon Si Ayutthaya, 29 April: 14.9 µg/m³, 0.8× usual Phra Nakhon Si Ayutthaya, 30 April: 21.0 µg/m³, 1.1× usual Phra Nakhon Si Ayutthaya, 1 May: 33.4 µg/m³, 1.8× usual Phra Nakhon Si Ayutthaya, 2 May: 39.0 µg/m³, 2.1× usual Phra Nakhon Si Ayutthaya, 3 May: 39.0 µg/m³, 2.1× usual Phra Nakhon Si Ayutthaya, 4 May: 33.4 µg/m³, 1.8× usual Phra Nakhon Si Ayutthaya, 5 May: 34.8 µg/m³, 1.8× usual Phra Nakhon Si Ayutthaya, 6 May: 39.2 µg/m³, 2.1× usual Phra Nakhon Si Ayutthaya, 7 May: 29.8 µg/m³, 1.6× usual Phra Nakhon Si Ayutthaya, 8 May: 16.2 µg/m³, 0.9× usual Phra Nakhon Si Ayutthaya, 9 May: 24.5 µg/m³, 1.3× usual Phra Nakhon Si Ayutthaya, 10 May: 18.6 µg/m³, 1.0× usual Ban Khlong Prawet Ban Khlong Prawet, 26 April: 11.8 µg/m³, 0.7× usual Ban Khlong Prawet, 27 April: 14.1 µg/m³, 0.9× usual Ban Khlong Prawet, 28 April: 11.4 µg/m³, 0.7× usual Ban Khlong Prawet, 29 April: 9.4 µg/m³, 0.6× usual Ban Khlong Prawet, 30 April: 19.7 µg/m³, 1.2× usual Ban Khlong Prawet, 1 May: 32.6 µg/m³, 2.0× usual Ban Khlong Prawet, 2 May: 34.2 µg/m³, 2.1× usual Ban Khlong Prawet, 3 May: 27.3 µg/m³, 1.7× usual Ban Khlong Prawet, 4 May: 26.1 µg/m³, 1.6× usual Ban Khlong Prawet, 5 May: 33.7 µg/m³, 2.1× usual Ban Khlong Prawet, 6 May: 33.2 µg/m³, 2.0× usual Ban Khlong Prawet, 7 May: 19.3 µg/m³, 1.2× usual Ban Khlong Prawet, 8 May: 20.4 µg/m³, 1.2× usual Ban Khlong Prawet, 9 May: 22.7 µg/m³, 1.4× usual Ban Khlong Prawet, 10 May: 14.8 µg/m³, 0.9× usual Laem Chabang Laem Chabang, 26 April: 9.5 µg/m³, 0.6× usual Laem Chabang, 27 April: 10.9 µg/m³, 0.7× usual Laem Chabang, 28 April: 8.9 µg/m³, 0.6× usual Laem Chabang, 29 April: 6.1 µg/m³, 0.4× usual Laem Chabang, 30 April: 10.5 µg/m³, 0.7× usual Laem Chabang, 1 May: 19.8 µg/m³, 1.3× usual Laem Chabang, 2 May: 32.1 µg/m³, 2.1× usual Laem Chabang, 3 May: 25.7 µg/m³, 1.7× usual Laem Chabang, 4 May: 20.5 µg/m³, 1.3× usual Laem Chabang, 5 May: 26.0 µg/m³, 1.7× usual Laem Chabang, 6 May: 33.1 µg/m³, 2.2× usual Laem Chabang, 7 May: 23.0 µg/m³, 1.5× usual Laem Chabang, 8 May: 13.5 µg/m³, 0.9× usual Laem Chabang, 9 May: 16.3 µg/m³, 1.1× usual Laem Chabang, 10 May: 14.9 µg/m³, 1.0× usual 26 Apr 28 30 1 May 2 4 6 8 10 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
Chiang Rai Chiang Rai, Thailand 9 5 May 21.4 7.2× Ban Houakhoua Bokeo, Laos 9 2 May 33.7 7.0× Mae Sai Chiang Rai, Thailand 9 2 May 31.2 3.9× Uttaradit Uttaradit, Thailand 5 2 May 27.8 3.7× Phayao Phayao, Thailand 9 2 May 30.1 3.5× Ranong Ranong province, Thailand 6 2 May 9.6 3.4× Chiang Mai Chiang Mai, Thailand 9 2 May 25.3 3.2× Nong Bua Lamphu Nong Bua Lamphu, Thailand 8 2 May 17.9 3.1× Pakxan Bolikhamsai, Laos 6 1 May 24.0 3.1× Lamphun Lamphun, Thailand 7 7 May 23.3 3.0× Phrae Phrae, Thailand 5 2 May 28.0 2.9× Loei Loei, Thailand 7 1 May 22.7 2.8× Phetchaburi Phetchaburi, Thailand 6 1 May 15.8 2.8× Lampang Lampang, Thailand 5 2 May 34.2 2.8× Pattani Pattani, Thailand 1 3 May 10.4 2.8× Phetchabun Phetchabun, Thailand 7 2 May 19.9 2.7× Ubon Ratchathani Ubon Ratchathani, Thailand 2 3 May 41.8 2.7× Udon Thani Udon Thani, Thailand 5 2 May 21.2 2.7× Sakon Nakhon Sakon Nakhon, Thailand 6 2 May 20.6 2.6× Samut Prakan Samut Prakan, Thailand 2 6 May 14.7 2.6× Si Sa Ket Si Sa Ket, Thailand 1 3 May 25.9 2.6× Kamphaeng Phet Kamphaeng Phet, Thailand 4 2 May 23.8 2.5× Phuket Phuket, Thailand 4 2 May 15.3 2.5× Hua Hin Prachuap Khiri Khan, Thailand 6 1 May 16.6 2.5× Kalasin Kalasin, Thailand 4 3 May 29.3 2.4× Sukhothai Sukhothai, Thailand 5 2 May 29.3 2.4× Nakhon Pathom Nakhon Pathom, Thailand 4 2 May 18.4 2.3× Nakhon Nayok Nakhon Nayok, Thailand 4 2 May 16.7 2.3× Nan Nan, Thailand 4 2 May 38.5 2.3× Phichit Phichit, Thailand 3 3 May 24.0 2.3× Ratchaburi Ratchaburi, Thailand 2 2 May 21.8 2.2× Nong Khaem Bangkok, Thailand 1 2 May 19.7 2.2× Laem Chabang Chon Buri, Thailand 1 6 May 15.2 2.2× Mueang Nonthaburi Nonthaburi, Thailand 2 2 May 18.4 2.1× Chaiyaphum Chaiyaphum, Thailand 1 2 May 22.9 2.1× Ban Khlong Prawet Bangkok, Thailand 1 2 May 16.4 2.1× Amnat Charoen Amnat Charoen, Thailand 1 3 May 29.4 2.1× Phra Nakhon Si Ayutthaya Phra Nakhon Si Ayutthaya, Thailand 1 6 May 18.9 2.1× Mukdahan Mukdahan, Thailand 2 2 May 32.3 2.1× Vientiane Vientiane Prefecture, Laos 1 30 April 34.2 2.0× Surin Surin, Thailand 1 4 May 17.3 2.0× Ban Samae Dam Bangkok, Thailand 3 2 May 20.7 2.0× Nakhon Sawan Nakhon Sawan, Thailand 1 2 May 26.5 2.0× Roi Et Roi Et, Thailand 1 5 May 27.5 2.0× Bangkok Bangkok, Thailand 2 2 May 20.8 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 Thailand and Laos
Number 4 of 24 episodes in Thailand and Laos since our records began, by cities reached.
Central Thailand, March 2025 53 Western Thailand, February 2024 51 Central Thailand, January 2025 50 North-western Thailand, April and May 2024 45 North-western Thailand, May 2023 41 Western Thailand, April 2023 35 Western Thailand and Laos, January and February 2023 34 North-western Thailand, May 2023 30 North-eastern Thailand, October 2024 24 Northern Thailand, November and December 2025 22 Western Thailand, February 2025 17 North-western Thailand, May 2023 17 Bars: cities reached; colour: the level of the episode's highest daily reading. All 24 .
Use this page SmogRank, North-western Thailand, April and May 2024: 45 cities with PM2.5 at twice their usual or more, 29 April to 7 May 2024, smogrank.com/episodes/2024-04-north-western-thailand (accessed 3 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.
