SmogRank / Episodes / Thailand

Northern Thailand, 9 February 2024

For 1 day, on 9 February 2024, 9 cities in Thailand had PM2.5 at least twice their usual for the time of year. The worst reading was Sukhothai, Sukhothai, Thailand: 77.6 µg/m³ on 9 February, about 2.3× its usual 33.1.

No cause namedWe have no fire or smoke records for these days, so we only say what the measurements show.
Cities reached9in 1 country
Days19 February 2024
Worst day9 February9 cities counted
Furthest above usual2.7×Chaiyaphum

Day by day

9 February 9 cities at twice their usual or more
Khon KaenNakhon RatchasimaUdon ThaniBuri RamLoeiSurinPhichitSakon NakhonSaraburiLop BuriNakhon NayokSing BuriAmnat CharoenSi Maha PhotChai NatMukdahanPhra Nakhon Si AyutthayaPakxanUttaraditKhlong LuangNong ChokSuphan BuriKhlong Sam WaSai MaiKamphaeng PhetKhan Na YaoLak SiLat KrabangBueng KumSaphan SungBang KapiMueang NonthaburiBan Khlong PrawetPhraeBangkokNong KhaemNakhon PathomKanchanaburiLampangMae SotLamphunUbon RatchathaniNakhon SawanPhetchabunSi Sa KetYasothonKalasinSukhothaiNong Bua LamphuChaiyaphum
6 Feb789101112
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

SukhothaiSukhothai, 6 February: 56.0 µg/m³Sukhothai, 7 February: 55.3 µg/m³Sukhothai, 8 February: no readingSukhothai, 9 February: 77.6 µg/m³, 2.3× its usual 33.1Sukhothai, 10 February: 69.8 µg/m³Sukhothai, 11 February: no readingSukhothai, 12 February: no readingChaiyaphumChaiyaphum, 6 February: 54.1 µg/m³Chaiyaphum, 7 February: 77.5 µg/m³Chaiyaphum, 8 February: no readingChaiyaphum, 9 February: 74.0 µg/m³, 2.7× its usual 27.1Chaiyaphum, 10 February: 44.5 µg/m³Chaiyaphum, 11 February: no readingChaiyaphum, 12 February: no readingNong Bua LamphuNong Bua Lamphu, 6 February: 43.1 µg/m³Nong Bua Lamphu, 7 February: 60.6 µg/m³Nong Bua Lamphu, 8 February: no readingNong Bua Lamphu, 9 February: 71.2 µg/m³, 2.6× its usual 27.1Nong Bua Lamphu, 10 February: 35.1 µg/m³Nong Bua Lamphu, 11 February: no readingNong Bua Lamphu, 12 February: no readingPhetchabunPhetchabun, 6 February: 38.7 µg/m³Phetchabun, 7 February: 54.3 µg/m³Phetchabun, 8 February: no readingPhetchabun, 9 February: 68.6 µg/m³, 2.0× its usual 33.6Phetchabun, 10 February: 53.9 µg/m³Phetchabun, 11 February: no readingPhetchabun, 12 February: no readingNakhon SawanNakhon Sawan, 6 February: 59.5 µg/m³Nakhon Sawan, 7 February: 60.2 µg/m³Nakhon Sawan, 8 February: no readingNakhon Sawan, 9 February: 68.4 µg/m³, 2.0× its usual 33.5Nakhon Sawan, 10 February: 35.5 µg/m³Nakhon Sawan, 11 February: no readingNakhon Sawan, 12 February: no readingKalasinKalasin, 6 February: 62.6 µg/m³Kalasin, 7 February: 66.8 µg/m³Kalasin, 8 February: no readingKalasin, 9 February: 66.1 µg/m³, 2.1× its usual 31.9Kalasin, 10 February: 29.9 µg/m³Kalasin, 11 February: no readingKalasin, 12 February: no readingUbon RatchathaniUbon Ratchathani, 6 February: 63.6 µg/m³Ubon Ratchathani, 7 February: 72.4 µg/m³Ubon Ratchathani, 8 February: no readingUbon Ratchathani, 9 February: 62.8 µg/m³, 2.0× its usual 30.8Ubon Ratchathani, 10 February: 25.3 µg/m³Ubon Ratchathani, 11 February: no readingUbon Ratchathani, 12 February: no readingYasothonYasothon, 6 February: 54.6 µg/m³Yasothon, 7 February: 59.6 µg/m³Yasothon, 8 February: no readingYasothon, 9 February: 59.3 µg/m³, 2.1× its usual 28.8Yasothon, 10 February: 21.8 µg/m³Yasothon, 11 February: no readingYasothon, 12 February: no readingSi Sa KetSi Sa Ket, 6 February: 42.7 µg/m³Si Sa Ket, 7 February: 43.2 µg/m³Si Sa Ket, 8 February: no readingSi Sa Ket, 9 February: 50.5 µg/m³, 2.1× its usual 23.7Si Sa Ket, 10 February: no readingSi Sa Ket, 11 February: no readingSi Sa Ket, 12 February: no reading6 Feb789101112
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.
Good0–50
Moderate51–100
Sensitive groups101–150
Unhealthy151–200
Very unhealthy201–300
Hazardous301+

Every city it reached

CityDaysHighestUsualAbove usual
ChaiyaphumChaiyaphum, Thailand1 74.09 February27.12.7×
Nong Bua LamphuNong Bua Lamphu, Thailand1 71.29 February27.12.6×
SukhothaiSukhothai, Thailand1 77.69 February33.12.3×
KalasinKalasin, Thailand1 66.19 February31.92.1×
YasothonYasothon, Thailand1 59.39 February28.82.1×
Si Sa KetSi Sa Ket, Thailand1 50.59 February23.72.1×
PhetchabunPhetchabun, Thailand1 68.69 February33.62.0×
Nakhon SawanNakhon Sawan, Thailand1 68.49 February33.52.0×
Ubon RatchathaniUbon Ratchathani, Thailand1 62.89 February30.82.0×

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 Thailand

Number 17 of 23 episodes in Thailand since our records began, by cities reached.

Bars: cities reached; colour: the level of the episode's highest daily reading. All 23.

Use this page

SmogRank, Northern Thailand, 9 February 2024: 9 cities with PM2.5 at twice their usual or more, 9 February 2024, smogrank.com/episodes/2024-02-09-northern-thailand (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.