A dense blanket of toxic haze continued to cover Bangkok and large parts of Thailand on Friday, as fine particulate matter (PM2.5) levels exceeded safety limits in 45 provinces nationwide, prompting authorities to warn that unhealthy air conditions could persist through January 23.
The Air Pollution Problem Communication Center (APPC), under the Pollution Control Department (PCD), reported that 24-hour average PM2.5 concentrations ranged from 7.4 to 89.1 microgrammes per cubic metre (µg/m³).
In many locations, readings surpassed the national safety threshold of 37.5 µg/m³, raising concerns over potential health impacts.
Bangkok and its surrounding provinces — including Nonthaburi, Pathum Thani and Samut Prakan — recorded widespread unhealthy air quality.
Officials identified one red-zone area in Bang Phut subdistrict of Muang Nonthaburi, where pollution levels were classified as hazardous to public health.
The most severe pollution nationwide was reported in Mueang district of Nong Khai province in the Northeast. Several additional red-zone areas were also detected in Ayutthaya and Saraburi, where residents were advised to limit outdoor activities and take precautionary measures.
While air quality deteriorated across much of the country, southern provinces continued to experience relatively cleaner conditions and were largely spared from the worst of the pollution episode.
According to the PCD’s seven-day forecast, PM2.5 levels are expected to increase across Bangkok and the North, Northeast, Central, Eastern and Western regions between January 17 and 23.
Meteorological conditions during this period are likely to hinder the dispersion of pollutants, contributing to the prolonged haze. The South, however, is forecast to remain mostly unaffected.
In response to the ongoing situation, the Aeronautical Radio of Thailand (Aerothai) has been supporting cloud-seeding and atmospheric dispersion flights since December as part of broader efforts to alleviate air pollution and improve air quality.
