BANGKOK, THAILAND – A severe load of ultrafine particulate matter shrouded about one-third of Thailand, including Bangkok, in health-damaging smog on Wednesday.
Large Areas Recorded Red-Zone Pollution
According to the Geo-Informatics and Space Technology Development Agency (GISTDA), PM2.5 readings across wide parts of the country were in the red range on Wednesday morning, classified as highly harmful to health. The central plain, including the Bangkok metropolitan area and several neighboring provinces, was particularly affected.
In these regions, concentrations were well above the government threshold of 37.5 micrograms per cubic meter (µg/m³) and in some places reached levels officially considered dangerous. While central and eastern areas were dominated by red zones, southern provinces reported comparatively better air quality on GISTDA maps.
Stagnant Air and Multiple Emission Sources
The intense pollution was amplified by stagnant weather conditions that caused pollutants to accumulate near the ground. In the Bangkok region, traffic emissions and industrial activities were identified alongside regional burning processes as key contributors.
Under these conditions, particles were unable to rise into higher air layers and remained trapped over densely populated areas. This led to persistent smog over large urban centers.
Health Authorities Issue Urgent Warnings
Health agencies called on residents in affected areas to take immediate precautions, especially vulnerable groups such as children, older people, and those with respiratory or cardiovascular diseases. They recommended staying indoors as much as possible, limiting physical activity outdoors, and wearing N95 masks when going outside was unavoidable.
People were advised to seek medical attention if they experienced symptoms such as coughing, shortness of breath, or eye irritation. Prolonged exposure was considered capable of causing serious health effects.
Recurring Seasonal Smog Episodes
The current smog episode again highlighted recurring air-quality problems during the cooler months, when inversions prevent the dispersion of pollutants. Such episodes regularly occurred in the dry and cold season and especially affected densely populated urban areas.
Authorities continued to monitor the situation closely. Forecasts indicated that without a change in weather or additional measures, such as artificial rain through cloud seeding, conditions in some regions could persist or worsen.
Officials Stress Need for Ongoing Information
Residents in affected regions were urged to follow current advisories from official bodies. These included GISTDA, which provided maps of the spatial spread of PM2.5, and the Pollution Control Department, which released continuous measurements and health recommendations.
The agencies underlined that continuous information and consistent self-protection were crucial to limiting health risks during phases of extremely poor air quality.
“Ongoing information and consistent self-protection are crucial in phases of extremely poor air quality.”
said officials from the Pollution Control Department.