Northern Thailand Faces Severe Air Pollution Crisis as Chiang Mai Records Hazardous PM2.5 Levels

Northern Thailand is grappling with an escalating air pollution emergency as hazardous smog from wildfires and agricultural burning continues to blanket Chiang Mai and surrounding provinces. Air quality has deteriorated to dangerous levels, with particulate matter (PM2.5) concentrations far exceeding safety thresholds and posing serious health risks to residents and visitors alike.

According to recent monitoring, PM2.5 levels in Chiang Mai reached 360 micrograms per cubic metre (µg/m³) at Chiang Mai University in the Muang district, significantly surpassing the national safety standard of 37.5 µg/m³. In the neighbouring Mae Hong Son province, the district of Pai recorded an even more alarming PM2.5 concentration of 222.8 µg/m³ over a 24-hour period, with an air quality index of 472 — the highest in the country — maintained for 42 consecutive days of severe impact.

The crisis is driven by a combination of seasonal agricultural burning and widespread forest fires. Satellite data has shown a record number of 4,750 hotspots across Thailand, predominantly in forested areas, as farmers clear fields ahead of the planting season. Dry conditions have also facilitated the spread of natural wildfires, compounding the pollution burden.

Health officials have issued urgent warnings about the dangers of prolonged exposure to PM2.5. These microscopic particles, smaller than 2.5 micrometres, can penetrate deep into the lungs and enter the bloodstream, triggering inflammation and exacerbating respiratory conditions. Dr Atikun Limsukon, a respiratory and critical care specialist at Chiang Mai University’s Faculty of Medicine, emphasized that even individuals without prior health issues are at risk, citing a case of a 19-year-old foreign tourist who developed severe lung inflammation after visiting Pai and Chiang Mai.

Local residents are already experiencing adverse health effects. Families in Chiang Mai have reported frequent nosebleeds and skin rashes among children, prompting some to consider relocation. One parent told the BBC that his six-year-old daughter has suffered recurring nosebleeds, leading the family to evaluate moving during the peak pollution season to protect their children’s health.

The environmental and public health toll has been severe. The Environmental and Pollution Control Office 1 in Chiang Mai confirmed that PM2.5 levels across northern provinces remain dangerously high. Chronic patients in the region have seen rapid deterioration, and healthcare providers are observing increased cases of respiratory distress linked to the ongoing haze.

As the pollution persists, authorities are under pressure to implement stronger measures to curb open burning and manage wildfire risks. The situation underscores the recurring challenge of seasonal air pollution in northern Thailand, where the months of November to March typically mark the peak fire season due to both human-caused and natural fires.

With visibility severely reduced and a persistent hang in the air, communities across Chiang Mai, Pai, and other affected areas continue to face significant disruptions to daily life, tourism, and public health. Ongoing monitoring and coordinated intervention remain critical to mitigate the impact of this protracted environmental crisis.