Thailand

Thailand’s economic growth and development have brought prosperity but also significant environmental challenges, particularly air pollution. The main sources of pollution include traffic emissions in urban areas, crop burning and transboundary haze in northern regions, and industrial emissions in manufacturing zones. 

The northern part of the country is the most affected due to agricultural activity, where wildfires and crop burning—both domestic and from neighboring countries—cause severe pollution episodes. Air quality worsens during the dry season (November to April), especially when farmers burn sugarcane residues, leading to extreme pollution across the country.

Thailand’s annual mean PM2.5 exposure is 27 µg/m³, which is 5.4 times the WHO guideline of 5 µg/m³. The health impacts are severe, with 32,000 deaths recorded in 2019 due to air pollution, equivalent to 46 deaths per 100,000 people. Agricultural burning and dry weather conditions intensify fires, further deteriorating air quality. However, in recent years, air quality improvements have been recorded, with an 8% reduction in PM2.5 concentrations in 2020, bringing the national average to 23 µg/m³. Similar declines of 9% and 11% in PM10 and O₃ levels were observed, with the annual average concentrations of PM10 and the highest 8-hour average O₃ recorded at 43 ug/m³ and 81 ug/m³ in 2020, respectively (BUR4, 2022). Between 2000 and 2019, the summertime average of the daily 8-h maximum O₃ concentrations increased on average by 1.8 per cent per year in urban areas. O₃ was the only gaseous pollutant that exceeded the Thailand National Ambient Air Quality standard (NAAQs) set to 100 ppb for hourly O₃ concentration. Despite these improvements, ozone remains the only gaseous pollutant exceeding Thailand’s National Ambient Air Quality Standard (NAAQS), increasing 1.8% per year between 2000 and 2019.

Thailand has responded by tightening its air quality regulations, including lowering the permissible daily PM2.5 limit from 50 µg/m³ to 37.5 µg/m³. The Pollution Control Department (PCD), under the Ministry of Natural Resources and Environment, operates approximately 165 monitoring stations nationwide, though some areas remain underserved. The WHO air quality database includes data from 26 sites in Thailand, providing insights into pollution trends. Moving forward, continued enforcement of air quality standards, expansion of monitoring networks, and regional cooperation on transboundary haze will be essential to mitigating Thailand’s air pollution crisis.