Combatting the PM2.5 Crisis with GISTDA: From Research to the “Check Phoon” App: Technology for all

Combatting the PM2.5 Crisis with GISTDA: From Research to the “Check Phoon” App: Technology for all
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Air pollution is a significant environmental and public health problem in Thailand. Notably, PM2.5 and ozone (O₃) often exceed the standard levels. This is extremely harmful to people’s health.
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Currently, air pollution is escalating into a national crisis. In particular, Northern Thailand and Chiang Mai Province have persistently experienced the worst air quality throughout this past April. This problem occurs every year from December to May. However, it is difficult to resolve this issue if we do not know its sources and fail to take serious action.
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Space technology is a cutting-edge tool in air pollution management, as satellites can accurately estimate PM2.5 concentrations by measuring Aerosol Optical Depth (AOD), which serves as a key variable for air quality analysis. Moreover, satellites can be used to monitor hotspots and burned areas, providing clear evidence to identify emission sources.
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An in-depth satellite analysis reveals that “biomass burning” is a significant contributor to the PM2.5 crisis in Northern Thailand.
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Many people are aware of the PM2.5 problem. More than 90% of PM2.5 pollution is generated by open burning, vehicle emissions, fuel combustion in the industrial and construction sectors, and daily human activities. When combined with weather conditions such as high pressure and stagnant air. This causes dust to accumulate in the atmosphere and increase in concentration, leading to severe air pollution. Furthermore, during dry seasons, air masses can carry transport haze from countries, causing transboundary pollution.
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However, to identify the true sources of PM2.5 and address the problem in a targeted, timely, and sustainable manner, it is necessary to understand the chemical composition of PM2.5 in different areas. Previous studies have shown that PM2.5 sources vary depending on location, altitude, and Diurnal variations . Furthermore, research conducted by Thai scientists indicates that the primary sources of PM2.5 in Thailand are human activities, including biomass burning.
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This conclusion is consistent with preliminary findings from the ASIA-AQ project, a collaboration between GISTDA, NASA, NIER, and researchers from academic institutions in Thailand and abroad. As part of the project, NASA used the DC-8 and G-III aircraft to collect data and measure air quality parameters in March. Analysis of PM2.5 chemical composition during the dry season at low altitudes in Chiang Mai and Phrae provinces revealed that Organic Aerosols (OA) accounted for the largest proportion.
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This research directly identifies the main emission sources of the PM2.5 crisis in Northern Thailand. Currently, data from the “Check Phoon” from April 1 to 19, 2026, demonstrates that thirty monitored districts are experiencing PM2.5 levels exceeding the standard and posing health risks. Seven districts in Nan and Chiang Rai provinces have recorded PM2.5 levels at or above 125 micrograms per cubic metre for at least three consecutive days. The criteria for the official declaration of disaster-affected areas require PM2.5 concentrations to remain at 125 µg/m³ or higher for five consecutive days.
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On April 22, 2026, NASA released satellite images showing Chiang Mai and its surrounding areas covered in smog. (https://science.nasa.gov/.../smoke-shrouds-northern.../). This illustrates the severity of PM2.5 pollution in Chiang Mai Province. Notably, the number of hotspots in Northern Thailand remained relatively low throughout January. However, it increased significantly from February to April.
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GISTDA has an important role in air pollution management in Thailand.
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Given the importance of space and geospatial technology in addressing the PM2.5 crisis worldwide, the Geo-Informatics and Space Technology Development Agency (GISTDA) leverages satellite-based decision support systems for the policy-level management of wildfires and air pollution, covering the entire incident lifecycle from prevention to recovery. Through continuous satellite monitoring, GISTDA has developed a fire-risk map identifying high-risk areas, enabling officials to proactively plan and allocate resources for monitoring, containment, and loss reduction before incidents occur.
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During an incident, real-time monitoring through continuous hotspot tracking helps accurately identify the locations of wildfires and agricultural fires, allowing ground teams to take prompt action. After an incident, satellite mapping data helps analyse past burning patterns, assess wildfire behaviour for restoration planning, and establish firebreaks in unburned areas. This promotes burn-free agriculture and helps ensure product quality standards.
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GISTDA provides wildfire and haze management data through its space technology-based “Disaster Management Decision Support System (Disaster Platform)” (https://disaster.gistda.or.th/). Furthermore, GISTDA has improved public access to this information through the “Check Phoon” application, which provides real-time hourly PM2.5 alerts based on users’ locations, enabling them to make informed decisions about their daily activities. In addition, GISTDA has integrated PM2.5 data into the “LIFE DEE” application, a health and wellness platform, by adding features such as the Heat Index, improved access to healthcare facilities, and enhanced public services for people with disabilities and the elderly.
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The beginning of “Check Phoon” forms research into technology for people.
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In 2019, GISTDA recognised the potential of satellites to estimate PM2.5 levels. At that time in Thailand, the idea that satellites could measure air pollution had not yet been widely recognised, as air quality monitoring mainly relied on sensors installed at monitoring stations. This led to research funded by the National Research Council of Thailand in 2019.
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GISTDA studied the capabilities of satellites worldwide and found that several of them were suitable for PM2.5 monitoring. Although these satellites do not directly measure particulate matter like ground-based sensors, they can detect Aerosol Optical Depth, a key variable used to estimate PM2.5 concentrations. Following the completion of this research and its publication in an international journal, a nationwide PM2.5 map for Thailand was developed. GISTDA continues to monitor this data and has expanded its use to raise public awareness through the development of the “Check Phoon” application, which was officially launched in late 2020.
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Since its initial version, which achieved an accuracy of approximately 50–60% in estimating PM2.5 levels compared with monitoring stations operated by the Pollution Control Department, GISTDA has continuously improved the model. GISTDA has incorporated artificial intelligence (AI) to analyse various parameters and improve the model’s accuracy. Currently, the PM2.5 values derived from satellite data and displayed in the Check Phoon application are highly consistent with data from internationally standardised monitoring stations operated by the Pollution Control Department, with an average error of no more than 4–5 micrograms per cubic metre.
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Although ground monitoring stations provide highly accurate measurements at their installed locations, they may not cover all areas. Satellites, on the other hand, have the advantage of monitoring larger geographical areas. The “Check Phoon” application fills data gaps in areas without ground stations by providing high-resolution PM2.5 data, with a spatial resolution of up to 1 × 1 square kilometre, based on the user’s current location. This near-real-time data is updated hourly, and the application forecasts PM2.5 levels up to 3–4 hours in advance, facilitating safer and more effective activity planning Furthermore, the application allows users to access historical PM2.5 data for up to 20 years.
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Next year, the Check Dust application will expand its PM2.5 reporting by providing alerts for other air pollutants, such as nitrogen dioxide, sulphur dioxide, and ozone, which are also being monitored. In addition, the monitoring area will be expanded to include neighbouring countries.
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International Collaboration in Addressing Transboundary Pollution.
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GISTDA recognises that air pollution cannot be effectively addressed by one country alone, as particulate matter is a borderless pollutant. Therefore, GISTDA has established collaborative networks with international organisations, including the ASIA-AQ (Airborne and Satellite Investigation of Asian Air Quality) project in partnership with NASA and the GEMS-based Asian Air Quality project with South Korea. These collaborations utilise satellite technology to improve the accuracy of air pollution monitoring and management. Furthermore, the Mekong-Lancang Cooperation project has identified PM2.5 and transboundary air pollution as urgent priority issues.
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GISTDA’s role in systematically managing air pollution demonstrates the power of space and geospatial technology in transforming space-based observations into accessible tools for the public. These data not only help the public monitor their health but also provide critical information for government policy decisions, supporting targeted measures to control burning and manage wildfires. The ultimate goal is to ensure sustainable clean air for all Thais.