Tracking the Invisible: Monitoring Air Pollution from Space

By Keran Wang, Sheryl Rose Reyes and Taisei Ukita
BANGKOK, Thailand, Jan 14 2026 – Take a deep breath.

Did you know that in many countries in Asia and the Pacific, the air we breathe falls short of the safety standards for air quality set by the World Health Organization? While the start of a new year signals new beginnings, it also marks the continuation of the recurring air quality crisis across many countries in the region.

In 2024, 25 of the most polluted cities were in the Asia-Pacific region, with dangerous levels of fine particulate matter (PM2.5) that significantly exceeded the annual maximum levels of 5 micrograms per cubic meter.

Oftentimes, when we think of air pollution, we associate it with car exhaust and factory chimneys belching black smoke. But air pollution is not just the cost of urban development – it is a multi-hazard crisis caused by wildfires, sand and dust storms, and volcanic eruptions that respect no borders. Access to clean air is a human right and countries who contribute the least to air pollution are often the most vulnerable.

Rising temperatures create a vicious cycle: rising heat leads to intensifying wildfires, releasing toxic smoke composed of carbon dioxide, carbon monoxide, and PM2.5 into the air we breathe. Furthermore, heat accelerates the breakdown of waste, generating even more pollutants.

Volcanic eruptions add sulfur dioxide and volcanic ash to the mix, and these pollutants can linger in the atmosphere for months. The result? Climate change exacerbates air pollution, which in turn aggravates the climate crisis — a feedback loop that puts both human health and ecosystems at risk and transforms local hazards into regional challenges.

Can a heavily polluted environment be restored? In principle, yes, but doing so requires transformative change and collective action in our economy and society. Improving urban mobility requires prioritizing efficient public transport, including low-emission vehicles, cleaner, greener alternatives such as walking, cycling, and ride-sharing.

Nature-based solutions, including green cooling corridors, can further improve air quality by lowering surface temperatures and providing buffers against desertification, land degradation, drought, and sand and dust storms.

However, not all sources of air pollution can be addressed through emission reductions alone. There are inherent limits to prevention at the source, particularly for air pollution caused by natural hazards. This requires a shift in focus from mitigation toward adaptation and preparedness.

Earth observation plays a critical role in monitoring, early warning, and informed decision-making. Advanced sensors aboard platforms such as Sentinel-5 Precursor and Geostationary Environment Monitoring Spectrometer (GEMS) detect key atmospheric pollutants including nitrogen dioxide (NO2), sulfur dioxide (SO2), tropospheric ozone, and carbon monoxide at unprecedented spatial and temporal scales.

The collaboration of ESCAP with regional partners for the Pan-Asia Partnership for Geospatial Air Pollution Information exemplifies how satellite data can be integrated with surface observations to create robust monitoring systems. These datasets enable tracking transboundary pollution events, from agricultural fire smoke to volcanic sulfur emissions to urban photochemical smog.

Satellites bridge the existing gaps from ground-based observations, providing authorities with the spatial coverage needed to understand and monitor air pollution and formulate effective policies.

The Clean Air for Sustainable ASEAN project recognizes that addressing the transboundary air pollution crisis requires strengthened monitoring and decision-making capacities enabled by technology-driven solutions. The application, Check Phoon (Thai: Phoon, meaning dust), or the PM2.5 Monitoring System, developed by the Geo-informatics Information and Space Technology Development Agency of Thailand, is an innovative platform that leverages space technology to support air quality monitoring and public health protection by providing real-time, high-resolution PM2.5 concentration data across Thailand.

The application is available in both web-based and mobile applications, and the system integrates satellite data, such as from Himawari, meteorological information, PM2.5 sources including hotspots (active fire detections), and ground-based validation from PM2.5 monitoring stations.

Building on the framework of SatGPT for flood hotspot mapping, an iteration of SatGPT for volcanic hazards has been proposed with potential to support the understanding and management of air pollution linked to volcanic activity. has been proposed with potential to support the understanding and management of air pollution linked to volcanic activity.

The Regional Action Programme on Air Pollution advances air quality management through science-based cooperation, sharing of best practices, and strengthened technical and financial support across ESCAP member States.

Complementing this effort, the Regional Space Applications Programme facilitates the sharing of Earth observation data and expertise that are critical for monitoring air pollution and assessing the impacts.

These initiatives contribute to accessible and actionable geospatial information that strengthens early warning systems, enabling authorities to forecast and quantify air quality with greater precision.

The transboundary nature of air pollution demands a stronger and more urgent call to action. While the Asia-Pacific region has demonstrated remarkable resilience in the face of cascading disasters, regional cooperation must accelerate to match the scale and pace of this evolving crisis.

Keran Wang is Chief of Space Applications Section, ESCAP; Sheryl Rose Reyes is Consultant, Space Applications Section, ESCAP; Taisei Ukita is former Intern, Space Applications Section, ESCAP.

The authors would like to thank Sangmin Nam, Director of the Environment and Development Division of ESCAP, for his contributions to this article.

IPS UN Bureau

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