Contributed to by Geospatial Scientist Dr. Cesar Ivan Alvarez, as part of the Centre for Climate Resilience, this study highlights how Earth observation and remote sensing technologies can effectively monitor air pollution disaster risks and inform public health protections for vulnerable urban communities, specifically focusing on South American contexts.

The Global Crisis of Air Quality and the Role of Monitoring

Air pollution is defined as the contamination of environments by physical, chemical, or biological agents from both natural and anthropogenic sources. It represents the most significant environmental threat to human health globally, contributing to over 8.1 million deaths annually. This chapter specifically focuses on Air Pollution Disasters (APDs) (extreme events where pollutant concentrations far exceed regional standards and overwhelm local response capacities). While traditional monitoring relies on ground-based networks (AQMNs), these are often limited by high costs and geographical gaps, particularly in rural areas. Consequently, Earth Observation (EO) has emerged as a revolutionary alternative, providing the large-scale spatial and temporal coverage necessary to assess air quality risks from regional to global levels.

Applications of Earth Observation in Air Pollution Research

The integration of satellite-based remote sensing has transformed the understanding of air pollution risks associated with various phenomena. Researchers utilize regression models to combine EO data with ground measurements, allowing for the estimation of pollutant concentrations in areas lacking physical monitoring stations. Key applications include the monitoring of wildfires, where sensors track smoke dispersion and quantify burned biomass to inform early warning systems. Furthermore, EO technologies allow for the continuous monitoring of volcanic plumes and the study of how social behaviors, such as lockdowns or civil unrest, impact atmospheric composition. Finally, by linking EO data with epidemiological information, researchers can better understand the connection between air quality and chronic respiratory or cardiovascular diseases.

Empirical Results: Wildfires and Social Upheaval

The chapter highlights the practical utility of EO through two significant case studies. In the first, an analysis of the 2020 Western US wildfire season utilized satellite and lidar data to track smoke plumes. The study found that smoke reached the upper troposphere, enabling it to travel across the Atlantic and measurably impact air quality in Europe. The second case study focused on Quito, Ecuador, examining the atmospheric effects of social disruptions. Using the TROPOMI sensor on Sentinel-5P, researchers observed that NO2 levels increased during civil protests in 2019 due to traffic congestion and combustion, whereas they dropped sharply during the 2020 COVID-19 lockdown. These findings underscore the profound and immediate impact of human activity on air quality.

Technological Challenges and Future Prospects

Despite its successes, current EO technology faces several hurdles. Spatial resolution ranging from 5.5 to 7 km for sensors like TROPOMI can be too coarse for analyzing small-scale urban microclimates. Additionally, satellites currently cannot directly measure particulate matter (PM2.5), and data accuracy is often hindered by cloud cover and a lack of vertical resolution, which makes it difficult to distinguish ground-level pollution from that at higher altitudes. However, the future remains promising with upcoming missions such as Sentinel-4, Sentinel-5, TEMPO, and MAIA. These missions are expected to provide revolutionary, high-resolution data that will allow for more targeted interventions and a deeper understanding of the health impacts of specific pollutants.

Conclusion: An Essential Tool for Disaster Management

In conclusion, EO technologies have revolutionized the assessment and mitigation of environmental risks on a global scale. By providing continuous data for regions with limited infrastructure, they have become indispensable for tracking air quality during significant natural and anthropogenic events. As satellite sensors evolve and integrate more closely with atmospheric models and ground measurements, they will serve as essential tools for policymakers and public health officials to make informed decisions, reduce pollution, and protect the environment and human health.

Source: Alvarez, C. I., López, S., Gualotuña, D. Atmospheric composition and sensing. Data-Driven Earth Observation for Disaster Management 25, 431-442 (2026). https://doi.org/10.1016/B978-0-443-33803-8.00043-3.