Researchers have recently conducted a groundbreaking study using Landsat and Sentinel-2 satellites to track and measure nitrogen oxide (NOx) emissions from power plants with exceptional accuracy. These satellites, initially designed for land surveying purposes, have proven to be valuable tools for environmental monitoring and combating air pollution.
The Sentinel-2 satellite, part of the European Space Agency’s Copernicus program, is equipped with a high-resolution multispectral imager that can capture detailed images of the Earth’s surface. While originally intended for monitoring vegetation health and detecting changes in land cover, Sentinel-2 has now been utilized to map NOx emissions by a team of researchers led by Daniel Varon from Harvard.
The study focused on several power plants in Saudi Arabia and the United States, including a detailed analysis of Riyadh Power Plant 9 over a 13-year period. This plant, which utilizes a combination of crude oil, natural gas, and diesel, exhibited significant NOx emissions that were detectable by both Landsat and Sentinel-2 satellites. The researchers were able to observe seasonal and long-term trends in emissions, such as a summer peak likely attributed to increased air conditioning use.
By leveraging specific parts of the satellite sensors that are adept at detecting nitrogen dioxide (NO2), the researchers were able to quantify the concentration of NO2 in the atmosphere and determine emission rates from sources like power plants. This method involved analyzing light measurements from areas with NO2 plumes compared to reference scenes without plumes, allowing for a comprehensive understanding of atmospheric pollution.
The ability to track emissions with satellites is crucial for monitoring air pollution on a global scale. While launching dedicated satellites for this purpose can be costly, utilizing existing satellites like Landsat and Sentinel-2 provides a cost-effective solution for gathering valuable information on pollution and emissions. Additionally, the upcoming launch of Sentinel-2C, the follow-up mission to Sentinel-2A and -2B, will further enhance continuous imaging capabilities in 13 spectral bands.
The findings of this study contribute to the utility of Sentinel-2 satellites in air quality monitoring by pinpointing pollution sources, particularly in urban areas where sources are numerous and closely located. This unexpected capability highlights the potential for repurposing existing satellite technology for environmental monitoring and underscores the importance of innovative approaches in combating air pollution.
Overall, the research conducted by Varon et al. showcases the significant impact that satellite observations can have on quantifying NOx emissions and provides valuable insights into addressing environmental challenges associated with poor air quality and climate change. The utilization of existing satellite resources for monitoring pollution sources represents a cost-effective and efficient strategy for advancing environmental protection efforts worldwide.
