In the sun-scorched expanses of California’s Salton Sea region, a silent, invisible pollutant has long evaded comprehensive monitoring. Ammonia (NH₃), a key player in atmospheric chemistry, has remained understudied due to its short lifespan and patchy monitoring coverage. However, a recent study led by Dr. S. Hasheminassab of the Jet Propulsion Laboratory at the California Institute of Technology has shed new light on this elusive pollutant, with significant implications for the energy sector and air quality management.
The study, published in the journal *Atmospheric Measurement Techniques*, employed an innovative approach: airborne longwave-infrared (LWIR) hyperspectral imaging. This cutting-edge technology, with a spatial resolution of approximately 2 meters, was used to map and characterize NH₃ emissions in two regions near the Salton Sea— Mecca in the northwest and Imperial in the southeast. The surveys, conducted in March and September 2023, revealed striking spatial and seasonal variability.
“Our findings showed that average NH₃ levels in Imperial were 2.5–8 times higher than those in Mecca,” Dr. Hasheminassab explained. “This disparity is primarily linked to large, concentrated animal feeding operations (CAFOs), geothermal power plants, fumaroles, and intensive agricultural activities.”
The study’s ground-based mobile monitoring corroborated these findings, with elevated NH₃ levels detected near these sources. Notably, the highest concentrations were found downwind of CAFOs with large cattle populations. This data underscores the utility of airborne LWIR hyperspectral imaging in detecting and mapping NH₃ at hyperlocal scales, including sources absent from existing inventories.
The implications for the energy sector are significant. Geothermal power plants, a renewable energy source, were identified as notable NH₃ emission sources. This information could guide future plant designs and operations to minimize emissions. Moreover, the study highlights the need for routine airborne campaigns and the development of next-generation satellite missions with higher spatial resolution to achieve comprehensive, large-area monitoring.
Dr. Hasheminassab’s work not only informs air quality management strategies but also emphasizes the importance of improving emission inventories for effective mitigation of NH₃-driven air pollution. As the energy sector continues to evolve, such insights will be crucial in balancing renewable energy production with environmental stewardship.
This research could shape future developments in atmospheric monitoring technologies and strategies. By providing a more accurate and comprehensive picture of NH₃ emissions, it paves the way for more effective air quality management and policy-making. As Dr. Hasheminassab puts it, “Our study is a step towards achieving a more nuanced understanding of atmospheric chemistry and its impacts on air quality.”