California's coast is routinely exposed to various contamination sources, including industrial discharges, agricultural runoff, airborne pollutants, and accidental spills such as oil leaks. These pollutants pose risks to marine ecosystems, fisheries, and human health.
Pollutants have previously been monitored using traditional water sampling techniques and lab analysis, but while these methods are accurate, they often fall short in coverage and timeliness.
Satellite remote sensing is an alternative way to observe pollutants across larger areas, but it can struggle to detect specific contaminants at low concentrations or in complex mixtures. Maintaining high-resolution, continuous monitoring remains a persistent challenge.
The Current Study
NASA scientists have developed custom sensors to detect pollutants in dynamic marine environments. These sensors can identify hydrocarbons, heavy metals, organic compounds, and particulate matter in water and air samples using techniques like fluorescence spectroscopy and electrochemical detection.
The sensors have been engineered to endure the harsh conditions in space, including vacuum, radiation, and extreme temperatures, as they are installed on the ISS.
To ensure their accuracy, the sensors are calibrated against known standards to detect pollutants at parts-per-trillion or parts-per-billion levels. They can operate continuously or on a set schedule, analyzing signals onboard with integrated electronics and filtering algorithms to reduce noise and extract valuable data.
Synchronized with the ISS's orbit and aligned with satellite overpasses, the sensors operate as a synergistic, multi-platform dataset. Mounted on portable payloads outside the ISS, they can target specific pollution hotspots, from storm-impacted zones to industrial discharge points.
Results and Discussion
The proof-of-concept study demonstrates the effectiveness of the ISS sensors in detecting pollutants along California's coastline. The sensors detected elevated hydrocarbon levels in specific areas linked to known oil spills with near-real-time detection that significantly outpaced traditional methods.
The sensors also maintained sensitivity over time, despite environmental stressors like biofouling and temperature shifts. Additionally, the sensors detected heavy metals like lead and mercury near established industrial discharge sites, pollutants that are notoriously challenging to monitor continuously.
They also gathered data on a range of organic contaminants, such as polycyclic aromatic hydrocarbons and airborne particulate matter, painting a detailed picture of pollution types and sources. Crucially, the instruments could differentiate between pollutants and track trends over time.
Their data matched satellite imagery and ground-based readings, filling critical gaps in areas where conventional monitoring was limited or delayed. These real-time measurements provided immediate data during pollution events, enabling authorities to act quickly with mitigation and cleanup efforts.
This deployment highlights a significant step forward in environmental monitoring technology. The sensors' precision and continuous operation deliver detailed pollution profiles over time, revealing pollutant origins, movement, and environmental behavior.
Download your PDF copy now!
Conclusion
The results of this study mark a major advance in remote sensing and environmental science. With high sensitivity and rapid response, NASA's EMIT sensors improve on traditional monitoring methods and help to provide important data for protecting coastal ecosystems.
As sensor technology improves, instruments like these will continue to expand their scope of detection and reliability. Building a broader network of space-based sensors could create a comprehensive, real-time monitoring system to guide policy, improve pollution responses, and support sustainable management of coastal environments.
Journal Reference
Press Release. NASA. NASA Sensor on Space Station Eyes Contamination off California Coast. Accessed on 12th June 2025. https://www.nasa.gov/missions/station/iss-research/emit/nasa-sensor-on-space-station-eyes-contamination-off-california-coast/