A recent study led by scientists at NASA’s Jet Propulsion Laboratory in Southern California and the nonprofit Aerospace Corporation shows how high-resolution maps of ground-level ammonia plumes can be generated with airborne sensors, highlighting a way to better track the gas.

A key chemical ingredient of fine particulate matter—tiny particles in the air known to be harmful when inhaled—ammonia can be released through agricultural activities such as livestock farming and geothermal power generation as well as natural geothermal processes. Because it’s not systematically monitored, many sources of the pungent gas go undetected.

Published in Atmospheric Chemistry and Physics, the study focuses on a series of 2023 research flights that covered the Imperial Valley to the southeast of the Salton Sea in inland Southern California, as well as the Eastern Coachella Valley to its northwest. Prior satellite-based research has identified the Imperial Valley as a prolific source of gaseous ammonia.