Saito and his colleagues launched the study after noticing unusually high emissions of the halocarbon HFC-32 at Cape Ochiishi in Hokkaido, Japan, following the earthquake. The researchers have studied atmospheric halocarbons at this site since 2006, Saito said. The researchers then took air-monitoring data from several stations in Japan and used atmospheric modeling to determine how much of the emissions were due to the 2011 earthquake and tsunami.