Arctic ozone hole research. Scientist wears radiation protection suit after inspecting the radar dome used to track balloon-borne experiments during the CHEOPS-3 (CHEmistry of Ozone in Polar Stratosphere) project at Kiruna, Sweden, in January & February 1990. Scientists from France, Germany & the U.S. conducted a number of ground- & balloon-based experiments including measurements of atmospheric ozone & sampling or measuring various pollutants. Some balloon-borne experiments passed through Polar Stratospheric Cloud (PSC) formations. PSCs contain ice particles which are suspected as acting as substrates for the chemical reactions that destroy ozone.