Organic peroxy radicals (RO2) and Criegee intermediates (CI, carbonyl oxides) are key reactive species in atmospheric chemistry and play crucial roles in the formation of secondary organic aerosol (SOA). Organic peroxy radicals (RO2) and Criegee intermediates (CI, carbonyl oxides) are key reactive species in atmospheric chemistry and play crucial roles in the formation of secondary organic aerosol (SOA). Analytical Chemistry Materials Science Phys.org – latest science and technology news stories