Denso Corporation has developed with Toyota Motor Corporation a claimed world-first non-fluorocarbon car air conditioner using natural refrigerant, carbon dioxide (CO2). Toyota's fuel cell hybrid vehicle FCHV, launched on Dec. 2, uses this new CO2 car air conditioner. The majority of the world's car air conditioners use hydrofluorocarbon refrigerant (HFC-134a) that is a substitute of chlorofluorocarbon (CFC-12) and is harmless to the ozone layer.  However, HFC-134a's impact on global warming is still large, although smaller than that of CFC-12, a Denso spokesman said.