Comment Sought on Ceiling Concentration When Using CO_2 in Motor Vehicle Air Conditioning Systems

摘要

On September 17, 2009 (74 FR 47774-47775), EPAannounced the availability of a human health effects review of carbon dioxide (CO_2) that the agency will consider as it moves forward to address listing CO_2 as an acceptable substitute for ozone-depleting substances (ODS) in motor vehicle air conditioning (MVAC) systems. On September 21, 2006 (71 FR 55140), the agency proposed to list R-744 (CO_2) as "acceptable with use conditions" as a substitute for chlorofluorocarbon (CFC)-12 in MVAC end uses. The September 17, 2009 proposed rule makes available for public comment information on the toxicological impacts of short-term exposures to CO_2 in the confined space of a vehicle passenger compartment. Based on the information made available for comment, EPA is considering setting a ceiling limit for CO_2 concentration in the passenger compartment.