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Scientists from the University of Munich have found that a new refrigerant for car air-conditioning mandated for use by the European Union (EU) produces a gas similar to WW1 poison phosgene when burnt.
The findings place the researchers at the centre of a major industrial dispute between German premium car manufacturer Daimler and European politicians.
Use of the previously-approved refrigerant R134a has been forbidden in Europe since 2011 because the gas has a global warming potential more than a thousand times greater than that of carbon dioxide.
The recommended substitute, R1234yf, was developed by Honeywell and Dupont and has roughly the same carbon impact as CO2 itself. Honeywell said there are now more than 500,000 cars using R1234yf and the number is expected to reach more than two million by the end of this year.
However, Daimler refuses to use R1234yf in its new cars because it says it can ignite and releases the toxic gas hydrogen fluoride if a vehicle has a collision and catches on fire. The refusal places Daimler in breach of European law and the European Commission has launched legal proceedings against Germany (http://www.euractiv.com/transport/eu-take-legal-action-germany-dai-news-532892).
The row has been the subject of heated debate in Germany, with several car makers, research organisations and authorities springing to Daimler's defence.
The latest study by researchers at the University of Munich shows that, when combusted R1234yf, releases carbonyl fluoride as well as hydrogen fluoride. Andreas Kornath, Professor of Inorganic Chemistry at the University of Munich, said: “Our analysis has shown that 20% of the gases produced by combustion of the compound consist of the even more poisonous chemical carbonyl fluoride.
“The risk analyses carried out by the manufacturers of the refrigerant so far have not taken carbonyl fluoride into account. In light of our results, we advise that the risks associated with R1234yf should be urgently reassessed.”
Carbonyl fluoride is structurally related to phosgene, which contains chlorine in place of fluorine. The gas can penetrate the skin and cause severe irritation of the eyes, the skin and the airways. If inhaled, it can damage the alveoli in the lungs, allowing it to reach the bloodstream and cause death, said the University.
The results of the study are at odds with independent research commissioned by the EU that was published in March and said the new refrigerant was safe to use. (http://ec.europa.eu/enterprise/sectors/automotive/environment/macs/index_en.htm#h2-1)
Daimler has said that it wants to use the original refrigerant until it has developed air-conditioning systems that use carbon dioxide as a refrigerant.