Cfc - 11 and cfc - 12 have the highest concentrations of the man - made chlorocarbons , around 0 . 27 and 0 . 55 ppbv , respectively measured at mauna loa in 1997 , fig . 5 6 . as indicated in their gwp values , these two gases are strong infrared absorbers 在多种人造的氯氟碳化合物中，以cfc - 11及cfc - 12的浓度最高，分别约为0 . 27及0 . 55ppbv量度于冒纳罗亚观象台, 1997 ,见图五和六。
Patents on removal of olefins in hcfcs and hfcs at home and abroad are gathered up and classified , principles and characteristics of every method are reviewed , the author also points out that adsorption method is an imporant research trend in refining technology of hcfcs and hfcs 摘要概括了国内外氢氯氟烃和氢氟烃中烯烃脱除方法的专利文献，评述了各种方法的原理、特点，并指出吸附法是当前氢氯氟烃和氢氟烃精制技术的发展趋势之一。
In february 1992 , nasa scientists announced that levels of chlorine monoxide resulting from the breakdown of cfc ' s were at record levels above the northern hemisphere near the arctic and that these conditions could cause an ozone hole to develop over much of europe , canada , russia , and northern portions of the united states by the year 2000 1992年2月，美国国家航空与航天局科学家宣布，北极附近的北半球源于氯氟化碳分解的一氧化氯处在前所未有的水平上，同时宣布这种情况可能引起欧洲、加拿大、俄罗斯和美国北部等许多地区臭氧空洞的发展。
