HFCs have been introduced to replace environmentally-damaging HCFCs which can both destroy the Earth’s protective ozone layer and are potent greenhouse gases.
High precision measurements of three CFCs, three HCFCs, six HFCs, three PFCs, and SF6 were made at five Chinese background stations from January 2011 to December 2012.
Since 2007, scientists have been searching to find the cause of a sudden and unexpected global rise in atmospheric methane, a potent greenhouse gas, following almost a decade in which concentrations had stayed relatively constant.
A 20-year record of atmospheric measurements of the hydrofluorocarbon (HFC-152a), at 11 globally distributed sites, shows an atmospheric mixing ratio increasing from 1.2 in 1994 to 10.1 ppt at the end of 2014.
Here we present the first continuous histories of the abundance and emissions of three PFCs (CF4, C2F6 and C3F8) from 1800 to 2014.
Halons are man-made compounds, which have been mainly used as fire retardants. Because they contribute to stratospheric ozone loss, their usage is now greatly restricted under the Montreal Protocol.