Hydrochlorofluorocarbons (HCFCs) are human-made chemicals that have been used as temporary replacements for chlorofluorocarbons (CFCs) in refrigerants because they decompose more readily in the atmosphere and thus pose less of a threat to Earth’s protective ozone layer. Levels of HCFCs have been measured in the stratosphere, and the concentrations of many different HCFCs have been steadily increasing since the mid- to late 1990s.
One important drawback of the use of HCFCs as a replacement for CFCs is that HCFCs:
a) biomagnify in food chains in the Arctic ecosystem
b) combine with water vapor to form acid precipitation
c) are greenhouse gases that contribute to climate change
d) react with carbon monoxide ( CO ) to form ozone in the troposphere