Which of the following statements about HFCs and HCFCs is true?

The statement regarding HFCs and HCFCs that is true is that they decompose when released in the lower atmosphere. Hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are chemicals that have been used as refrigerants and in other applications. When these substances are released into the atmosphere, they can undergo photolytic breakdown processes, particularly in the lower atmosphere where they are exposed to sunlight. This decomposition can lead to the formation of other compounds, but it does mean that they do not persist indefinitely in the environment.

The other options lack accuracy in their claims. While HFCs and HCFCs do not deplete the ozone layer to the same extent as chlorofluorocarbons (CFCs), they are not completely safe for the environment due to their potential contribution to greenhouse gas effects and, in the case of HCFCs, their ozone depletion potential. Furthermore, while HFCs do not contribute directly to ozone depletion, they can have environmental implications such as contributing to global warming. Therefore, understanding their decomposition in the lower atmosphere helps clarify their behavior and impact.