Residence time is the amount of time in which a substance remains in a reservoir, such as the atmosphere. for example, the residence time of carbon tetrafluoride (cf4) in our atmosphere is more than 50,000 years. in contrast, carbon dioxide (co2) has a residence time that is much shorter. which statement best explains how the residence time of a substance affects the atmosphere? a. substances that have a longer residence time are more beneficial to the atmosphere. b. substances that have a shorter residence time make up a smaller portion of the atmosphere. c. substances that have a longer residence time will cycle faster through the atmosphere. d. substances that have a shorter residence time do not stay in the atmosphere as long.