Where do the 80 and 82 spikes come from in the m spec of 1-bromopropane?

The m spec presents a series of spikes from 79 to 82. The propane group alone cannot contribute a m this high and bromine bonded to anything cannon contribute a m this low. 79 and 81 are explained by bromine isotopes, but where do the 80 and 82 come from?