Halogenated organic species over the tropical rainforest

Long-lived halogenated carbon compounds are important contributors to stratospheric ozone loss, and the most persistent anthropogenic ones are controlled by the Montreal Protocol. Of the shorter-lived halocarbons, methyl chloride (CH3Cl) and methyl bromide (CH3Br) are the most abundant chlorine and bromine containing gases in the troposphere, and a fraction may reach the stratosphere. CH3Cl contributes up to 15% of the tropospheric organic chlorine, CH3Br up to about 50% of the organic bromine. Since they are of great importance to ozone, their sources and sinks should be well understood. However, inverse model studies suggest a missing source of methyl chloride located in the tropics. Recent studies indicate that CH3Cl and to a lesser extent CH3Br are emitted by tropical ecosystems.