Atmospheric chemistry in volcanic plumes

Area of Science:

• Atmospheric Chemistry
• Volcanology
• Environmental Science

Background:

• Quiescently degassing volcanoes emit chemically active plumes.
• Previously unexplored halogen and heterogeneous reactions influence plume chemistry.
• Field observations reveal complex chemical processes in volcanic plumes.

Purpose of the Study:

• To investigate the chemical cycles involving halogens in quiescent volcanic plumes.
• To model the impact of these reactions on atmospheric composition, including ozone and mercury.
• To assess the role of volcanic emissions in atmospheric mercury levels.

Main Methods:

• Numerical modeling of volcanic plume chemistry.
• Incorporation of halogen species and heterogeneous reactions.
• Simulation of sulfur dioxide and radical interactions.

Main Results:

• Sustained high levels of reactive bromine cause significant ozone destruction.
• High sulfur dioxide concentrations reduce hydroxyl radical lifetime, affecting methane.
• Bromine chemistry drives mercury oxidation, reducing its atmospheric lifetime.

Conclusions:

• Volcanic plumes exhibit complex halogen-mediated atmospheric chemistry.
• These processes significantly impact ozone and mercury cycling.
• Further field measurements are needed to validate modeled effects on mercury deposition and health impacts.