Oxidation of mercury by atmospheric halogens

The neurotoxin methyl mercury can be created through processes initiated by the oxidation of elemental mercury. Halogens and halogen oxides may have an impact in this process (see reactions below). Our group monitors halogen oxides and other trace gases in the coastal atmosphere of Florida, where halogens may be released from sea salt or from biogenic sources, the site is approximately 1 km from the coastline, and IO and BrO have been observed in the marine boundary layer.

Hg0 + Br/I → products (1)
HgBr/I + (Br,BrO,I,IO) → products (2)

IO boundary layer vertical profiles

Ongoing Research Questions

  • What are the background concentrations and vertical profiles of halogen oxides?
  • Is there a free tropospheric source for BrO/IO?
  • What other conclusion can be drawn about the oxidative capacity and mercury in the coastal environment?
  • What is the role of halogen oxides in coastal particle formation ?