EVIDENCE FOR A 50-PERCENT INCREASE IN H2O2 OVER THE PAST 200 YEARS FROM A GREENLAND ICE CORE

HYDROGEN peroxide has attracted increasing attention from atmospheric chemists over the past decade, because in the gas phase it acts as a reservoir species of OH radicals 1,2, and in the aqueous phase it plays a key role in the oxidation of SO2 to H2SO4 in clouds 3. It is also known to have an adverse effect on trees and plants 4. In 1984, hydrogen peroxide was identified as one of the dominant trace species in polar ice 5, introducing the possibility of constructing a record of atmospheric hydrogen peroxide concentrations from ice-core data. Here we present such a record for the past 700 years from Summit, Central Greenland. We find that hydrogen peroxide concentrations have increased by 50% over the past 200 years, with most of the increase occurring in the past 20 years, indicating that human activities may be responsible for such a dramatic change.