Monday, November 12, 2018, 12:15PM - 1:15PM
University of East Anglia
SEEC room S228 (Sievers Room)
It is possible to drill down in to the layer of deep ‘firn’ that overlies the world’s ice caps, and pump air out of this porous snow-ice material. This ‘firn air’ represents air of increasing age with greater depth. Not all atmospheric gases are preserved in firn air, but enough are to begin to build a picture of past hemispheric-scale ‘background’ air pollution. In this talk I will present some preliminary measurements from firn air collected in Greenland this year (the “EGRIP” campaign), and show how this might help complement and extend data from our earlier Arctic firn air campaigns. The ultimate aim is to reconstruct continuous histories of several gaseous pollutants from the mid-20th century to the present day. As illustrations I will focus on two groups of gases; (1) industrial chlorinated hydrocarbons that we now think might be capable of affecting stratospheric ozone; and (b) non-methane hydrocarbons (NMHCs) and their nitrated reaction products that might yield some insight in to the state of the “oxidising capacity” of the lower part of the atmosphere in which we all live (the troposphere).
Free and open to the public.