Suppression of chlorine activation on aviation-produced volatile particles S. K. Meilinger1, B. Kärcher2, and Th. Peter3 1MPI f¨ur Chemie, Mainz, Germany 2DLR Oberpfaffenhofen, Institut für Physik der Atmosphre, Wessling, Germany 3ETH Laboratorium für Atmosphärenphysik, Zürich, Switzerland
Abstract. We examine the effect of nanometer-sized aircraft-induced aqueous
sulfuric acid (H2SO4/H2O) particles on atmospheric ozone
as a function of temperature. Our calculations are based on a previously derived parameterization for the regional-scale perturbations of the sulfate
surface area density due to air traffic in the North Atlantic Flight Corridor
(NAFC) and a chemical box model. We confirm large scale model results that at temperatures
T>210 K additional ozone loss -- mainly caused by hydrolysis of BrONO2 and
N2O5 -- scales in proportion with the aviation-produced increase of the background aerosol surface area.
However, at lower temperatures (< 210 K) we isolate two effects which efficiently reduce the aircraft-induced perturbation:
(1) background particles growth due to H2O and HNO3 uptake enhance scavenging losses of
aviation-produced liquid particles and (2) the Kelvin effect efficiently limits
chlorine activation on the small aircraft-induced droplets by reducing the
solubility of chemically reacting species. These two effects lead to a substantial reduction of heterogeneous chemistry on aircraft-induced volatile
aerosols under cold conditions. In contrast we find contrail ice particles
to be potentially important for heterogeneous chlorine activation and reductions in ozone levels.
These features have not been taken into consideration in previous global studies of the atmospheric impact of
aviation. Therefore, to parameterize them in global chemistry and transport models,
we propose the following parameterisation: scale the hydrolysis reactions by the aircraft-induced surface area
increase, and neglect heterogeneous chlorine reactions on liquid plume particles
but not on ice contrails and aircraft induced ice clouds.
Citation: Meilinger, S. K., Kärcher, B., and Peter, Th.: Suppression of chlorine activation on aviation-produced volatile particles, Atmos. Chem. Phys., 2, 307-312, doi:10.5194/acp-2-307-2002, 2002.