Suppression of chlorine activation on aviation-produced volatile particles

S. K. Meilinger (1) , B. Kärcher (2) , Th. Peter (3)

1 MPIC - Max-Planck-Institut für Chemie
2 IPA - DLR Institut für Physik der Atmosphäre = DLR Institute of Atmospheric Physics
3 ETH Laboratorium für Atmosphärenphysik

We examine the effect of nm-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 ozone depletion. 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.

Domaines: Océan, Atmosphère

S. K. Meilinger, B. Kärcher, Th. Peter. Suppression of chlorine activation on aviation-produced volatile particles. Atmospheric Chemistry and Physics Discussions, 2002, 2 (4), pp.983-998. ⟨hal-00300865⟩