Aviation and the Global Atmosphere

Aviation and the Global Atmosphere
Taking 2.0 pptm as a reference mixing ratio for subsonic aircraft soot in 2015 at 12 km and 50°N, an approximate SAD of 0.03 µm2 cm-3 is obtained when assuming
(as a first approximation) spherical particles of 2 g cm-3 density (Pueschel et al., 1997) and a bimodal size distribution peaked at 20 and 100 nm radii with equal
contribution in mass. If the particles are not assumed to be spherical but can be represented by fractal geometry, their SAD could lead to an enhancement by a factor
of about 4 (Jennings et al., 1999) over the spherical case. This seems more appropriate than 30, as suggested by Blake and Kato (1995). DeMore et al. (1997)
recommend reaction efficiencies for O3 decomposition between 0.003 and 1 x 10-5 , with one O2 molecule produced for each O3 reacting. As noted above, this O3 decomposition is not catalytic because reaction sites on soot are rendered inactive when they are used or when the particle becomes coated with H2SO4 .
Table of contents | Previous page | Next page
Other reports in this collection
http://www.ipcc.ch/ipccreports/sres/aviation/051.htm (10 von 10)08.05.2008 02:42:31
IPCC Homepage