The influence of African air pollution on regional and global tropospheric ozone A. M. Aghedo1,2, M. G. Schultz3, and S. Rast1 1Max Planck Institute for Meteorology, Hamburg, Germany 2International Max Planck Research School on Earth System Modelling, Hamburg, Germany 3ICG-II, Research Centre, Jülich, Germany
Abstract. We investigate the influence of African biomass burning, biogenic, lightning
and anthropogenic emissions on the tropospheric ozone over Africa and
globally using a coupled global chemistry climate model. Our model studies
indicate that surface ozone concentration may rise by up to 50 ppbv in the
burning region during the biomass burning seasons. Biogenic emissions yield
between 5–30 ppbv increase in the near surface ozone concentration over
tropical Africa. The impact of lightning on surface ozone is negligible,
while anthropogenic emissions yield a maximum of 7 ppbv increase in the
annual-mean surface ozone concentration over Nigeria, South Africa and Egypt.
Our results show that biogenic emissions are the most important African
emission source affecting total tropospheric ozone. The influence of each of
the African emissions on the global tropospheric ozone burden (TOB) of
384 Tg yields about 9.5 Tg, 19.6 Tg, 9.0 Tg and 4.7 Tg for biomass
burning, biogenic, lightning and anthropogenic emissions emitted in Africa
respectively. The impact of each of these emission categories on African TOB
of 33 Tg is 2.5 Tg, 4.1 Tg, 1.75 Tg and 0.89 Tg respectively,
which together represents about 28% of the total TOB calculated over Africa.
Our model calculations also suggest that more than 70% of the tropospheric
ozone produced by each of the African emissions is found outside the
continent, thus exerting a noticeable influence on a large part of the
tropical troposphere. Apart from the Atlantic and Indian Ocean, Latin America
experiences the largest impact of African emissions, followed by Oceania, the
Middle East, Southeast and south-central Asia, northern North America (i.e.
the United States and Canada), Europe and north-central Asia, for all the
Citation: Aghedo, A. M., Schultz, M. G., and Rast, S.: The influence of African air pollution on regional and global tropospheric ozone, Atmos. Chem. Phys., 7, 1193-1212, doi:10.5194/acp-7-1193-2007, 2007.