Effects of business-as-usual anthropogenic emissions on air quality 1The Abdus Salam International center for Theoretical Physics, Earth System Physics, Trieste, Italy
01 Aug 2012
2Atmospheric Chemistry Department, Max Planck Institute for Chemistry, Mainz, Germany
3European Commission, Joint Research Centre, Ispra, Italy
4Institut für Physik der Atmosphäre, Johannes – Gutenberg Universität Mainz, Mainz, Germany
5The Cyprus Institute, Energy, Environment and Water Research Center, Nicosia, Cyprus
6King Saud University, Riyadh, Saudi Arabia
*now at: Öko-Institut e.V., Berlin, Germany
**now at: Air and climate change-mitigation, European Environment Agency, Copenhagen, Denmark
Received: 22 Mar 2012 – Published in Atmos. Chem. Phys. Discuss.: 05 Apr 2012Abstract. The atmospheric chemistry general circulation model EMAC has been used to
estimate the impact of anthropogenic emission changes on global and regional
air quality in recent and future years (2005, 2010, 2025 and 2050). The
emission scenario assumes that population and economic growth largely
determine energy and food consumption and consequent pollution sources with
the current technologies ("business as usual"). This scenario is chosen to
show the effects of not implementing legislation to prevent additional
climate change and growing air pollution, other than what is in place for the
base year 2005, representing a pessimistic (but plausible) future.
Revised: 05 Jul 2012 – Accepted: 11 Jul 2012 – Published: 01 Aug 2012
By comparing with recent observations, it is shown that the model reproduces
the main features of regional air pollution distributions though with some
imprecisions inherent to the coarse horizontal resolution (~100 km)
and simplified bottom-up emission input.
To identify possible future hot spots of poor air quality, a multi pollutant
index (MPI), suited for global model output, has been applied. It appears
that East and South Asia and the Middle East represent such hotspots due to
very high pollutant concentrations, while a general increase of MPIs is
observed in all populated regions in the Northern Hemisphere. In East Asia a
range of pollutant gases and fine particulate matter (PM2.5) is
projected to reach very high levels from 2005 onward, while in South Asia air
pollution, including ozone, will grow rapidly towards the middle of the
century. Around the Persian Gulf, where natural PM2.5 concentrations are
already high (desert dust), ozone levels are expected to increase strongly.
The population weighted MPI (PW-MPI), which combines demographic and pollutant
concentration projections, shows that a rapidly increasing number of people
worldwide will experience reduced air quality during the first half of the
21st century. Following this business as usual scenario, it is projected that
air quality for the global average citizen in 2050 would be almost comparable
to that for the average citizen in East Asia in the year 2005, which
underscores the need to pursue emission reductions.
Citation: Pozzer, A., Zimmermann, P., Doering, U.M., van Aardenne, J., Tost, H., Dentener, F., Janssens-Maenhout, G., and Lelieveld, J.: Effects of business-as-usual anthropogenic emissions on air quality, Atmos. Chem. Phys., 12, 6915-6937, doi:10.5194/acp-12-6915-2012, 2012.