East Asian air pollution to have bigger global impact under climate

East Asian air pollution to have bigger global
impact under climate change
29 January 2015
Issue 401
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Source: Glotfelty, T.,
Zhang, Y., Karamchandani,
P., & Streets, D.G. (2014).
Will the role of
intercontinental transport
change in a changing
climate? Atmospheric
Chemistry and Physics
14(17): 9379–9402.
DOI:10.5194/acp-149379-2014. This study is
free to view at:
[email protected]
Read more about:
Air pollution, Climate
change and energy
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1.Liu, J., Mauzerall, D.L., &
Horowitz, L.W. (2009).
Evaluating inter-continental
transport of fine aerosols:(2)
Global health impact.
Atmospheric Environment
43(28): 4339–4347.
Greater amounts of air pollutants emitted in East Asia will move around the
globe under climate change, a recent study predicts. Changes to wind speeds and
air pressure will mean that movement of pollution from this region is enhanced
under a changing climate. These results highlight the need for globally coordinated
efforts to tackle air pollution and climate change.
Long-range transport of air pollution between continents means pollutants can have
negative effects on human health and ecosystems far from their sources. For example, an
earlier study1 estimated that intercontinental transport of fine aerosols was responsible for
90 000 premature deaths around the world in 2000.
This study focused on the transport of pollution from East Asia, the most significant source
of intercontinental pollution in the Northern Hemisphere. Its location, at lower latitudes,
means that pollution emitted here can move more easily around the globe, compared with
North American and European emissions.
The researchers estimated changes in intercontinental transport of a large range of
pollutants from East Asia between 2001 and 2050. They were interested in how climate
change would affect atmospheric processes and thus the contribution of East Asian
emissions to air pollution in other regions.
The model used combines meteorological processes and atmospheric chemistry and allows
simulation of the trends of climate change every 10 years throughout the 50 year period.
Simulations under different emission and climate scenarios for spring 2001 and 2050 were
performed to characterise changes in intercontinental transport of emissions in a changing
climate. They assumed that climate change would progress as per the IPCC’s A1B scenario,
which assumes rapid economic and population growth up until the mid 21 st century.
Key results include projected rises in global average levels of tropospheric ozone and PM 2.5.
Ozone from East Asia will add an additional 0.8 parts per billion (ppb) to global average
levels, going from 1.2 ppb in 2001 to 2.0 ppb in 2050, the model suggests. Average PM 2.5
concentrations could also increase from 0.32 micrograms per cubic metre (µg/m3) in 2001,
to 0.39 µg/m3 in 2050.
Other pollutants from East Asia that are also predicted to rise around the world include
carbon monoxide, sulphur dioxide and peroxyacetyl nitrate. More mercury and black carbon
from the region could also be deposited in other parts of the world.
There are two major atmospheric pathways for pollution from East Asia. One transports
emissions up to the Arctic, and the other takes them west to North America. As a result,
these two regions are particularly affected by East Asian pollution, and climate change will
increase these flows, according to the study.
A North Pacific area of low pressure, known as the Aleutian Low, is expected to become
stronger by 2050. This will lead to greater circulation of air that transports more pollution
from East Asia to the Arctic. In addition, wind speeds over East Asia will become quicker,
taking pollution towards North America more quickly.
The study’s authors say these results demonstrate the need for governments around the
world to collaborate in developing integrated, collaborative emission control strategies.
These should consider the complex relationship between air pollutants and climate change.