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Intercontinental scale transport of air pollution. John Murlis Department of Geography University College London Based on a presentation by Henning Rodhe Stockholm University. Overview. Pollution acts on a wide range of scales Impacts vary across scales - PowerPoint PPT Presentation
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Intercontinental scaletransport of air pollution
John MurlisDepartment of GeographyUniversity College London
Based on a presentation by Henning RodheStockholm University
Overview
• Pollution acts on a wide range of scales• Impacts vary across scales• Management regimes developed, but gaps remain• Evidence for impacts on different scales:
– Acidification/Eutrophication
– Ozone
– Aerosols/Particulate matter
• Conclusions
Pollution Acts on a Range of Scales
• Local
• Regional
• Intercontinental/Hemispheric
• Global
The Great London Smog
Disaster, 1952
Regional scale pollutantsLifetime days to weeks
Components related to - Acidification (SOx, NOx, NHx)- Eutrophication (NOx, NHx) and- Aerosol formation (SOx, NOx,
NHx, Carbon compounds)Particulate matter
Regional air pollutionWhat are the issues?
• Acidification: soil chemistry, lake ecology (SOx, NOx, NHx)
• Eutrophication: algal blooms, biodiversity (NOx, NHx)
• Excess ozone: health, vegetation, climate (NOx, VOC, CO)
• Aerosols: health, climate (SOx, NOx, NHx, VOC,..)
• Corrosion (SOx, H+, O3, NOx, )• Toxic species (Hg, Pb, Cs-137, PCB …)
Continental and hemispheric scale
pollutants
Life time weeks to months
Tropospheric ozoneand its precursors(NOx, VOC, CO..)
Particulate Matter?
Daniel Jacob, 2002
Huntzinger &Schlager 2004
North America CO over Germany
Model calculations by Derwent et al. 2002
Origins of model ozone at Mace Head, Ireland
Global scale pollutants
Lifetime > years
* Longlived greenhouse gasesand ozone depleting substances: CO2, CH4, N2O, CFCs,..
* Stratospheric aerosols * Mercury
Keating et al., 2004
Evolution of the perceived spatial scale of air pollution problems in the US
Regional/Hemispheric Scale
• Acidification and Eutrophication
• Sulphur and Nitrogen
Soil sensitivity to acid deposition
Kuylenstierna et al. Ambio 2001
Terrestria l E co system S en sitivity to A cid ic D ep o sitio n in So u th A sia
S ource : K uylenstie rna et a l. 200 1
Simplified model of precipitation acidity:
[H+] = [SO42-] + [NO3
-] - [NH4+] -
[Ca2+]
When [H+] > 0: ‘real’ [H+]
When [H+] < 0: [HCO3-]
Number of years to deplete base cations in soil
NE India 150 (40 – 220)
Malaysia 110 (40 – 160)
S China 17 (6 – 35)
Hicks et al. 2004
Sulfur
Continental scale transport of man-made sulfur
Tarrason & Iversen, 1998
European sources North American sources
Magnuz EngardtSMHISwedenPers. com.
Sulfur deposition
MATCH model calculations (RAPIDC)by Magnuz Engardt, SMHI, Sweden
Oxidized sulfur
Estimates of S depositionEmissions only from Andra Pradesh, Kamataka, Goa
Nitrogen
MATCH model calculations (RAPIDC)by Magnuz Engardt, SMHI, Sweden
Oxidized sulfur Oxidized nitrogen
Estimates of S and N depositionEmissions only from Andra Pradesh, Kamataka, Goa
S and N
Future Emissions?
Global SO2 emission scenarios (SRES)Tg S/yr
1990 2010 2030 2050 2070 2090
120
60
180
Nakicenovic et al. 2000
2000 2005 2010 2015 2020 2025 2030
Emissions of SO2 from land-based sourcesin the 25 EU countries and from internationalshipping in European sea areas
IPCC Special Report on Emissions Scenarios
NOx
N America
Europe
FSU China
E Asia
S Asia
Conclusions on S and N(Acidification and Eutrophication
Intercontinental transport does occur but how significant is it?
UNECE Task force will assess for N Northern Hemisphere
Ozone
From Wild et al.JGR June 2004
Contributions to ozone over Japanfrom Europe, US,East Asia and Japan
Total
European
N American
E Asian
Local
Estimate of a possible increase in surface ozone2000 to 2100
Prather et al. GRL 2003
Keating et al.2004
Conclusions on ozone
*Potential for large increase of ozone levels in many tropical and subtropical countries (China, India, Africa) as NOx emissions go up
* Ozone and its precursors (CO, VOC, NOx) subject to substantial intercontinental transport
* N H background of ozone may reach standardvalues set for health during this century
Aerosols
Pollution haze over NE India and the Bay of Bengal
December 2004
Brown haze over Nepal, UNEP ABC Assessment report 2002
Aerosol optical depth over ChinaAugust 2004
MODIS satellite data
Fig. 5. Simulated (top) and obs
Extinction of sunlightdue to aerosols in China
Observations - JJA
Model - JJA
Qian et al. Tellus B 2003
N of ITCZS of ITCZ
Total
NSS-sulfate
Ammonium
Potassium
Norman et al. 2003
Aerosol componentsin surface airduring ABC
Calcium
Sea salt
Trans-Pacific transport path of Asian dust to North America in April 1998
Cloud forcing dueto sulfate aerosols
Temperatureresponse
Ekman & Rodhe, 2003
Conclusions on aerosols
Intercontinental scale transport doesoccur (episodically) but how
significant as a driver of control strategy ?
1. Aerosols and health: urban & regional
2. Aerosols and climate: global (interactionswith radiation and with clouds)
3. Tropospheric ozone: regional/hemispheric(agriculture, health)
3. N, S: regional/hemispheric (Acidification/eutrophication)
A subjective expert ”concern list” of air pollution issues at different scales:
Prospects for the future
- Sulfur emissions:up in China, India ..down in Europe, US ..global total up - or down
- NOx: up in many developing countries- NH3:?- Ca: probably down
Conclusions• Transport on a Regional/Hemispheric Scale
established for wide range of air pollutants• Further work needed to establish full significance• At this stage, most concern about tropospheric
ozone• Some concern about pm/aerosol• N and S Significant but regional transport still
dominates• As local and regional pollution comes under
control, longer range transport will be more significant
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