Global and Local Dust/Smoke over the US
Rudolf HusarWashington University
EPA Science Advisory Board Science Workshop, Dc. 11, 2003
Emerging Scientific Topics: Transboundary Air Pollutants
Local, Regional, Global Pollution
Before 1950s:
LocalSmoke, Fly ash
Post- 2000s:
GlobalGlobal Change
1970s-1990s:
RegionalAcid Rain, Haze
Industrial Sulfur Emission Density
US SOx Emission Trend
Industrial Sulfur Emissions Hotspots:
E. North America
Europe and
E. Asia
The US and European S Emissions have declined since the ’70s
Within the next generation S will likely approach the natural levels
Regional Haze Rule:Transition Toward a Sustainable Air Quality
Goal of RH Rule: To attain ‘natural conditions’ by 2064
Global Pollution
Windblown Dust
Industrial Aerosols
Major Scientific Issues:
What is the Natural Condition?
How do manmade and natural emissions compare now?
How do humans perturb natural processes?
Biomass Smoke
Main ‘Global’ Air Pollutants:
•Particulate Matter: Dust, Smoke, Haze
• Ozone and Precursors
Steady, Seasonal
Sporadic, Seasonal
Global (Satellite) Sensing Revolution in the 1990s
Aerosol Optical Depth (AVHRR)
Global-scale air pollutant transport existed since….The difference is that now we can observe and document it
The new data show that the global aerosol pattern is dominated by dust and smoke.
Global Fire Locations August, January
May 15, 1998Smoke from Central American Fires
• Smoke is detected by SeaWiFS and TOMS (green) satellites and surface visibility data, Bext
•The smoke plume extends from Guatemala to Hudson May in Canada
PM10 Concentrations During the Smoke Event
A füstfelhő útjában mindehol a megengedett érték feletti aeroszol koncentrációt okozott, és a levegő homályossága gátolta a légiforgalmat
May-June 2003 Siberian Fires
Aircraft Detection of Siberian Forrest Smoke near Seattle, WA
Jaffe et. al., 2003
Asian Dust Cloud over N. America, April 1998
On April 27, 1998 the dust cloud arrived in North America.
Regional average PM10 concentrations increased to 65 g/m3
In Washington State, PM10 concentrations exceeded 100 g/m3
Asian Dust 100 g/m3
Hourly PM10
Korea
Mongolia
China
The Perfect Dust StormApril 7, 2001
Sahara Dust TransportSupporting Evidence: Satellite & PM10 Data
SeaWiFS satellite shows Sahara Dust reaching Gulf of Mexico
June 30, 1993
July 5, 1992
June 21 1997
> 80 g/m3
Origin of Fine Dust Events over the US
Sulfate is local, no major spikes
Gobi dust transport in springSahara dust import in summer
Spikes of fine dust over the entire US are mainly from intercontinental transport
The Perfect Dust Storm
Summary
• Global Sensing – Modeling Revolution – ‘May you live in interesting times’– We are in the midst of an observational revolution (satellites, monitoring networks).
– The global distribution and transport of some pollutants can be monitored daily
– Global models are also maturing into effective analytical and predictive tools
• Results to Date: – Compelling evidence for significant global-scale transport of PM and Ozone
– Qualitative estimates of ‘extra-jurisdictional’ impact on the US air quality– There is good potential for quantification of natural and non-US impacts
The science community is vigorously pursuing global pollutant transport
It seems timely to incorporate global air pollutant transport into AQ management processes as well
Thank You
Challenge 21: Science – Management Link
Sensing and recognition (monitoring)
Reasoning and explaining (sciences)
Decision making, action (management)
Sustainable Development in an ever-changing world:Sensory-Motor Loop:
Sahara and Local Dust Apportionment
• The maximum annual Sahara dust contribution is about 1 g.m3
• In July the Sahara dust contributions are 4-8 g.m3
Annual
July
Vertical Distribution of Aerosols – Space-borne Lidar
• Long rang transport occurs mostly in elevated layers
• Elevated layers mix with BL air
• Cloud interaction is clearly discernable
Winker et., al. 1995
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