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