Terry J. Keating, Ph.D. Office of Air & Radiation U.S. Environmental Protection Agency International Transport of Air Pollutants (ITAP)

Animation of CO Concentrations Observed by NASA’s MOPITT/TERRA

What have we learned about International Transport? While most air quality problems are due to local or regional sources, the U.S. is both an importer and exporter of air pollution.

Transboundary flow can be important during exceedances of the NAAQS, as well as during exceedances of Canadian & Mexican policy objectives. Transboundary Flows with Canada & Mexico What do we know? Major emissions sources have been located along both borders, and new sources continue to be built. SO 2 Ann Emiss, BRAVO

What do we know? Some of the most dramatic examples of international transport are not anthropogenic. On July 8, 2002, forest fires in Quebec created a smoke plume that blanketed the U.S. East Coast. [NASA MODIS image]

In May 1998, fires in Central America create a smoke plume across the central U.S. Imports from Central America Flows from Central America carry smoke, as well as other pollutants, including pesticides. Pesticide use per acre in Central America exceeds the US by a factor of 10. What do we know? GOES-8 Satellite Image, CIMSS Univ of Wisconsin

Dust, metals, and other pollutants are transported from North Africa across the Atlantic to the Caribbean and the Southeastern U.S. Saharan Dust over Miami = 10 – 100  g/m 3 24 hr PM NAAQS = 65  g/m 3 PM  g/m 3 PM 10 [Prospero 1999] [Prospero 1999] Pathogens in Saharan Dust have been linked to coral decline in the Caribbean. [Shinn et al 2000] Imports from Africa What do we know?

The U.S. exports ozone precursors, mercury, and other pollutants to the North Atlantic. The impact on attainment of European policy objectives may be significant. Days predicted to exceed the EU ozone standard that would not exceed the standard in the absence of North American emissions. [Li et al., 2001] Exports to Europe What do we know?

Imports to Alaska & Arctic Mercury, POPs, and other pollutants are carried into the Arctic, by circulation patterns and “global distillation.” Air Transport Pathways Arctic Air Mass In Summer and Winter [Crane & Galasso, 1999] What do we know?

Mercury Deposition ~40% of all Hg deposition to the lower 48 states comes from emission sources outside the U.S. or from U.S. emissions that have been transported across international boundaries Global mercury emissions inventory for 1995 (provided by AMAP) Emissions distribution Contribution of different continents What do we know? [EPA, 1997] From Travnikov, EMEP MSC-E

Dust from Chinese Deserts, fossil fuel emissions, and other pollutants travel across the Pacific and impact the Western U.S. Imports from Asia What do we know? [Aerosol Index, NASA TOMS] World Energy Use [EIA, 2002] Emissions in Asia are expected to grow with further economic development, offsetting emissions decreases in the United States.

Simulated increase in mean U.S. surface ozone (ppbv) from tripling of Asian emissions (1985 to 2015). Future ozone impacts could be enough to offset the benefits of 25% decrease in U.S. emissions! Jacob et al. [1999] Imports from Asia What do we know?

The Tightening Vise Implications for the U.S.? Ozone concentration HistoricalFuture (alternate view) Hemispheric background Regional Local Standard Future From Keating, West, and Farrell (in press)

IPCC-SRES global emission trends vs. national medium- term projections NO x VOC CO SO 2 Implications for the U.S.? From Markus Amann, IIASA What will future emissions be?

The International Challenge For EPA to achieve it’s own strategic goals and objectives, we need to: –develop a better understanding of the impact of other countries on the US –develop a better understanding of the impact of the US on other countries –help reduce these pollution sources through cost-effective appropriate technology, recognizing linkages between pollution problems Implications for the U.S.?

The End

Improving Our Understanding EPA ITAP Working GroupEPA ITAP Working Group What are we doing?

Improving Our Understanding EPA ITAP Working GroupEPA ITAP Working Group International and National Scientific WorkshopsInternational and National Scientific WorkshopsIncluding: Trans-Pacific Transport, Seattle, July 2000 Trans-Atlantic Transport, New York, June 2001 Hemispheric Transport, Germany, Oct 2002 What are we doing?

Improving Our Understanding EPA ITAP Working GroupEPA ITAP Working Group International and National Scientific WorkshopsInternational and National Scientific Workshops OIA-ORD Speciated Mercury MonitoringOIA-ORD Speciated Mercury Monitoring Including: Including: Cheeka Peak, Washington Barrow, Alaska Mauna Loa, Hawaii What are we doing?

Improving Our Understanding EPA ITAP Working GroupEPA ITAP Working Group International and National Scientific WorkshopsInternational and National Scientific Workshops OIA & ORD Speciated Mercury MonitoringOIA & ORD Speciated Mercury Monitoring OAR/OAQPS Collaboration with NASAOAR/OAQPS Collaboration with NASA What are we doing?

Improving Our Understanding EPA ITAP Working GroupEPA ITAP Working Group International and National Scientific WorkshopsInternational and National Scientific Workshops OIA & ORD Speciated Mercury MonitoringOIA & ORD Speciated Mercury Monitoring OAR/OAQPS Collaboration with NASAOAR/OAQPS Collaboration with NASA OAR/OAQPS Intercontinental transport and Climatic effects of Air Pollutants (ICAP) ProjectOAR/OAQPS Intercontinental transport and Climatic effects of Air Pollutants (ICAP) Project What are we doing?

Intercontinental Transport & Climatic Effects Global Modeling of Ozone and Related OxidantsGlobal Modeling of Ozone and Related Oxidants –Jacob, Harvard Univ Global and Regional Climate Impact of AerosolsGlobal and Regional Climate Impact of Aerosols –Jacobson, Stanford Univ Emission Inventories for Climate-Forcing PollutantsEmission Inventories for Climate-Forcing Pollutants –Streets, Argonne National Lab Modeling of Trans-Pacific TransportModeling of Trans-Pacific Transport –Hanna, Carolina Environmental Programs What are we doing?