# Presentation: 789133

## Long-Range Transport of Air Pollution  

**Terry J. Keating & Jason West**
**Office of Air & Radiation**
**U.S. EPA**

**Long-Range Transport ****of Air Pollution  **

**Notes:**
John Beale:

We’re here to talk about the International Transport of Air Pollutants or ITAP.  

We believe that this is a very important issue that is looming on the horizon and will continue to grow in importance.  We believe that we need to begin taking a hard look at how we, as an Agency, are going to respond to this issue.  

Two years ago, (in May 2000), OAR and OIA invited all the other offices in the Agency to participate in an ITAP Working Group, to explore 
	what we know about international transport
	what we are doing about it currently
	what we need to do about it in the future.

The group has participants from almost all Offices and many Regions.

## Overview

**What do we know about atmospheric transport of air pollution across nations and continents and seas?**
**What are the implications of this long range air transport for U.S. and global environmental quality?**
**What are the implications for global energy systems development and for the role of renewables in future global energy economies?**
**How well are these issues understood, and what additional information or analyses are needed?**

**Notes:**
John Beale:

The purpose of today’s meeting is to:

Provide you with a brief overview of what we know about this phenomenon.

Present the conclusions that this group has come to about what this might mean for the Agency.

 Get your views on how you think we should proceed to address this issue, as an Agency. 

For the first part of the presentation, I’m going to turn the floor over to Terry Keating, who is one of the co-chairs of the ITAP Working Group.  

After we run through the presentation, OIA and ORD (and any other offices represented) will provide additional comments.    

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

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

***What do we know?***

**Notes:**
This animation shows data from the first global measurements of CO.  The data was gathered by MOPITT, a Canadian instrument, flying on NASA’s Terra satellite.  

In the Spring, you can see large plumes of CO leaving Asia and impacting the US, as well as plumes coming off the coast of Africa.
In Summer, you can see a large plume of CO from India and SE Asia, pollution events in Mexico City and the Northeast US, and forest fires in Canada and Russia.
In the Fall, you can see the impact of biomass burning in equatorial South America and Africa.

## What do we know?

**Asia**

**N. America**

**Europe**

**PBL**

**Free troposphere**

**WCB**

**subsidence**

**boundary layer advection**

**Tropopause**

**HEMISPHERIC POLLUTION BACKGROUND**

**“****Direct”**
**intercontinental**
**transport**

**Mixing**

- From Daniel Jacob

***What do we know?***

**A variety of pollutants are transported long distances.**
**	****(Hg, POPs, O****3****, particles, reactive N, pathogens, radioactivity)**
**Transport affects air quality through discrete events and through increases in the hemispheric or global burden.**
**Mechanisms for transport depend on pollutant characteristics.**

**Notes:**
Daniel Jacob

## Dust storms and fires provide examples of discrete transport events.

**On April 16, 1998, a huge dust cloud formed over China and was pushed eastward by a frontal system ....**

**[NASA SeaWIFS]**

***What do we know?***

**...****. nine days later, some of the dust reached the California coastline.**

## GOES Satellite Image

**During the April 98 Dust Event, regional average PM10 levels reached 65 μg/m****3 ****compared to typical values of 10-25 μg/m****3****.  On April 29, the PM10 exceeded 100 μg/m****3**** over parts of Washington and Oregon**

***What do we know?***

**Events can be detected in satellite imagery and surface monitoring networks.**

**IMPROVE Observations**

## Historical records suggest a large increase in “background” O3 due to anthropogenic activity.  Recent observations confirm an increasing trend.

**Ozone trend at European mountain sites, 1870-1990 [Marenco et al., 1994]**

***What do we know?***

## Surface O3 Enhancement from Asian Emissions During TRACE-P Predicted by GEOS-CHEM

**Anthropogenic**

**Biomass burning**

**The Asian anthropogenic source contributes significantly to surface ozone in the western U.S.  (mean 2-4 ppbv), while the influence from Asian biomass burning source emissions is negligible.**

**M.J. Evans, Harvard**

- From Daniel Jacob

***What do we know?***

**Models provide useful insights, but “the complexity challenges the limits of our current models.”**

**Notes:**
Daniel Jacob

## While most air quality problems are due to local or regional sources, the U.S. is both an importer and exporter of air pollutants.

***Implications for the U.S.?***

**Notes:**
Notes for Terry Keating:

First of all, I’d like to point out that we’re joined on the phone by my co-chair from OIA, Marilyn Engle, who couldn’t be here today.  

The arrows on this map depict some of the major flows of air pollutants into and out of the United States.

I’m going to quickly describe each of these flows, starting with flows within North America and then working my way around the map counterclockwise.

## Transboundary Flows with Canada & Mexico

**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**

**Major emissions sources have been located along both borders, and new sources continue to be built.**

**SO****2**** Ann Emiss, BRAVO**

***Implications for the U.S.?***

**Notes:**
Pollution flows both ways across our northern and southern borders.  

These flows contribute to exceedances of our ambient air quality standards as well as exceedances of standards in Canada and Mexico.  
The figure on the left shows the average wind pattern on summer days with the highest ozone levels.   You can see significant winds that carry pollutants in Southern Texas and across Southeastern Canada.
(The yellow areas are are the source regions that account for most of the pollutants in several key cities: Houston, Atlanta, Chicago, Columbus, and New York.)
The flows, however, don’t always go north.  You may remember last July’s forest fires in Quebec that literally darkened the sky from New England to DC.     

As the three national economies and energy systems become further integrated, continued development along both borders is an increasingly important source of emissions.   
The figure on the right shows an annual emissions inventory for SO2 developed as part of the BRAVO study, looking at visibility in Big Bend National Park.  Ignoring the tall spike south of Mexico City, which is a volcano, you can see the emissions spike caused by the Mexican power plants, Carbon 1 and 2.

## 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**

***Implications for the U.S.?***

**[EPA, 1997]**

**From Travnikov, EMEP MSC-E**

## Imports to Alaska & Arctic

**Mercury, POPs, and other pollutants are carried into the Arctic, and trapped by circulation patterns**

**Air Transport Pathways**

**Arctic Air Mass**
**In**** ****Summer**** ****and**** ****Winter**

- [Crane & Galasso, 1999]

***Implications for the U.S.?***

**Notes:**
Europe and Asia both contribute to pollution in the Arctic, where mercury and POPs tend to accumulate and pose a health threat to indigenous people and ecosystems.  
Transport into the Arctic is driven by the expansion and contraction of the Arctic Air Mass, which in winter extends down over many parts of industrialized Europe and Asia.   

## The Developing World

**Continued growth in population and energy use is expected in developing countries, especially in Asia.  As emissions increase elsewhere, it will become increasingly difficult to meet objectives here in the U.S.**

**World Energy Use:**
**1970-2020**

- [EIA, 2002]

***Implications for the U.S.?***

## Simulated increase in mean U.S. surface ozone (ppbv) from tripling of Asian emissions (1985 to 2015).

**The ozone impacts of future growth in Asia could be enough to offset the benefits of 25% decrease in U.S. emissions! **

**Jacob et al. [1999]**

***Implications for the U.S.?***

## IPCC-SRES global emission trends vs. national medium-term projections

***Implications for the U.S.?***

**From Markus Amann, IIASA**

**What will future emissions be?**

## International Development and Use of Renewable Energy Sources Will ...

**Change the magnitude, distribution, and characteristics of emissions.**
**What emissions will result from the renewable energy sources and what emissions will these sources displace?**
**What will be the change in chemical composition of emissions?**
**e.g., sulphate v. black carbon**
**What will be the change in the release characteristics of emissions?**
**e.g., tall stacks v. distributed stove pipes**

***Implications for Renewable Energy?***

**Notes:**
After looking at this evidence and doing a survey of activities and interests around the Agency, we’ve come to the following five conclusions:

The U.S. is both an importer and exporter of air pollutants.

## International Development and Use of Renewable Energy Sources Will ...

**Change the magnitude, distribution, and characteristics of emissions.**
**Provide opportunities to decrease multiple pollutants and achieve multiple policy objectives simultaneously.**
**What are the full, life-cycle environmental impacts?**
**Criteria Pollutants, Toxic Pollutants, Greenhouse Gases and Aerosols, Nutrient and Acidifying Deposition****	**
**What are the impacts on other policy objectives?**
**Local Health Impacts, Long Range Transport Impacts, Climate Change, Energy Security**

***Implications for Renewable Energy?***

**Notes:**
After looking at this evidence and doing a survey of activities and interests around the Agency, we’ve come to the following five conclusions:

The U.S. is both an importer and exporter of air pollutants.

## International Development and Use of Renewable Energy Sources Will ...

**Change the magnitude, distribution, and characteristics of emissions.**
**Provide opportunities to decrease multiple pollutants and achieve multiple policy objectives simultaneously.**
**Provide potential cost-effective means of achieving domestic goals.**
**What are the relative costs and benefits of investment in the international development of renewable energy sources versus investment in domestic pollution control? **
**What would be the impact of pursuing pollution control internationally on domestic development of renewable energy sources?**

***Implications for Renewable Energy?***

**Notes:**
After looking at this evidence and doing a survey of activities and interests around the Agency, we’ve come to the following five conclusions:

The U.S. is both an importer and exporter of air pollutants.