The Atmosphere Doesn’t Recognize Borders

In addition to revealing how pollution levels can change in certain areas over time, satellites have played a key role in showing how pollutants can travel from one part of the globe to another. While pollutants disperse over time and can be removed from the atmosphere by rain and other meteorological processes, satellites have occasionally observed giant rivers of pollution persisting for weeks and streaming from one continent to another. In recent years, most of these rivers had sources in Asia, flowing east across the Pacific to western North America. But satellites have also observed pollution wafting from North America to Europe, and from Europe to North Africa and Asia.

“These lines we draw on a map that separate us do not exist,” said Anousheh Ansari, an Iranian-American tourist who spent nine days on the International Space Station in 2006. “The Earth is moving all the time. There is nothing that stays constant, and there is no way you can contain a problem. The problem on the other side of the world will eventually spread.”

Satellite view of the Eastern Hemisphere showing pollution travelling between countires.
Once pollution enters the atmosphere, it is spread by the prevailing winds, without regard for borders. (NASA image by Robert Simmon, using data from the NOAA Environmental Visualization Laboratory.)

In 2014, a team of researchers began to quantify the connection. While it’s well known that significant amounts of dust and pollution from China end up over the United States, the researchers wanted to determine how much of that pollution from China has its origins in the demand for goods from the United States. They concluded that a significant amount—between three and ten percent—of sulfate pollution in the western United States is the result of export-related pollution from China.

“We’ve outsourced our manufacturing and much of our pollution, but some of it is blowing back across the Pacific to haunt us,” said Steven Davis, a University of California earth scientist and co-author of the study. “Given the complaints about how Chinese pollution is corrupting other countries’ air, this paper shows that there may be plenty of blame to go around.”

NASA Earth Observatory would like to thank the following people for providing content and science reviews: Ginger Butcher, Steven Davis, Bryan Duncan, Jack Fishman, Ralph Kahn, Nickolay Krotkov, Rudolf Husar, Zifeng Lu, Randall Martin, and William Morgan.

  1. References

  2. Amann, M. et al. (2013, October) Regional and Global Emissions of Air Pollutants: Recent Trends and Future Scenarios. Annual Reviews, 38, 31-35.
  3. Chin, M. et al. (2014) Multi-decadal aerosol variations from 1980 to 2009: a perspective from observations and a global model. Atmospheric Chemistry and Physics, 14, 3657–3690.
  4. Chow, J. et al. (2007, October) Will the Circle Be Unbroken: A History of the U.S. National Ambient Air Quality Standards. Journal of the Air & Waste Management Association, 57 (10).
  5. Duncan, B. et al. (2013, December) The observed response of Ozone Monitoring Instrument (OMI) NO2columns to NOxemission controls on power plants in the United States: 2005–2011. Atmospheric Environment, 81, 102–111.
  6. Davidson, C. (2012, March 13) Air Pollution in Pittsburgh: A Historical Perspective. Journal of the Air Pollution Control Association, 29 (10), 1035-1041.
  7. Fett, R. & Isaacs, R. (1979, October) Concerning Causes of “Anomalous Gray Shades” in DMSP visible imagery. Journal of Applied Meterology, 18 (10), 1340-1351.
  8. Fishman, J. et al. (1990, March 20) Distribution of tropospheric ozone determined from satellite data. Journal of Geophysical Research, 95 (D4), 3599-3617.
  9. Fioletov, V. et al. (2011, November 11) Estimation of SO2 emissions using OMI retrievals. Geophysical Research Letters, 38 (21), 1811.
  10. Environmental Protection Agency (1979, October) Protecting Visibility: An EPA Report to Congress. Accessed March 25, 2014.
  11. Fishman, J. et al. (2008, June) Remote Sensing of Tropospheric Pollution from Space. Bulletin of the American Meterological Society, 89 (6), 805-821.
  12. Hilboll, A. et al. (2013, April 18 ) Long-term changes of tropospheric NO2over megacities derived from multiple satellite instruments. Atmospheric Chemistry and Physics, 13, 4145-4169.
  13. Hsu, N.C. et al. (2012, March 29) Global and regional trends of aerosol optical depth over land and ocean using SeaWiFS measurements from 1997 to 2010, Atmospheric Chemistry and Physics, 12, 8037-8053.
  14. Husar, R. & White, W. (1975, July 15) On the Color of the Los Angeles Smog. Atmospheric Environment, 10, 199-204.
  15. Husar, R. et al. (2011, July 7) Satellite-Based Measurement of Atmospheric Aerosols. Aerosol Measurement Principles, Techniques, and Applications.
  16. Hyslop, N. (2009, January) Impaired visibility: the air pollution people see. Atmospheric Environment, 43 (1), 182-195.
  17. Itashi, S. et al. (2011) Up/Down trend in the MODIS Aerosol Optical Depth and its relationship to the Sulfur Dioxide Emission Changes in China during 2000 and 2010. Atmospheric Chemistry and Physics Discussions, 11, 21971-21993.
  18. Li, C. et al. (2010, April 29) Recent large reduction in sulfur dioxide emissions from Chinese power plants observed by the Ozone Monitoring Instrument. Geophysical Research Letters, 37 (8).
  19. Li, C. et al. (2013, December 16) A fast and sensitive new satellite SO2 retrieval algorithm based on principal component analysis: Application to the ozone monitoring instrument. Geophysical Research Letters, 40 (23), 6314–6318.
  20. Lin, C. et al. (2012, February 17) Transport of Asian ozone pollution into surface air over the western United States in spring. Journal of Geophysical Research Atmospheres, 117 (16).
  21. Lin, J. et al. (2014, January 21) China’s international trade and air pollution in the United States. PNAS, 111 (5), 1736-1741.
  22. Lu, Z. et al. (2013, November 25) Ozone Monitoring Instrument Observations of Interannual Increases in SO2 Emissions from Indian Coal-Fired Power Plants during 2005−2012. Environmental Science & Technology, 47 (24), 13993-14000.
  23. McLinden, C. et al. (2012, February) Air quality over the Canadian oil sands: A first assessment using satellite observations. Geophysical Research Letters, 39 (4).
  24. Martin, R. (2008, November) Satellite remote sensing of surface air quality. Atmospheric Environment, 42 (34), 7823-7843.
  25. Monks, P. et al. (2009, October) Atmospheric composition change—global and regional air quality. Atmospheric Environment, 5268-5350.
  26. Parrish, D. et al. (2011, December) Air quality progress in North American megacities: A review. Atmospheric Environment, 45 (39), 7015-7025.
  27. Poole, R. (2010, February 23) Earthrise: How Man First Saw the Earth (New Haven, CT: Yale University Press)
  28. Randerson, D. et al. (1968) A Study of Air Pollution Sources As Viewed by Earth Satellites. Journal of the Air Pollution Control Association, 18 (4) 249-253.
  29. U.S. Forest Service Interpreting Visibility Data. Accessed March 25, 2014.
  30. U.S. Forest Service US Forest Services Causes of Poor Visibility. Accessed March 25, 2014.
  31. Worden, H.M. et al (2012, September 28) Decadal record of satellite carbon monoxide observations, Atmospheric Chemistry and Physics, 13, 839-850.
  32. Yang, K et al. (2013, September 19) First observations of SO2 from the satellite Suomi NPP OMPS: Widespread air pollution events over China. Geophysical Research Letters, 40 (18), 4957-4962.