Effect Measure

Particulate air pollution is local

Air pollution exists in two physical forms: as a gas (molecules) and as particles (usually heterogeneous agglomerations of huge numbers of molecules stuck together). Particles in the air are also called aerosols. Depending upon their size (really their aerodynamic behavior), their abundance and their composition, they can affect our lungs, vegetation or visibility. They can come from anywhere. Sometimes they are formed “in place” by secondary chemical reactions of precursor pollutants. Photochemical oxidant pollution (“smog”) is of this type. Sometimes it is of natural origin and can be transported over huge distances. Dust storms in Asia can wind up as particulates over the US continent. And sometimes they are of local or regional origin, for example, sent up the stacks of power plants. In fact a new study from NASA (the National Aeronautical and Space Agency) suggests most surface particulates in US air are local:

Researchers using an innovative global aerosol tracking model have for the first time produced a global estimate of sources and movements of aerosols near the ground where they can affect human health and run afoul of environmental regulations. Previously, researchers studying aerosols moving between continents focused primarily on tracking a single type of aerosol, such as dust or black carbon, or measuring their quantities throughout the atmosphere. This left gaps in understanding where ground-level particulate pollution comes from.


[Mian Chin, an atmospheric scientist at NASA’s Goddard Space Flight Center, Greenbelt, Md.] and colleagues estimate that between 65-70 percent of surface particulate matter in the eastern U.S. originates from regional pollution aerosols from fuel combustion in North America. The report was in the Nov. 1 edition of the European Geosciences Union’s Atmospheric Chemistry and Physics.

They also found that 30-40 percent of fine particulates in the western U.S. come from local pollution sources. The model results estimated that just 2-6 percent of U.S. surface fine particulates come from fuel combustion particles emitted outside of North America, including Asia and Europe. About 50 percent of surface fine particulate matter in the western U.S. stems from a natural source: dust transported from Asia or from local deserts and organic aerosols from vegetation. (NASA)

Here’s a pic of haze over the eastern US (Cape Cod, Massachusetts is that thing that looks like a flexed arm at the upper right):


The lesson here is pretty clear. If you want to clear the air (and your lungs), you’ll get the biggest effect from controlling your local and regional air pollution sources, mainly vehicles and large stationary sources like power plants.

We can’t blame anyone on the other side of the planet for this. But you knew that, didn’t you? I mean, really. In your heart you did know that, didn’t you?


  1. #1 llewelly
    November 19, 2007

    I don’t see why you’re making such a big deal about it. Particulate pollution from coal powerplants kills only 60,000 Americans a year. Surely that’s not nearly as bad as Terrorism or the Economy.

  2. #2 Caledonian
    November 19, 2007

    Does the composition of particulate matter, well, matter? I’ve heard that the US is being contaminated with heavy metals – particularly mercury – released from China’s use of coal. More precisely, that most of what contamination exists is the result of China’s coal.

  3. #3 revere
    November 19, 2007

    Caledonian: Yes, it matters. US powerplants are the major sources of mercury in our environment, not China. This study shows that their power plants don’t contribute much. But ours do.

  4. #4 Caledonian
    November 19, 2007

    Thanks, revere. That’s good to know. Well… not ‘good’, but it lets me know where my attention should be focused.

    Has there ever been a concerted effort by healthcare professionals to get the public to look at the consequences of our energy-generation strategies?

  5. #5 revere
    November 19, 2007

    Caledonian: Try Physicians for Social Responsibility. Probably lots more but I’m not remembering them.

  6. #6 Crist Warren
    November 20, 2007

    I’ve been reading up a bit on air pollution, and I’m left wondering whether we should be more concerned about ambient air pollution or air pollution from far off places like China. I know the Adirondacks have been severely affected by sulfur dioxides resulting in acid rain, but Helmut Mayer from the Meteorological Institute, University of Freiburg, in Germany stated that ambient air quality has been associated with high levels of mortality and morbidity in many cities. Could the emissions from local sources be the primary cause of this correlation or is it a combination of both ambient air quality and far off sources such as power plants in developing countries?

  7. #7 revere
    November 20, 2007

    Crist: The relative contributions of local versus distant sources has not been well delineated, which is why this particular work is important. Its conclusion is that the local sources predominate. We will have to see if this conclusion holds up as other data are gathered.

  8. #8 Ashley H
    November 20, 2007

    I researched further into your blog and I found a peer reviewed article that elaborates more on the effects of aersols and other forms of pollution in the environment, and how they adversely affect our health. Aerosols, pollutant gases, and other components such as “organic compounds, aero-allergens, sulfates, and trace metals” have been found to be linked to higher incidences of cardiovascular disease in the United States today.
    I think you make a wonderful point in that we as Americans need to realize that we are providing a lot of the resources that lead to a great deal of the overall pollution that exists in our environment today. The US uses up a ton of resources and creates a ton of pollution. Americans need to step back and realize that before it is too late.

    “Study Investigates Association of Air Pollution and Health Effects.” Journal of Environmental Health 63.6 (Jan 2001): 42. Health Reference Center Academic. Gale. Potsdam Libraries – SUNY. 20 Nov. 2007
    < http://find.galegroup.com/itx/start.do?prodId=HRCA>.

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