Effect Measure

Ozone from China

It used to be my job to teach the environmental health survey course for public health students and air pollution was a topic I spent a lot of time on because it interested me and intersected some of my research work. One of the things I taught my students was that some air pollutants were very local — carbon monoxide (CO) being a good example; levels of CO on one side of the street could vary significantly from those on the other side by virtue of traffic patterns or street canyon effects — while others were considered regional pollutants. Ozone (O3) was my example of choice. It isn’t emitted by sources by formed as a secondary pollutant via chemical reactions in the atmosphere from chemical precursors like volatile organics and nitrogen oxides (juiced with sunlight) which were emitted by sources (primary pollutants). Thus ozone was an area-wide pollutant with not as much spatial variation, although there was a paradoxical suburban-rural high ozone effect caused by additional reactions of high precursors in the city “eating up” some of the ozone they had produced, leaving a relatively lower ozone level. It turns out my former teaching didn’t go far enough in its areal reach. A new paper in Nature suggests that a significant proportion of background ozone in the lower levels of the atmosphere may be a result of long range transport from East Asia, especially China:

?In springtime, pollution from across the hemisphere, not nearby sources, contributes to the ozone increases above western North America,? said lead author Owen R. Cooper, Ph.D., of the NOAA-funded Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder. ?When air is transported from a broad region of south and east Asia, the trend is largest.?

[snip]

Cooper and colleagues from NOAA?s Earth System Research Laboratory in Boulder, Colo., and eight other research institutes used historical data of global atmospheric wind records and sophisticated computer modeling to match each ozone measurement with air-flow patterns for several days before it was recorded. This approach essentially let the scientists track ozone-producing emissions back to a broad region of origin.

[snip]

When the dominant airflow came from south and east Asia, the scientists saw the largest increases in ozone measurements. When airflow patterns were not directly from Asia, ozone still increased but at a lower rate, indicating the possibility that emissions from other places could be contributing to the ozone increases above North America. The study used springtime ozone measurements because previous studies have shown that air transport from Asia to North America is strongest in spring, making it easier to discern possible effects of distant pollution on the North American ozone trends. (NOAA Press release; I also read the paper, but the press release is more comprehensible and clearer; Cooper et al., Increasing springtime ozone mixing ratios in the free
troposphere over western North America, Nature Vol 463| 21 January 2010| doi:10.1038/nature08708)

Just so there’s no confusion, ozone in the lower layer of the atmosphere, where we live, is bad. It’s not only a greenhouse gas, but it damages the lungs and vegetation and crops. Ozone is the primary constituent of photochemical oxidant pollution, otherwise known as “smog.” Ozone in the next layer of the atmosphere (the stratosphere) is good for human health because it absorbs higher frequency ultraviolet light that might otherwise damage human health. This is why we are worried about the “ozone hole” in the stratosphere. So ozone is “good” up there, “bad” down here, where we are.

This study is still preliminary and doesn’t quantify the contribution from across the Pacific. But it does show once again how tightly interconnected we are. Ozone precursors and hence ozone production are decreasing in the US and western Europe, but a rapidly industrializing East and South Asia could potentially cancel out the benefits. The rest of the world is now returning the favor we did them when we were industrializing.

What goes around, comes around. And around. And around.

Comments

  1. #1 Balk Onyx
    January 25, 2010

    . Ozone precursors and hence ozone production are decreasing in the US and western Europe, but a rapidly industrializing East and South Asia could potentially cancel out the benefits.

    How much of those “benefits” are accounted for by Western companies relocating their pollution-heavy facilities to poorer nations?

    What goes around indeed.

  2. #2 M. Randolph Kruger
    January 25, 2010

    Well Revere, you got this one pegged. Screw the Co2 bubba its the CO thats being transported thats more important. You remember Mary H? She was amazed at the satellite pictures that I sent to her that tracked CO across the oceans. Neither Alaska or Hawaii pass the Clean Air Act standards in the wintertime from that transport, much less California or even Tennessee. It is attributed to incomplete combustion of village level coal. That may or may not be true but for years you have heard me say it but now you are confirming just that fact. The atmosphere is lousy with the stuff and its like smoking 2 packs a day for airline pilots on the North Pac routes. Ozone takes a long time to migrate upwards but CO moves quickly.

    The US and the EU are less than a 10th of world pollution in the C areas because we have cut and cut and cut some more. The idea is that by cutting coal fired plants we would clean up the air. Yeah, well maybe minimally. There is no clean coal but if we could rebuild the existing coal plants to newer standards we might with scrubber technology be able to knock the crap out of the emissions from ours too. The Chinese? Forget it.

    A local environmental realist who went to China told me that there is NO way for the Chinese to change this in even 10 generations. The cost to the US is and will be huge for this masturbation session of wind and solar conversion, its a lie and they know it. They still have to have a wind farm the size of Colorado to power a city the size of New York for its daytime uses. But its all about the money and even he said that by mandate the Chinese wouldnt be able to inside of those 10 generations to pull it off because there are no real alternatives to them. He actually said that he feared the Chinese because they shortly will run out of available energy sources and that it would lead to more nuke plants or a stab for resources in the Persian Gulf. The latter he said was the most likely thing to occur. The logic was that it takes years to build a proper nuke plant, but would only take weeks to gain control of oil fields. Especially if the Iranians were providing support.

    I also would say that based on the MODIS satellites 10 year run now that the effects of our cuts were long ago surpassed by the Asian increases.

  3. #3 revere
    January 26, 2010

    Randy: I am confirming nothing about your contentions. My point was much different. CO varies dramatically from place to place, even within the space of 10 yards. Photochemical oxidants don’t, They tend to be area-wide pollutants. That’s all I was saying. You read far too much into it.

  4. #4 anon
    January 29, 2010

    ozone in the lower layer is also bad for flu-viruses
    while ozone in upper layer is also good for them.
    is there a connection between ozone and flu-season ?
    or ozone and death-rates ?
    can we please get computer-readable time-series of
    ozone concentration to test this ?
    Or is it copyright