Two new studies: One amazing but not all that surprising, the other amazing and a bit incredible.
Ever since humankind figured out that whole fire thing -- actually even before, when fires were spontaneously created by nature -- we have been living with air pollution. Originally it was pollution from burning wood and other biomass. But we've come a long way from those primitive days and have gotten quite good at fouling the air and our lungs by burning other stuff like coal and petroleum as well as biomass.
Signature -- and Deadly -- Air Pollution Events
The nadir in U.S. air quality probably came in the mid-twentieth century with the widespread use of coal. The county's worst air pollution event occurred in Donora, Pennsylvania, in 1948 when emissions from a local steel mill and zinc-smelting plant, combined with meteorological conditions, produced a deadly smog that killed 20 people. (More here.)
Tragic as the Donora event was, it was dwarfed by a five-day air pollution event in London called the Big Smoke or Great Smog of 1952 that killed an estimated 4,000 people (though as many as 8,000 more people may actually have perished from the smog). The culprit for the London event, scientists believe and some research has shown, is thought to be fine particulate matter from the soot pollution resulting from the burning of coal.
Today’s Air Pollution in the United States: Better but …
Since then, much of the developed world has cleaned up its air quality act -- requiring catalytic converters on cars and air pollution controls on power plants has significantly reduced pollutant emissions and saved lives. (More on the history of catalytic converter technology.) The U.S. Environmental Protection Agency estimates that in 2010 the Clean Air Act Amendments prevented some 160,000 premature deaths.
Nevertheless, air pollution is still around and it still kills. The National Oceanic and Atmospheric Administration estimates that there are about 50,000 premature deaths in the United States each year because of air pollution.
Air Pollution in the Developing World
Things are of course much worse in the developing world where regulations are weak and enforcement lax. A paper by Stephen Lim of the Institute for Health Metrics and Evaluation and co-authors reported in the British journal The Lancet last December that there are about three million premature deaths worldwide due to ambient air pollution.
What I found really astounding from this study is that air pollution was the ninth largest cause of death in the world, well above factors related to poor diet (with the exceptions of childhood malnutrition and obesity) and poor sanitation. The only other environmental factor that killed more was indoor air pollution from burning solid fuels.
(Note: a paper by Raquel Silva of the University of North Carolina and co-authors just published in the journal Environmental Research Letters concluded that air pollution is responsible for about two million deaths worldwide.)
Two other recent papers help to put these numbers into perspective.
It Matters Where You Live, Especially in China
Not infrequently, government officials come up with strange policies. If you are a scientist and you are lucky, every once in a while one of these kinds of policies can provide the setting for a perfect experiment to learn something about the world. Writing in the Proceedings of the National Academy of Sciences, Yuyu Chen of Peking University and co-authors report on the insights gained about the effects of air pollution from a policy promulgated in China between 1950 and 1980.
The policy provided for free heating of all homes and offices in China north of the Huai River by provisioning the area with free coal to fuel residents' and workers' boilers.
(No such provisioning was provided to homes and offices south of the Huai River. The rationale was that the northern regions were cold and needed heat while the south was not and did not. I personally experienced this policy a few times in the late 1980s when I visited the Shanghai area (which is south of the Huai River) around December and January. I remember sitting in my Chinese colleagues' offices with my winter coat buttoned up to my neck and stamping my feet to keep the blood flowing. My hosts would explain, somewhat sheepishly, that we were in the south and did not need any heat. There was some relief when I was in the offices of more senior officials who I guess got special dispensation to use a space heater when a soft American like me visited.)
One of the consequences of this policy was that there was a huge disparity in the air quality of the north and south. The concentrations of particulate matter in the north were about 55 percent (a factor of 1.5) higher than those in the south. The authors estimate that, as a result, life expectancies in the north were shortened by about 5.5 years, primarily due to cardiorespiratory ailments. Like I said, air pollution kills.
A Pain in the Side?
OK, I'm sure you’re not all that surprised to learn that a person's life can be significantly curtailed by breathing polluted air day in and day out. But did you ever consider the possibility that air pollution might cause appendicitis?
It does, says Gilaad Kaplan of the University of Calgary. In a paper published last week in the journal Environmental Health Perspectives, the authors report on the results of a 12-city study involving 35,811 patients that were hospitalized with appendicitis from 2004 to 2008. These data were then compared with measurements of local ambient ozone concentrations.
The authors found a significant correlation between elevated ozone concentrations and perforated appendicitis (which, by the way, is worse than the other kind, non-perforated appendicitis). They estimate that there is "an 11% to 22% increase in perforated appendicitis with every 16 [parts per billion] ppb increase in daily 1-hour maximum ozone levels when averaged over the previous 3 to 7 days." Why? The authors speculate that "[o]zone may selectively influence the pathogenesis of perforated as compared to nonperforated appendicitis."
So there you have it. We all know air pollution is bad, but I bet you hadn’t thought that air pollution might be a contributing factor for appendicitis. And while there’s good news that we have been cleaning up our act, through the Clean Air Act and other regulatory and technological methods, the latest science shows we still have a ways to go. Gosh, all of a sudden I have a pain in my side. Is it the right side or the left side I need to worry about? Sorry, gotta go.