Trees and volcanoes cause smog! (More myths from the "Wise Use" movement).

Author:Callahan, Tim
Position:Anti-environmental movement
 
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As I drive to work each day, there is a point on the Ventura Freeway, just before it drops into the lower parts of the San Gabriel Valley, where I am treated to a panoramic view of much of the Los Angeles basin. Almost invariably, the vista includes a layer of brown air hovering close over the horizon. This casts (to indulge in a pun) something of a pall over my spirits.

However, according to the anti environmentalist "Wise Use" move meet, I really have nothing to worry about. Smog, after all, is little more than a minor irritant. I have this on the authority of none other than the late Dr. Dixy Lee Ray, who in her final years was an officer of the Mountain States Legal Foundation (that creation of Joseph Coors which gave us James Watt, Ronald Reagan's bad choice for Secretary of the Interior, and Ann Gorsuch, Watt's bad choice for head of the Environmental Protection Agency) and an enthusiastic spokesperson for the "Wise Use" movement. Speaking on a talk show on religious radio station KKLA in 1993, Dr. Ray reassured a caller in the following exchange:

Caller: Is ozone that is produced

at sea level . . . harmful to human

beings, as opposed to ozone that

is produced in the upper atmosphere?

Ray: . . . The ozone at ground

level, if there's too much of it, can

cause some irritation in the respiratory

system and can cause

people's eyes to water and make

them cough. But otherwise, it

doesn't have any deleterious effect, no.

Caller: Is ozone produced at sea

level?

Ray: Yes, it is and it's produced

whether human beings are there

or not, particularly in the Los

Angeles Valley.

Caller: Can you tell me what produces

{ozone} in the Los Angeles

Valley? Smog?

Ray: No, it's produced by the

interaction of hydrocarbons with

sunlight. And because there's so

much sunlight in southern California,

the hydrocarbons--which

are those wonderful things that

you smell coming off pine trees

. . . so it causes a blue haze when

you look into the distance--those

are hydrocarbons that are given

off mainly by plant life. When the

sunlight hits the plants, it interacts

with those hydrocarbons and

produces ozone.

While she was speaking of only two of the many pollutants in the chemical soup that people breathe each day in southern California--hydrocarbons and ozone--Ray, supposedly speaking as a scientist, was making the same old claim once made by Ronald Reagan: that smog comes from trees. Let's dissect Ray's remarks in some detail, starting with her assertion that ozone in the lower atmosphere is largely harmless. (Readers of this article should be warned in advance that I will be considering scientific issues in some detail. While this may be tough going for some, it is necessary in refuting the claims of the "Wise Use" movement.)

Along with oxides of nitrogen, ozone is an oxidant--that is, an unstable compound that will break down in such a way as to release atomic oxygen. Atomic oxygen attacks the tissues of the lungs at the molecular level, disrupting chemical bonds. Put very simply, ozone and oxides of nitrogen are highly corrosive; the greater their concentration in the air, the harsher their effect on delicate tissues such as the eyes and the lungs. Despite her claim that sea level ozone was only a minor irritant, Ray knew better. In her 1990 book Trashing the Planet, she has this to say about ozone:

Another photo oxidant, ozone, is

possibly the most damaging of all air

pollutants derived from human

activity. Ozone accumulates in

quantities toxic to vegetation in

all industrial regions of the world.

It is a product of photochemical

oxidation between oxides of nitrogen

and volatile organic substances.

The latter may be unburned

hydrocarbons--for example,

from automobile exhausts in

cars not equipped with catalytic

converters--or it may be various

organic solvents. Ozone is known

to cause severe injury and even

death to certain forest trees. The

best known cases are the decline

of white pine in much of eastern

North America and ponderosa

and Jeffry pine in the San Bernardino

Mountains of California.

{emphasis added}

How was it that ozone, which Ray described in 1990 as "possibly the most damaging of all air pollutants derived from human activity," was changed into the minor irritant that Ray spoke of three years later? Or that ozone went from something that killed trees in 1990 to something that was indirectly created by them in 1993? To find these answers, all we need do is to put the quote from her book in its context. In Trashing the Planet, Ray was arguing that acid rain was not the culprit environmentalists claimed it to be, and so ozone became the convenient fall guy. Since the right wing audience of the religious radio show was already rabidly anti-environmentalist, the listeners were not likely to be critical of anything Ray had to say or to call her to account for her in consistencies.

Ray's three assertions--that ozone would be produced in the lower atmosphere regardless of human activity, that it is produced by the interaction of sunlight and hydrocarbons, and that those hydrocarbons are largely produced by plants--are, respectively, a technical truth hiding a falsehood, a sloppily garbled half truth, and a bit of these two mixed with an outright lie. Specifically, sea level ozone is formed when sunlight splits nitrogen dioxide into nitric oxide and atomic oxygen. The atomic oxygen reacts with molecular oxygen to form ozone. Now it is technically true that, in nature, oxides of nitrogen are produced by certain bacteria, forest fires, and lightning, so that a small amount of sea-level ozone would indeed be produced in the absence of human activity. However, the main source of oxides of nitrogen in southern California is combustion: nitrogen combining with oxygen at high temperatures. So whether it's from gas water-heaters and ovens, coalfired power plants, or automobiles, most of the nitrogen dioxide in the air--and, thus, most of the sea-level ozone--is directly produced by human beings.

As for Ray's second claim, hydrocarbons contribute to increasing the level of ozone in smog by a very indirect route. Ozone in the lower atmosphere often reacts with water to form hydroxyl radicals. These hydroxyl radicals will either react with impurities in the air to break them down or react at night with nitrogen dioxide to form nitric acid, which is either washed out of the atmosphere by rain or broken down by sunlight the next day into hydroxyl radicals, nitric oxide, and atomic oxygen.

In L.A. smog, the soupy mix of unburned and partially burned hydrocarbons reacts with hydroxyl radicals and oxygen to form organic peroxides. These, in turn, react with nitric oxide to form nitrogen dioxide. By generating even more nitrogen dioxide than was produced by combustion, these peroxides contribute more of the source material that sunlight will turn into ozone. Thus, the ozone level goes up when hydrocarbons are added to the soup, but ozone is not created by a simple interaction between sunlight and hydrocarbons, as Dr. Ray asserted.

As for Ray's third claim--that hydrocarbons come from trees--here she was particularly devious. Her characterization of hydrocarbons as "those wonderful things that you smell coming off pine trees" is technically correct to the degree that the terpenes, which are indeed given...

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