Wow. What a lively discussion this has turned into... And I thought I was the only one with a bias against Consumer Reports. I sell appliances in a "big box home repair" chain. I run the other way when I see them coming in with the CR magazine under their arm. CR bases their reviews on Subscribers' inputs. No way to tell if they are even being told the truth with their surveys. My 2cents.

 

About 800 people are killed annually by mal-functioning toasters.

 

Exactly one of the points I've been trying to make. There is no way to know how accurate the survey is. Every poll, every survey has a certain margin of error.

 

What I've been trying to point out is some of the flaws in CR, and that while they can be informative, they are not 100% perfect and could stand some improvement in several areas. Thanks for the link I will write them and ask. And, if I get a response I will post it. However, I'm not too optimistic that I will receive a real reply and not a "canned" form letter. But, I'll give it a try.

 

It does seem that is a primary concern of theirs.

 

im sure a lot more people are killed by defects in automobiles than toasters. dont believe me,ask Ford !

 

Regards to you Mr. Chocoholic...and don't forget, it was Al Gore who invented the Internet.

1. Will is correct in his understanding of how and why natural chlorinated compounds get washed out in the lower atmosphere: they are far less stable, and far more soluble, than CFCs. CFCs -- chlorofluorocarbons -- are entirely synthetic, man-made chemicals. Their very advantages (they are very stable -- virtually inert -- and thus do not easily react with other chemicals) cause them to remain intact for many years, mix with the atmosphere very thoroughly, and eventually seep into the stratosphere (the upper atmosphere), where there is an ozone concentration, or ozone layer. At those altitudes, solar ultraviolet light (UV) is much more potent -- powerful enough to break down even CFCs into their constituent elements (including chlorine).

That, in short, is why CFCs can reach the stratospheric ozone layer in significant quantities, while most naturally occurring chlorine compounds normally can't. And that's why a disproportionate and growing percentage of stratospheric chlorine comes from CFCs, not natural sources.

2. Yes, CFC production has been pretty well quantified, and I've seen papers showing a pretty close linkage between quantities of CFCs produced over the years, and the amounts eventually found in the atmosphere.

CFCs are used not only as spray propellants (they've been banned in the U.S. as propellants for some years, in fact), but also in industrial solvents, in auto headlights (halogen), in refrigerators and in air conditioners (Freon and similar compounds). Their uses had been escalating very rapidly over the past several decades, until recent treaties limited their production.

The problem with CFCs in the stratosphere is that even though the concentra- tions may be small, one chlorine molecule can destroy thousands of ozone molecules. Once released to roam in the stratosphere, a chlorine monoxide molecule drifts around, reacting over and over with all ozone molecules it contacts, via a complicated series of chemical reactions. (I'm not a chemist, but the equations have been published in major scientific journals I've read.) That's why even relatively small concentrations of CFCs in the atmosphere can have a disproportionately destructive effect on ozone -- if meteorological conditions are right. That brings us to...

3. Marsha is on the right track in her understanding as to why ozone depletion can't and won't become a global threat. The reason: meteorology.

First: why worry about the amount of atmospheric ozone? Because atmospheric ozone blocks out a great deal of damaging solar ultraviolet radiation from reaching the ground. In the absence of ozone, UV would reach us in much greater amounts, possibly causing much more skin cancer, and possibly even damaging crops and wildlife.

Is it possible for ozone levels to steadily decline over time? Probably not.

Ozone (O3) is always being destroyed and created by natural processes. O3 that is broken down by solar UV is also constantly replenished by UV's action in breaking down oxygen. In other words, O3 simply isn't going to steadily decline and vanish. As long as there is oxygen and UV to act on it, Mother Nature will always make more ozone. Other things equal, there's a natural balance of ozone creation and destruction. Levels fluctuate wildly over the years, seasons, even days; but like a choppy ocean surface, there's always a natural sea level of ozone in the atmosphere.

But some scientists worry that the addition of man-made CFCs into the so-called natural balance will throw things out of kilter, causing overall O3 levels to decline. The discovery of the Antarctic ozone hole in 1985 fueled that fear. And if CFCs cause eventual ozone depletion over populated areas, an environmental and health nightmare could ensue.

This is theory only, and in my view, pure hokum. Global ozone levels have not been responding in the way the CFC depletion theory suggests. To make their case, environmentalists and government scientists have been shamelessly distorting the data -- for example, measuring declining trends in ozone by arbitrarily picking out years with unusually high ozone levels, and using those as the base years for comparisons. But ozone levels constantly, naturally fluctuate, especially during the 11-year solar cycle. Not surprisingly, even an average ozone year looks like depletion when measured against a peak year in the ozone cycle.

Dr. Linwood Callis of NASA led an agency investigation of the causes of ozone fluctuations during the 1980s. As he told me: The overwhelming portion of the ozone depletion in the 1980s was due to natural causes, and the effect of CFCs was really quite small -- less than one-half of one percent. (His paper Ozone Depletion in the High Latitude Lower Stratosphere: 1979-1990 appeared in the Journal of Geophysical Research, Vol. 96, No. D2, Feb. 20, 1991, pp. 2921-2937.) Callis went on to say that he thought that scientists blaming CFCs for ozone depletion were being less than honest.
Even so, the bottom line is not CFCs, chlorine, or even ozone levels. From a health and environmental standpoint, the only worry is UV levels. And guess what? The only actual measurements of UV penetrating to the ground show that UV levels have been going DOWN, not up. Scientists link the decline of UV to increasing cloud cover in recent years. Obviously, you can't have a cancer epidemic if UV is declining, rather than increasing. At any rate, reality hasn't exactly been conforming to the theories of the alarmists. (See Joseph Scotto, et al., Biologically Effective Ultraviolet Radiation: Surface Measurements in the United States, 1974 to 1985, in Science, Vol 239, p. 762.) Well, what about that Antarctic ozone hole? First of all, it isn't a hole. The ozone hole is a temporary, chlorine-enhanced thinning of the O3 layer over Antarctica during our (northern) autumn months. It requires the following meteorological ingredients: (a) a lengthy polar night -- i. e., a prolonged absence of UV radiation.

This allows (b) the buildup of chlorinated compounds, unmolested by UV, in the (c) polar vortex -- a vast, self-contained whirlpool of air over the Antarctic region. The vortex largely isolates polar air from mixing with air outside the region, thus diluting the chlorine concentrations.

Now add (d) super-cold, high-altitude temperatures, which causes ice clouds to form in the stratosphere. The ice crystals provide surfaces upon which chemical reactions between chlorine and ozone can take place much more rapidly and efficiently than by mere mixing in the air. Finally, add (e) the sudden appearance of the sun after the long polar night. This adds high levels of UV to the chemical soup, which breaks down chlorine compounds into their constituent elements -- such as highly reactive chlorine monoxide. The chlorine monoxide -- not the CFCs themselves -- then reacts on the surfaces of the ice crystals with ozone molecules, breaking them down.

A few weeks later, as the polar weather changes, the vortex breaks up, allowing the infusion of outside air into this chemical soup -- and soon, all the reactions stop. Ozone is then rapidly and naturally replenished by solar UV action on oxygen, and the ozone hole quickly refills.

If ANY of these ingredients are absent, you won't have ozone depletion. And the ONLY place that has them all is Antarctica. Even the Arctic region does not have as well-defined and isolated a vortex, because mountains there break it up. Nor do the stratospheric temperatures there get as cold...which means you don't get an abundance of ice crystals to act as a catalyst for accelerating the chemical reactions.

In February 1992, NASA held a news conference to announce record levels of chlorine monoxide over the Arctic, and to predict very significant ozone loss, 30 to 40 percent within weeks. Capt. Planet (alias Al Gore) started moaning about the ozone hole over Kennebunkport (George Bush's home), and got a law passed to accelerate bans on CFCs.

But the hole didn't exist then, and never occurred. The weak Arctic vortex broke up, the temperatures weren't cold enough...and there was no significant depletion. This lends empirical support to the skeptic's case that ozone depletion can't occur to any significant degree outside of Antarctica, no matter how much chlorine monoxide gets up into the stratosphere, from whatever source, natural or human.

Bottom line: don't worry about a cancer epidemic from ozone depletion. It apparently takes more than just chlorine monoxide to destroy ozone: it also takes the right meteorological conditions...conditions that exist ONLY in the Antarctic, and ONLY during the austral spring (our autumn).

By the way, lest anyone worry about Antarctic penguins and polar bears: Don't. The amount of solar UV there at the height of the ozone hole is even less than the amount during the Antarctic summer! Reason: the angle of the sun is much lower in the austral spring, when the hole appears, than it is in the Antarctic summer. For the same reason that you can't get a suntan at dawn, you get less UV in the spring than the summer. Any animal that can survive the sun during the polar summer, can survive it during the spring ozone hole.

Good day,
Greg

 

Isn't that what I said?