The depletion of the ozone layer has been declared almost unuiversally due to the catalytic affect of chlorine found in CFC, chlorofluurochlorine. and other molecules (ODS Ozone depletion substances,see table link below). The theory goes tht the ODS rise in the atmosphere where one chlorine atom can catalytically destroy thousands of ozone moelcules. Here is a random link to a random description, Another source regarding Ozone depletion Table of substances depleting the Ozone layer Search on google 'ozone hole depletion' Here is the problem as I see it. The ODS are relatively heavy molecules wrt air and chlorine. (Atomic nos.:Chlorine 17, Oxygen 8 and nitrogen 7). I had thought that the source for chlorione in the ozone, or a major source, would be chlorine evaporated from swimming pools. Why? Because the evaporated chlorine is much lighter than CFCs and ODS and of infinitely greater abundance than ODS. In fact, I am hard pressed how CFC's could ever reach the altitude necessary to mix with the ozone layer. Only through disturbances in the atmosphere, updrafts etc can any molecule heavier than air rise. This makes me think that the ODS (heavy molecules) are unfairly attacked as the ozone layer boogy man and that we ought to close down the swimming pools to protect ourselves from skin cancer. Any suggestions? Geistkiesel
Chlorine is so active chemically that any chlorine released from the surface would combine chemically with anything with even slightly reductive and consequently precipitate out of the atmosphere far before the chlorine could reach the upper atmosphere. The problem with CFCs is that they are so inert. It takes a big jolt of energy (e.g., UV) to break their chemical bonds. Thus they can make it to the upper atmosphere while other gases containing chlorine cannot. The CFCs are a transport mechanism for bringing chlorine from the surface to the upper atmosphere. The CFCs make it to the upper atmosphere because they are dissolved in the atmosphere. Gravity has little affect on the composition of a gaseous solution. Even suspended particles (dust motes) can make it to the upper atmosphere. Brownian forces are much stronger than gravity for small particles.
When you say the evaporated chlorine precipitates out, are you saying the combination with the oxygen or nitrogen in the air? probably, not, could you elaborate a bit? I mean even though precipitated there is still the chlorine and the combined atom. Why couldn't the chlorine keep rising whatever combined state it was in? Thanks. Geistkiesel
By precipitate I meant precipitation -- i.e., rain. The "chlorine" smell from swimming pools is primarily the chloride ion. This ion is quite soluble in water and is also highly reactive. Most ground-released chlorine simply dissolves in air-borne water and fall back to earth as acid rain. The remainder will react with almost anything (dust, pollutants, ...), which in turn will dissolve in water in the air. It takes a long time for molecules to get to the upper atmosphere. Chlorine released from the ground will come into contact with organic compounds and/or water vapor and fall back to earth. Very little will make it to the upper atmosphere.
D H, I see. In locations with a dry climate say 4 cm/year rain with average temperatures in high nineties for 1/2 a year on the average, minimum, for a dry summer with no rain, which is not unusual where I am, and a fairly high density of swimming pools, urban population centers 30k - 60k range with no major pollutant sources, can chlorine make it to elevation and compete measurably with with CFCs or ODS with respect to Ozone decay? I am building a worst case of minimum rain, organic organic pollutants and dust, with low atmospheric vapor and extended elevated temperatures. Geistkiesel
I personally suspect that the ozone hole is largely due just to the natural pattern of atmospheric circulation. After all, it is located over antarctica, which is notably devoid of both refrigerators and swimming pools. However, antarctica does get relatively little sun and therefore relatively little UV for ozone formation, and I suspect that the atmospheric circulation just doesn't bring ozone formed in other locations down to antarctica. I am really giving an uninformed opinion here, so feel free to ignore it or correct it. I just don't see how CFCs could "target" antarctica. -Dale
DaleSpam, D H who has been responding to my posts seems knowledgeable on the subject and he is consistent with what little I have looked a. Perhaps he canm enlighten us some on the issues. Actually this was my first impression, instinctive as it was. I first questioned the circumstances when the first ozone hole was measured and how there was a determination that something was corrupting the ozone layer. As the seasons cycle the amount of sunshine falling on the poles varies. Likewise, as in average planet temeperature the history does not stretch very far to the past, relativiley speaking. A degree or two over a century is quite meaningless, it seems when consider there aren't many measurements of the average temperature over, t - 5 centuries. I do not want to understate pollution or greenhouse effects or ozone depletion as they seem theoretically solid, it is the measurment that I am concerned with. If we, the planet, go off on a theoretical tangent that proves trivial and we miss a major factor for lack of inclusion in the theoretical model we will, or could, be stepping in some very nasty self made socio-politico-econmico doodoo. . As A natural sceptic, a burden some posture when striving for accuracy, in not underestimating claimed harmful effects, such as greenhouse and the ozone layer conditions, nor over accepting theoretical models. There is always a problem when considering the enormous size of the parameters. For instance it would not seem too difficult to estimate the sources of million of cubic feet of methane gas inserted into the atmosphere by those organic substances with a naturally high indexed condition of measured flatulence. Is this a problem, aphysical problem of negative pollution effecting health, I mean, not so much economic or political? I do not know, but there sure are a lot sources generating methane gasses on a daily basis. It seems that the oceans have a huge capacity to process waste disposal from sheer volume considerations alone. Whale shit, is this a problem? However, large quantities of waste can accumulate harmfully when ocean currents are not cleaning the near shore waste as rapidly as it accumulates. Some rivers have tear generating effects when industrial puollution is maintained under economic neccessity arguments. Atmospheric pollutiion is another questionable process. If a plant has been alloted 500,000 tone of annual pollution as a limit and they are able to cut their levels down to 100,000 tons, for instance, the EPA rules (at one time at least), allowed the plant to sell 400,000 tons of pollution rights to other plants. Geistkiesel
Ozone in the upper atmosphere is constantly being created by UV radiation hitting oxygen and depleted by chemical processes. The amount of ozone in the upper atmosphere is that level at which the production rate equals the depletion rate. The production rate, which is independent of the ozone level, varies with the seasons and with latitude. The depletion rate obviously increases as the ozone level increases but also depends on the concentrations of gases that interact with ozone. The addition of chlorine and other ozone depleters hastens ozone depletion, thereby changing the level at which ozone production and depletion reach a balance. The total amount of ozone in the atmosphere is an amazingly small quantity. Compressing all the ozone in the atmosphere to standard temperature and pressure would result in a layer of ozone only 3 millimeters thick or so. edited to add It takes 1-2 years for gases released from the ground (e.g., CFCs) to reach the upper atmosphere. The gases are fairly well distributed around the globe by the time they make it that high. Since CFCs last about 100 years in the upper atmosphere, their source of origin has little if any bearing on their current location. In other words, some of the CFCs released from Anytown, USA in the 1950s are above the Antarctic now. My first job out of college was working on the Nimbus 7 SBUV/TOMS experiment (Solar Backscatter Ultraviolet / Total Ozone Mapping System) in the late 1970s. I remained a skeptic regarding ozone depletion for quite some time after that first stint. I have since changed my mind; the evidence regarding anthropomorphic causes of ozone depletion is quite overwhelming. OTOH, I remain a skeptic regarding conjectures on humanity causing global warming.
Thanks for that, I didn't realize that the environmental lifetime is so long for CFCs. That is much more credible with that piece of info. Well, I don't see much disadvantages in the use of the non-CFC refrigerants that we have now. I guess they are a little less compressible, but certainly not enough to make a big difference for most applications. The atmospheric circulation and low UV must be the reasons that antarctica is most susceptible to the presence of the (fairly uniformly distributed) CFCs. I think that the ozone hole and global warming are probably not strongly related, so it is probably not unreasonable to accept an industrial explanation for one and reject it for the other. -Dale
