4 ms·

>Chlorofluorocarbons (CFCs) are heavier than air, so how do scientists suppose that these chemicals reach the altitude of the ozone layer to adversely affect it

by desdiv 8y ago

>Chlorofluorocarbons (CFCs) are heavier than air, so how do scientists suppose that these chemicals reach the altitude of the ozone layer to adversely affect it? >Although the CFC molecules are indeed several times heavier than air, thousands of measurements have been made from balloons, aircraft and satellites demonstrating that the CFCs are actually present in the stratosphere. The atmosphere is not stagnant. Winds mix the atmosphere to altitudes far above the top of the stratosphere much faster than molecules can settle according to their weight. Gases such as CFCs that are insoluble in water and relatively unreactive in the lower atmosphere (below about 10 kilometers) are quickly mixed and therefore reach the stratosphere regardless of their weight. [0] https://www.scientificamerican.com/article/chlorofluorocarbons-cfcs/ https://www.scientificamerican.com/article/chlorofluorocarbo... That's the first Google result for searching "Chlorofluorocarbon heavier than air".

RobertRoberts 8y ago
That article says this: "Because CFCs are so long-lived in the lower atmosphere, there is ample time and opportunity for them to become well mixed and eventually to reach the stratosphere." They all go to one place? Consider the plastic patch in the Pacific, even there, there are currents that move everything there. I've never heard of currents in the air that push everything to the south pole, and then straight up. In fact, I'd tend to believe the air goes up at the equator, and down at the poles (in general).
- puzzlingcaptcha 8y ago
  "Why has an “ozone hole” appeared over Antarctica when ozone-depleting substances are present throughout the stratosphere?" [PDF] https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyquestions/Q10.pdf https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyq...
  - RobertRoberts 8y ago
    This was an interesting read. >chlorine and bromine reactions to produce the ozone hole in Antarctic springtime Why isn't chlorine and bromine considered just as bad as CFCs, if they are in fact the chemicals causing the problem? >...most of the emissions occur in the Northern Hemisphere." >...winds and convection redistribute and mix air efficiently throughout the troposphere on the timescale of weeks to months* The paper indicates that there's an equal amount of these gases all over, and that they _aren't_ congregating at the south pole. Yet, go read the comments on this board, so many people that shout me down don't seem to know this. It's incredible how so many "smart" people are convinced of something, and get raging mad when questioned. Is it because they believe it without actual proof, or haven't researched it thoroughly themselves? >Stratospheric air motions then transport these gases upward and toward the pole in both hemispheres. One guy here claimed it was "mountains" that moved the air. Which is silly, because of all kinds of reasons, the least of which is that mountains would only cause a localized updraft, not a planet wide updraft. I am starting to think HN is fully of "true believers" that will hunt anyone down for questioning anything at all. There are references in this document to other sources that are not included here. And obviously to question many scientists work these days is tantamount to blasphemy regardless. >Once formed, PSC particles fall to lower altitudes because of gravity. Why does gravity affect one type of element but not others? >The most common source of CFCs are refrigerants, but fire suppression systems for aircraft and aerosols also emit CFCs into the atmosphere. https://sciencing.com/sources-cfcs-8405334.html https://sciencing.com/sources-cfcs-8405334.html How much CFCs in the air does it take to create a hole _and_ maintain that hole for decades? This is almost where every discussion from the effects of homelessness, government budgets, wars, etc... all fall apart. No one has any real numbers. It's all "guessing", yet we are "certain" enough say "don't you dare question the orthodoxy". >"...the highly reactive chlorine gas ClO remains chemically active for a longer period, thereby increasing chemical ozone destruction." 51.4524 g/mol Chlorine Monoxide, ClO (The CFC gas from the article) 70.9056 g/mol Cl2 (mustard gas) 44.0095 g/mol Carbon Dioxide, CO2 14.006747 g/mol Nitrogen, N 18.01528 g/mol Water, H2O Again, I am an ignoramus, but ClO looks to be quite a heavy gas. Cl2 stayed in the trenchs in WWI, carbon dioxide is heavy enough to pour like "water". Yet the claim is that PSCs (which are made of water) "fall from gravity" yet their molar mass in a fraction of the other gases. Again, I think it's possible to have every gas everywhere. But a single gas 4 times heavier than something that "gravity" pulls from the sky, stays up in air for months wreaking havoc?
    - puzzlingcaptcha 8y ago
      I think you will find some answers in other articles from the series (especially Q8 and Q9), all of which are available at https://www.esrl.noaa.gov/csd/assessments/ozone/2014/twentyquestions/ https://www.esrl.noaa.gov/csd/assessments/ozone/2014/twentyq... I will just point out about the gas diffusion that up to ~100km or so above ground turbulent mixing is the prevalent force. You can look at concentration of argon gas (Ar2 ~80g/mol) which also does not change in that altitude. About the PSC particles 'falling from gravity' keep in mind these are no longer gases (the operative word is 'particles') so you want to look at their density not molecular weight. (Simplistically, one mol of any gas is 22.4 L while one mol of water/ice is ~0.018 L.)
- rdiddly 8y ago
  They go to all places.

by desdiv 8y ago

RobertRoberts 8y ago

That article says this: "Because CFCs are so long-lived in the lower atmosphere, there is ample time and opportunity for them to become well mixed and eventually to reach the stratosphere." They all go to one place? Consider the plastic patch in the Pacific, even there, there are currents that move everything there. I've never heard of currents in the air that push everything to the south pole, and then straight up. In fact, I'd tend to believe the air goes up at the equator, and down at the poles (in general).

puzzlingcaptcha 8y ago
"Why has an “ozone hole” appeared over Antarctica when ozone-depleting substances are present throughout the stratosphere?" [PDF] https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyquestions/Q10.pdf https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyq...
- RobertRoberts 8y ago
  This was an interesting read. >chlorine and bromine reactions to produce the ozone hole in Antarctic springtime Why isn't chlorine and bromine considered just as bad as CFCs, if they are in fact the chemicals causing the problem? >...most of the emissions occur in the Northern Hemisphere." >...winds and convection redistribute and mix air efficiently throughout the troposphere on the timescale of weeks to months* The paper indicates that there's an equal amount of these gases all over, and that they _aren't_ congregating at the south pole. Yet, go read the comments on this board, so many people that shout me down don't seem to know this. It's incredible how so many "smart" people are convinced of something, and get raging mad when questioned. Is it because they believe it without actual proof, or haven't researched it thoroughly themselves? >Stratospheric air motions then transport these gases upward and toward the pole in both hemispheres. One guy here claimed it was "mountains" that moved the air. Which is silly, because of all kinds of reasons, the least of which is that mountains would only cause a localized updraft, not a planet wide updraft. I am starting to think HN is fully of "true believers" that will hunt anyone down for questioning anything at all. There are references in this document to other sources that are not included here. And obviously to question many scientists work these days is tantamount to blasphemy regardless. >Once formed, PSC particles fall to lower altitudes because of gravity. Why does gravity affect one type of element but not others? >The most common source of CFCs are refrigerants, but fire suppression systems for aircraft and aerosols also emit CFCs into the atmosphere. https://sciencing.com/sources-cfcs-8405334.html https://sciencing.com/sources-cfcs-8405334.html How much CFCs in the air does it take to create a hole _and_ maintain that hole for decades? This is almost where every discussion from the effects of homelessness, government budgets, wars, etc... all fall apart. No one has any real numbers. It's all "guessing", yet we are "certain" enough say "don't you dare question the orthodoxy". >"...the highly reactive chlorine gas ClO remains chemically active for a longer period, thereby increasing chemical ozone destruction." 51.4524 g/mol Chlorine Monoxide, ClO (The CFC gas from the article) 70.9056 g/mol Cl2 (mustard gas) 44.0095 g/mol Carbon Dioxide, CO2 14.006747 g/mol Nitrogen, N 18.01528 g/mol Water, H2O Again, I am an ignoramus, but ClO looks to be quite a heavy gas. Cl2 stayed in the trenchs in WWI, carbon dioxide is heavy enough to pour like "water". Yet the claim is that PSCs (which are made of water) "fall from gravity" yet their molar mass in a fraction of the other gases. Again, I think it's possible to have every gas everywhere. But a single gas 4 times heavier than something that "gravity" pulls from the sky, stays up in air for months wreaking havoc?
  - puzzlingcaptcha 8y ago
    I think you will find some answers in other articles from the series (especially Q8 and Q9), all of which are available at https://www.esrl.noaa.gov/csd/assessments/ozone/2014/twentyquestions/ https://www.esrl.noaa.gov/csd/assessments/ozone/2014/twentyq... I will just point out about the gas diffusion that up to ~100km or so above ground turbulent mixing is the prevalent force. You can look at concentration of argon gas (Ar2 ~80g/mol) which also does not change in that altitude. About the PSC particles 'falling from gravity' keep in mind these are no longer gases (the operative word is 'particles') so you want to look at their density not molecular weight. (Simplistically, one mol of any gas is 22.4 L while one mol of water/ice is ~0.018 L.)
rdiddly 8y ago
They go to all places.