HSC Stuff > HSC Chemistry

Ozone and Montreal Protocol

(1/1)

mylinh-nguyen:
Can someone help explain the fluctuations of this graph, how come ozone is still decreasing even after the Montreal Protocol
and how do I assess validity of secondary sources

jakesilove:

--- Quote from: mylinh-nguyen on June 12, 2017, 08:42:51 pm ---Can someone help explain the fluctuations of this graph, how come ozone is still decreasing even after the Montreal Protocol
and how do I assess validity of secondary sources

--- End quote ---

Hey! The Montreal Protocol was only in 1989; it took a while to phase out CFCs completely, which is why the graph continues to trend downwards. Once CFCs were completely phased out, the Ozone concentration starts to increase again! You can't expect a single treaty to fix the problem completely :) It took time!

However, the Ozone concentration went up as we started to prefer HCFCs, and HFCs. And, concentration stayed constant prior to our use of CFCs. That explains each area of the graph!

To assess the validity of secondary sources, we ask whether the source answers the question you are trying to pose. So, if you were looking to find out about the trend of Ozone concentration over time, this would be a very valid source! However, if you were interested in Wombat breeding cycles, you'd probably need to look elsewhere :)

mylinh-nguyen:

--- Quote from: jakesilove on June 12, 2017, 10:14:27 pm ---Hey! The Montreal Protocol was only in 1989; it took a while to phase out CFCs completely, which is why the graph continues to trend downwards. Once CFCs were completely phased out, the Ozone concentration starts to increase again! You can't expect a single treaty to fix the problem completely :) It took time!

However, the Ozone concentration went up as we started to prefer HCFCs, and HFCs. And, concentration stayed constant prior to our use of CFCs. That explains each area of the graph!

To assess the validity of secondary sources, we ask whether the source answers the question you are trying to pose. So, if you were looking to find out about the trend of Ozone concentration over time, this would be a very valid source! However, if you were interested in Wombat breeding cycles, you'd probably need to look elsewhere :)

--- End quote ---

thank you!!

Tino_BCP:
Also just something to add is that ozone depletion caused by CFC's and HCFC's occur in the stratosphere. However it takes roughly 40 years for these compounds to actually migrate from the troposphere to the stratosphere so this can also be a factor to consider.

Navigation

[0] Message Index