Why is there so much ozone?

1 Answer
Aug 18, 2017

Well, the amount of ozone actually varies in different parts of the world. Sunnier areas have more ozone than darker areas.

You are right that there is a process where ozone is consumed. This reaction mechanism is most likely (Physical Chemistry: A Molecular Approach):

#"O"_3(g) + color(red)(cancel(color(black)("Cl"cdot(g)))) => color(red)(cancel(color(black)("ClO"cdot(g)))) + "O"_2(g)#
#ul(color(red)(cancel(color(black)("ClO"cdot(g)))) + "O"cdot(g) => "O"_2(g) + color(red)(cancel(color(black)("Cl"cdot(g)))))#
#"O"_3(g) + "O"cdot(g) -> 2"O"_2(g)#

However, there is also a process that creates ozone from UV light:

#"O"_2(g) stackrel(hnu" ")(=>) color(red)(cancel(color(black)(2"O"cdot(g))))#
#ul(color(red)(cancel(color(black)(2"O"cdot(g)))) + 2"O"_2(g) => 2"O"_3(g))#
#3"O"_2(g) -> 2"O"_3(g)#

These processes usually don't balance each other out, so ozone will remain for quite some time.

However, if as humans we happen to make more gases containing #"Cl"cdot(g)# and #"Br"cdot(g)# as a result of our daily activities, you can see that it does catalyze ozone destruction.

That's not necessarily a good thing, as ozone in the stratosphere (what we call the ozone layer) does help reduce the intensity of the sunlight we get.