Far as the ozone layer goes:
Most of you have been in the vicinity of an arc welder as it's fired up. Notice that rather pleasant odor soon as it does? That's ozone! An arc welder in operation produces ozone for about a 25-foot radius, as its UV rays strike the oxygen in the air. So do tanning lamps, lightning, or any other source of UV rays. As the sun is shining into a large part of our atmosphere 24/7, ozone is constantly being produced by it. Thus, it's renewed as fast as it's destroyed. Science doesn't yet know what makes the holes in the ozone layer, & can't do anything about it, but, if the sun is shining into that hole, you can bet it's producing ozone! (Too much ozone can irritate our airways, & break down rubber & some plastix.)