Hi Toyger. I've never heard of this word before in my 26 years years of English lol. I had to look it up myself, and apparently it means' the reminiscence of ozone' (if I'm being honest, I'm still doubtful that it's actually a word.) Very confusing in itself but the definition you said is what I would agree with. I bet I could ask a 1000 native English speakers if they knew what 'ozoney' meant, and all of them would think i'm making the word up. Just disregard it. Very strange choice of words in whatever book you're reading, and if it's specifically meant for learning I think it's very silly to include such a word. Hope that gives you some clarification.

It smells of ozone ( for him). If you ever smelled the air before the storm or just after it, then that would be the smell he’s described. As it is argued that 80% of taste is actually smell he made this comparison because he couldn’t describe in other way. ( it’s very challenging to describe flavours.. how would you describe the flavour of cauliflower, celery or mussels without talking about the texture? ;)

Yes! O3 is ozone while O2 is oxygen. I believe I read an article online that said you can smell ozone right after a lightening strike during a thunderstorm - however I’m not 100% sure. There is also ozone treatment in dentistry so some might have tasted it there. However, most people probably don’t know what ozone tastes like. An important point we can make here is with the -y at the end of the word. Generally, English speakers add a y to the end of a word to turn it into an adjective - even if it’s not a real word! Some other examples are filth - filthy, slime - slimy, etc. etc. So if you see a “y” attached to the end of a noun, chances are it’s an adjective :)