Re: any ex smokers?
I smoked for maybe 12 years, and did a lot of bad drugs. Although I quit long before I started boxing - I can confidently say that there is no noticeable effects from prior usage and I have above average conditioning. Your cells eventually regenerate, and your lungs eventually return to a better state.
To be honest, I think only 1 year of smoking - and 8 months ago is a drop in the bucket and shouldn't be holding you back much now. Although I might be a little presumptious to say that. TBH - I would examine what your overall fitness pr conditioning routine is like and see where you could be falling short.
I don't mean to make negative assumptions, I wish you all the best and hope you can reach your goals.