I hate to be harsh, but could it be you are really fibbing to yourself about not having adverse effects on your health? I mean, I'm not accusing or anything like that, but if you don't think cigarettes are hurting you at all, then why would you ask?
In my twenties, I told myself I would quit smoking when I was 30. But I didn't. Then I said would quit when they started hurting me. Well, they did (bronchitis, shortness of breath), but it was subtle and I ignored it, so I kept on smoking. For decades.
The bronchitis kept cropping up several times a year, sometimes really severe. I blamed it on allergies, as it usually presented in the spring or fall. I was lying to myself (to continue my habit!). I didn't admit that at the time, but I do now.
Long story short, it's been 3 1/2 years since my last cigarette, and I couldn't be more thankful. It wasn't a piece of cake to quit; I still had urges, but I had my vape to smooth me during a couple of semi-rough times.
I haven't been sick at all since I smoked my last cigarette (July 2, 2013). I can breathe, I can laugh without coughing, I don't have to clear my formerly gurgly throat every time I talk, and my house and my body no longer stiink. And my fingernails and toenails grow so fast I can't keep up.
Part of the explanation in this riddle is that we need oxygen to live and thrive. When we smoke burning tobacco, carbon monoxide attaches itself to our red blood cells, displacing the oxygen. Therein lies part of the trouble, not to mention the tar buildup in our lungs, rendering them less efficient to distribute the oxygen (which won't be distributed by the red blood cells anyway because they contain carbon monoxide, vicious cycle there).
Some smokers seem to escape it. I knew that wouldn't be me. I pushed the envelope way too long anyway.
Best wishes, whatever you choose.