One cigarette a day doesn't sound that bad for you. 40-a-day smokers exist and while they're unhealthy, they're not universally dying in their fifties, so one fortieth of that effect seems small.
The biggest risk of smoking one cigarette a day is not that it will give you cancer, it's that it will give you nicotine addiction which will lead to smoking twenty a day and getting cancer. Radon exposure doesn't have that effect.
Cancer isn’t the only risk though, the 100 other things are pretty bad too. It isn’t ‘just’ that you might die of cancer, it’s the decades of leg ulcers, stroke, heart and lung disease etc.
yes cancer is only one of the more deadly and more reliably attributable to cigarettes things
there are quite many things made much more likely with smoking which would end very deadly but modern medicine has learned to to move into the non deadly if treated in time area, which doesn't mean it it doesn't leaves you with long lasting side effects...
like most cases in my environment of smokers having "likely smoking caused" issues fall under that category (so far, aging/time tends to let you see more death in your environment and I'm not yet that old)
Those are some powerful claims, do you have any links for that? Generally 2-pack smokers that started early ie in their 20s or even earlier don't live till retirement where I live, but I agree its a small sample and generally such people don't live a healthy life overall.
and the more ways you add risk through your live the more likely you will die an early death
it's just basic statistics
and for the same reason you will find someone who does add all the risks but somehow still dies with 90+, if your sample size is large enough and factors complicated enough you are pretty much guaranteed to find some pretty big outliers
but realistically speaking it a pretty bad idea to assume you are such an outlier, but many people tend to ("basically") do exactly that (due to an combination of subconsciously avoiding reality and simply not thinking things through)
A couple of sources putting the life expectancy cost at 10-20 minutes per cigarette.
Smoking for 40 years that would be 5 months at 1 a day or 17 years at 40 a day.
I think that's all consistent with what you said: 2 packs a day and you usually, but by no means always, don't make it to retirement at ~66. Five months is enough that I'd take some care to avoid it, though.
The biggest risk of smoking one cigarette a day is not that it will give you cancer, it's that it will give you nicotine addiction which will lead to smoking twenty a day and getting cancer. Radon exposure doesn't have that effect.