How much alcohol/day is equivalent to a half a pack of regular cigarettes/day?

There is no equivalency here.

What leads you to that conclusion?

There is no equivalency here. @ARE_you_kidding_me is correct.
Both are bad for different ways.

I’d say a sixer, just a guess.

Sounds like a good biology graduate thesis question. Maybe someone has already answered it.
I would go with the low hanging fruit and compare financial damage costs for each. A pack of cigs in Alberta is $20 after tax and dirt cheap for alcohol. You can list the exact prices and post here.
In Ontario premiere Ford is trying to have a $1 buck a beer in his province. So I would say that 12 beers is equlivant to a half pack of normal cigarettes.
Hope this is a good start to answering your question
If I guess for your question I would say 2 beers are as bad as 0.5 packs of cigarettes. . Just a caveat I don’t smoke or drink.

@RedDeerGuy1
Wait what? A pack of smokes is twenty fucking dollars in Canada?! Good god, who can afford to smoke then.

@ARE_you_kidding_me Thats the idea. Alberta is trying to force smokers to quit. $20 was the price before 2003. It keeps going up.

Smoking affects your lungs, drinking affects your liver. No comparison.

@RedDeer Govt shouldnt legislate prices for recreational choices imo, not their job if its legal. Imo.
Its 4.45 a pack here. Decent top shelf liquor is affordable, too.

• Prices of cigarettes by region Canada | Statista
https://www.statista.com › Consumer Goods & FMCG › Tobacco

It was considered a deterrent to smoking to cut back on the health care for those that resulted in cancer because of smoking habits.
The Government will continue to tax heavily the Cigarette industry because cigarettes have a
carcinogen in them.

You are comparing apples and oranges.

Interesting.
I just posted another OP about this

Here it is:
https://www.fluther.com/216916/who-says-the-following-statement-regarding-smoking-and-drinking/

Apples and oranges. You can’t compare.