[enzino]

Exactly, you mention beliefs, while the point was (is?) one of science. By the way, have you ever heard of banning coal BBQs? I'm not sure at all that the exposure is less severe. Say you are at a party, there's a BBQ 20ft away, and some annoying guy lights a cig 10ft away. I'd bet you money that the BBQ harms you more, or at least emits more than 4 times (you need to scale by the square, diffusion of a fluid) PM2.5 than the cigarette.

[dahart]

Yes, I mentioned beliefs and was admitting that some of the behavior you saw might be based more on human beliefs than science. It wouldn’t be the first time it ever happened, right? ;)

I have heard of banning coal BBQs. I’m sure you’re absolutely right that the instantaneous exposure per second can be worse if you’re close and downwind from one than a cigarette from the same distance. But how often do you go to a party? Is it dozens of times per day, every day? Because that’s how often I bump into smokers when walking around downtown. Part of the CDC’s point is that the damage is cumulative, and you need to integrate over time and space. Exposure to one big source for a short time can be a little bit bad, while exposure to many small sources for a long period of time can be much worse.

[enzino]

I was referring to a specific situation (a university campus) that already banned smoking from all indoor areas, and all outdoor areas within 100ft from buildings (could have been 200, I don't remember). The question was whether to ban it everywhere. That scene I used of the party was very accurate, you'd have about 1 in 20 people who smoked. You'd not bump into smokers in any other settings, basically. (You'd maybe see a random smoker smoking on their own far away from buildings.) This was early 2010s at a west coast university.

[enzino]

Also, you don't need to be downwind from the BBQ. It's a point emission of fluid (particulate). It diffuses. The intensity scales with the square of the distance. (Same exact process as the cigarette smoke.)