Interesting: Explainer on the actual potency of secondhand weed smoke

InvisibleEye

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Interesting article on Slate.com: http://goo.gl/tPXXF

«Recreational marijuana use became legal under Washington state law on Thursday and will likely be legal under Colorado law within a month. Jubilant smokers gathered under Seattle’s Space Needle to celebrate. Although smoking weed in public is still illegal, police looked the other way. Could a nonsmoking observer get high just from being near all that pot?

Only if he or she got very close. Researchers from the National Institute on Drug Abuse investigated the effects of “sidestream” marijuana—the smoke coming from the burning end of the joint—in 1986. They placed participants in an 8-by-7 room without ventilation and burned a series of marijuana cigarettes, removing the mainstream smoke through tubing. When the subjects were exposed to the smoke of four joints over the course of one hour, THC metabolites were detectable in some of their urine tests, but the tests were more often clean. The participants’ subjective assessment of “highness” was not significantly different from when they were exposed to placebo cigarettes.

Then the researchers intensified the experiment, burning 16 joints in an hour. After breathing the more highly concentrated smoke, the volunteers got indisputably high. Their subjective assessment of their mental states varied significantly from the placebo condition, and the urine tests consistently came back positive. The researchers noted that their results closely mirrored the effects of actively smoking one joint.

The take-home message from the study is that it’s possible, but difficult, to experience effects from sidestream pot smoke in normal social situations. The second phase of the protocol—burning 16 joints in a tiny room for an hour—is a scenario rarely experienced in ordinary life and certainly not comparable to being in a well-ventilated public place. Other studies in which participants have experienced legitimate contact highs have been equally extreme. In a Norwegian study, for example, volunteers were crammed in a car with six burning joints over a 30-minute period. »
 
Not sure about this one - did they remove ALL of the mainstream smoke from the room? Because that's definitely not what happens in reality. When I pull on a joint, I always exhale quite a bit of that smoke back into the room, which contributes a lot more to the haze than the "sidestream" coming off of the joint.
 
ITT: hotboxes are pointless.

We must have understood the article differently.
What I took away from it is that the secondhand smoke from 16 joints over an hour in a closed room is roughly equal to smoking one joint. That means (if we believe those numbers) that hotboxes add about 6% to the effectiveness of a joint - per person. So, if 4 people are in a car, and share a joint, you get 6% bonus X 4 people = 24% bonus high, shared equally among the 4 people.
If one joint in a hotbox = 124% of a joint in the outside air, it seems pretty worthwhile to me.
 
Not sure about this one - did they remove ALL of the mainstream smoke from the room? Because that's definitely not what happens in reality. When I pull on a joint, I always exhale quite a bit of that smoke back into the room, which contributes a lot more to the haze than the "sidestream" coming off of the joint.

I don't think that the smoke you exhale has too much goodness left in it. But you are right that it certainly could add something. In fact, I tested this with a girlfriend in highschool - she only inhaled what I exhaled, and claimed that she got high after about 4 or 5 of my hits. If we estimate that she got as high as if she had taken one real hit (low estimate; she usually took 5 or more), then 5 of my secondhand hits = 1 regular (direct) hit.
Therefore, the 124% figure I gave above for 4 people may be an underestimate. Counting exhalation, it could easily be 150%. Which means your weed will go 50% further in a hotbox (with 4 people).
 
if you're smoking joints in a small unventilated area then it's going to make a huge difference as half the joint is throwing off smoke at the end of it and not being inhaled at all.

if you're fully absorbing vape hits then this is not an issue at all.
 
I don't think that the smoke you exhale has too much goodness left in it.

Well, when you take a breath, the air in your lungs goes from about 20% oxygen by volume down to 14-16%, so you breathe out something like three-fourths of the oxygen you breathed in. I know it's kind of ad-hoc to assume similar figures for THC, but personally I'd be surprised if the smoke I exhaled were any less than 50% as potent as when I inhaled it. I think that factor could be creating quite a bit of error in this study.
 
On the topic of people only absorbing x per-cent of smoke,
Consider this: what you see as "smoke" is actually a particulate mist of solid and liquid. It's an aerosol of liquid and solid in (usually much cooler) gas. (This explains why you can blow smoke in someone's face without melting them)
THC and most plant cannabinoids have melting points around 170 C, so what is typically inhaled (even hot smoke cannot be much hotter than 50 degrees C or it would scald and destroy tissue) is actually solid phase THC suspended in warm air. The cannabinoids are only ever a vapour in the vapourisation chamber or near the point of combsution.
 
@Slimvictor

Say you're smoking a gram joint, with those figures, you would be getting a gain of 0.06 grams from the smoke coming off the joint, plus minimal effect from the spent smoke.

Maybe "pointless" was the wrong choice of words.

Not worth the hassle, IMO.
 
So, does the fact that THC is solid and not vaporous make my lungs absorb more of it, or less?
 
Given that the solid "particles" of THC are more likely to stick to the surface of your lungs (doe to gravity and their adhesive properties) I would wager you'd absorb more of it as an aerosol rather than a gas. Once the THC globs land it's not very likely they will be kicked back up by air currents.

Not to mention I doubt your lungs could hold up to 170C gas entering them.
 
Say you're smoking a gram joint, with those figures, you would be getting a gain of 0.06 grams from the smoke coming off the joint, plus minimal effect from the spent smoke.

That is not what my figures above said - it seems more like 1 gram -> 1.5 grams of effect, based on the 150% figure, assuming you have 4 people (and if you are smoking a one-gram joint alone, I think that you probably don't care much about conserving your weed!).
Maybe a better way to say it is that, with a 1-gram joint, one-third of the potential is lost if you smoke it outside, but in a hotbox you can use all of it.
 
I don't know, this article seems to say that particle deposition in the respiratory tract can vary between 20% and 90%. If the particles are larger than a few um in diameter then most are going to stick, but any smaller and a substantial quantity will be exhaled.
 
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