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Comment by skwb | Hacker News Reader

Vaping certainly does damage air quality by releasing ultafine aerosol particulate matter (also known as pm10 or pm2.5) [0]. It's worth noting that these are associated with respiratory distress and can contribute to stroke and heart attacks as well as asthma. In fact, we now have compelling epidemiological evidence that vaping almost doubles risk of cardiac events [1].

Think about it like this: would I want to run a marathon on a bad air day in China? Probably not.

[0]. https://www.nature.com/articles/s41370-017-0005-x?fbclid=IwA... [1]. https://www.ucsf.edu/news/2018/08/411476/risk-heart-attacks-...

Edit: Study 1 focused on PM10 (particulate matter smaller than 10 microns) air quality levels, and not PM2.5. PM 10 tends to be associated with more acute respiratory distress, while PM2.5 is a more chronic threat [2]. Nevertheless, there is sufficient evidence that monitoring environmental PM10 levels remains an important public health metric.

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> In fact, we now have compelling epidemiological evidence that vaping almost doubles risk of cardiac events

If you continue to smoke tobacco.

"Scientific" studies like this that assert causation when all they have is correlation, based on surveys that we know little about (and likely wouldn't be able to learn the full details of even if one was energetic enough to hunt down the original paper), certainly don't do anything to convince me. If anything, it just increases my suspicion around the "science" we're fed.

This is literally the same argument that was used in the 60s to defend full-blown tobacco smoking. There are ways to establish causation besides the randomized controlled trial.

Well they have correlation that remains correlated after you adjust the model for other risk factors. So is that direct evidence? No.

But when you add in the other lines of evidence, you start building a case. It's sorta like a murder trial (not withstanding a separate discussion of our criminal justice system...) where the case is built over lines of evidence.

And as one of my graduate professors once said, "there is no double blind randomized trial for the efficacy of parachutes" ;) [0].

[0]. https://www.bmj.com/content/327/7429/1459

> But when you add in the other lines of evidence, you start building a case. It's sorta like a murder trial (not withstanding a separate discussion of our criminal justice system...) where the case is built over lines of evidence.

When you're dealing with a murder trial, whether harm has occurred is clear. In this case, not only is there a lack of evidence for causation, there's not even any evidence for harm.

People have died of cardiac events and lung cancer. Some people have used e-cigarettes. Some have not. Is there evidence that connects the use of e-cigarettes to these deaths? That's for science to decide.

Similarly: People have died of cardiac events and lung cancer. Some people have chewed gum while walking. Some have not. Is there evidence that connects chewing gum while walking? That's for science to decide. As it is, we have none. But until then, I'd rather not have it outlawed or be forced to pay for research without some reasonable reasoning that there may be some significant risk involved.

That's interesting, but there's something I don't quite get about it, so I am genuinely asking: are the pm2.5 or pm10 the problem, or is it what they're made of? Because I can understand that a 2.5micron sized soot particle (or droplet of water containing soot) can cause health issues when it ends up in the lungs; but what if the droplet is entirely made of something that doesn't cause irritation and is immediately metabolised to something else?

I believe it's the fact that it causes inflammation when your body tries to remove foreign masses. It's a good function that your body does to keep things anew. However, doing it constantly is a problem because it causes long term inflammation and oxidative stress. [0]

[0]. https://www.jacionline.org/article/S0091-6749(18)30029-0/pdf

Yes, I sort of understand, but you're talking about "masses".

I am wondering if the particulate in the studies cited above is not simply made of droplets of propylene glycol and glycerol- which might be well tolerated and simply absorbed and metabolised.

The pdf you linked starts with the statement:

"Decades of research has converged on an understanding that all combustion-derived particulate matter (PM) is inflammatory to some extent in the lungs". (Italics mine)

Particulate emitted by an ecig should not be combustion-derived.

Well two things. You don't need combustion to make chemical changes to organic material. E-cigs still chemically change the organic compounds. We know this experimentally [0].

Second, just because it's not a combustion product, doesn't mean it's safe. The reason why we get lung cancer form asbestos is that the mineral fibers are unable to be fully broken down, and cause long term irritation. Think sand or dust [1].

[0]. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954153/ [1]. http://www.npi.gov.au/resource/particulate-matter-pm10-and-p...

I remain with my original question: the original study you cited compares aerosols generated by e-cig smokers with the similar sized dust, pollution and soot particles commonly found outside. There is a correct assumption that particles of that size, when found outside in polluted environments, are especially harmful, because of their geometrical properties combined with the fact that they carry harmful substances. Is it correct to compare pm10 generated by combustion engines with pm10 generated by an atomizer that vaporizes a pharmacy-grade pure- and in theory harmless- substance? Would the same instruments have classified as pm10 water droplets of the appropriate size?

Hmm, your first link only measured PM10 at a vaping convention. Have they compared this to the PM10 of a non-vaping convention in the same space with similar amounts of people? Isn't PM10 a lot less harmful than PM2.5?

The article does discuss other studies on PM2.5, but they seem to be conflicting (some says indoor vaping increases PM2.5, some say it doesn't. Can you edit your comment to reflect the uncertainty here?

For what it's worth, the marathons in China are quite fun.

Looking over the methods, I don't think this specific study included measurements of similar conference density. That said, I would suppose that most conferences wouldn't generate much PM10. Off the top of my head, you could probably compare it to a poorly ventilated kitchen.

For scientific rigor I will edit to include this nuance. PM10 tends to be associated with more acute problems, while PM2.5 is associated with more chronic problems [0]. PM10 remains a closely monitored public health reporting metric. Taken together however, the notion that vaping is "just water vapor" is fraudulent (and knowing the historical context of the tobacco industry, knowingly so [1]).

I will allow myself to complain that there are many threads in this comment section that make very broad statements that are unsubstantiated by science. Though I suppose it's the cross to bear for scientists arguing in good faith.

[0]. http://www.euro.who.int/__data/assets/pdf_file/0006/189051/H... [1]. https://www.wnyc.org/story/gleaning-truth-merchants-doubt/

>In fact, we now have compelling epidemiological evidence that vaping almost doubles risk of cardiac events [1].

Somewhat misleading since more than half of those studied were smoking and vaping. From the study:

Among the 9,352 current and former e-cigarette users, 333 (3.6 percent) had experienced a heart attack at some point, with the highest percentage (6.1 percent) among those who used e-cigarettes daily. In the analysis, a quarter of the 2,259 people who currently used e-cigarettes were former smokers of conventional cigarettes and about 66 percent of current e-cigarette users were also current cigarette smokers.

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