Everybody is talking about vaping and “popcorn lung” again

A previous version of this article showed a wildly inaccurate graph*. I had previously calculated the density of diacetyl in popcorn factory air using its density in a liquid state (0.990 g/ml) rather than its density in a gaseous state (.0036 g/ml) which put the popcorn factory exposure at 275 times what it should have been, and I apologise for any confusion (thanks to NeilR for catching my mistake in the comments below).

I should have known better, as I’ve read numerous times over the years that average exposure to diacetyl in popcorn factories where bronchiolitis obliterans (popcorn lung) was developed by workers was much lower than exposure to diacetyl from smoking cigarettes. This is commonly pointed to as evidence that diacetyl didn’t cause popcorn lung because smoking has not been found to be a risk factor for it, while others argue that popcorn lung may go undiagnosed in smokers with respiratory illnesses and that even if diacetyl wasn’t the only cause, there is evidence that in high doses it can cause harm to airways in laboratory animals. I’d also like to point out once again that the specific cases shown below are only the specific cases shown below. Some e-liquid aerosols contain much higher levels of diacetyl than the averages from the studies available, and some contain none at all.

Additionally, I added data from the Farsalinos study to the updated graph. There were some requests that I add other information, such as numbers reported by Five Pawns, but I can’t reasonably add liquid concetration data to a graph of daily inhaled diacetyl from aerosol, smoke, and air.

You all know what it is I’m talking about, so I’m not going to reinvent the wheel here. Check out FarsalinosThe Daily Caller’s articleSuck My Mod’s thoughts on it, or my guide to vaping and health if you want to learn more. I just wanted to graphically show you the magnitude of diacetyl exposure in a few specific cases.

Harvard: 9 microgram/cartridge average, 239 microgram/cartridge maximum

Farsalinos: average of 56 microgam/5 mL of vaporized e-liquid

Popcorn factory: 0.2 ppm diacetyl

Cigarettes: average of 336 micrograms/cigarette

Each green square represents one microgram of inhaled diacetyl. The Harvard study seems to have used cigalike-style equipment for all of their testing, and most of those cartridges are advertised as lasting for 200-400 puffs, which is similar to the number of puffs in a pack of cigarettes (10-19 puffs per cigarette), so one cartridge to one pack of cigarettes to one full working day in a factory seemed like an alright comparison. Farsalinos assumed a 5mL per day vaping habit in his calculation.

The Math

Harvard study: 9 micrograms was the average mass of diacetyl found in the aerosol produced by one flavor cartridge in the recent Harvard study.  The worst offender from the study was 239 micrograms and is also included.

Farsalinos: Farsalinos conducted tests last year that found a median daily exposure level of 56 micrograms per day for a vaper who went through 5mL per day.

Cigarette study: 6,718 microgams was the average mass of diacetyl found in the smoke from a single cigarette by the 2006 UC Davis study, multiplied by 20 for a pack.

Popcorn factory:  760,320 micrograms. 2765 micrograms. The concentration of diacetyl inside one of the factories where a worker did contract bronchiolitis obliterans averaged 0.2 ppm (maximum of 80 ppm during parts of the mixing process) as reported by OSHA. Here’s the math I used to convert that into mass/day inhaled:

*This is where I previously made that huge little mistake. 0.990g/mL was entered where 0.0036g/mL currently is, leading to a preposterous number for daily exposure:

If it looks like I missed or overlooked anything here (again), please, let me know. And please, don’t try adding any additional meaning to the facts I’ve presented here. And of course, this chart would look a little different if we took specific e-liquids with higher concentrations of diacetyl and calculated exposure from vaping 60mL of e-liquid per day rather than vaping a milliliter or two out of a cigalike or 5 millilters out of an ego.

Originally written by Shawn C. Avery 11th Dec 2015. Reproduced here with grateful thanks to David Newell @dnglos and Web Archives