# Elizabeth comments on Do you believe in hundred dollar bills lying on the ground? Consider humming

• This is consistent with the dose being 130µl of a dilute liquid

Can you clarify this part? The liquid is a reactive solution (and contains other ingredients) so I don’t understand how you calculated it.

I agree the integral is a reasonable interpretation and appreciate you pointing it out. My guess is low frequent applications are better than infrequent high doses, but I don’t know what the conversion rate is and this definitely undermines the hundred-dollar-bill case.

• My prior is that solutions contain on the order of 1% active ingredients, and of things on the Enovid ingredients list, citric acid and NaNO2 are probably the reagents that create NO [1], which happens at a 5.5:1 mass ratio. 0.11ppm*hr as an integral over time already means the solution is only around 0.01% NO by mass [1], which is 0.055% reagents by mass, probably a bit more because yield is not 100%. This is a bit low but believable. If the concentration were really only 0.88ppm and dissipated quickly, it would be extremely dilute which seems unlikely. This is some evidence for the integral interpretation over the instantaneous 0.88ppm interpretation—not very strong evidence; I mostly believe it because it seems more logical and also dimensionally correct. [2]

[2] If you multiply 0.11ppmhr by 8 hours, you get 0.88ppmhr^2, which doesn’t make sense.

• Yeah I definitely misread that ppm/​hour. I’m unsure how to interpret *hrs, that seems nonsensical. I’m under a tight deadline right now but have reached out to some bio friends for help. Assuming this doesn’t turn out to be a typo, I’d like to give you a bounty for catching this, can you PM me your paypal info?

• I have received a bounty on paypal. Thanks for offering, as well as for laying out the reasoning in this post such that it’s easy to critique.

• Wait if 0.11ppm*hr is the integral, doesn’t that suggest the total amount is 0.11ppm? My biologist friends have failed me but that’s this twitter comment’s interpretation.

on the reagent math: I believe the methycellulose is fairly bulky (because it’s sold separately as a powder to inhale), which makes the lower about of NO more believable.

• I don’t know what you mean by “total amount” because ppm is a concentration, but that tweet’s interpretation agrees with mine.

The wording ppm*hour being a typo for ppm/​hour does not make sense to me because that would be dimensionally very strange. That could mean the concentration increases by 0.11 ppm per hour every hour, but for how long? A single dose can’t cause this increase indefinitely. The only ways that I could see exposure being measured sensibly are:

• ppm * hour (NO concentration of nasal air, integrated exposure over time, it is unspecified whether the concentration is 0.11 ppm for 1 hour or 19.8 ppm for 10 seconds or whatever)

• ppm (NO concentration of nasal air, peak)

• ppm (NO concentration of nasal air, average over the 8 hour interval between doses)

• ppm (concentration of the 0.56ml of nasal spray, so 0.11 ppm would be 0.06 nL or 0.06 µg or something of NO delivered).

• I don’t know what you mean by “total amount” because ppm is a concentration

The spray is clearly delivering a set amount, but describing it in ppm. Since the volume and density of air inside then nose isn’t changing, you can treat the change as a count rather than concentration.

that tweet’s interpretation agrees with mine.

My understanding of the tweet’s model is that [actual released amount] * [8 hours] = 0.11ppm, so [released amount] = 0.11/​8.

I still don’t understand your number. Could you expand the equation behind “If NO is produced and reacts immediately, say in 20 seconds, this means the concentration achieved is 19.8 ppm”?