4 ms·

Why would CO2 be caused by vaping? And surely the amount of CO2 caused by a cigarette is dwarfed by the amount exhaled by a person?

gpm 1y ago
A person outputs about 1kg of CO2 per day, which is less than 1 gram per minute. A cigarette weighs roughly a gram, which means it probably emits roughly 3 grams of CO2... or less... (The O2 comes from the environment, and weighs 32 to carbons 12, but the cigarette isn't actually pure carbon). I don't know... that's maybe detectable? You'd need a pretty sensitive CO2 sensor and to be tying it to other signs to avoid "someone else walked into and out of the room"... but in principle...
- FireBeyond 1y ago
  > A person outputs about 1kg of CO2 per day, which is less than 1 gram per minute. I'm skeptical about this. Normal adult tidal volume is about 500mg, with a normal respiratory rate of 12/min, so 6L/min. Normal air is about 0.05% CO2, so you're at 3 grams/minute atmospherically that is inspired and expired. We actually output closer to 4% CO2. 240ml/minute. With the windows and doors closed in my 10x20 living space and 4 people, CO2 can easily go from a baseline 4-500PPM to over 1000 in an hour. That's not 240 grams of CO2 doing that. https://airly.org/en/the-composition-of-inhaled-and-exhaled-air/ https://airly.org/en/the-composition-of-inhaled-and-exhaled-...
  - gpm 1y ago
    For what it's worth here's a NASA document using the same 1kg/day number: https://ntrs.nasa.gov/api/citations/20090029352/downloads/20090029352.pdf https://ntrs.nasa.gov/api/citations/20090029352/downloads/20... I don't know where I originally got that value from, it's one that has stuck in my head for years.
  - vitus 1y ago
    You're mixing your units -- 0.05% of 6L is 3mL. In order for that to weigh 3g, atmospheric CO2 would have to be as dense as water. Most figures I see peg 1mL of CO2 at closer to 2mg (it's about 50% heavier than the equivalent atmospheric volume, since that's mostly N2 with some O2). Your estimate of 240 mL / minute is about 346L per day, or about 700g of CO2. That's roughly the same order of magnitude as the cited 1 kg / person / day. edit: Another way of thinking about it: if you scale up your numbers to grams per day, you'd end up with a ludicrous 346 kg / human / day. Multiply that by 12/44 (mass of Carbon-12 vs CO2), and that's the equivalent of a human shedding 100kg of carbon every day from just breathing. Most humans don't even weigh that much.
    - FireBeyond 1y ago
      You're absolutely right, I apologize - I did mix units, and my thoughts collapse from there.

gpm 1y ago

A person outputs about 1kg of CO2 per day, which is less than 1 gram per minute. A cigarette weighs roughly a gram, which means it probably emits roughly 3 grams of CO2... or less... (The O2 comes from the environment, and weighs 32 to carbons 12, but the cigarette isn't actually pure carbon). I don't know... that's maybe detectable? You'd need a pretty sensitive CO2 sensor and to be tying it to other signs to avoid "someone else walked into and out of the room"... but in principle...

FireBeyond 1y ago
> A person outputs about 1kg of CO2 per day, which is less than 1 gram per minute. I'm skeptical about this. Normal adult tidal volume is about 500mg, with a normal respiratory rate of 12/min, so 6L/min. Normal air is about 0.05% CO2, so you're at 3 grams/minute atmospherically that is inspired and expired. We actually output closer to 4% CO2. 240ml/minute. With the windows and doors closed in my 10x20 living space and 4 people, CO2 can easily go from a baseline 4-500PPM to over 1000 in an hour. That's not 240 grams of CO2 doing that. https://airly.org/en/the-composition-of-inhaled-and-exhaled-air/ https://airly.org/en/the-composition-of-inhaled-and-exhaled-...
- gpm 1y ago
  For what it's worth here's a NASA document using the same 1kg/day number: https://ntrs.nasa.gov/api/citations/20090029352/downloads/20090029352.pdf https://ntrs.nasa.gov/api/citations/20090029352/downloads/20... I don't know where I originally got that value from, it's one that has stuck in my head for years.
- vitus 1y ago
  You're mixing your units -- 0.05% of 6L is 3mL. In order for that to weigh 3g, atmospheric CO2 would have to be as dense as water. Most figures I see peg 1mL of CO2 at closer to 2mg (it's about 50% heavier than the equivalent atmospheric volume, since that's mostly N2 with some O2). Your estimate of 240 mL / minute is about 346L per day, or about 700g of CO2. That's roughly the same order of magnitude as the cited 1 kg / person / day. edit: Another way of thinking about it: if you scale up your numbers to grams per day, you'd end up with a ludicrous 346 kg / human / day. Multiply that by 12/44 (mass of Carbon-12 vs CO2), and that's the equivalent of a human shedding 100kg of carbon every day from just breathing. Most humans don't even weigh that much.
  - FireBeyond 1y ago
    You're absolutely right, I apologize - I did mix units, and my thoughts collapse from there.