Try breathing in a bag.
Air is 21% oxygen. On average, a resting adult breathes in about 250ml of oxygen per minute.
Air is about about 0.04%. The average adult expels approximately 200ml to 250ml of carbon dioxide per minute. Roughly the same as the o then they intake.
So the relative percentage of C02 increases extremely rapidly in any small volume of air, compared to relative reduction in oxygen.
Up to 0.5% (5,000 parts per million): Considered safe for prolonged exposure, this level is typically used as an occupational exposure limit.
1% to 2%: Can cause drowsiness and poor air quality perception.
3%: May lead to impaired hearing, headache, and increased blood pressure and pulse rate.
5% and above: Can lead to shortness of breath, dizziness, confusion, and even loss of consciousness. Exposure at this concentration for several hours can be dangerous to human health.
Above 8%: Can be fatal.
More? Once someone expires, the percentages reach an unwanted steady state!
Even in a tightly closed building, CO2 buildup can impact cognition.
And build up in the atmosphere impacts the heat balance of the planet.
Your exhalations are only pollution when they destabilize healthy levels. So that’s a bit of a straw man concern.
Breathing (outside of plastic bags, and unventilated buildings): fits within normal planetary balance of C02. Not a concern as a pollutant.
Continuously burning billions of tons C02 generating chemicals for decades, another matter.
Dumb argument. Is water a pollutant because of the drowning risk?
> Your exhalations are only pollution when they destabilize healthy levels. So that’s a bit of a straw man concern.
So CO2 is not a pollutant because it is a product of breathing.
Regarding,
> Dumb argument. Is water a pollutant because of the drowning risk?
It might be counter intuitive - because water is not a risk in most contexts. But on another planet where water is an unusual corrosive, then of course it could be a pollutant.
And even on Earth, if some production system kept pumping our environment full of water as a side effect of some process, to the point of endangering or killing ecosystems, in that context it would be a pollutant.
A pollutant is when the accumulation of some left over of a process significantly alters and harms its environment.
Pollutant is a statement about some material’s impact in its context. It isn’t something inate, without context.
They have a lot of properties that can be useful in materials - hydrophobicity, lipophobicity, chemical resistance, low friction, etc.
They are certainly used in some niches (like medical devices, protective clothing, advanced manufacturing) that people would agree are Important, but a significant percentage of production goes into, and a significant amount of contamination comes out of, stuff like stain-proofing couches and making food packaging grease resistant. I’m under the impression that a lot of environmental contamination likely also comes from their use in firefighting foams - a useful application to be sure, but there are some things it’s not a great idea to spray straight into the environment.
> Are they chemically bonded to something that reduces bio-interactivity?
A huge part of the story of PFAS is that they are quite resistant to (permanent) chemical bonding, which has often lead to them being thought of as “inert” in a sense that is conflated with safety. But this sense of inertness is a bit of a red herring when it comes to biology (plenty of things interact with receptors without covalently bonding) and meanwhile makes them highly persistent both within organisms and in the environment.
“PFAS” as a literal chemical category feels pretty broad. The ones best established to be harmful are fluorosurfactants like the whole list explicitly targeted here. But broadness is also kind of the point because there are tons of chemicals in use that are likely to have similar accumulative properties that have never really been studied for health effects, and which can’t really be assumed to be harmless if the others aren’t.
Are these chemicals dangerous in the forms that they're found in the environment, e.g. there are unlikely to be many pools of acid. Are they chemically bonded to something that reduces bio-interactivity?
I don't agree with the approach "you can't do anything new until you prove it's safe". I also am very skeptical of the EPA ever since they declared CO2 a pollutant (sorry, my exhalations are not "pollution").
Like every sane person I want a clean environment. Like any rational person, I want to understand the trade-offs of regulations before I support or oppose them.