Indoor Carbon Dioxide Levels Could Be a Health Hazard, Scientists Warn (theguardian.com) 172
An anonymous reader quotes a report from The Guardian: Indoor levels of carbon dioxide could be clouding our thinking and may even pose a wider danger to human health, researchers say. The authors of the latest study -- which reviews current evidence on the issue -- say there is a growing body of research suggesting levels of CO2 that can be found in bedrooms, classrooms and offices might have harmful effects on the body, including affecting cognitive performance. "There is enough evidence to be concerned, not enough to be alarmed. But there is no time to waste," said Dr Michael Hernke, a co-author of the study from the University of Wisconsin-Madison, stressing further research was needed. Writing in the journal Nature Sustainability, Hernke and colleagues report that they considered 18 studies of the levels of CO2 humans are exposed to, as well as its health impacts on both humans and animals.
Traditionally, the team say, it had been thought that CO2 levels would need to reach a very high concentration of at least 5,000 parts per million (ppm) before they would affect human health. But a growing body of research suggests CO2 levels as low as 1,000ppm could cause health problems, even if exposure only lasts for a few hours. The team say crowded or poorly ventilated classrooms, office environments and bedrooms have all been found to have levels of CO2 that exceed 1,000ppm, and are spaces that people often remain in for many hours at a time. Air-conditioned trains and planes have also been found to exceed 1,000ppm.
Traditionally, the team say, it had been thought that CO2 levels would need to reach a very high concentration of at least 5,000 parts per million (ppm) before they would affect human health. But a growing body of research suggests CO2 levels as low as 1,000ppm could cause health problems, even if exposure only lasts for a few hours. The team say crowded or poorly ventilated classrooms, office environments and bedrooms have all been found to have levels of CO2 that exceed 1,000ppm, and are spaces that people often remain in for many hours at a time. Air-conditioned trains and planes have also been found to exceed 1,000ppm.
Re:have they accounted for (Score:5, Funny)
that's methane
Buy a CO2 monitoring device (Score:4, Informative)
You can get them for about $80. It changed my life: I now properly ventilate my apartment and workplace, and am much more productive.
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483 PPM according to the monitor on the wall of my office. Bought it during the winter, when I was worried that having the windows closed would cause CO2 to spike, and it did (routinely breaking 1600 PPM); left it up because heck, it uses almost no power and it's kind of neat to know.
Once you've got an idea for the pattern - how much one person in a closed room changes the level per hour, how much difference it makes to have a door or window or whatever open, etc. - the monitor probably isn't needed any mor
move into a drafty house (Score:5, Interesting)
these energy efficient homes are killing us.
Re:move into a drafty house (Score:5, Interesting)
these energy efficient homes are killing us.
Solution: Heat recovery ventilation [wikipedia.org].
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Then you still have particulate matter and chemicals to deal with. A greenhouse might be a better investment.
Re:move into a drafty house (Score:5, Interesting)
Humidity is a real pain. The amount of water vapor the air can hold varies with temperature. So if the air outside is -10 C and 70% humidity, and you heat it up to 20 C to use indoors, it's no longer at 70% humidity. The humidity will drop because the air's capacity to hold water will increase as you heat it. To compensate for this, you have to add water vapor. But doing so cools the air (converting liquid water to vapor is endothermic - that's why your sweat cools you off as it evaporates). So even if your heat exchanger is 100% efficient, you still have to add energy to the incoming air to keep it at the same temperature as the outgoing air.
Air conditioning runs into a similar problem. As you cool the air, the humidity increases. You take 35 C air outside and cool it to 20 C, and your inside air reaches 100% humidity. To correct for this, air conditioners over-cool. They'll cool the air to (say) 10 C. The humidity hits 100% and excess water vapor condenses and drops out the air (why water drips out of your air conditioner). Then the air is warmed back up to 20 C dropping its humidity below 100%. Since the process is the reverse of evaporation above, it's exothermic. But the energy you gain goes into the water (or rather, whatever the water condenses onto - that's why your chilled beer warms up as water condenses on the bottle), not the air. So you still have to heat up the air from 10 C to 20 C.
One of the solutions in Asian homes (where people are typically barefoot, and sit on the floor) is in-floor heating and cooling. You don't bother trying to heat/cool the air. Instead, you heat/cool the floor. This sets up a direct temperature exchange between the floor and your body for comfort, while minimizing the complications of regulating the humidity in the air.
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Even when the goal is to heat / cool the air, in-floor is more efficient, particularly when you have high ceilings.
Imagine that you have a convention centre, and a bunch of people you're trying to keep cool (~20C) in a hot climate (~35C), all giving off heat. If you have your AC vents at the ceiling, you end up with an inverted stratification where there's consistently warm air near the people at the ground (who are emitting said heat) and cold air near the ceiling that has to diffuse / convect down. You ha
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There is a definite advantage, if properly designed, to supplying the cool air at the floor and returning/exhausting it from the ceiling, especially for
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To repeat:
The "hot air rising, cold air sinking" is an ideal stratification, which will occur A) in the absence of significant diffusion, and B) given sufficient mixing time - two constraints that are far from universally guaranteed (and if they're guaranteed, would apply to both floor-entry and ceiling-entry systems). Key to preventing this is that the fact that if your AC inlets are on the ceiling, then this is the guaranteed coldest place in the room. Air is n
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Most homes are actually ventilated by opening windows; the furnace & A/C are typically recirculation, only. Houses with supply at the floor were basically designed for heating, not cooling, or for the convenience of running the ductwork in the basement or crawl space. Also, many houses without basements heat and cool from overhead.
Server rooms using an underfloor supply plenum a
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It seems like a more sophisticated heat exchanger could deal with that issue. When the water vapour from the warm air condenses in the heat exchanger, it could be recovered and used to humidify the incoming air. Vice versa for AC.
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You're mixing up countercurrent and concurrent heat exchangers. Concurrent approaches 15C/15C. Countercurrent approaches 25C/5C. And it gets very close if you can neglect issues like water vapour.
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Just remember that a 100% efficient heat exchanger does not recover 100% of the energy from the exhaust side.
Actually, it does: Counterflow heat exchanger [quora.com]
If exhaust air from inside is going out at a comfortable 25C and you are exchanging with intake air from outside at 5C, then assuming 100% efficiency the intake rises to 15C and the exhaust cools to 15C.
Both flows go into different directions. The warm exhaust at the beginning of its travel is in thermal contact with the intake at the end of its travel, i.e. after that has already been preheated by the exhaust having travelled further. You get a nice gradient along the travel of both counterflowing fluids going from inside temperature down to outside temperature.
Of course real heat exchangers are not 100% efficient, so you still lose some heat, but not as much
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TFS says that air conditioning causes it too.
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I would be more concerned about the air conditioning, as when it's running the house is pretty well sealed up. With gas heating, the furnace has to pull in fresh air to replace the air that goes up the flue.
Re:move into a drafty house (Score:4, Interesting)
Rubbish. Architects have to adhere to stringent regulations for everything, including ventilation capacity. Energy efficient homes are more than capable of keeping CO2 levels acceptable.
A problem does arise when the homeowner decides not to ventilate and closes all the ventilation openings, without monitoring CO2 levels. Home ventilation suppliers responded to that by offering demand-controlled ventilation systems (using a CO2 sensor to set motor speed). Those systems may need to have their setpoints changed thanks to this research.
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Architects maybe, builders, not so much.
Where a through-wall vent is required (as is required for our lounge as we have a wood burner) - the "standard" offering is basically a gaping hole in the wall with a grille over it which you can paint. That's both unattractive and inefficient and leads to people blocking the grille up with tape or whatever.
In our case, we put in a baffled vent (which cost maybe +£5 over the unbaffled version) - it's still got the same airflow volume as we're required to have, b
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I'm curious what amount of plant biomass is necessary to make a meaningful impact on O2 and CO2 levels.
People like to say that plants purify the air. On the otherhand the pollen report for my region tells me that plants produce a lot of particulates that contribute to poor air quality.
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One large tree might suck up 100 lbs of CO2 in a year. A human being exhales about 1000ish lbs of CO2 a year. So, the answer is, a huge biomass for a tiny CO absorption. Completely unrealistic to improve indoor CO2 levels. This may also offer clues to the otherwise inexplicable failure of the movie Biodome.
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The main thing that plants do for indoor air quality is increase the humidity, which frequently lacks in interior spaces. Humidity is not just a comfort issue, but it also helps suppress various pollutants - it helps keep dust out of the air, and hydroxyl radicals are a key pathway for the decomposition of many types of pollutants (particularly organic compounds).
The vast majority of the water that you pour into a plant pot ends up in your air. It's like pouring it into a humidifier. Of course, you need en
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An elevated indoor level of CO2 is an indicator of elevated levels of airborne organic pollutants. These will also interfere with cognition and health in general.
Studies done early in the research for the ISS found that pothos plants and spider plants are both very good at removing common indoor airborne organic pollutants such as formaldehyde. I researched this in the late 1980s as I was moving my family into a brand new manufactured home and outgassing from carpets and glues was a concern. Keeping a numb
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People like to say that plants purify the air. On the otherhand the pollen report for my region tells me that plants produce a lot of particulates that contribute to poor air quality.
Some plants don't produce much pollen. Most of the ones we use inside fall into that category. Plants do purify the air. Have you ever noticed that they get dustier faster than other stuff inside? I don't know if that's just due to respiration, or it's some magic-seeming ionic effect, or both, but plants definitely filter air, to the point that you have to actually dust many houseplants.
We use spider plants and Ficus for air quality improvement.
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Yes, the pre-ISS studies used both plants and activated charcoal: the studies compared the effectiveness of several different approaches. This was in fact science, by the definition that scientific researchers use.
Pothos plants were found to be surprisingly effective in clearing formaldehyde and similar common pollutants. Also a pothos plant was forever ---once established the plant would live as long as the ISS lived--- while activated charcoal had to be periodically replaced.
However activated charcoal d
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Well, the key word you used it mass. The plant breaks apart the CO2 so it can use the carbon to grow. The O2 is a waste product. So if you can figure out how much of the mass of the plant is carbon, you can then figure out how much CO2 it had to break apart to acquire that mass. As you might guess for a typical house plant - where a good portion of the mass is water anyway, the answer is going to be "not very much".
retroscientists (Score:1)
So the older the research is the more valid it is to you? Why not base everything on 19th century science instead of 20th century science?
The thing about science is that each new paper attempts to reconcile observations, improve estimates, and increase our overall understanding of reality. You don't get to decide that the Mercury and Apollo programs were the pinnacle of scientific discovery and anything after 1969 must be from frivilous alarmists.
Re:Yes, the Navy and NASA have no clue about CO2 (Score:4, Informative)
A lot of the reason for our increased understanding of the negative impacts of higher CO2 levels is precisely because of research conducted on the ISS, where CO2 levels are both A) higher than on most environments on earth, and B) fluctuate significantly, allowing for crew health to be correlated with CO2 levels.
It's very difficult to keep ISS CO2 levels low, but research is pointing to the importance of keeping it as low as you realistically can.
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7000 ppm is the starting point for acute, perceptible symptoms. Cognitive impairment and long-term health effects come into play at much lower levels. They're demonstrating different effects that occur at different levels.
Think about it this way: How many cigarettes does it take to double your risk of lung cancer? A few per day maybe, over a period of years. How many cigarettes does it take to cause arrhythmia or a heart attack? Probably several packs in an hour, if not more.
It is normal to see a huge diffe
Get a window fan (Score:5, Interesting)
Set up a nice cross-breeze, strike a blow against local warming, get a little fresh air.
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AC keeps the air circulating quite nicely, I think.
Why are you trying to kill us all? :-)
Get A Whole-House Fan (Score:2)
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It'a like having a biplane in your attic!
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Well, lessee.....at night, the temps aren't getting much below 80F, often staying above 80F right now...getting August weather in July. And we're likely in the 75%+ humidity at any given time now, or higher....and you think I want to shut off my AC, open a window and blow that crap air in?
LOL...My AC pretty much cuts on mid April and doesn't shut off till about early to mid November here in the New Orleans area.
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Well, is your AC drawing on outside air, or is it just recirculating indoor air? I've had enough of living in tropical and even subtropical climates for a while, but summers here in my temperate coastal region are getting hot enough to want AC. When it's on, though, it's basically a window fan that also cools the air while keeping the bugs out, which is all in all a very nice arrangement (though I hate that it's getting necessary).
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I guess recirculating, it's a normal central AC unit that cools the whole house.
Go outside (Score:2, Insightful)
Go outside and play!
Submariners regularly experience higher (Score:4, Interesting)
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Did the Navy do a study about cognitive decline ?
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not a problem *for them*
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Please note: "stressing further research was needed", in other words, this is an appeal for funding. It's almost certainly complete bollocks.
Re:Submariners regularly experience higher (Score:5, Insightful)
When you post a link to a source which is known to be incredibly biased, it doesn't support your point at all. And makes it look like you have an axe to grind.
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I do like that your citation comes up with the conclusion: "I figure if the Navy thinks it is safe for men who have their finger on the nuclear weapons keys, then that is good enough for me."
What a truly dumb approach to science.
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The Navy doesn't want to spend money fixing the problem, but they really should, because typical office co2 levels affect human cognition [thinkprogress.org]. People are literally less intelligent in high co2 conditions.
The military abuses enlisted severely. When you enlist you give up many supposed rights, like the right to know what the military is doing to you medically. They got my dad hooked on uppers in Korea. He was in ATC.
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Yes, I get all of my health information from "wattsupwiththat.com" and "notrickszone.com". I'm sure that they're excellent sources for unbiased metaanalyses of the literature. ;)
c02 is probably the canary (Score:2, Insightful)
OTHER gasses / solvents / aerosols / dusts are the brain killing gorilla in the room. Brand new offgassing carpets, sheet rock, paint, cleaning products, sealants, all kinds of under-studied nasty stuff is floating around in public air in spots.
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Good point; CO2 is sensed in buildings as a proxy for body odor.
That burning sensation... (Score:5, Interesting)
CO2 is what your lungs are sensitive to, and what causes that burning sensation when you hold your breath for over 30 seconds. Contrary to what most people assume, when you hold your breath and your lungs start burning, it is not because the O2 levels are low, but because the CO2 levels are increasing. When the CO2 in the lungs increases too much it results in respiratory acidosis. In the Apollo 13 mission, they had plenty of O2, but they also were at risk of having too much CO2 (since the scrubbers in that part of the ship were only designed to remove the CO2 exhaled by two people and not three). So the big emergency was trying to find a way to get the CO2 out of their air and down to a safe level.
Interestingly, your lungs will not detect a lack of O2. If the O2 was totally removed from the air, and replaced with something inert like nitrogen, you would slowly go unconscious and eventually die. In fact, various states are considering using this method to execute death row inmates (simply removing the O2 from the air) since it would be humane and nearly fool-proof.
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Do finger detect hammer? Is the brain involved?
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The breathing reflex is controlled in the brainstem. The chemoreceptors that feed the system are located in the aorta, carotids, and brainstem.
https://en.wikipedia.org/wiki/... [wikipedia.org]
Re:That burning sensation... (Score:4, Informative)
Indeed, anoxia without associated hypercapnia is probably the most painless way to die. It's so painless that it's insidious, having caused a number of plane crashes over the years. Mild hypoxia leads to symptoms similar to alcohol consumption - impaired decision making, impaired motor skills, etc. The impaired decision making makes it even harder for a person to notice and react to their hypoxic state. As the oxygen partial pressure continues to fall, it steadily progresses from there to loss of consciousness, and eventually, death.
It's hypercapnia that makes you suffer when you hold your breath or breathe air in a confined space.
Re:That burning sensation... (Score:4, Informative)
Interestingly, your lungs will not detect a lack of O2.
This isn't entirely true. You are correct that you won't get that panic-burning sensation when hypoxia occurs without CO2 buildup, however your body can detect, via the peripheral chemoreceptors, low O2 levels without a corresponding increase in CO2 concentrations in the blood, and it will increase the respiratory effort accordingly. This can be observed during exercise or when visiting high altitudes.
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I work around the inert gas Argon and we have O2 sensors on the machines and sometimes on our belts to make sure we don't accidentally die. Inert gasses are very dangerous because their are few if any symptoms before unconsciousness and death.
Yep, like I said, you won't get that panic feeling. The effects are more subtle. You resp rate will increase but you probably won't even notice it before you pass out. It's an odd quirk that the only condition we are made consciously aware of by our bodies is the CO2 buildup even though our bodies also know when O2 drops as well. I suppose "stop holding your breath dummy!" or "take your head out of the damn hole idiot!" were more common and easily rectifiable situations than stumbling into a pocket of heav
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Ha! It is exactly because firing squads and hangings are problematic (gory, difficult for onlookers, variation in outcome even when procedure is the same etc..) that they are discussing the N2 option. Hanging in particular is a very non-exact science...
If the USaians need to be bashed over their death penalty, it is that they have not adopted the N2 already. Years ago, Michael Portillo did a documentary for the BBC Horizon series called "How to kill a human being". Back then the Americans did not want the N
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+1 Trivia I'd Probably Heard Before But Forgot
Plants plants (Score:5, Interesting)
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and more plants! In every room of the house/school/office/store/jail
The wrong type of plants are the reason that got a lot of folks into jail in the first place.
On the other hand, in a chilled out prison population, there might be less violence.
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Insufficient atmospheric moisture is far more common of a problem than excess, and low humidity leads to indoor air quality problems.
No, the amount of CO2 that they remove will not be significant. But the amount of water vapour that they add can be.
Scientific basis (or excuse) to avoid meetings (Score:2)
FTFA: "In the real world, CO2 concentrations in office buildings normally don’t exceed 1,000 ppm, except in meeting rooms, when groups of people gather for extended periods of time."
Sorry, I will be unable to attend your all-day PI Planning session because it will hurt my brain.
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Maybe this explains why the worst decisions are made in meeting rooms.
CO2 Cycle ... (Score:2, Informative)
When the human body "combusts" hydrocarbons it breaks carbon chains and replaces them with O2 attached to each carbon atom. This is the same process that occurs whenever you "set fire" to a carbon-chain compound (gasoline, diesel fuel, paper, whatever). The co2 that is produced gets "dissolved" in the water that comprises most of each "ugly bag of mostly water". This forms Bicarbonate and Hydrogen ions. In the lungs the bicarbonate is converted back to a gasseous state and "migrates" across the membrane
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Don't breathe (Score:4, Funny)
"Indoor Carbon Dioxide Levels Could Be a Health Hazard"
So we halve the Dioxide and use Carbon Monoxide, then we won't have to bother anymore.
Stop drinking sparkling beverages at home! (Score:2)
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Being curious, I looked up the numbers. One can of Coke has 2.2 grams of CO2.
Humans exhale about 1 kg/day, so it takes about 3 minutes to exhale a similar amount as contained in one can of Coke.
hey did you know (in other news) (Score:1)
I Started to Pass Out on Crowded Light Rail (Score:2)
Earlier Harvard study (Score:3)
https://thinkprogress.org/excl... [thinkprogress.org]
Old news, on Slashdot (Score:2)
Is Conference Room Air Making You Dumber? (nytimes.com) [slashdot.org]
Cognitive performance (Score:2)
Makes sense. CO2 is more dense than dry air and would tend to settle into your parent's basement.
Never mind the CO2, pass the CH4 (Score:2)
Alzheimers (Score:2)
I'm nearly 40, and it's just amazing how the very same lessons just keep being forgotten. I can't imagine how frustrating this will be for me when I'm 80.
It's not the CO2, it's not the pollution, it's not the cigarette smoke, it's not the junk food, it's not the sugar, it's not the fat, it's not the carbs, it's not the sedentary, it's not the manual labour, it's not the indoors, it's not the UV rays, it's not the alcohol, it's not the drugs.
It's the always CO2, it's the always pollution, it's the always ev
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Meth doesn't kill users in one dose.
Knife to the heart, no, but knife to other parts, aka ritual bleeding, is fine.
Ebola virus, I don't know enough about. But last I checked, many viruses are weakened and then used momentary vaccines; some viruses don't need to be weakened. Perhaps we don't [yet] know how to weaken ebola to within safe dosages.
All of that said, I imagine that one single ebola virus unit (cell?) won't kill you. And, of course, a thin enough knife, aka needle or laser or radiation, doesn't
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I don't believe the "irrevocably altered" part. Well, I should qualify that. Learning to ride a bicycle irrevocably alters your brain too. But I don't believe that the negatives of either alterations is forever a problem.
I'll grant you that there exist viruses that are too virulent (finally, it took forty years!) to survive a dose, in much the same way as getting hit on the end by a ten-tonne anvil.
1000 ppm here we come (Score:1)
Causality? (Score:1)
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possible long term brain damage
no, nitrogen wouldn't matter though
i don't know about argon actually
Re: How...? (Score:1)
While you may think of CO2 as an inert gas, it is highly active in the human respiratory system. If the partial pressure rises slightly then it inhibits the removal of CO2 from the lungs, and in turn the blood and the cells in the body and it kills you.
In any confined space build up of CO2 will kill you before loss of oxygen will.
There is also a physiological response to high CO2 (it's that feeling you get when you hold you breath as long as you can) but not to low oxygen.
Watch Apollo 13 or read about the
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Is your view that all chemical compounds are equivalent? Try adding 0,1% hydrogen cyanide to your air and see what you think of the result ;)
At elevated levels, carbon dioxide causes severe respiratory and nervous system distress, generally credited to respiratory acidosis (reduction of blood pH levels) interfering with hydrolysis of acetylcholine by acetylcholinesterase. Substitution of nitrogen by argon or vice versa (at atmospheric pressure) do not cause detectable symptoms at any level.
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maybe she also wants her extra apostrophe back
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92% efficiency for an air-to-air heat exchanger is totally unrealistic.
Furthermore, I'm looking at the Energy Star site [energystar.gov] and I don't see this.