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Name: rosette
Status: other
Age: 40s
Location: N/A
Country: N/A
Date: Sunday, October 27, 2002


Question:
please explain to my son on an elementary level, how the oxygen is replenished in our homes/cars if we keep all the windows closed for extended time periods (Oct- Mar-winter in Ny) He's worried that we may not be getting enough air in the house, especially if we are all breathing it in. Please respond as he is nervous about this and we have to keep our windows open until we get a response.


Replies:
Rosette,

A very interesting question. I don't have an answer from any particular research, but I will tell you my understanding of this matter.

Your son has a very good point. During the time homes are closed up (for example, wintertime), air quality can reach unhealthful levels.

We rely during the summer for open windows and the occasional open door to allow some venting of the air in the house out to the environment, and replenishment with 'fresh' air.

There are many materials which can contribute to the unhealthful air I mentioned above. Some are:

smoke from smoking and cooking

volatile components of dyes from carpeting and fabrics, and of finishes on furniture ond floor polishi

"dirt" stirred up by walking inside the house of materials deposited on carpeting including residues of herbicides, pesticides, salts, etc.

volatile residue of cleaning material, for example, remaining small amounts of dry cleaning materials on clothing, drapes, etc.

volatile compounds from the combustion of heating material

natural chemical releases from the earth which enter the home via cellar floor cracks, eg. radon

To the extent a house is tightly buttoned-up, the conc entrations of these materials can reach levels where irritation can be caused to human mucous membranes. Any amount of venting of home air to dissipate such materials can have immediate effects in diminishing the unhealthy components of interior air.

Having mentioned all these possible sources of materials which could make house air unhealthy, we should remember that the oxygen we need for survival in home air is only a minor component of the air we breathe. Oxygen levels can be substantially reduced in an air sample before our bodies would perceive a problem.

One should not become paralyzed into fearing for their 'air health'; HEPA filters are available which can reduce airborne contaminants substantially. As your son mentions, the easiest method is to 'air out' the house with fresh air to get rid of pigments, dyes, and other "air pollution". Personal, I never wear shoes in the house, so no contaminants enter the home as residues of pesticides or herbicide or even plant fertilizers.

While the safety of some of the contaminants has been established, other contaminants have not been evaluated. This is an open field awaiting research which could have great influence in establishing home planning methods which insure the venting of contaminants and replacement with fresh air. Perhaps your son will one day want to do a scientific study of this issue.

Thanks for using NEWTON!

Ric Rupnik


Rosette -

My first thought is to tell your son that there have been no reports deaths due to this problem among the millions of homes in the world. That seems to tell me we are safe even with all the doors and windows closed.

Beyond that, even well built homes have an interchange of air with the outside - Every time you open the door... feel the draft that likely comes in around even closed windows... notice the draft around electrical outlets.

If we were to live in a non-permeable plastic bag, your son's concern would be real, but that is not the case. You have likely noticed the notes on plastic bags - "this is not a toy" and "a suffocation hazard." But if you look at what they "rap" the new homes in, it is described as a vapor barrier. It stops moisture from going through, but allows air through.

Tell you son to breath easy.

Larry Krengel


There is little need for concern that oxygen will be depleted. First, even a single room contains a LOT MORE OXYGEN than anyone would need for respiration. Second, even though the windows and doors are closed, houses exchange a lot of air with the outside unless it is sealed. This is further increased every time someone comes in or out of the house. Only in very confined spaces such as an empty refrigerator, does one have to be concerned with a lack of adequate oxygen for respiration. Some modern structures have been make "air tight" but even in these cases it is the volatile chemicals that diffuse out of carpets and furnishings that are of more concern than a lack of oxygen.

Vince Calder


Rosette,

Although, for purposes of energy conservation, homes are increasingly built to minimize air infiltration, there is virtually no chance that the home in which you live is air-tight. Fresh air leaks in, like it or not. Every time you enter and leave, air inside is exchanged with and replenished by air from outside. The heating system causes air-flows that contribute to the inside/outside exchange. Range hoods and attic fans (even when not operating) are paths through which air may enter and leave. Drafts near windows and doors can be evidence of air exchange. He need not worry, his (your) home undoubtedly has sufficient air exchange.

Regards,

ProfHoff 495



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