The Fresh Air Challenge

by Janelle Klein MSN, ARNP

Fresh air is essential to health.  We live in an amazingly interactive and mutually dependant environment.  Plants put free oxygen (O2) in the air, which we must have and we (and other animals) make carbon dioxide (CO2) that the plants must have to survive.

Air is composed of about 78% nitrogen, about 21% oxygen and 0.04% carbon dioxide.  The body uses the oxygen and exhales air with about 15% oxygen.  At the same time our lungs breathe out about 4.2% carbon dioxide, which is than 105 times more than inhaled air!

If the oxygen concentration in our blood drops low over a long period of time, such as happens when a person smokes or breathes second hand smoke, the body will adapt by increasing the amount of red blood cells.  This is an attempt to capture more oxygen from the lungs.  Unfortunately, this adaptation increases a person's risk for stroke.  However, if the oxygen levels in the air are high, for extended periods of time, the lungs can be damaged by oxidative stress. 

However, the body is comparatively more tolerant with increased levels of oxygen than it is with carbon dioxide.  Even a small increase of carbon dioxide in the air is toxic to the human.  Breathing in air that contains carbon dioxide levels as low as 2 to 3% can cause shortness of breath and cause the body to automatically starting to breath deeply and rapidly in order to get rid of carbon dioxide.  Governmental records show that people have died with levels as low as 8% for only 5 minutes although generally 30% carbon dioxide is considered lethal. 

Fresh air is absolutely necessary to keep people alive and well!  So make sure your homes and places where you spend your time have a continual source of fresh air. 

Two important things that help fresh air be fresh are: 

1) Green plants (they use up carbon dioxide) and

2) Contact with water (rain, ocean surf, flowing rivers).

Those two things are not generally abundant inside our houses.  So we can compensate for that fact by keeping our windows open as much as possible.  This is especially important at night or while we sleep.  Also, never run your car or an engine (such as a generator) inside a closed garage.  Not even for a quick test! 

Here is fun little challenger for people who love a math!  Figure the following scenario:

Two people go into a air tight room and do not come out for 12 hours. 

Calculate the % of oxygen and % carbon dioxide in the air at the point they leave the room.

Here are a few additional facts that will help you solve this brain stretcher:

The bedroom is 10 feet wide X 10 feet long and for the ease of calculation we will make the ceiling 10 feet high.

There are 28.32 liters of air in a cubic foot. 

A normal human breaths about 8 liters of air, per minute, at rest.  

Here are the answers:

The oxygen would decrease to about 18.6%

The carbon dioxide would increase to about 1.8%.

A level of 1.8% is getting very close to a problem.  So the moral of the challenge is that you should make sure that you have fresh air circulating in your home and work place at all times.

Click here to read another article about how your nose protects your lungs.