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Q: Animal respiration. ( Answered 5 out of 5 stars,   0 Comments )
Subject: Animal respiration.
Category: Science > Biology
Asked by: federico-ga
List Price: $10.00
Posted: 21 Oct 2002 12:50 PDT
Expires: 20 Nov 2002 11:50 PST
Question ID: 86080
What quantity of carbon dioxide per day is contained in the exhaled
respiration of an average adult human being?
Subject: Re: Animal respiration.
Answered By: bobbie7-ga on 22 Oct 2002 13:21 PDT
Rated:5 out of 5 stars
Hello Federico, 

Thank you for your question.

According to the solutions to “Take a Breath Worksheet” from the
College of Chemistry – University of California -  Berkeley, 432 L. of
carbon dioxide is exhaled by an average adult per day.

This is how the results were obtained:

The volume of a breath and number of breaths per minute will vary with
the size of the person and the level of activity.

A reasonable range for the average volume of a breath is 0.1-1.0
liters.  0.5 liters is the volume of an average breath, so we will use
that number for the calculation.

“The average volume of air moved during normal quiet breathing is 0.5
L. “
College of Science and Mathematics, James Madison University

The average person breathes approximately 15 times per minute during
normal activity.

For one person, the approximate volume of air exhaled per day is: 

0.5 L of air   15 breaths   60 minutes   24 hr   10,800 L of air
------------ X ---------- X ---------- X ----- = ---------------------
  breath          min.         hr.        day            day

“The next assumption to consider is what portion of the volume of air
exhaled is carbon dioxide. The maximum it could be is ~20%, which is
the amount of oxygen in the atmosphere. However, it is unlikely that
the conversion of oxygen to carbon dioxide is 100% efficient. A
reasonable estimate is that one quarter to one half of the oxygen
inhaled is converted to carbon dioxide. We'll pick one quarter for the
calculation, which is 4% of the air exhaled. Thus, the approximate
volume of CO2 exhaled by one person is:

10,800 L of air               432L of CO2
---------------   x  0.04 =   -----------
     day                          day

College of Chemistry – University of California, Berkeley

chapter 4, on the average 288 L of carbon dioxide are produced per day

A short excerpt from this text:
“At rest, the average sized adult produces approximately 200 ml of
carbon dioxide per minute. Carbon dioxide production (VCO2) is of
course a continuous process, as is oxygen consumption. VCO2 increases
during exercise and declines slightly during sleep. On the average,
288 L of carbon dioxide are produced per day (1440 min x 200 ml
CO2/min). (..) Carbon dioxide elimination is accomplished by bringing
fresh air into the lungs; there is no other way to excrete the body's
CO2 production. A minuscule amount of carbon dioxide, less than 1%, is
excreted by the kidneys as bicarbonate.”
Source: Mt. Sinai Hospital Website

360 L a day of carbon dioxide is given off by a human being lying down
flat on his back. This is a calculation made based on 250 ml. carbon
dioxide exhaled per minute.

Averaging out the three above figures, (432+288+360), we can assume
that 360 L. of carbon dioxide per day is exhaled by an average adult
human being.

Additional information that may interest you:

Normal Respiratory Rates:
Adults:   12-20/minute
Children: 18-24/minute
Infants:  40-60/minute

The average volume of gas inhaled/exhaled in one breath for an adult
male is 500 mL.
Rogers State university

During normal breathing about 6-7 mL of air moves in and then out of
the lungs with each breath for every kg a person weighs. Thus, if you
weigh about 70kg (155lb), the amount that you breath in and out with
each breath is about 500 mL and is referred to as the tidal volume.

“The concentration of carbon dioxide in an exhaled breath varies with
time; the first portion contains no carbon dioxide and comes from the
upper respiratory tract where no gas exchange takes place (the
anatomical dead space - 2mls/kg). The concentration of carbon dioxide
then rises rapidly to a plateau of about 5% as alveolar gas is
breathed out.”

“In the life-supporting process of aerobic respiration, oxygen from
incoming air enters the blood; and carbon dioxide, a waste gas from
the metabolism of food, is exhaled into the atmosphere. Air entering
the lungs contains about 21 percent oxygen and 0.04 percent carbon
dioxide. Air leaving the lungs contains about 14 percent oxygen and
about 4.4 percent carbon dioxide. The composition of the air changes
between inspiration and expiration, when the air is deep in the lung
Western Skies Dialysis Website

Search Criteria:

amount of carbon dioxide exhaled 
carbon dioxide eliminated expiration
carbon dioxide exhaled respiration average adult 
average end tidal volume carbon dioxide in adults

I hope you find this helpful.

Best Regards,
federico-ga rated this answer:5 out of 5 stars
The answer was well researched, well documented, and well explained.
The researcher is quite evidently very intelligent and very
systematic.I'm delighted!

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