Re:[asa] Another perspective on CO2

My professional area is submarine life support systems, so I can make
some comment on Bill's question. Unlike an industrial worker who gets
to go home for 16 hours each day, a submariner is exposed 24/7. We are
very conservative about exposing sailors to all sorts of chemicals in
the submarine atmosphere. For that reason, we are usually well below
OSHA or similar levels. Our standard for 90 day exposure to CO2 is 0.5%
average (that's 5,000 ppm) with no measurable medical effect on humans.
Now of course, 90 days do not equal a lifetime exposure.

CO2 alters the pH of blood, but I'm not aware studies of this at low
levels. I believe that the pH of oceans might be more susceptible.
Studies of plant life have been done may times, but if I remember right,
the results are complex and even possibly contradictory. I've heard of
plants growing faster, but not producing seed or fruit as well. I head
that Biosphere 2 was being used for a study of trees in controlled CO2
enriched space.

Al McCarrick

Bill wrote:

The other aspect of CO2 concentration in the atmosphere is its effect on
human health. The presence of CO2 in our lungs (or maybe in our blood?)
is what stimulates us to breathe. Is there any research on the effects
of higher CO2 concentrations on human health?

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Received on Wed Jan 31 10:35:13 2007