Re: Scientific Study of Nitrox and Air use

Greg Mossman wrote:
"-hh" wrote:

So in a nutshell the question is if "half of zero" really is
better than "zero".

I think the better question is whether 0.04% is really zero.

We currently can't lower the risk below 0.04%. That's what makes it
effectively zero.

And considering that we know that 25% of the Adult population has a PFO
which IIRC has roughly 4x the DCS risk, this means that we're aware of
a subpopulation with roughly a 0.20% risk, yet because no Rec Agency
requires a diving candidate to undergo a PFO screening test as part of
their pre-certification medical, the "Accepted Industry Practice" is
choosing to ignore this demonstrably higher risk. YMMV on if you agree
with them, but DAN has stated that this PFO-attributable condition is
an acceptably "small" (relative) risk in diving.



If 0.04% is zero, 0.08% is twice zero and would still be zero. However,
that defense won't work very well, say, in a DUI case when you try to
convince the judge that you're not really drunk because you only blew a
0.08% on the Breathalyzer and that's really just zero because it's merely
twice zero.

The fallacy in this example is twofold. First, we're talking about
trying to reduce risk, not increasing it. Second, in the case of
alcohol, it is possible to consume some small amount and have a blood
alcohol that's below 0.04%, but with diving, if we proverbially even
stick a toe in the water, its a step function to an activity risk floor
of 0.04%.

We aren't (yet) capable of reducing this "background noise" without
effectively total cessation of diving activity, whereas even an
alcoholic can safely eat a vanilla cupcake, and "zero" DWI's are due to
the driver's consumption of 2 TSP/4hrs of cough syrup.


And the pragmatic question is even if it did achieve "half
a zero", is it significant enough to be worth paying an
extra $8/tank for?

What price to put on the all saved lives? I dunno.

Cross that bridge once we come to it, for the road we're on might not
even lead us there.


If I had my way, I'd sue whoever invented air for product liability.

Don't worry, you'll get to meet Him, eventually, to plead your case:
we pretty well know that air is toxic to human life, although it has a
half-life of 74 years (as per most life insurance companies :-)


Plus you have all the collateral benefits, some real, some imaginary.


You should have said collateral "effects", for they're not all
necessarily beneficial: if nothing else, spending the extra money for
Nitrox means less cash remaining for booze :-)

And yes, the effects encompass both the physiological and psychological
realms, which in Humans can be very difficult to quantitatively
partition, particularly when the test subject's motivation levels are
an uncontrolled variable.


-hh

.

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