from sources in the home, especially lead paint.
They also report finding 770 adults with evidence of
lead poisoning. Of the 634 for which the source of the
exposure was determined, 82 percent were work-related,
primarily from exposure to painting, fabricating metals,
and automotive work. Non-work sources included
firearms including five with gunshot wounds, painting,
and making lead fishing weights.
There is good reason to be concerned with lead
toxicity. However, there was no mention of exposure to
aircraft exhaust, and for good reason. It is so diluted that
it is literally lost in the atmosphere. Let us check some
numbers.
The article indicates that general aviation uses 250.5
tons of lead per year or 0.7 tons per day. Let’s compare
that with the total weight of the atmosphere above the
United States. The weight of the air pressing down on
the earth is about 1 ton per square foot. The National
Geographic Atlas indicates that the total area of the
United States is 13. 3 million square miles. Each square
mile includes 27. 9 million square feet, so the total weight
of air over the United States would be 371 million tons,
so the daily ration of lead to air would be 0.7 part to 371
million parts on a weight basis.
But you might say an aircraft is a point source leading
to a concentration of lead. Anyone who has watched
aerobatics with smoke generators knows that the smoke
becomes invisible in less than a minute. Even the huge
amount of smoke generated with the false bomb runs
during AirVenture dissipates quickly. Aircraft generate
a high level of turbulence, but even if the air would
return to a non-turbulent state, Brownian motion and
thermal and mechanical currents would rapidly dilute
the lead-air mixture. The lead would be in the vapor
phase during combustion in the cylinder and would be
discharged as very fine particles. Particles in the micron
size range act like another gas even though their density
is high.
I think EAA should invite the Friends of the Earth
to attend AirVenture and bring their measuring
equipment. First they would find that EAA members
are environmentally responsible when they pick up the
Kleenex they just dropped. I project they would find
that it would take years, if not centuries, for someone
New Lifetime Members
Alan White (EAA 60137), Superior, Wisconsin
Brian Willett (EAA 146096), Gilbert, Arizona
David Henning (EAA 146096), Port Orange, Florida
Jan Bohannon (EAA 881416), Bowling Green, Kentucky
James Brown (EAA 390248), Piqua, Ohio
James Brown (EAA 123064), West Alexandria, Ohio
Richard Taylor (EAA 96129), Medina, Washington
Joe Wyatt (EAA 579134), Nashville, Tennessee
George Fleet (EAA 861004), Calgary, AB, Canada
Charles Caldarale (EAA 376570), Minneapolis, Minnesota
Keith Hugo (EAA 378067), Centerville, Ohio
Thomas Strohl (EAA 799821), Fairlee, Vermont
Justin von Linsowe (EAA 124098), Metamora, Michigan
Thomas Mainland (EAA 211077), Racine, Wisconsin
Paul Franklin (EAA 606632), Middletown, California
Samuel Munn (EAA 29755), San Antonio, Texas
to inhale enough lead at the most active airport in the
world to reach a medically significant level of lead in
their blood.
William Splinter, PE, EAA 277067
Lincoln, Nebraska
I enjoyed the well-written article “Fuels for the Future”
in the February EAA Sport Aviation by Jeffrey Decker; this
was a complicated and difficult subject, and he presented
it well.
The comments on ethanol in fuel by Doug Macnair,
in my view, are very accurate. Macnair says that “ethanol
drastically changes the water separation of the fuel and its
vapor pressure.”
I agree; this can lead to phase separation with resultant
corrosion by the water/ethanol phase and engines being
presented with gulps of ethanol-laced water to digest. Ethanol
is a major component for maintaining vapor pressure, and
a variable content leads to a variable vapor pressure. He also
points out that the substantially lower energy content of
ethanol means higher fuel consumption.
The presentation of SwiftFuel as a viable alternative is
questionable; this is partly because the presented costs of
such a fuel were too vague.
The patents held by SwiftFuel are easily retrieved from
the United States Patent and Trademark Office and are
no mystery. What is immediately obvious is that this
