Breathing out poison

American biomedical
researchers at the Harvard
School of Public Health,
Boston, have devised a
simple instrument to
accurately measure carbon
monoxide (co) in a person's
lungs (Environment Science
Technology, Vol 29, No 1).

The device, invented by
the Harvard scientists
Kiyoung Lee and Yukio
Yanagisawa, consists of a
mouthpiece, an air trap
system and an adsorbent
tube.

A subject is asked to
inhale room air deeply, hold
it for 20 seconds and blow
into the mouthpiece. The
system traps only the last
part ofthe exhalation, which
is the air emanating from
deep within the lungs and
indicates the co level for the
body. The sample is then
passed on to the adsorber
where co is collected by a
zeolite-based material and
analysed for co levels.