[aprssig] Chemical sensors

[Russ Chadwick]

Does anyone know of an inexpensive sensor that can measure the concentration
of a given gas in the atmosphere?  For example, something that could give
the concentration of poison gas as might be used in a terrorist chemical
attack.  A device that could monitor the concentration of this gas might be
a good addition to APRS weather stations situated in large cities.  I'd
appreciate it if you could send me any URLs off line.

Thanks.

Russ Chadwick    KB0TVJ
Boulder, Colorado, USA
http://www.wxqa.com