Ambient carbon monoxide monitor

A portable instrument was designed and two units were built to monitor the concentration of CO in ambient air. The air flows through a sampling section that is approximately 43 cm long with a 28 pass optical system that produces a total path of 12 meters. Gas filter correlation methods are employed for the detection and discrimination against other gas species in the air. An H2O monitor built into the main instrument measures the concentration of H2O and automatically accounts for a small amount of interference by the gas. Interference by all other atmospheric gases is negligible. The minimum detectable concentration of CO is less than 0.02 ppm. The instrument is powered either by batteries or by a battery pack.