Long-path laser monitor of carbon monoxide: system improvements.

A system for measurement of long-path absorption of carbon monoxide has been redesigned for improved performance. The diode laser source is frequency stabilized by automatically correcting the laser current and is limited to a single-wavelength output by a tunable étalon. As a result, sensitivity variations of the system to CO are limited to +/-0.7%, and system response is linear with respect to CO concentrations.

Carbon monoxide automobile emissions measured from the interior of a traveling automobile.

During a procedure to monitor carbon monoxide (CO) concentrations inside a traveling car, it was discovered that CO emissions from individual passing vehicles produced accurately measurable increases in the CO concentration. The CO produced by individual vehicles varied by three orders of magnitude; this finding demonstrates that a relatively small number of cars can be responsible for a high percentage of total vehicle CO Emissions.