20+
Please note that some urban areas may have high environmental
levels of CO. This can cause a rise in exhaled CO of a few ppm
above that which is normally present on the breath. In these cases
it is possible for a non-smoker to appear at the bottom of the 'light
smoker' range (7 – 10 ppm).
The above table applies when the unit is measuring expired CO with
the switch in middle position. When measuring FCOHb, with the
switch in the top position, the red indicator will illuminate whenever
the expired CO measurement is 7 ppm and above.
References
1. Carbon monoxide in breath in relation to smoking and
carboxyhemaglobin levels.
Wald NJ, Idle M, Boreham J, Baily A
Thorax 1981; 36, 366-369
2. Definition of a reliable threshold value for detecting
current smokers by CO measurement
Marino Luigi; Latini Roberto; Barbano Gina; Bazzerla Giorgio;
De Luca Anita, Nardini Stefano - Respiratory and TB Unit-
General Hospital- Via forlanini, 71-I-31029-Vittorio Veneto (TV-
ITALY).
Heavy smoker
Flashing red with
alarm
11