Exhaled carbon monoxide: a non-invasive biomarker of short-term exposure to outdoor air pollution

BMC Public Health

Table 2 Level of exhaled carbon monoxide and carbon monoxide in ambient air level

Variables	Mean	Standard deviation	p
Baseline exhCO (ppm)	13.4	7.6
exhCO at the end of the working day (ppm)	18.5	9.5	0.004
2 last hours ambCO^a	5.6	4.4
4 last hours ambCO^a	5.7	4.5	0.01
6 last hours ambCO^a	6.3	4.7
ambCO	6.6	3.8

ambCO ambient carbon monoxide, exhCO exhaled carbon monoxide
^aMean values of ambCO before the measurement of exhCO at the end of the working day (in ppm)

ISSN: 1471-2458