Carbon monoxide limiting oxygen concentrations

High levels of sulfur not only form dangerous oxides, but they also tend to poison the catalyst in the catalytic converter. As it flows over the catalyst in the exliaust system, the sulfur decreases conversion efficiency and limits the catalyst s oxygen storage capacity. With the converter working at less than maximum efficiency, the exhaust entering the atmosphere contains increased concentrations, not only of the sulfur oxides but also, of hydrocarbons, nitrogen oxides, carbon monoxides, toxic metals, and particulate matter. 

B. Carbon Monoxide CO is an odorless, colorless gas that competes avidly with oxygen for hemoglobin. The affinity of CO for hemoglobin is more than 200-fold greater than that of oxygen. The threshold limit value (TLV) of CO for an 8-hour work day is 25 parts per million (ppm) in heavy traffic, the concentration of CO may exceed 100 ppm. 

Once the response of the sensor is stabilized at the chosen oxygen pressure, we adjust the carbon monoxide partial pressure. The field of study has been voluntarily limited to low concentrations of carbon monoxide, that is, below 200 ppm. We have then been able to check that, whatever the experimental conditions, the electric response of the sensor is stable and reversible. 

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