Which pair of emission readings would most likely indicate a good catalytic converter?

A good catalytic converter is designed to reduce harmful emissions by converting them into less harmful substances as part of the exhaust system. Therefore, the reading of emissions can provide insight into the effectiveness of the catalytic converter.

When looking at the pair that indicates a good catalytic converter, low levels of nitrogen oxides (NOx) and low levels of carbon monoxide (CO) are significant indicators. A well-functioning catalytic converter successfully reduces both NOx and CO emissions, which are byproducts of combustion that can be harmful to the environment and human health.

Low NOx levels suggest that the conversion of nitrogen oxides, which contribute to smog formation, is occurring effectively. Similarly, low CO levels indicate that the carbon monoxide, a toxic gas, is also being adequately processed. When both of these emissions are low, it reflects the catalytic converter’s proper operation and its ability to perform its intended function of minimizing harmful tailpipe emissions.

In contrast, high NOx suggests inefficiency in reducing those emissions, while high CO indicates combustion issues not being addressed by the catalytic converter. Therefore, the combination of low NOx and low CO demonstrates that the catalytic converter is operating effectively, supporting the assertion that option C is the correct choice.