During the smog check, which emissions-related part may often be examined for tampering?

The catalytic converter is a critical component of the vehicle's emissions control system, designed to reduce harmful gases from engine exhaust before they are released into the atmosphere. During a smog check, it is particularly important to examine the catalytic converter for signs of tampering because it plays a vital role in meeting federal and state emissions standards.

Tampering can involve physical modifications, removal, or the installation of non-compliant aftermarket parts that compromise the converter's functionality. This can lead to an increase in harmful emissions such as carbon monoxide, hydrocarbons, and nitrogen oxides, which are detrimental to air quality and public health. Inspectors are trained to identify any alterations or defects in the catalytic converter, making it a focus point during inspections to ensure compliance with environmental regulations.

The other components listed, while important to the vehicle's operation and emissions control, such as the fuel tank, air filter, and muffler, do not have the same level of critical impact on emissions as the catalytic converter, nor are they as frequently targeted for tampering.