Which type of emissions do three-way catalytic converters effectively reduce?

Three-way catalytic converters play a crucial role in reducing pollutants produced by internal combustion engines. Their design is intended to simultaneously reduce three primary types of emissions: hydrocarbons (HC), carbon monoxide (CO), and nitrogen oxides (NOX).

Hydrocarbons are unburned fuel particles that result from incomplete combustion, and these converters help oxidize them into carbon dioxide and water. Carbon monoxide is a poisonous gas that forms due to insufficient oxygen during combustion, and the catalytic converters convert it into harmless carbon dioxide. Nitrogen oxides are produced at high combustion temperatures and can contribute to smog and acid rain; the converter reduces these emissions back to nitrogen and oxygen.

The other options refer to either different pollutants or combinations that do not align with the primary function of the three-way catalytic converter. Hence, the chosen answer accurately describes the specific emissions that these converters are designed to reduce effectively, highlighting their importance in meeting environmental regulations and improving air quality.