What major pollutant is primarily targeted by smog checks?

The major pollutant primarily targeted by smog checks is carbon monoxide (CO). Smog checks are designed to reduce emissions from vehicles that contribute to air pollution, and carbon monoxide is a notable component of vehicle emissions that is harmful to human health. This colorless, odorless gas is produced during the incomplete combustion of fossil fuels and is particularly prevalent in urban areas with heavy traffic.

Carbon monoxide can cause a variety of health problems, including impaired oxygen transport in the bloodstream, which can be especially dangerous for individuals with pre-existing health conditions. Smog checks aim to ensure that vehicles are running efficiently and meeting federal and state emissions standards, thereby reducing the amount of CO and other harmful pollutants emitted into the atmosphere.

While nitrogen oxides (NOx), carbon dioxide (CO2), and particulate matter (PM) are important pollutants also addressed by environmental regulations and vehicle emissions standards, the specific focus of smog checks primarily highlights carbon monoxide reduction. This focus is crucial for improving air quality and protecting public health.