Which of the following are considered critical air pollutants?

Critical air pollutants, often referred to as "criteria pollutants," are specific substances that have been identified by the Environmental Protection Agency (EPA) as harmful to public health and the environment. These pollutants are monitored and regulated under the Clean Air Act due to their widespread presence and potential for severe impact.

The correct choice lists carbon monoxide, lead, nitrogen dioxide, ozone, sulfur dioxide, and particulate matter as critical air pollutants. Each of these pollutants has established National Ambient Air Quality Standards (NAAQS) that aim to protect human health and the environment.

• Carbon monoxide is a colorless, odorless gas produced by combustion processes, and it can affect oxygen delivery in the body.

• Lead can have serious neurological effects, particularly in children, even at low exposure levels.

• Nitrogen dioxide contributes to respiratory problems and is a component of smog.

• Ozone, while beneficial in the upper atmosphere, can cause respiratory issues and other health problems when present at ground level.

• Sulfur dioxide is linked to acid rain and various respiratory problems.

• Particulate matter encompasses a mix of tiny particles and droplets in the air that can penetrate deep into the lungs and even enter the bloodstream.

In