National Ambient Air Quality Standards do not apply to which of the following?

National Ambient Air Quality Standards (NAAQS) are established by the EPA under the Clean Air Act to protect public health and the environment from harmful air pollutants. These standards apply to specific pollutants that are commonly found in the ambient air and can pose risks to human health and the environment.

Carbon dioxide is classified as a greenhouse gas rather than a traditional air pollutant in the context of the NAAQS. While it is crucial for discussions around climate change and is monitored for its rising levels in the atmosphere, the NAAQS primarily focus on pollutants that have immediate health effects and are associated with smog, acid rain, and other direct health impacts.

On the other hand, sulfur dioxide, nitrogen oxides, and carbon monoxide are included in the NAAQS because they have established health-based standards due to their adverse effects on air quality and human health. The purpose of the NAAQS is to set limits on these specific pollutants to protect public health and the environment, which is why carbon dioxide is not included in the same category.