Question

what is the main focus of the primary standard for critical air pollutants? promoting visual appeal ensuring human health protecting industrial facilities shutting down businesses

Explanation:

The primary standard for critical air pollutants is set by the Environmental Protection Agency (EPA) under the Clean Air Act. Its main purpose is to safeguard public health. Visual appeal, industrial facility protection, and business shutdowns are not the core objectives of these primary standards.

Answer:

ensuring human health