Final answer:
Two common air quality concerns protected against by the Clean Air Act are airborne sulfuric acid and airborne metals like mercury, both of which pose significant health and environmental risks. The Act does not address sewage or deforestation, which are outside its primary focus.
Step-by-step explanation:
The Clean Air Act is a comprehensive federal law that regulates air emissions from stationary and mobile sources. Among other things, it authorizes the Environmental Protection Agency (EPA) to establish National Ambient Air Quality Standards (NAAQS) to protect public health and the environment. The EPA has identified and set standards for six common air pollutants, which are referred to as criteria pollutants:
These pollutants are known to cause and contribute to a wide range of health issues, including respiratory problems, cardiovascular disease, and neurological effects, as well as environmental damage such as acid rain, which impacts forests and bodies of water. Regarding the student's question, two common air quality concerns that the Clean Air Act protects against are: