Final answer:
Laws require the enforcement of National Ambient Air Quality Standards when toxic substances in the air exceed acceptable limits. The EPA can impose fines and mandate that companies install specific anti-pollution equipment to control emissions.
Step-by-step explanation:
When toxic substance levels in the air rise above established limits, the law, particularly the Clean Air Act, requires that the Environmental Protection Agency (EPA) enforce National Ambient Air Quality Standards. These standards are in place to protect both public health and the environment, with primary standards focusing on human health, and secondary standards focusing on public welfare concerns such as environmental damage. Command-and-control regulations specify allowable amounts of emissions and require companies to install pollution control technologies, such as equipment on smokestacks or automobile tailpipes. If these limits are exceeded, companies can face penalties, fines, or be required to take measures to reduce their pollutant output.
The goal of these regulations is to ensure that the social costs of pollution are accounted for by the firms. Contaminants have enforceable concentration values, and the EPA sets a Maximum Contaminant Level (MCL) for various air pollutants. If a company exceeds the MCL, it may be subject to enforcement actions, including fines and penalties. Specific technologies may also need to be implemented to control the pollution and meet the required standards.