The U.S. government has been working for over 50 years to address air quality concerns for its citizens and to regulate and reduce overall emissions going into the atmosphere. In the 1970s the Clean Air Act (CAA) was established which is a comprehensive federal law that regulates air emissions from stationary and mobile sources. The CAA established and authorized the Environmental Protection Agency (EPA) to protect public health and welfare through National Ambient Air Quality Standards (NAAQS) which regulate emissions and hazardous air pollutants. The goal of the CAA was to have NAAQS in every state by 1975. However, it was amended in 1977, and then again in 1990, to extend the deadlines for these standards, as many of the impacted industries and organizations had failed to meet the originally established timelines.