Final answer:
Air quality in the United States is cleaner than it was roughly 50 years ago, owing to effective anti-pollution policies and a reduction in key air pollutants such as carbon dioxide by 12% between 2007 and 2012.
Step-by-step explanation:
The air quality in the United States today is generally cleaner than it was roughly 50 years ago. Despite the population growth of 63 percent and the economy increasing more than 3.8-fold from 1970 to 2020, the implementation of various anti-pollution policies has led to significant progress in reducing air pollution. Data from the U.S. Energy Information Administration (EIA) show that emissions of key air pollutants, including carbon dioxide emissions, have declined substantially, with a 12% reduction (740 million metric tons) between 2007 and 2012 alone.
These improvements reflect efforts taken to address the compounding stress that humanity's use of fossil fuels and urbanization have been putting on the Earth's atmosphere. Due to new technologies and regulations, along with changes in energy use and public awareness, the United States has made headway in combating pollutants like soot, hydrocarbons, carbon monoxide, nitrogen oxides, and sulfur oxides, contributing to a cleaner environment and enriched quality of life beyond what is reflected in the GDP.