Concern over environmental problems first began to engage public opinion in the United States during the 1950s, when high pollution levels in major cities such as Los Angeles, Chicago, and Pittsburgh, combined with the popularity of Rachel Carson’s book, Silent Spring, aroused concerns over the impact that unfettered industrialization was having on the quality of life and the health of the American people. During the next several decades, federal, state, and local governments began to issue regulations directed at reducing smog in urban areas and improving the quality of rivers and streams throughout the country. In general, most Americans reacted favorably to such regulations, but by the 1980s, the environmental movement had engendered a backlash as some people complained that excessively radical measures could threaten the pace of economic growth and a loss of jobs in the workforce. By the end of the century, concern over the environment was deeply entangled with concerns over the state of the national economy. Still, it was clear that the quality of life in environmental terms was much improved for the vast majority of Americans compared to what had existed prior to World War II.