What regulation was most significant in reducing air pollution in Los Angeles during the 1950s and 60s?

The Clean Air Act was significant in reducing air pollution in Los Angeles during the 1950s and 60s because it established a comprehensive federal framework for regulating air pollutants. Enacted in 1970, it marked a pivotal shift towards a more proactive stance in air quality management, providing the government with the authority to set national air quality standards and requiring states to develop plans to achieve and maintain these standards.

Although initiatives specifically targeting vehicle emissions played a crucial role in the efforts to tackle smog in Los Angeles, the broader impact of the Clean Air Act aimed at integrating various pollution sources and required a systematic approach to air quality that included public health protections. The act not only addressed industrial emissions but also included robust regulations for mobile sources, such as automobiles, which were primary contributors to air pollution in Los Angeles.

Moreover, the Water Quality Act and Industrial Emissions Standards did not primarily focus on the air quality challenges that Los Angeles faced during this period, as they concentrated more on water pollution and emissions from industrial sources respectively, rather than the widespread smog driven by vehicle emissions. Thus, the Clean Air Act stands out as the key regulation that provided the foundational framework necessary for long-term reductions in air pollution in the region.