Environmental regulations have played a significant role in reducing the use of lead in gasoline and improving air quality. Lead was initially added to gasoline in the form of tetraethyl lead TEL as an anti-knock agent to improve engine performance and reduce knocking. However, the combustion of leaded gasoline released lead particles into the atmosphere, which posed significant health risks to humans and the environment.In the 1970s, scientific research began to reveal the harmful effects of lead exposure, including neurological damage, developmental issues in children, and various other health problems. As a result, governments around the world started implementing environmental regulations to phase out the use of lead in gasoline.In the United States, the Environmental Protection Agency EPA introduced the Clean Air Act in 1970, which aimed to reduce air pollution and protect public health. One of the key components of this act was the gradual reduction of lead content in gasoline. The EPA set a series of increasingly stringent standards for lead content, which led to a significant decrease in the use of leaded gasoline.By the mid-1980s, unleaded gasoline became the standard fuel for new vehicles, as they were equipped with catalytic converters that required unleaded fuel to function properly. The use of leaded gasoline continued to decline, and by 1996, the sale of leaded gasoline for on-road vehicles was completely banned in the United States.Similar regulations were implemented in other countries, leading to a global decline in the use of leaded gasoline. As of 2021, leaded gasoline has been phased out in almost all countries, with only a few still allowing its use for specific purposes, such as aviation fuel for piston-engine aircraft.The reduction in leaded gasoline usage has had a significant positive impact on air quality. Studies have shown that lead levels in the air have decreased dramatically since the implementation of these regulations. This has led to a reduction in lead exposure for the general population, resulting in improved public health and a decrease in lead-related health issues.In conclusion, environmental regulations have been crucial in phasing out the use of lead in gasoline and mitigating its harmful effects on air quality and public health. The success of these regulations demonstrates the importance of science-based policy-making and international cooperation in addressing environmental and health concerns.