Final answer:
California was the first state to regulate emissions from lawn and garden equipment, establishing the California Air Resources Board in 1967 and influencing national and state emissions standards.
Step-by-step explanation:
The state of California was the first state to regulate the emissions from lawn and garden equipment. This regulation is part of a set of comprehensive environmental laws that began to be enacted in the late 1960s and early 1970s in the United States. The California Air Resources Board was established in 1967, even before the federal Clean Air Act was signed into law. The federal Environmental Protection Agency (EPA) has since adopted California's emission standards nationally, starting with the 2016 model year. California continued to play a pioneering role in environmental regulation, evident by its ongoing efforts to set stricter emission standards and challenging the revocation of its authority to set higher standards than the federal government during the Trump Administration. This leadership has influenced many other states and the District of Columbia to adopt higher standards as well.