The process you're describing relates to air quality regulations and emissions standards, which are typically enforced by government agencies to mitigate air pollution and protect environmental and public health. In various countries, such regulations often target the emissions of certain pollutants from various sources, such as vehicles, industrial facilities, and power plants.
In the United States, for example, the Environmental Protection Agency (EPA) sets limits on the emission of these pollutants under the Clean Air Act. The aim is to control the levels of harmful substances in the atmosphere, reduce the impact of climate change (through carbon dioxide and other greenhouse gases), and improve overall air quality. Compliance with these regulations helps to minimize the adverse effects of air pollution on human health, ecosystems, and the climate.