Vehicle emissions control
Starting in the 1950s and 1960s, various regulatory agencies were formed with a primary focus on studying the vehicle emissions and their effects on human health and the environment.
The regulatory requirements of the Clean Air Act, which was amended many times, greatly restricted acceptable vehicle emissions.
By the 1974 model year, the United States emission standards had tightened such that the de-tuning techniques used to meet them were seriously reducing engine efficiency and thus increasing fuel usage.
The new emission standards for 1975 model year, as well as the increase in fuel usage, forced the invention of the catalytic converter for after-treatment of the exhaust gas.
In 1972, General Motors proposed to the American Petroleum Institute the elimination of leaded fuels for 1975 and later model year cars.
[citation needed] The production and distribution of unleaded fuel was a major challenge, but it was completed successfully in time for the 1975 model year cars.
For example: to meet this challenge, General Motors created a new "Emissions Control Systems Project Center" (ECS) first located at the AC Spark Plug Engineering Building in Flint, Michigan.
The amendments also required a procedural change for the creation of gasoline to ensure there are less emissions of hydrocarbons (HC), carbon monoxide (CO), nitrogen oxides (NOX), particulate matter (PM), and volatile organic compounds (VOCs).
[7] Throughout the years, the Environmental Protection Agency (EPA) continued to implement new regulations to reduce harmful emissions for vehicles.
Despite the plethora of negative health impacts discovered, no regulatory requirements were implemented to reduce lead levels in gasoline until 1983.
In short, the EU forms the policy (by setting limits such as the European emission standard) and the member states decide how to best implement it in their own country.
In the United Kingdom, matters concerning environmental policy are "devolved powers" so that some of the constituent countries deal with it separately through their own government bodies set up to deal with environmental issues: However, many UK-wide policies are handled by the Department for Environment, Food and Rural Affairs (DEFRA) and they are still subject to EU regulations.
[10] It was very important to system designers to meet the emission requirements using a minimum quantity of catalyst material (platinum and/or palladium) due to cost and supply issues.
Air injection is now used to support the catalytic converter's oxidation reaction, and to reduce emissions when an engine is started from cold.
The air injected upstream of the converter supports combustion in the exhaust headpipe, which speeds catalyst warmup and reduces the amount of unburned hydrocarbon emitted from the tailpipe.
In a typical system, vapors from the fuel tank and carburetor bowl vent (on carbureted vehicles) are ducted to canisters containing activated carbon.
Some US states are also using a technology which uses infrared and ultraviolet light to detect emissions while vehicles pass by on public roads, thus eliminating the need for owners to go to a test center.
