Editing Vehicle emissions control (section)

==History==
{{more citations needed|date=November 2010}}
Throughout the 1950s and 1960s, various federal, state and local governments in the [[United States]] conducted studies into the numerous sources of air pollution. These studies ultimately attributed a significant portion of air pollution to the automobile, and concluded air pollution is not bounded by local political boundaries. At that time, such minimal emission control regulations as existed in the U.S. were promulgated at the municipal or, occasionally, the state level. The ineffective local regulations were gradually supplanted by more comprehensive state and federal regulations. By 1967 the State of [[California]] created the [[California Air Resources Board]], and in 1970, the federal [[United States Environmental Protection Agency]] (EPA) was established. Both agencies, as well as other state agencies, now create and enforce emission regulations for automobiles in the United States. Similar agencies and regulations were contemporaneously developed and implemented in [[Canada]], [[Western Europe]], [[Australia]], and [[Japan]].

The first effort at controlling pollution from automobiles was the [[PCV valve|PCV (positive crankcase ventilation)]] system. This draws crankcase fumes heavy in unburned hydrocarbons – a precursor to [[photochemical smog]] – into the engine's intake tract so they are burned rather than released unburned from the crankcase into the atmosphere. Positive crankcase ventilation was first installed on a widespread basis by law on all new [[Model year|1961-model]] cars first sold in California. The following year, [[New York (state)|New York]] required it. By 1964, most new cars sold in the U.S. were so equipped, and PCV quickly became standard equipment on all vehicles worldwide.<ref name=Petersen>{{cite book | last = Rosen (Ed.) | first = Erwin M. | title = The Peterson automotive troubleshooting & repair manual | publisher = Grosset & Dunlap, Inc. | year = 1975 | isbn = 978-0-448-11946-5 }}</ref>

The first legislated [[Exhaust system|exhaust (tailpipe)]] [[emission standards]] were promulgated by the State of California for 1966 model year for cars sold in that state, followed by the United States as a whole in model year 1968.  Also in 1966, the first [[emission test cycle]] was enacted in the State of California measuring tailpipe emissions in PPM (parts per million).  The standards were progressively tightened year by year, as mandated by the EPA.

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. This was not possible with existing [[Tetraethyllead|leaded]] [[gasoline]], because the lead residue contaminated the platinum catalyst. In 1972, [[General Motors]] proposed to the [[American Petroleum Institute]] the elimination of leaded fuels for 1975 and later model year cars.{{Citation needed|date=November 2016}} The production and distribution of unleaded fuel was a major challenge, but it was completed successfully in time for the 1975 model year cars. All modern cars are now equipped with catalytic converters to further reduce vehicle emissions.

Leading up to the 1981 model year in the United States, passenger vehicle manufactures were faced with the challenges in its history of meeting new emissions regulations, how to meet the much more restrictive requirements of the [[Clean Air Act (United States)|Clean Air Act]] (United States) per the 1977 amendment. 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.  Its purpose was to "Have overall responsibility for the design and development of the carborated and fuel injected closed loop 3-way catalyst system including related electronic controls, fuel metering, spark control, idle speed control, EGR, etc. currently planned through 1981."<ref name=GMtoday>{{Cite magazine|magazine=GM Today |title=(untitled) |volume=6 |number=8 |publisher=General Motors|date=September 1980}}</ref><ref name="auto">{{Cite book|first=Ronald W.|last=Cox|title=Wheels Within Wheels|pages=29–30 |publisher=Kindle Direct Publishing|date=2018|isbn=978-1987537116}}</ref><ref name="auto1">{{Cite book|first=Ronald W.|last=Cox|title=Delco Electronics|pages=111–127 |publisher=Kindle Direct Publishing|date=Dec 2020|isbn=9798575886945}}</ref>

In 1990, the Clean Air Act (CAA) was amended to help further regulate harmful vehicle emissions. In the amendment, vehicle fuel regulations became more stringent by limiting how much sulfur was allowed in diesel fuel. 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 (NO<sub>X</sub>), particulate matter (PM), and volatile organic compounds (VOCs). Changes made to the CAA also required the use of oxygenated gasoline to reduce CO emissions.<ref name=":1">{{Cite web |last=US EPA |first=OAR |date=2016-06-27 |title=Timeline of Major Accomplishments in Transportation, Air Pollution, and Climate Change |url=https://www.epa.gov/transportation-air-pollution-and-climate-change/timeline-major-accomplishments-transportation-air |access-date=2024-05-10 |website=www.epa.gov |language=en}}</ref>

Throughout the years, the Environmental Protection Agency (EPA) continued to implement new regulations to reduce harmful emissions for vehicles. Some of the more important update standards are as follows.

* 1983: For areas with big pollution problems, Inspection and Maintenance programs were created, meaning vehicles would need to get tested for emissions.
* 1985: Changed the allowable amount of gasoline to 0.1 grams per gallon.
* 1991: Lowed the allowable emissions of HC and NOx for vehicle tailpipes
* 1993: Began developing new vehicle technology to help triple the fuel economy in family sedans, thus reducing harmful emissions.
* 1996: Lead in gasoline officially banned. New regulations created with intentions of innovating vehicle design to be cleaner for the environment and improving engine performance.
* 1998: Diesel engine standards further increased in efforts to reduce ozone and PM emissions for various vehicles including industrial equipment.
* 1999: Tailpipe emission standards are finalized, sulfur contents in gasoline are reduced, and various boats/other marine vehicles using diesel had reduced emission limits for NOx and PM.<ref name=":1" />

=== History of lead in gasoline ===
In 1922, lead was added to gasoline as an antiknock agent. It was not until 1969, nearly five decades later, that research began to show the negative health affects related to lead as a pollutant. Despite the plethora of negative health impacts discovered, no regulatory requirements were implemented to reduce lead levels in gasoline until 1983. Slowly, countries began banning use of lead in gasoline entirely from the years of 1986 to 2021. Japan was first to ban lead in gasoline in 1986, with North and South America following with nearly every country in the two continents banning lead by 1998. Africa was the latest to ban lead in gasoline with most countries banning in 2004 and 2005 and the last, Algeria, which didn’t ban it until 2021.<ref>{{Cite journal |last=Ritchie |first=Hannah |author1-link=Hannah Ritchie |last2=Roser |first2=Max |author2-link=Max Roser |date=2024-03-01 |title=How the world eliminated lead from gasoline |url=https://ourworldindata.org/leaded-gasoline-phase-out |journal=Our World in Data}}</ref>