Many emissions standards focus on regulating pollutants released by automobiles (motor cars) and other powered vehicles.
Others regulate emissions from industry, power plants, small equipment such as lawn mowers and diesel generators, and other sources of air pollution.
The first automobile emissions standards were enacted in 1963 in the United States, mainly as a response to Los Angeles' smog problems.
Three years later Japan enacted their first emissions rules, followed between 1970 and 1972 by Canada, Australia, and several European nations.
Regulations on nitrogen oxide emissions (NOx) were introduced in the United States, Japan, and Canada in 1973 and 1974, with Sweden following in 1976 and the European Economic Community in 1977.
[8] In 2014, the EPA published its "Tier 3" standards for these vehicles, which tightened air pollution emission requirements and lowered the sulfur content in gasoline.
The states must also promulgate miscellaneous emissions regulations in order to comply with the National Ambient Air Quality Standards.
[10] In December 2021 EPA issued new greenhouse gas standards for passenger cars and light trucks, effective for the 2023 vehicle model year.
[citation needed] California is attempting to regulate greenhouse gas emissions from automobiles, but faces a court challenge from the federal government.
On 19 May 2009, news reports indicate that the Federal EPA will largely adopt California's standards on greenhouse gas emissions.
[15] California and several other western states have passed bills requiring performance-based regulation of greenhouse gases from electricity generation.
In an effort to decrease emissions from heavy-duty diesel engines faster, CARB's Carl Moyer Program funds upgrades that are in advance of regulations.
Vehicle owners are excluded from modifying their property in any way that has not been extensively researched and approved by CARB and still operate them on public highways.
China's State Environmental Protection Administration (SEPA) upgraded emission controls again on 1 July 2004 to the Euro II standard.
The standards and the timeline for implementation are set by the Central Pollution Control Board under the Ministry of Environment & Forests.
[39] The standards were based on those adopted by the original US Clean Air Act of 1970, but the test cycle included more slow city driving to correctly reflect the Japanese situation.
This gave manufacturers breathing room to properly engineer solutions and also incentivized fixing the best-selling models first, leading to smoother adoption of clean air standards and fewer drivability concerns than in many other markets.
The regulation designated a total of 196 communities in the Tokyo, Saitama, Kanagawa, Osaka and Hyogo Prefectures as areas with significant air pollution due to nitrogen oxides emitted from motor vehicles.
The regulation was amended in June 2001 to tighten the existing NOx requirements and to add PM control provisions.
This delay was introduced in part to harmonize the NOx and PM Law with the Tokyo diesel retrofit program.
[53] The regulation for testing of existing vehicle exhaust gases is Official Newspaper number 30004 published 11 March 2017.
Members of the European Economic Community (EEC) had a unified set of rules, considerably laxer than those of the United States or Japan.
Germany gave financial incentives to buyers of cars that met US or ECE standards, with lesser credits available to those that partially fulfilled the requirements.
[1] Sweden was one of the first countries to instill stricter rules (in 1975), placing severe limitations on the number of vehicles available there.
These standards also caused drivability problems and steeply increased fuel consumption - in part because manufacturers could not justify the expenditure to meet specific regulations that applied only in one very small market.
[61] One problem with the strict standards was that they did not account for catalyzed engines, meaning that vehicles thus equipped had to have the catalytic converters removed before they could be legally registered.
[69][70][71] Emissions tests on diesel cars have not been carried out during MOTs in Northern Ireland for 12 years, despite being legally required.
The current policy is to fully harmonize Australian regulations with United Nations (UN) and Economic Commission for Europe (ECE) standards.
[78] In April 2023, the Australian government released its National Electric Vehicle Strategy, which included a commitment to introduce a Fuel Efficiency Standard to address greenhouse gas emissions.
[79] The government undertook consultation on the model for the standard in April and May 2023, and they intend to introduce legislation by the end of 2023[80] Research commissioned by environmental NGO Solar Citizens has calculated that a Fuel Efficiency Standard that started at 95g CO2/km and reduced to 0g CO2/km over ten years would save Australian motorists $11b over the first five years.