Emissions standards

Emissions standards seek to protect the environment and the climate by setting limits on the amount of pollutants and greenhouse gases (GHGs) that may be emitted by motor vehicles, factories, and other sources of anthropogenic air pollution.

Background

The evolution of emissions standards began largely in response to the heavy vehicular traffic and industrialization of major urban areas. At the beginning of the twentieth century, the word “smog” was used to describe the grim atmospheric haze created by smoke and sulfur dioxide from burning coal. This haze was especially noticeable in large cities such as London, which had already suffered from the effects of burning coal for centuries. As automobiles became popular, pollutants from coal were joined by photochemical smog, created by emissions from gasoline engines and other sources, releasing that were acted upon by sunlight.

Over time, with increased scientific research, the global scope and long-range impact of air pollution became more apparent, and local efforts to prevent further damage were joined by national and international policies and agreements. In the United States, the Environmental Protection Agency (EPA) sets National Ambient Air Quality Standards, which regulate carbon monoxide, lead, nitrogen dioxide, particulate matter, ozone, and sulfur dioxide. These key pollutants are measured by both volume and weight, and measurements are made based on the amount of fuel input. Regulations based on fuel input have been criticized as being less relevant to overall than regulations based on output.

One of the most significant international agreements regulating emissions is the Kyoto Protocol of 1997, which implemented the suggestions of the 1992 United Nations Framework Convention on Climate Change. An important feature of the protocol is that industrialized nations agreed to cover more of the initial costs of reducing than did developing nations. Also, the promoted and other viable economic incentives that make international cooperation in combating global warming more practical.

Stationary Emissions Standards

Factories and power plants have been subject to varying emissions standards, with a focus on regulating major sources. In the United States, the Clean Air Act Extension of 1970 was amended in 1990 to define major sources as individual or grouped stationary sources with the capacity to release 9 metric tons or more per year of a single pollutant, or 23 metric tons or more per year of combined pollutants. Coal, which is still used all over the world, is a significant source of dangerous mercury pollution, and many nations, including China, are still heavily dependent on coal for power. In 2005, the EPA issued the Clean Air Mercury Rule in an attempt to reduce mercury emissions from coal-burning power plants in the United States. The EPA under the administration of President Donald Trump, whose agenda was typically in favor of reducing environmental protection restrictions, severely limited enforcement of a 2012 rule designed to restrict mercury emissions from coal and oil-fired plants on the basis that it was unnecessarily financially burdensome for the industry. However, the EPA under the administration of President Joe Biden announced in early 2022 that it would be reinstating the rule. In addition to then announcing revisions to the mercury emissions rule to make it even stronger, at that point the EPA also introduced proposed new rules for limiting emissions from both existing and new coal-fired and gas-fired plants. In a major setback to the fight against climate change, that proposal was shut down by the US Supreme Court in June 2022 in a ruling that argued that the EPA did not have the power to regulate greenhouse gas emissions in power plants.

Efforts to reduce emissions continued after the ruling, though. In 2024, the EPA announced a new emissions rule to cut down on toxic emissions known to cause cancer, including ethylene oxide and chloroprene, from chemical plants. The rule would impact more than two hundred facilities, many of which were located near majority-Black neighborhoods in the southern United States, resulting in a reduction of over 6,200 tons of harmful air pollutants each year.

Road-Based Vehicular Emissions Standards

One of the most significant sources of global air pollution is the exhaust from cars and trucks. While the image of factory smokestacks is often used as a symbol for air pollution, the cumulative effect of millions of vehicles, even with catalytic converters, is potentially catastrophic. In 2004, carbon dioxide emitted by personal vehicles in the United States alone reached 314 million metric tons. By 2022, the EPA estimated that a traditional passenger vehicle was emitting about 4.6 metric tons of carbon dioxide per year. Within the European Union, emissions standards differentiate between diesel and gasoline fuel, as well as between vehicles of different weights and sizes. Testing also takes the temperature of an engine into account. Between 2012 and 2015, the EU gradually phased in an emissions target for 130 grams per kilometer for new cars. In 2021, the target was changed to 95 grams per kilometer, and in early 2023 new legislation was approved that set a goal of only selling zero-emissions cars in the EU by 2035. Some of Europe’s standards have been adopted in Asian countries, including India and China.

In the US, the Biden Administration proposed strict new automobile emissions standards in April 2023, which placed an emphasis on the increased production of electric vehicles (EV) by the auto industry. The following year, the EPA unveiled its final rule on the proposed regulation. Under the new rule, cars produced between 2027 and 2032 would be subject to meeting benchmarks that required 56 percent of new vehicle sales to be electric by 2023 and 13 percent to be partially electric, or hybrid, vehicles. Supporters of the new regulation noted that it would result in a reduction of over 7 billion tons of carbon emissions into the atmosphere, greatly reducing air pollution that contributes to climate change.

Nonroad Vehicular Emissions Standards

Locomotives, boats, aircraft, and farm and lawn equipment are also sources of air pollution, and attempts have been made to control their toxic emissions. Along with and other by-products of combustion, diesel engines used in locomotives and boats emit sulfur, and the piston engines in aircraft emit lead. In 2007, tougher emissions standards for marine diesel engines that had been set by the EPA began to take effect, with the goal of reducing the level of sulfur in fuel by 99 percent, and stricter standards were set for newly constructed engines. Smaller boats often use gasoline engines similar to those found in cars and trucks, and although not as prevalent, they release the same pollutants as road-based vehicles. Engine emission standards for aircraft have been set by the United Nations International Civil Aviation Organization, and there has been a trend toward greater regulation of this mode of transportation.

Context

The creation and enforcement of emissions standards is one of several long-term strategies for reducing GHGs and combating global climate change. Other strategies reject the use of altogether and seek to find and promote alternative sources of energy. Many legal and political complexities have arisen in determining which corporate entities or governments are responsible for preventing environmental damage to the air in another community, since the air is not restricted by political borders of any kind.

Key Concepts

• catalytic converters: devices that reduce vehicular carbon monoxide exhaust by converting it into carbon dioxide
• emissions trading: a practice in which the right to pollute is turned into an exchangeable commodity, motivating polluters to reduce their emissions so they can profit by selling the right to others
• Kyoto Protocol: a binding international agreement that includes a detailed plan to reduce greenhouse gas emissions
• maximum achievable control technology (MACT) standards: standards designed to limit air pollution from stationary sources (usually heavy industries)
• smog: the noticeable brown haze created by vehicular and industrial emissions and other fossil emissions, especially prevalent in large cities
• volatile organic compounds: carbon-based substances that can easily enter the atmosphere through vaporization

Bibliography

Daly, Matthew. "New EPA Rule Says 200 US Chemical Plants Must Reduce Toxic Emissions That Are Likely to Cause Cancer." ABC News, 9 Apr. 2024, abcnews.go.com/US/wireStory/new-epa-rule-200-us-chemical-plants-reduce-109035624. Accessed 9 Apr. 2024.

"EPA Issues New Rules Aimed at Cutting Carbon Emissions, Boosting Electric Vehicles and Hybrids." NBC News, 20 Mar. 2024, www.nbcnews.com/science/environment/epa-issues-new-rules-aimed-cutting-carbon-emissions-boosting-electric-rcna144172. Accessed 9 Apr. 2024.

"Greenhouse Gas Emissions from a Typical Passenger Vehicle." US Environmental Protection Agency, 30 June 2022, www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle#. Accessed 19 May 2023.

Hansjürgens, Bernd, ed. Emissions Trading for Climate Policy: U.S. and European Perspectives. Cambridge UP, 2005.

Nilsen, Ella. "EPA to Bring Back Mercury Pollution Rules That Were Nixed under Trump Administration." CNN, 31 Jan. 2022, www.cnn.com/2022/01/31/politics/epa-mercury-pollution-coal-plants-climate/index.html. Accessed 19 May 2023.

Nilsen, Ella. "EPA Proposes New Rules That Would Dramatically Slash Planet-Warming Pollution from Power Plants." CNN, 11 May 2023, www.cnn.com/2023/05/11/politics/epa-power-plant-rules-climate/index.html. Accessed 19 May 2023.

"Reducing CO2 Emissions from Passenger Cars—Before 2020." European Commission, EU, ec.europa.eu/clima/policies/transport/vehicles/cars‗en. Accessed 25 Feb. 2021.

Reed, Alan. Precious Air: The Kyoto Protocol and Profit in the Global Warming Game. Leathers, 2006.

Russell, Rachel. "New Cars Sold in EU Must Be Zero-Emission from 2035." BBC News, 28 Mar. 2023, www.bbc.com/news/world-europe-65105129. Accessed 19 May 2023.

Sperling, Daniel, and James S. Cannon, eds. Driving Climate Change: Cutting Carbon from Transportation. Academic Press, 2007.

Tietenberg, T. H. Emissions Trading: Principles and Practice. Resources for the Future, 2006.