What are emissions? Where do they come from?
National Trends, Criteria Pollutants, Sources, Rules and Regulations
Measuring, reporting, and using emissions data
Emissions measurement, data storage, reporting and evaluation, modeling and software
What are emissions? Where do they come from?
Emissions is the term used to describe the gases and particles which are put into the air or emitted by various sources.
National Trends
The amounts and types of emissions change every year. These changes are caused by changes in the nation's economy, industrial activity, technology improvements, traffic, and by many other factors. Air pollution regulations and emission controls also have an effect. The National Air Pollutant Emission Trends report summarizes long-term trends in emissions of air pollutants and gives in-depth analysis of emissions for the current year. The report also discusses emission evaluation and prediction methodologies.
Criteria Pollutants
The United States Environmental Protection Agency (EPA) is mainly concerned with emissions which are or could be harmful to people. EPA calls this set of principal air pollutants, criteria pollutants. The criteria pollutants are carbon monoxide (CO), lead (Pb), nitrogen dioxide(NO2), ozone (O3), particulate matter (PM), and sulfur dioxide (SO2). There are also a large number of compounds which have been determined to be hazardous which are called air toxics.
Sources
There are many sources of emissions. These have been grouped into four categories: point, mobile, biogenic, and area.
Rules and Regulations
In 1970 The United States Congress passed Clean Air Act(CAA) Amendments (the CAA was passed in 1963) which set into motion a nationwide effort to improve the country's air quality. Since then additional laws and regulations have been added including the 1990 Amendments to the Clean Air Act.
To read about these rules and regulations see:
Measuring, reporting, and using emissions data
Measurement
In order to make improvements in the air quality, the amount of pollutants in the air must be measured. The Emissions Measurement Center develops standards and evaluates testing methods so that regulations can be developed and enforced.
What is an Emission Factor?
An emission factor is a relationship between the amount of emissions that are released and the activity of the producer. Emission factors are used to predict emission levels for different industries.
What are Emission Inventories?
Emission inventories are quantities of pollutants measured over time. Emission inventories can be compared with air pollutant levels in an area to determine if increased emissions decreases the air quality.
Data Storage
Once the measurements are made the information must be collected and stored so that it can be used to evaluate the air quality and effects of the regulations. The Clearinghouse for Inventories and Emissions Factors (CHIEF) is a centralized resource for emissions data.
Modeling
The emissions data that is gathered is also used to create models which can help to predict what air quality will be like in the future and what effect new regulations might have on air quality.
Software
Computer software programs have been created to help people to evaluate and sort out the pollution data that has been collected.
To find out more about emissions try this more detailed Air Pollution Emissions Projects Page.
FAQs
Emissions are the tiny particles or gases that are released into the air from different sources. Common human sources of emissions include exhaust from transportation, industrial processes, and other technologies. Not all emissions are polluting emissions.
What is the summary of air pollution? ›
Air pollution is contamination of the indoor or outdoor environment by any chemical, physical or biological agent that modifies the natural characteristics of the atmosphere. Household combustion devices, motor vehicles, industrial facilities and forest fires are common sources of air pollution.
What are the 7 main causes of air pollution? ›
Air pollution is caused by solid and liquid particles and certain gases that are suspended in the air. These particles and gases can come from car and truck exhaust, factories, dust, pollen, mold spores, volcanoes and wildfires. The solid and liquid particles suspended in our air are called aerosols.
What are the emissions causing pollution? ›
There are two types of emissions that impact on the environment, air quality and human health: greenhouse gas emissions and air pollutant emissions. Greenhouse gas emissions, such as carbon dioxide (CO2), trap heat from the sun in the earth's atmosphere, causing the 'greenhouse effect' and climate change.
What are the two main types of air pollution emissions? ›
Primary air pollutants: Pollutants that are formed and emitted directly from particular sources. Examples are particulates, carbon monoxide, nitrogen oxide, and sulfur oxide. Secondary air pollutants: Pollutants that are formed in the lower atmosphere by chemical reactions.
What are the five main effects of air pollution? ›
Public health concerns include cancer, cardiovascular disease, respiratory diseases, diabetes mellitus, obesity, and reproductive, neurological, and immune system disorders. Research on air pollution and health effects continually advances.
What is the largest cause of air pollution? ›
The Burning of Fossil Fuels
Most of the air pollution takes place due to the incomplete burning of fossil fuels. These include coal, oil, and gasoline to produce energy for electricity or transportation. The release of CO at a high level indicates how much fossil fuel is burned.
Why is air pollution a huge problem? ›
Long-term health effects from air pollution include heart disease, lung cancer, and respiratory diseases such as emphysema. Air pollution can also cause long-term damage to people's nerves, brain, kidneys, liver, and other organs. Some scientists suspect air pollutants cause birth defects.
Who has the worst air quality in the world? ›
What is the biggest cause of emissions? ›
Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years. The largest source of greenhouse gas emissions from human activities in the United States is from burning fossil fuels for electricity, heat, and transportation.
air pollution: the presence of substances in the air that can have harmful effects on human health and the environment. air pollutant: any airborne particle or substance that can cause harm to an ecosystem.
What are the largest pollution emissions? ›
1 – Fossil fuels – It is no surprise that the fossil fuels sector is the most polluting in the world. Despite this knowledge, emissions from fossil fuels keep increasing. After a brief decline during the Covid 19 pandemic, they grew by 1% in 2022, reaching 40.5 gigatons of CO2.
What is the definition of emissions of pollution? ›
Emissions is the term used to describe the gases and particles which are put into the air or emitted by various sources. National Trends. The amounts and types of emissions change every year.
What are the different types of emissions? ›
Types of emissions
- emissions from the use of refrigerants in air conditioning units.
- emissions from fuels used in transport.
- fugitive emissions, such as methane leaks from coal mines.
- production of electricity by burning coal.
Emissions are substances released into the air and are measured by their concentrations, or parts per million, in the atmosphere. The main greenhouse gases are water vapor (H20), carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs) and sulfur hexafluoride (SF6).
What are harmful emissions? ›
Toxic, or hazardous, air pollutants are substances that cause or are suspected of causing cancer, birth defects, or other serious harms. They can be gases, such as hydrogen chloride, benzene and toluene or compounds and metals such as asbestos, cadmium, mercury and chromium.
