Pollutant: A substance (gas, liquid or solid) that is harmful to people, animals or plants. By coming into contact with them, pollutants can make the air, water and soil around us harmful to human health, to animals, and to plants. Some examples of air pollutants are: carbon monoxide (CO), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), particulate matter (PM10 and PM2.5). Examples of water pollutants include polychlorinated biphenyls (PCBs), vinyl chloride, benzene, and trace metals such as arsenic, chromium, and nickel.
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Environmental standard: An environmental standard is a value, generally defined by regulation, which specifies the maximum permissible concentration of a potentially hazardous chemical in the environment, generally in the air or in water. Environmental standards are sometimes also referred to as ambient standards. In the case of air quality standards, they are usually given in units of ppm and µg/m3: These units refer to the concentration of air pollutants - ppm stands for “parts per million”, and µg/m3 stands for “micrograms per cubic meter”. Environmental standards are normally compared to an average time. For example, the environmental standard for NO2 set by the Environmental Protection Agency (EPA) is an annual average of 0.053 ppm. This means that hourly measurements of NO2 concentrations are averaged over a period of one year. If the resulting average is above the standard concentrations of this pollutant are considered to be harmful to human health.
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Carbon monoxide (CO): A colorless gas or liquid, and is practically odorless. The main sources of CO are unvented kerosene and gas space heaters; leaking chimneys and furnaces; back-drafting from furnaces, gas water heaters, wood stoves, and fireplaces; gas stoves; automobile exhaust; and tobacco smoke. CO has been associated with several adverse health effects in people. At low concentrations, they include fatigue in healthy people and chest pain in people with heart disease. At higher concentrations, the effects are impaired vision and coordination; headaches; dizziness; confusion; nausea. This pollutant is fatal at very high concentrations.
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Ozone (O3): An odorless, colorless gas composed of three atoms of oxygen. Ozone occurs naturally in the Earth’s upper atmosphere—10 to 30 miles above the Earth’s surface—where it forms a protective layer that shields us from the sun’s harmful ultraviolet rays. However, O3 is also formed in the Earth’s lower atmosphere. Near ground level, ozone is formed when pollutants emitted by cars, power plants, industrial boilers, refineries, chemical plants, and other sources react chemically in the presence of sunlight. Ozone in the lower atmosphere is harmful to humans and is linked to many health problems, including irritation of the respiratory system, reduced lung function, aggravation of asthma, inflame and damage the lining of the lung, and others.
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Nitrogen Dioxide (NO2): Nitrogen dioxide (NO2) along with particles in the air can often be seen as a reddish-brown layer over many urban areas. The main sources of NO2 are motor vehicles, electric utilities, and other industrial, commercial, and residential sources that burn fuels. Short-term exposure to NO2 may cause increased respiratory illness in young children and harm lung function in people with existing respiratory illnesses. Long-term exposure may lead to increased susceptibility to respiratory infection and may cause alterations in the lung.
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Sulfur dioxide (SO2): SO2 is formed when fuel containing sulfur (mainly coal and oil) is burned, and during metal smelting and other industrial processes. The major health concerns associated with exposure to high concentrations of SO2 include effects on breathing, respiratory illness, alterations in pulmonary defenses, and aggravation of existing cardiovascular disease. Children, the elderly, and people with asthma, cardiovascular disease or chronic lung disease (such as bronchitis or emphysema), are most susceptible to adverse health effects associated with exposure to SO2.
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Particulate Matter (PM10 and PM2.5): Particulate matter is the generic term used for a type of air pollution that consists of complex and varying mixtures of particles suspended in the air we breathe. Particles are present everywhere, but high concentrations and/or specific types of particles have been found to present a serious danger to human health. PM is a combination of fine solids such as dirt, soil dust, pollens, molds, ashes, and soot; and aerosols that are formed in the atmosphere from gaseous combustion by-products such as volatile organic compounds, sulfur dioxide and nitrogen oxides. Particulate pollution comes from such diverse sources as factory and utility smokestacks, vehicle exhaust, wood burning, mining, construction activity, and agriculture. Particles of special concern to the protection of lung health are those known as fine particles, less than 2.5 microns in diameter. (For comparison, a human hair is about 75 microns in diameter.) Fine particles are easily inhaled deeply into the lungs where they can be absorbed into the bloodstream or remain embedded for long periods of time. A recent study showed a 17% increase in mortality risk in areas with higher concentrations of small particles. Particulate matter air pollution is especially harmful to people with lung disease such as asthma and chronic obstructive pulmonary disease (COPD), which includes chronic bronchitis and emphysema, as well as people with heart disease. Exposure to particulate air pollution can trigger asthma attacks and cause wheezing, coughing, and respiratory irritation in individuals with sensitive airways. Recent research has also linked exposure to relatively low concentrations of particulate matter with premature death. Those at greatest risk are the elderly and those with pre-existing respiratory or heart disease.
Source: http://www.lungusa.org/air/pm_factsheet99.html
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Air Quality Index (AQI): A measure for reporting air quality. It tells you how clean or polluted the air is, and what associated health concerns you should be aware of. The AQI focuses on health effects that can happen within a few hours or days after breathing polluted air. The Environmental Protection Agency (EPA) uses the AQI for five major air pollutants regulated by the Clean Air Act: ozone (O3), particulate matter, carbon monoxide (CO), sulfur dioxide (SO2), and nitrogen dioxide (NO2). The AQI goes from zero to 500. The higher the AQI value the greater the level of air pollution and the greater the health danger. The AQI scale is divided into six categories. Each category is given a color to present the information visually. These are shown in the table below.
Source: http://www.epa.gov/airnow/aqibroch/
Air Quality Index (AQI) Values Levels of Health Concern Colors
When the AQI is in this Range: ...air quality conditions are: ...as symbolized by this color:
0-50 Good Green
51-100 Moderate Yellow
101-150 Unhealthy for Sensitive Groups Orange
151-200 Unhealthy Red
201-300 Very Unhealthy Purple
301-500 Hazardous Maroon

According to the Environmental Protection Agency (EPA), the definitions of levels of concern are:

  • Good: The AQI value for your community is between 0 and 50. Air quality is considered satisfactory and air pollution poses little or no risk.
  • Moderate: The AQI for your community is between 51 and 100. Air quality is acceptable; however, for some pollutants there may be a moderate health concern for a very small number of individuals. For example, people who are unusually sensitive to ozone may experience respiratory symptoms.
  • Unhealthy for Sensitive Groups: Certain groups of people are particularly sensitive to the harmful effects of certain air pollutants. This means they are likely to be affected at lower levels than the general public. For example, children and adults who are active outdoors and people with respiratory disease are at greater risk from exposure to ozone, while people with heart disease are at greater risk from carbon monoxide. Some people may be sensitive to more than one pollutant. When AQI values are between 101 and 150, members of sensitive groups may experience health effects. The general public is not likely to be affected when the AQI is in this range.
  • Unhealthy: AQI values are between 151 and 200. Everyone may begin to experience health effects. Members of sensitive groups may experience more serious health effects.
  • Very Unhealthy: AQI values between 201 and 300 trigger a health alert, meaning everyone may experience more serious health effects.
  • Hazardous: AQI values over 300 trigger health warnings of emergency conditions. The entire population is more likely to be affected.
    Source: http://www.epa.gov/airnow/aqibroch/
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    Floatables: Waterborne materials which are buoyant or semi-buoyant and float either on or below the water surface. These materials, which are generally man-made, may be transported to sensitive environmental areas such as bathing beaches where they can become an aesthetic nuisance. Certain types of floatables also cause harm to marine wildlife and can be hazardous to navigation. Source: http://www.hydroqual.com/Receive/floatables.htm
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    Pathogens: Human pathogens (pathogenic microorganisms) include bacteria, viruses, parasites or fungi, which are known or reasonably believed, to cause disease(s) in humans. Examples of water-borne pathogens are E. coli, Cryptosporidium, and G. lamblia (giardiasis).
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    Hypoxia: A deficiency of oxygen or low levels of dissolved oxygen in water (~< 3 ppm). Hypoxia is extremely stressful to most aquatic life and can result in the death of water organisms.
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    Combined Sewer Overflow: This term refers to discharge of mixtures of storm-water and domestic waste when the flow capacity of a sewer system is exceeded during rainstorms. During a storm, excessive combined sewer overflows (CSO), if uncontrolled, may overload a sewer system and result in flooding or untreated discharge to streams. Wastewater treatment plants with combined sewers can also be burdened to the point where a severe loss of treatment efficiency occurs or the arriving flows become great enough that it becomes life threatening and the flow in the sewage system is allowed to by-pass the treatment plant and be discharged directly to a river. Sewage discharged without treatment to the river is a source of biological, chemical and aesthetic pollution.
    Source: http://www.sewer-overflow.com/
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    Waste Transfer Stations: A facility where haulers take trash, recyclables, and yard trim. Material is then moved and delivered to its corresponding facility for processing. Transfer stations are defined as a fixed facilities used for the primary purpose of transferring solid waste from one solid waste transportation vehicle to another. Dumpsters or other comparable solid waste containers loaded and unloaded onto a transportation vehicle are not included in this definition. Waste transfer stations are of concern to local residents because they are accompanied by a substantial amount of truck traffic and air pollution.
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    Putrescible Material: Refers to food wastes and organic matter that rots and decomposes.
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    Industrial Solid Waste: Solid waste generated by manufacturing or industrial processes. Such waste may include, but is not limited to, waste resulting from the following manufacturing processes: electric power generation, fertilizer/agricultural chemicals, food & related products/by-products, inorganic chemicals, iron & steel manufacturing, leather & leather products, nonferrous metals manufacturing, organic chemicals, plastics & resins manufacturing, pulp & paper industry, stone, glass, clay & concrete products, textile manufacturing, rubber & miscellaneous plastic products, transportation equipment, and water treatment. This term does not include mining waste or oil and gas waste.
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    Hazardous Solid Waste: Many households and businesses use materials in their day to day activities that produce wastes that can injure or even threaten living things. These waste products are called hazardous wastes. Hazardous waste must be handled in special ways to prevent threats to human health and the environment. Paint products, solvents, some batteries, household cleaners and pesticides are typical examples. When disposed of in the municipal landfill or otherwise improperly managed, these materials have the potential of contaminating the ground water -- our drinking water supply.
    Source: http://www.dep.state.fl.us/waste/categories/hazardous/default.htm
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    Health Risks: A measure of the chance that you will experience health problems if you are exposed to substances such as the air pollutants described above. Breathing toxic substances and air pollutants can increase your chances of getting cancer, emphysema and other respiratory and heart disorders.
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    Risk Assessment: A tool used to estimate the increased risk of health problems in people who are exposed to different amounts of pollution and toxic substances. The risk assessment process is generally divided into four steps: hazard identification, exposure assessment, dose-response assessment, and risk characterization.
    Source: http://www.epa.gov/air/oaqps/air_risc/3_90_024.html
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    Hazard Identification: Refers to the kinds of health problems caused by a pollutant. It describes the illnesses caused by a toxic air pollutant and the amount of evidence for those illnesses.
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    Exposure Assessment: Estimates the size of the increased health risks, which depends on the level of pollution people are exposed to in the environment and the duration of this exposure, and the number of people exposed.
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    Dose-Response Assessment: Refers to the different health problems observed at different exposures or levels of pollution. Mathematically, the dose-response assessment shows the change in the likelihood of health effects with changes in the levels of exposure to a pollutant.
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    Risk Characterization: Refers to the extra risk of health problems in the exposed population. It uses the above three steps to describe the type and size of any increased risk expected as a result of exposure to the air pollutant. It also includes a discussion of the uncertainties associated with the risk estimates.
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    Additional information about these terms can be found in the following web pages:

  • Information about the Air Quality Index (AQI) provided by EPA: http://www.epa.gov/airnow/aqibroch/

  • Information about sources of indoor carbon monoxide (CO) provided by EPA: http://www.epa.gov/iaq/co.html

  • Information about nitrogen dioxide (NO2) provided by the Clean Air Trust: http://www.cleanairtrust.org/nitrogendioxide.html

  • Information about nitrogen dioxide (NO2) and nitrogen oxides (NOx) provided by EPA: http://www.epa.gov/air/urbanair/nox/what.html

  • Information about ozone (O3) and its effects on human health provided by EPA: http://www.epa.gov/airnow/health/smog.pdf

  • Information about sulfur dioxide (SO2) provided by EPA: http://www.epa.gov/air/aqtrnd95/so2.html

  • Information about sulfur dioxide (SO2) provided by the Clean Air Trust: http://www.cleanairtrust.org/sulfurdioxide.html

  • A glossary of terms related to chemical safety provided by The Physical and Theoretical Chemistry Laboratory, Oxford University: http://ptcl.chem.ox.ac.uk/MSDS/glossary.html

  • Fact sheet on particulate matter air pollution provided by the American Lung Association: http://www.lungusa.org/air/pm_factsheet99.html

  • A glossary of terms and acronyms related to water pollution and management provided by the Environmental Protection agency (EPA): http://www.epa.gov/ednnrmrl/main/gloss.htm

  • Information about floatable water pollution control provided by HydroQual, Inc.: http://www.hydroqual.com/Receive/floatables.htm
  • List of the Principal Water Borne pathogens provided by the National Science Foundation (NSF): http://www.nsf.gov/od/lpa/forum/colwell/rc02abelwolman/tsld031.htm

  • Definition and classification of human pathogens provided by Singapore’s National Environment Agency (NEA): http://www.fishbase.org/Glossary/Glossary.cfm?TermEnglish=hypoxia

  • Information about combined sewer overflow (CSO) and sanitary sewer overflow (SSO) treatment provided by the Sewer Overflow Community web page: http://www.sewer-overflow.com/

  • Definitions of terms related to solid waste and mining permits provided by Mississippi’s Department of Environmental Quality: http://opc.deq.state.ms.us/epd/forms/solidwaste/solidmining.pdf

  • Information about hazardous waste provided by Florida’s Department of Environmental Protection: http://www.dep.state.fl.us/waste/categories/hazardous/default.htm

  • Information about risk assessment provided by EPA: http://www.epa.gov/air/oaqps/air_risc/3_90_024.html

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