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 |
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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Sources:
Additional information about these terms can be found in the
following web pages: