GlossaryHeading | GlossaryDetails |
Paris Agreement | The Paris Agreement, often referred to as the Paris Accords is an international treaty on climate change. Adopted in 2015, the agreement covers climate change mitigation, adaptation, and finance. |
Peroxyacetyl Nitrate (PAN) | A group of compounds formed from the photochemical reactions of nitrogen and organic compounds. PANs are components of smog and known to cause eye irritation. |
Persistence | Refers to the length of time a compound stays in the atmosphere, once introduced. A compound may persist for less than a second or indefinitely. |
Persistent Organic Pollutants (POPs) | They are organic compounds that are resistant to environmental degradation through chemical, biological, and photolytic processes. Because of this, they have been observed to persist in the environment, to be capable of long-range transport, bioaccumulate in human and animal tissue, bioaccumulate in food chains, and to have potential significant impacts on human health and the environment. |
Photochemical Reaction | A term referring to chemical reactions brought about by the light energy of the sun. The reaction of nitrogen oxides with hydrocarbons in the presence of sunlight to form ozone is an example of a photochemical reaction. |
Photochemical Smog | Complex mixture of air pollutants (oxidants) produced in the atmosphere by the reaction of hydrocarbons and nitrogen oxides under the influence of sunlight. Three of the most harmful photochemical oxidants are ozone (O3), peroxyacetyl nitrate (PAN) and various aldehydes. |
Photolysis | Chemical decomposition induced by light or other energy. |
Photosynthesis | It is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. |
Plume | A visible or measurable discharge of a contaminant from a given point of origin that can be measured according to the Ringelmann scale. |
PM 2.5 (Particulate Matter) | Tiny particles with an aerodynamic diameter less than or equal to a nominal 2.5 microns. This fraction of particulate matter penetrates most deeply into the lungs. |
PM10 | A criteria air pollutant consisting of small particles with an aerodynamic diameter less than or equal to a nominal 10 microns (about 1/7 the diameter of a single human hair). Their small size allows them to make their way to the air sacs deep within the lungs where they may be deposited and result in adverse health effects. It also causes visibility reduction . |
Point source | A single identifiable source that discharges pollutants into the atmosphere. Ex: Smokestack of power plant, chimney of a house etc. |
Poisoning | Poisoning occurs when any substance interferes with normal body functions after it is swallowed, inhaled, injected, or absorbed. |
Pollutant Standards Index (PSI) | A numerical index formerly used for reporting severity of air pollution levels to the general public. The PSI incorporated the five criteria pollutants -- ozone, PM10, carbon monoxide, sulphur dioxide and nitrogen dioxide -- into one single index. The higher the index, the higher the level of pollutant and the greater likelihood of health effects. |
Pollution | Addition of some exogenous substances in the environment which are harmful for organisms including human beings. |
Pollution cleanup | Devices or process that removes or reduces the level of a pollutant after it has been produced or has entered the environment. Ex: Automobile emission control devices. |
Pollution prevention | Device, practices or processes that prevent a potential pollutant from forming or from entering the environment or that sharply reduces or minimizes the amounts entering the environment. |
Polychlorinated biphenyls (PCBs) | Group of 209 different toxic, oily, synthetic chlorinated hydrocarbon compounds that can be biologically amplified in food chains and webs. |
Polycyclic Aromatic Hydrocarbons (PAHs) | Organic compounds which include only carbon and hydrogen with a fused ring structure containing at least two benzene (six-sided) rings. PAHs may also contain additional fused rings that are not six-sided. The combustion of organic substances is a common source of atmospheric PAHs. |
Population | Group of individual organisms of the same species living within a particular area |
Population density | Number of organisms in a particular population found in a specified area. |
Power plants | A power plant (also referred to as a generating station, power plant, powerhouse or generating plant) is an industrial facility for the generation of electric power. Each power station contains one or more generators, a rotating machine that converts mechanical power into electrical power by creating relative motion between a magnetic field and a conductor. The energy source harnessed to turn the generator varies widely. Most power stations in the world burn fossil fuels such as coal, oil, and natural gas to generate electricity, and some use nuclear power, but there is an increasing use of cleaner renewable sources such as solar, wind, wave and hydroelectric. |
Precipitation | Water in the form of rain, sleet, hail and snow that falls from the atmosphere onto the land and bodies of water. |
Primary pollutant | Chemical that has been added directly to the air by natural events or human activities and occurs in a harmful concentration. |