Definitions - p

Pandemic

This is usually defined as the act of replacing stale or noxious air with fresh air.

In the eco field it is also important to differentiate between what are termed passive ventilation and active ventilation. Passive ventilation is where no additional electrical or mechanical energy is required to make the ventilation work. Active ventilation on the other hand won't work without using additional energy.

Passive ventilation is an aspect of passive building design and often utilizes heat chimneys and natural air flows across the land to achieve adequate ventilation.

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Parallel Strand Lumber

Beams made from strands of wood fiber mixed with resins and pressed into large beams.

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Parallel Wiring

This is when a group of electrical devices, such as PV modules, are wired together to increase ampage, whilst the voltage remains constant.

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Parametrization

In climate modeling, this term refers to the technique of representing processes that cannot be explicitly resolved at the resolution of the model (sub-grid scale processes) by the relationships between the area averaged effect of such sub-gird scale processes and the larger scale flow.

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Passive House

An electric vehicle (EV) is a vehicle powered by electricity, offering an alternative to traditional gasoline or diesel-powered cars. EVs are broadly categorized into Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), Fuel Cell Electric Vehicles (FCEVs), and Hybrid Electric Vehicles (HEVs).


The battery that stores and provides the electricity for the vehicles is often an integral part of the vehicle and built into its frame, given the batteries are often heavy and as such are best placed close to the ground to lower the centre of gravity of the vehicle to improve handling and provide a degree of protection to the battery.

In order to be charged EV's need to visit a charging station which is compatible with the vehicle's charging system.    

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Passive Solar

Rewilding is the act of reintroducing species to areas where they previously went extinct. The assumption being that by them being reintroduced it makes the areas more 'wild' and therefore natural compared to what it was previously.


Rewilding needs to be undertaken very carefully as some are suggesting reintroducing species that were equivalent to the locally extinct species but not the same. This could have unintended consequences, as the presence of introduced species could have altered the ecosystems sufficiently to make the reintroduction of an extinct species no longer viable. Also native species could be thriving with the introduced species.

There is also discussion about the reintroduction of apex predators into areas where there is no apex predators - again, the eco system needs to be sufficiently robust to support such a change. 

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Passive Solar Design

Rewilding is the act of reintroducing species to areas where they previously went extinct. The assumption being that by them being reintroduced it makes the areas more 'wild' and therefore natural compared to what it was previously.


Rewilding needs to be undertaken very carefully as some are suggesting reintroducing species that were equivalent to the locally extinct species but not the same. This could have unintended consequences, as the presence of introduced species could have altered the ecosystems sufficiently to make the reintroduction of an extinct species no longer viable. Also native species could be thriving with the introduced species.

There is also discussion about the reintroduction of apex predators into areas where there is no apex predators - again, the eco system needs to be sufficiently robust to support such a change. 

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Passive Solar Energy

Passive Solar Energy is the energy captured by a building from the Sun and used to either heat or cool a building.


The heating is usually a direct mechanism, where as the cooling is done by using the Sun's energy to help displace heat within a building, for instance by 'sucking' air through a property using a roof ventilation system.

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Passive Solar Heating

This is usually defined as the act of replacing stale or noxious air with fresh air.

In the eco field it is also important to differentiate between what are termed passive ventilation and active ventilation. Passive ventilation is where no additional electrical or mechanical energy is required to make the ventilation work. Active ventilation on the other hand won't work without using additional energy.

Passive ventilation is an aspect of passive building design and often utilizes heat chimneys and natural air flows across the land to achieve adequate ventilation.

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Passive Ventilation

The living place or "home" of a particular organism or biological community.

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Peak Sun Hours

This is the equivalent number of hours per day when solar irradiance averages 1,000 w/m2. For example, six peak sun hours means that the energy received during total daylight hours equals the energy that would have been received had the irradiance for six hours been 1,000 w/m2. A term often used in association with solar panels.

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Perfluorocarbon

Perfluorocarbon (PFC) is a powerful greenhouse gas emitted during the production of aluminum.

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Perfluorooctanic Acid

A fluorinated chemical thought to be a carcinogen that is turning up in the bloodstream of humans and animals. PFOA and related perfluorochemicals have been used for decades to make a variety of nonstick and water-repellent products, including Teflon and other nonstick cookware, stain treatments for carpets, waterproof clothing, greaseproof liners of food packaging, and some personal care products.

In 2006, manufacturers reached a voluntary agreement with the U.S. EPA to eliminate almost all use of PFOA by 2015, although the use of other fluorinated chemicals will continue.

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Permafrost

Cork isn’t just for wine bottles anymore. Probably the most popular use of cork now is flooring because it provides natural thermal insulation, thus helping to lower energy consumption, and it also has the natural ability to absorb sound and shock. It is a type of flooring that suits most allergy sufferers and is very durable despite its rubbery feel. Did you know there is actually a Cork Oak tree? Well, there is and it’s a pretty cool tree that is responsible for all those wine corks and cork flooring. Cork is harvested by peeling away the bark from the trunk and branches every 9-12 years and does not necessitate the felling of the tree. And, Cork Oak trees do not die when their bark is removed like most trees.

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Persistent Pesticides

Pesticides that do not break down chemically or break down very slowly and remain in the environment after a growing season.

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Phantom Load

This is the small but not insignificant amount of energy that some of your appliances, such as your television, stereo, answering machine, and microwave oven are using when they are turned off.

Unplugging the devices when you’re not using them or plugging them into a power strip with an on/off switch is often the only way to avoid this waste of power.

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Phenols

Organic compounds that are byproducts of petroleum refining, tanning, and textile, dye, and resin manufacturing. Low concentrations cause taste and odor problems in water; higher concentrations can kill aquatic life and humans.

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Photoageing

Premature ageing of the skin as a result of excessive exposure to ultraviolet radiation.

Effects of photoageing on the skin include dryness, loss of elasticity, wrinkles, discolouration and changes in texture.

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Photochemical Smog

Air pollution caused by chemical reactions of various pollutants emitted from different sources.

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Photosynthesis

Rewilding is the act of reintroducing species to areas where they previously went extinct. The assumption being that by them being reintroduced it makes the areas more 'wild' and therefore natural compared to what it was previously.


Rewilding needs to be undertaken very carefully as some are suggesting reintroducing species that were equivalent to the locally extinct species but not the same. This could have unintended consequences, as the presence of introduced species could have altered the ecosystems sufficiently to make the reintroduction of an extinct species no longer viable. Also native species could be thriving with the introduced species.

There is also discussion about the reintroduction of apex predators into areas where there is no apex predators - again, the eco system needs to be sufficiently robust to support such a change. 

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Photovoltaic

This is usually defined as the act of replacing stale or noxious air with fresh air.

In the eco field it is also important to differentiate between what are termed passive ventilation and active ventilation. Passive ventilation is where no additional electrical or mechanical energy is required to make the ventilation work. Active ventilation on the other hand won't work without using additional energy.

Passive ventilation is an aspect of passive building design and often utilizes heat chimneys and natural air flows across the land to achieve adequate ventilation.

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Phthalates

Climate change is a change in the statistical distribution of weather over periods of time that range from decades to millions of years. It can be a change in the average weather or a change in the distribution of weather events around an average (for example, greater or fewer extreme weather events). Climate change may be limited to a specific region, or may occur across the whole Earth.

In recent usage, especially in the context of environmental policy, climate change usually refers to changes in modern climate. It may be qualified as anthropogenic climate change, more generally known as global warming.

Wikipedia - Climate Change entry

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Physiographic Region

A portion of the Earth's surface with a basically common topography and common morphology.

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Phytotoxic

Harmful to plants.

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Planned Obsolesence

The art of making a product break/fail after a certain amount of time. Not so soon that you blame the manufacturer, but soon enough for you to buy another one and make more profit for them.

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Plant Association

A grouping of plant species, or a plant community, that recurs across the landscape. Plant associations are used as indicators of environmental conditions such as temperature, moisture, light, etc.

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Plate Tectonics

Geologic theory that the bending (folding) and breaking (faulting) of the solid surface of the earth results from the slow movement of large sections (plates) of that surface.

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Pleistocene

Period in geologic history (basically the last one million years) when ice sheets covered large sections of the Earth's land surface not now covered by glaciers.

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Plug-in Hybrid

Also known as Plug-in Hybrid Electric Vehicles (PHEVs), plug-in hybrids are similar in design to conventional Hybrids except their battery can be recharged from an external power source such as electric vehicle charging points.

As a result they can travel significant distances, typically 40 miles, using just their electric motor before their internal combustion engine kicks in.

They are being widely touted as a means of cutting carbon emissions and urban air pollution, while improving vehicle fuel efficiency to a level where cars can travel upwards of 250 miles on a single tank of fuel.

A range of new plug-in hybrids are expected to be launched over the next two years, including GM's Chevy Volt and a new version of Toyota's Prius.

Plug in hybrids are expected to be more expensive than conventional cars, however they will result in reduced fuel costs and a number of governments are offering tax breaks to try and increase consumer take up.

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Plug-in Hybrid Electric Vehicles

Plug-in Hybrid Electric Vehicles (PHEVs) are vehicles which combine a gasoline engine with an electric motor and battery. Thus allowing for both electric and gasoline-powered driving and can be plugged in to recharge. 

Some designs permit the gasoline engine to be used to charge the battery, or the act of braking to charge the battery (regenerative braking).

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Polar Air Mass

A cold air mass that forms in a high-latitude source region.

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Pollutant

Substance, especially man-made, that pollutes or contaminates an environment.

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Pollution Prevention

Reducing the amount of energy, materials, packaging or water in the design, manufacturing or purchasing of products or materials in an effort to increase efficient use of resources, reduce toxicity and eliminate waste.

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Polybrominated Diphenyl Ethers

Polybrominated Diphenyl Ethers (PBDE), is an industrial toxic chemical used as a flame retardant in plastics, furniture and mattresses. This is being progresively banned.

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Polyculture

Polyculture is agriculture using multiple crops in the same space, in imitation of the diversity of natural ecosystems, and avoiding large stands of single crops, or monoculture. It includes crop rotation, multi-cropping, intercropping, companion planting, beneficial weeds, and alley cropping.

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Post Consumer Waste

Waste collected after the consumer has used and disposed of it.

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Postmodern Science

Postmodern Science is a 'branch' of postmodernism.

Postmodernism is "post" because it is denies the existence of any ultimate principles, and it lacks the optimism of there being a scientific, philosophical, or religious truth which will explain everything for everybody - a characterisitic of the so-called "modern" mind. The paradox of the postmodern position is that, in placing all principles under the scrutiny of its skepticism, it must realize that even its own principles are not beyond questioning. As the philospher Richard Tarnas states, postmodernism "cannot on its own principles ultimately justify itself any more than can the various metaphysical overviews against which the postmodern mind has defined itself."

Basically, postmodern science shies away from trying to create a 'unified truth' and rather focuses on the here and now and what is can be 'deduced' from that. The trouble is this leads to science by agreed consensus of observation and trust - rather than the traditional scientific approach of knowledge advancement by experimentation and proving of a hypothesis - i.e. the scientific method

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Power Conversion Efficiency

The ratio of output power to input power of the inverter.

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Power Pool

An association of interconnected electric systems in a region, often having an agreement to coordinate operations and plans for reliability improvements.

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Precambrian Rock

The oldest rocks, generally more than 600 million years old.

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Precautionary Approach

The approach promoted under the Framework Convention of Climate Change to help achieve stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous interference with the climate system.

Note: In essence this is the 'just in case' approach; the trouble with it is it assumes the cost of doing something is essentially 'free' compared to the future cost of not doing something. Rather the opportunity cost of doing something regardless is not clearly taken into account (i.e. could the money being spent now on inefficient energy sources to combat climate change have been better spent on further energy research that could ultimately lead to no real environmental pollution at all?)  Everything has a cost.

Also the precautionary approach 'weakens' the need for more rigorous scientific principal based research; i.e. you just need to show (and not truthfully prove) a possible outcome to give support to the precautionary approach.

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Precession

The tendency of the Earth's axis to wobble in space over a period of 23,000 years. The Earth's precession is one of the factors that results in the planet receiving different amounts of solar energy over extended periods of time.

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PreConsumer

Refers to recycled material that came from the manufacturing process. Pre-consumer recycling of scraps and discards diverts waste that may otherwise end up in landfills, and reduces use of raw materials.

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Prescribed Burning

Deliberate setting and careful control of surface fires in forests to help prevent more destructive fires and to kill off unwanted plants that compete with commercial species for plant nutrients; may also be used on grasslands. Also known as 'back burning'.

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Prevailing Wind

This is usually defined as the act of replacing stale or noxious air with fresh air.

In the eco field it is also important to differentiate between what are termed passive ventilation and active ventilation. Passive ventilation is where no additional electrical or mechanical energy is required to make the ventilation work. Active ventilation on the other hand won't work without using additional energy.

Passive ventilation is an aspect of passive building design and often utilizes heat chimneys and natural air flows across the land to achieve adequate ventilation.

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Price Preference

A percentage by which offered prices for recycled products are reduced for purposes of bid evaluation. 

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Primary Consumer

Primary consumers are usually herbivores that feed on plants and fungus, which are in turn Primary Providers. Secondary consumers, on the other hand, are mainly carnivores, and prey on other animals. Omnivores, who feed on both plants and animals, can also be considered a secondary consumer.

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Primary Energy

An electric vehicle (EV) is a vehicle powered by electricity, offering an alternative to traditional gasoline or diesel-powered cars. EVs are broadly categorized into Battery Electric Vehicles (BEVs), Plug-in Hybrid Electric Vehicles (PHEVs), Fuel Cell Electric Vehicles (FCEVs), and Hybrid Electric Vehicles (HEVs).


The battery that stores and provides the electricity for the vehicles is often an integral part of the vehicle and built into its frame, given the batteries are often heavy and as such are best placed close to the ground to lower the centre of gravity of the vehicle to improve handling and provide a degree of protection to the battery.

In order to be charged EV's need to visit a charging station which is compatible with the vehicle's charging system.    

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Primary Sector

That portion of a region's economy devoted to the extraction of basic materials (e.g., mining, lumbering, agriculture).

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Proxy Climate Indicators

Variables that are an indirect measure of some combination of climate-related variations back in time. These are used to determine temperature in a time when the thermometer was not yet invented. Examples include tree ring records, characteristics of corals, fraction of melted ice, concentration of salts and acids and the load of pollen trapped in air bubbles.

Note: Given these are indirect measures, the underlying accuracy of such measurements are not equivalent to direct measurement. Also the more indirect the measure (i.e. the more processes between what you are measuring and the temperature) the more inaccurate the representation of the temperature could be. Plus if one is not careful it is possible to 'cherry pick' your proxies to show (either knowingly or not) a pattern of temperatures not representative of the larger whole.

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Putrescible

Able to rot quickly enough to cause odors and attract flies.

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PV Module

A PV module is basically a solar photovoltaic module used in converting Sun light into electrical energy. They are usually manufactured as a sealed unit with a given output voltage and wattage rating. They are often grouped together to create a larger total power output. 

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Pyranometer

An instrument used for measuring global solar irradiance.

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Pyrolysis

This is the process used to create biochar.

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Click on a letter to see all the terms and definitions that begin with that letter.

A free Android app containing all these definitions is now available, called the Green Dictionary. Click here to see the entry on the Android market; or click here if on an Android phone.