Glossary of Environmental Science - P

P

• pay-by-weight systems - financial approaches to managing waste that charge prices according to the quantity of waste collected, rather than a price per pick-up or fixed annual charge, as typically applied to households for kerbside services. Pay-by-weight systems may provide an incentive to reduce waste generation.
• per capita consumption - the average amount of commodity used per person.
• pervious surface – one which can be penetrated by air and water.
• pesticide - means any substance or mixture of substances intended for preventing, destroying or controlling any pest. This includes substances intended for use as a plant growth regulator, defoliant, desiccant, or agent for thinning fruit or preventing the premature fall of fruit, and substances applied to crops either before or after harvest to protect the commodity from deterioration during storage and transport. (Food and Agriculture Organization of the United Nations, 2003).
• photosynthesis – the transformation of radiant energy to chemical energy by plants; the manufacture by plants of carbohydrates from carbon dioxide and water. The reaction is driven by energy from sunlight, catalysed by chlorophyll and releases oxygen as a byproduct. The capture of the Sun’s energy (primary production) to power all life on Earth (consumption).
• photovoltaic - the direct conversion of light into electricity
• phytoplankton– plant plankton cf. Plankton.
• plankton – mostly microscopic animal and plant life suspended in water and a valuable food source for animals cf. Phytoplankton.
• plant quality - a standard of plant appearance or yield.
• plastic - One of many high-polymeric substances, including both natural and synthetic products, but excluding rubbers. At some stage in its manufacture every plastic is capable of flowing, under heat and pressure, if necessary, into the desired final shape.
• Polluter Pays Principle (PPP) - the principle that producers of pollution should in some way compensate others for the effects of their pollution.
• polyethylene terephthalate (PET) – a clear, tough, light and shatterproof type of plastic, used to make products such as soft drink bottles, film packaging and fabrics.
• polypropylene (PP) - a member of the polyelofin family of plastics. PP is light, rigid and glossy and is used to make products such as washing machine agitators, clear film packaging, carpet fibres and housewares.
• polystyrene (PS) - a member of the styrene family of plastics. PS is easy to mould and is used to make refrigerator and washing machine components. It can be foamed to make single use packaging, such as cups, meat and produce trays.
• polyvinyl chloride (PVC) - a member of the vinyl family of plastics. PVC can be clear, flexible or rigid and is used to make products such as fruit juice bottles, credit cards, pipes and hoses.
• postconsumer material or waste - material or product that has served its intended purpose and has been discarded for disposal or recovery. This includes returns of material from the distribution chain; waste that is collected and sorted after use; kerbside waste cf. pre-consumer waste.
• potable – safe to drink.
• power- the rate at which work is done; electrically, power = current x voltage (P = I V)
• Precautionary Principle – where there are threats of serious irreversible environmental damage, lack of full scientific certainty should not be used as a reason for introducing measures to prevent that degradation (Rio Declaration).
• precipitation – (weather) any liquid or solid water particles that fall from the atmosphere to the Earth’s surface; includes drizzle, rain, snow, snow pellets, ice crystals, ice pellets and ha
• preconsumer material or waste - material diverted to the waste stream during a manufacturing process; waste from manufacture and production.
• pre-industrial - for the purposes of the IPCC this is defined as 1750.
• prescribed waste and prescribed industrial waste - Those wastes listed in the Environment Protection (Prescribed Waste) Regulations 1998 and subject to requirements under the industrial waste management policy 2000.Prescribed wastes carry special handling, storage, transport and often licensing requirements, and attract substantially higher disposal levies than non-prescribed solid wastes.
• primary productivity - the fixation rate at which energy is fixed by plants.
• producer responsibility – the legal responsibilities of producers/manufacturers for the full life of their products.
• producer – (ecology) a plant, that is able to produce its own food from inorganic substance; (energetics) an organism or process that generates concentrated energy from sunlight beyond its own needs.
• product stewardship – the principle of shared responsibility by all sectors involved in the manufacture, distribution, use and disposal of products for the consequences of these activities; manufacturing responsibility extending to the entire life of the product.
• Product – a thing produced by labour; mostly the material items we buy in shops; (ecology) the results of photosynthesis.
• productivity (ecology) - the rate at which radiant energy is used by producers to form organic substances as food for consumers.
• provisioning services – one of the major ecosystem services: the products obtained from ecosystems e.g. genetic resources, food, fibre and fresh water.
• pyrolysis - advanced thermal technology involving the thermal decomposition of organic compounds in the complete absence of oxygen under pressure and at elevated temperature.