U4 - Env Sci

• What is acidification?


  A process in which the pH drops as the conditions become more acidic
• What is acid rain?


  Precipitation with a lower pH than normal, resulting from atmospheric pollution by sulphur dioxide and nitrogen oxides which form sulfuric and nitric acids
• What is acoustic fatigue?


  Stress cracking of a material caused by repetitive vibrations induced by sound
• What is an activated carbon filter?


  A filter that reduces emissions of pollutants such as complex organic molecules that adsorb onto the surface of the activated carbon particles
• What is active traffic management?


  A method of controlling road lane usage and speed limits to smooth traffic flow and reduce congestion
• What are activation products?


  Atomic nuclei that become radioactive because they have absorbed neutrons that change them into less stable nuclei that emit ionising radiation
• What does acute mean?


  Exposure to a substance or symptoms that appear rapidly
• What is adsorption?


  The process by which atoms, ions, or molecules from a substance adhere to a surface of the adsorbent
• What is aerodynamics? 


  The study of airflow over surfaces to allow the design of surfaces that reduce wind resistance, turbulence, friction and noise generation
• What is ALARA (As low as reasonably achievable)?


  An approach to control of pollution, especially ionising radiation, where levels are kept as low as is practically achievable, taking into account economic and technological factors
• What are baffle mounds?


  Embankments that absorb and deflect noise, especially around mines, airports and major roads
• What is a bag filter?


  A method reducing atmospheric pollution caused by smoke and particulate matter
• What is a bequerel?


  The unit of activity of a radioactive source. 1 Bq = Nuclear decay per second. It is usually related to a standard mass of material.
• What is BATNEEC (best available technology not entailing excessive cost)?


  An approach to pollution control where control technology is used that achieves the lowest emission levels, without costing so much that further marginal gains would risk their financial viability
• What is bioaccumulation?


  The gradual accumulation of substances, such as pesticides or other chemicals, in an organism
• What is biodegradability?


  The capability of a substance to be broken down by microorganisms into simpler, non-polluting substances
• What is biomagnification?


  The increase in concentration of a substance, such as a toxic chemical, in the tissues of organisms at successively higher levels in a food chain
• What is bioremediation?

  Cleaning up a contaminated site using living organisms such as bacteria that chemically degrade the pollutants or plants that absorb the pollutants
• What is biotic index?


  A measure of pollution based on the presence, abundance and state of health of selected living organisms e.g. lichens for acid rain, aquatic invertebrates for water pollution
• What is blue baby syndrome?


  A health problem with several possible causes, where the haemoglobin in a baby’s blood does not carry enough oxygen. Nitrates in drinking water can be converted to nitrites which reduce the ability of haemoglobin to carry oxygen.
• What is a bund wall?


  A wall that surrounds a tank which would contain the contents if the tank leaked or burst
• What is carcinogenic action?


  The ability or tendency of a substance to cause cancer
• What is a catalytic converter?


  A device that reduces emissions of pollutant gases from petrol and diesel engines. Catalysts such as platinum, palladium and rhodium catalyse reactions with oxides of nitrogen, carbon monoxide and unburnt hydrocarbons
• What does chronic mean?


  Exposure to a substance or symptoms that appear over long periods of time
• What was the Clean Air Act (1956)?


  UK legislation to control smoke pollution by the establishment of smoke zones by making Control Orders in large urban areas
• What is a constant decent angle?


  A method of approaching an airport where the aircraft descends at a constant angle, usually 3º
• What is constant action?


  A pesticide that kill pests by coming in contact with them after spraying. Unlike systemic pesticides, they are not absorbed and translocated around the crops.
• What is contamination?


  Pollution caused by the pollutant staying in contact or mixing with materials such as soil, atmosphere, water or living organisms
• What are cooling towers?


  A method of reducing the temperature of effluent water to reduce thermal pollution and deoxygenation
• What is critical group monitoring?


  A method of monitoring pollutants, particularly radioactive discharges. If the members of the public that are most at risk are safe, then so is everyone else.
• What is critical pathway analysis?


  A technique used to predict the movement and concentration of pollutants in the environment to inform monitoring programs.
• What are cyclone separators?


  Devices that remove particulates from an air, gas, or liquid stream, without the use of filters, through vortex separation
• What is Db scale?


  A logarithmic scale used to measure sound levels
• What is degradability? 


  A measure of the ease with which a material breaks down
• What is desulphurisation? 


  The removal of sulphur or compounds containing sulphur such as sulphur dioxide
• What is a diffuse source?


  A source of pollution that is spread out and not easily identifiable, such as agricultural runoff
• What is dry flue-gas sulphurisation?


  A method of removing sulphur oxides from effluent gases using a slurry of crushed lime (mainly calcium carbonate)
• What are electrostatic precipitators?

  Filtration devices that remove fine particles, like dust and smoke, from a flowing gas using the force of an induced electrostatic charge
• What is eutrophication?


  The process by which nutrient levels in a water body increase to excessive levels such as the growth and subsequent die-off of plants and algae cause deoxygenation
• What is exposure?


  In ionising radiation control, this refers to an object or person receiving radiation, but not necessarily coming in contact with the source