Pollution Flashcards
(17 cards)
What is pollution?
energy or matter released into the environment with potential to cause adverse changes to an ecosystem
- usually caused by human activities but similar effects can be caused by natural events
What is the difference between pollution and pollutants?
POLLUTION is the undesirable change in the environment
POLLUTANTS cause the damage to the environments
How can we split pollution damage into two categories?
Give examples
DIRECT e.g. effluent discharge from factories or wastewater treatment plants which can kill aquatic organisms
INDIRECT e.g. sulfur dioxide emissions cause acid rain which can damage or kill trees and crops
How can we split the causes of pollutants into two categories?
Natural or anthropogenic
but the effect they have on the environment remains the same
How do we classify pollution?
based on the part of the environment which they affect, or result caused by a particular pollution
What are the major types of pollution?
air
water
noise
soil or land
Why do we need to understand existing chemicals?
chemical industry produces a large number of new chemicals each year - understanding the behaviour of existing chemicals helps in predicting the behaviour of new chemicals so decisions can be made about setting acceptable emissions, developing control methods and establishing monitoring programmes
Why is it important to understand the properties of pollutants?
they determine:
- the length of time it may be a problem
- level of harm caused
- where and how far it will travel
understanding how they cause problems can help anticipate and prevent pollution
How does state of matter affect a pollutant?
being a solid, liquid or gas affects a pollutants ability to be dispersed by moving water or air
- in general, solids are deposited close to the source while gases are transported easily in the atmosphere
How does energy form affect a pollutant?
the different pollutants that are energy forms such as noise, heat, ionising radiation of light, have widely varying impacts because of the way the energy behaves
How does density affect a pollutant?
affects what happens to dispersal of the particles of a solid - the denser they are, the closer to source they settle out
- gases denser than air sink nearer the source and close to the ground if there is insufficient wind to disperse them e.g. hydrogen cyanide at Bhopal, India, 1984 remained very close to the source affecting 500,000 people
- in liquids, denser particles sink more quickly
- denser materials sink nearer the source because they require more kinetic energy to keep them suspended e.g. lead dust = high density
What is a diffuse source?
Give examples
pollution from many sources with combined impacts
e.g. car exhausts
What is a point source?
Give examples
pollution from a defined place with a definitive effect
e.g. oil spills from a tanker
What are the categories of sources for pollution?
point source
diffuse source
How does persistence and degradability in terms of a pollutant?
How do we measure it?
a measure of the length of time that a pollutant remains in the environment before it breaks down chemically (degrades)
- measured as the time it takes for half a pollutant to break down (environmental half life) T1/2 ENV
Why environmental half life not a precise measure of persistence and degradability?
can be affected by environmental conditions
- light
- temp
- oxygen levels
- pH
- presence of bacteria
What is degradation?
How do we categorise degradation?
What categories can degradation fall into?
The process of breakdown
Categorised according to the feature causing breakdown
biodegradation: caused by living orgs, usually bacteria
photodegradation: caused by light
thermal degradation: caused by heat
