Pollution: Effects Of Environmental Features

Question 1

What features can affect the degradation of pollutants?
Name 5

Answer 1

Temperature
Light levels
Oxygen
PH
Pollutant interactions

Question 2

Describe how different temperatures can affect the degradation of pollutants

Answer 2

The chemical reactions that pollutants are involved in may occur more rapidly if the temperatures are higher

Question 3

give an example of a pollutant of which the degradation is affected by temperature

Answer 3

Sewage, breaks down more rapidly at higher temperatures but more rapid degradation can cause problems like deoxygenation

Question 4

How can light levels affect the degradation of pollutants?

Answer 4

They can provide the activation energy for the chemical reactions that involve pollutants

Question 5

2 examples of the affects light has on the degradation of pollutants

Answer 5

• photochemical smogs
• Photodegradation of some pesticides

Question 6

Explain how oxygen can affect the degradation of pollutants

Answer 6

It is involved in many of the chemical and biological reactions that pollutants are
The oxidation state of metals affects the solubility

Question 7

Examples of the reactions oxygen is involved in that pollutants are also involved in

Answer 7

• aerobic bacterial decomposition of sewage
• oxides of sulphide ores, producing sulphur dioxide

Question 8

How can PH affect the degradation of pollutants?

Answer 8

It can affect the solubility of substances

Question 9

How can pollutant interactions affect degradation of pollutants?

Answer 9

The presence of other pollutants may affect the behaviour of another one

Question 10

Give two examples of how pollutant interactions can cause pollutant degradation

Answer 10

• the interaction of NOx and hydrocarbons in photochemical smogs
• the combined effects of phosphates and nitrates in eutrophication

Question 11

Name 3 environmental factors that affect the dispersal of pollutants

Answer 11

• wind and water currents
• temperature inversions
• the presence of absorbent materials

Question 12

Explain how wind and water currents can affect the dispersal of pollutants

Answer 12

Because of the velocity and direction of air and water currents
It will affect how far a pollutant is dispersed and how much it is diluted

Question 13

Explain how effluent gases rise under conditions where there are no temperature inversions

Answer 13

• atmospheric temperatures in the troposphere usually decline with increasing altitude
• temp of warm pollutant gases make them less dense and more buoyant than surrounding cool air
• this allows them to rise, disperse and become diluted
• they cool down as they rise because of the surrounding air but they remain buoyant, and continue to rise and disperse

Question 14

What 4 factors allow temperature inversions to form?

Answer 14

• valleys
• low wind velocity
• cloudless skies
• mist or fog during the day

Question 15

Why do valleys allow temperature inversions to form?

Answer 15

They are areas that allow colder and denser air to collect

Question 16

Why do low wind velocities allow temperature inversions to form?

Answer 16

They mean that the air layers of different temperatures don’t mix

Question 17

Why do cloudless skies allow temperature inversions to form?

Answer 17

It means infrared energy can be radiated from the ground without being stopped which causes the ground to cool

Question 18

Why are cities that have locale like LA vulnerable to pollution problems?

Answer 18

-Cities like LA are in valleys
- there are alo high pollutant emissions in cities like LA
- these emissions can cause serious prolems because they become concentrated during temperature inversions
- e.g. smoke smogs and photochemical smogs

Question 19

Why does the presence of absorbent materials affect the dispersal of pollutants?

Answer 19

• pollutants may absorb onto materials e.g clay particles or organic materials in aquatic sediments
• they may immoblilse pollutants and stop them causing problems
• many naturally occurring toxic metal ions are immobilised by being absorbed onto soil clay particles

Question 20

Explain how absorbent materials affected the dispersal of Caesium-137 that was released after Chernobyl in 1986

Answer 20

• it was released into the atmosphere by the nuclear accident but was then washed out by the rain
• most that was washed into the soil was absorbed onto clay particles
• this means it is immobile and any radiation released is absorbed in the ground