Air Pollution

Question 1

What process forms CO? What are two ways CO is released into the atmosphere?

Answer 1

Incomplete combustion. Forest fires, burning of coal

Question 2

Give two possible, generic reactions for the formation of CO

Answer 2

2C + O2 –> 2COAlkane + O2 –> CO + H2O

Question 3

What is the largest source of anthropogenic CO?

Answer 3

Incomplete combustion of octane in cars

Question 4

By what reactions are CO and NO removed from exhaust by catalytic converters?

Answer 4

2CO + O2 –> 2CO22CO + 2NO –> 2CO2 + N2

Question 5

What is the largest natural source of CO?

Answer 5

Atmospheric oxidation of CH4 produced by decomposition of organic matter

Question 6

What is the chemical equation for the oxidation of CH4?

Answer 6

2CH4 + 3O2 –> 2CO + 4H2O

Question 7

What is the reaction for the formation of NO through oxidation?

Answer 7

N2 + O2 –> 2NO

Question 8

What are two natural sources of NO?

Answer 8

Bacterial synthesis and lightning

Question 9

What are two sources of N2O? (Natural and anthropogenic)

Answer 9

Conversion of (NO3)- to N2O by bacteriaArtificial fertilizers in agricultureManufacture of nitric acid

Question 10

What are the two main sulfur oxides?

Answer 10

SO2 and SO3

Question 11

What are some anthropogenic sources of SO2?

Answer 11

Burning of sulfur containing fuels (oil)Smelting of oresManufacture of sulfuric acid

Question 12

Provide the equation for the oxidation of sulfur

Answer 12

S + O2 –> SO2

Question 13

Provide the reaction processes that are used in the extraction of copper

Answer 13

2Cu2S + 3O2 –> 2Cu2O + 2SO22Cu2O + Cu2S –> 6Cu + SO2

Question 14

What are two natural sources of SO2? What is the primary product of both sources?

Answer 14

Volcanic activity and decay of organic matter. H2S produced by both.

Question 15

Provide the oxidation reaction of H2S

Answer 15

2H2S + 3O2 –> 2SO2 + 2H2O

Question 16

What is the primary property of SO2 that allows it to be removed from emissions?

Answer 16

It is an acidic gas

Question 17

What is meant by fluidized bed combustion?

Answer 17

Coal is mixed with limestone and heated until the limestone decomposes, releasing alkaline CaO. This reacts with SO2 produced by the coal.

Question 18

Provide the reaction scheme that describes fluidized bed combustion

Answer 18

CaCO3 –> CaO + CO22CaO + 2SO2 –> CaSO3 + CO2

Question 19

What is meant by ‘alkaline scrubbing?’

Answer 19

Alkali gas is sprayed into the flues of coal burning plants, where it reacts with SO2 gas being released.

Question 20

Provide the reaction scheme for generalized alkaline scrubbing

Answer 20

Ca(OH)2 + SO2 –> CaSO3 + H2OCaCO3 + SO2 –> CaSO3 + CO2

Question 21

Define the term ‘aerosol’

Answer 21

A solid or liquid particle suspended in a gas

Question 22

What size range do course aerosols inhabit?

Answer 22

2.5μm - 10μm

Question 23

What size range do fine aerosols occupy?

Answer 23

Less than 2.5μm

Question 24

What are anthropogenic sources of aerosols?

Answer 24

Soot, flue ash, metal particles (metalworking/foundries)

Question 25

What are natural sources of aerosols?

Answer 25

Pollen, dust, soot from forest fires

Question 26

What are some ways of removing aerosols from the air?

Answer 26

Filtration, sedimentation, scrubbing, electrostatic precipitation

Question 27

What is meant by 'electrostatic precipitation?'

Answer 27

Particles are passed through a series of negatively charged wires where they pick up negative charge. The particles then pass positively charged plates, which attract the negatively charged particles.

Question 28

What are volatile organic compounds (VOCs)?

Answer 28

Natural or anthropogenic products that are readily react with the atmosphere when released into it

Question 29

What are some examples of natural sources of VOCs?

Answer 29

Bacterial decay of organic matter to produce CH4Plant production of unsaturated hydrocarbons, e.g. terpenes

Question 30

What are some examples of anthropogenic sources of VOCs?

Answer 30

Unburnt hydrocarbons from combustion of organic substancesSolvents used for paints and cleaning productsIncomplete combustion of wood which produces aromatic and potentially carcinogenic compounds

Question 31

What effect does CO have on human health?

Answer 31

Joins to haemoglobin in blood and prevents oxygen transport

Question 32

What health effect do NOx compounds have on human health?

Answer 32

Fluid accumulation in lungs that can lead to infection or death

Question 33

What effect do SO2/SO3 have on human health?

Answer 33

Damages mucous membranes in nose, throat, and lungs

Question 34

What effects can VOCs have on human health?

Answer 34

Damage to liver, kidneys, and central nervous system. Aromatic hydrocarbons can cause cancer

Question 35

What type of acid is H2SO4?

Answer 35

A weak acid