Unit ED10: Gaseous and Particulate Releases to Atmosphere

Question 1

List the different types of emissions

Answer 1

• smoke
• dust
• vapor
• gaseous
• fume
• grit
• mist
• Fibre

Question 2

List the range of engineering controls for particulates

Answer 2

• cyclones
• fabric filters
• wet scrubbers
• electrostatic precipitators

Question 3

List the different engineering controls for gas and vapor

Answer 3

• absorption devices
• activated carbon adsorption devices
• incinerators
• peat filter beds

Question 4

What is absorption

Answer 4

Is the passage of one substance into or through the bulk of another medium

Question 5

What is adsorption

Answer 5

Is the adhesion or sticking together of molecules of a gas, liquid or dissolved solid to the surface of a solid or sometimes a liquid

Question 6

What is dark smoke?

Answer 6

Defined in reference to a shade on ringelmann chart - appears as or darker than shade 2

Question 7

What is black smoke

Answer 7

Compared with Ringelmann chart appear to be as dark or darker than shade 4

Question 8

List the types of substances that are released into the atmosphere

Answer 8

• benzene
• 1,4 butadiene
• Carbon Monoxide
• lead
• nitrogen oxide

Question 9

Explain the features of benzene and 1,4 butadiene

Answer 9

• VOC’s
• released from ovens, stoves, and energy emissions
• short term: cause tiredness and nausea, or even unconsciousness.
• long term: anaemia and leukemia
• contribute to the formation of ground-level ozone in the atmosphere

Question 10

Explain carbon monoxide

Answer 10

• 1% concentration in air by volume can cause death
• biggest cause vehicle emissions
• forms when insufficient oxygen present during combustion of carbon
• contributes to formation of ground level ozone

Question 11

Explain lead

Answer 11

• biggest source: mining ore, smelting fossil fuel burning power stations
• affects mental disorders in kids
• build up in CNS over time
• lead in air - breathed in - binds to RBC - through body
• kidney damage , HBP, and fertility

Question 12

Explain nitrogen oxide - NOx

Answer 12

• 2 gases nitric oxide and nitrogen dioxide
• contributes to acid rain
• contributes to depletion of ozone layer
• GHG

Question 13

Explain ground level ozone

Answer 13

• can harm health and damage plants
• reaction between VOC’s, NOx and sunlight produces ozone at ground level
• breathing difficulties
• affects how plants photosynthesis

Question 14

Explain PM10

Answer 14

• particles with diameter <10um
• main source vehicle emissions - diesel
• fine particles also from chemical reactions, construction work, dust from air

Question 15

Explain sulphur dioxide

Answer 15

• released from burning fossil fuel

- source - large combustion plants, power stations and oil refineries

Question 16

Explain how mass spectrometry works

Answer 16

• the gas to be analyzed is ionized by an electron beam.
• This produces positively charged molecules and molecular fragments.
• These are separated on the basis of their mass-to-charge ratio using e.g a magnetic sector analyzer.

Question 17

Explain how Deposition gauges works

Answer 17

• used for dust monitoring, fairly simple method of monitoring as does not require any electrical source.
• They do not provide day to day monitoring of pollutants and do not take into account changes in wind direction, etc.
• This is an extractive and periodic monitoring technique.

Question 18

Explain how Gravimetric analysis works

Answer 18

• involves accurately weighing a sample before and after exposure for the dust or pollutant.
• Exposure of the sample filters will take place for a predetermined time, and the pre-weighted filters will be used to collect the required sample and will then be weighed again.
• The gain in weight will represent the amount of pollutant collected over the period concerned. techniques.

Question 19

List how Bag filters work

Answer 19

• removes dust from the gas stream by passing it through a fabric filter
• The fabric must allow air to pass through it and remove the dust particles from the air
• Bag filter plants employ mechanical shaking devices to vibrate the bag
• Generally the bag is closed on the top and open at the bottom. The dust laden air enters the plant through the bottom and passes up and through the bag to leave the filter plant and though vents at the top

Question 20

Explain how Electrostatic precipitator works

Answer 20

• is a particulate and droplet control devise which uses electrical forces to remove particles from dust laden air stream
• An area of ionized air molecules is established, usually around a wire, by maintaining the wire at very high voltage (20 000v) this area of ionized air is called the corona.
• As dust particles flow through the corona, they collect the ions, then they themself become charged
• A plate called the collector plate which is maintained at the opposite electrical polarity than the wire and the particles attracts the particles. The particles are removed from the plate using a hammer by raping the top of the plate.

Question 21

Explain how a wet scrubber works

Answer 21

• the principle of all wet scrubbers is that water droplets is generated within devise and the particles are captured within the droplets.
• The droplets are then removed from the airstream which is clean.
• The droplets are collected as contaminated water and transported out of the devise for treatment or disposal.

Question 22

Explain the Offences under the Clean Air Act 1993

Answer 22

• dealt with in the Magistrates’ Court
• Offences are subject to an unlimited fine plus a daily fine if the offence continues.
• The emission of dark smoke from the chimney of any building is prohibited; the Act
  also applies to chimneys not attached to a building serving furnaces, fixed boilers or
  industrial plant.
• Although there are statutory defences under the Clean Air Act, they are not absolute
  defences.
  They are only available if every practical effort is made to avoid and/or minimise
  emissions.
• Subject to certain exemptions, it is an offence to cause or permit the emission of dark
  smoke from industrial or trade premises (as distinct from chimneys).