Aerosols 2

Question 0

How is aerosols formed?

Answer 0

By subdivision of larger/agglomeration of finer material

Question 1

Colloidal

Answer 1

Solid particles/ liquid droplets in air

Question 2

Sources primary

Answer 2

3mm seawater air bubbles, burst, jet of water - follows, fragments

Question 3

Secondary sources

Answer 3

Gaseous reactions H2S, NOx, NH3, 50:50

Question 4

Size and source related

Answer 4

> 10 micrograms m grinding, spraying, pulverising, 1-10 soil, process dusts, sea salts, 0.1 -1 combustion products, photochemical aerosols

Question 5

Large and small particles

Answer 5

Large are stationary, small sediment out, stick and collide

Question 6

Size depends on RH

Answer 6

RH soluble salts above saturated solution of salt -> water condense

Question 7

Saturated solution

Answer 7

Mixture of insoluble material and aerosols

Question 8

Fate

Answer 8

Where particles go

Question 9

% aerosol return to Earth

Answer 9

Dry deposition 20% , wet precipitation 80%

Question 10

Effects on humans

Answer 10

Reaching alveoli, even if inert interference with clearance mechanisms, carry adsorbed toxic gases and vapours

Question 11

Total solar radiation

Answer 11

Aerosols reflect radiation back to space, global warming reduced, gloom increases and artificial light needs

Question 12

Materials

Answer 12

Grime, acid mist corrosion, aerosols provide nuclei for corrosive attack

Question 13

AURN (automatic urban rural network) techniques, 300 run by DEFRA

Answer 13

Ozone - UV absorption, NOx - chemiluminescence energy emitted when NO reacts with O3 in evacuated chamber to form NO2, SO2 - UV fluorescence, CO - IR absorption (4.5-4.9), PM10 - Gravimetric filter

Question 14

Controls

Answer 14

Capture particles before enter air

Question 15

Gravity setting chambers

Answer 15

Large tanks reduce gas velocity and setting allowed during residence time

Question 16

Cyclones

Answer 16

Centrifugal force used to impact particles onto walls from which collected

Question 17

Wet scrubbers

Answer 17

Solid, liquid, gas removed by Water, requires good contact therefore water is sprayed or percolated down a packed bed