Electrical properties and measurement techniques

Question 1

Why are electrical properties of aerosols important?

Answer 1

Air-cleaning devices

Aerosol sampling and measuring instruments

Question 2

External force

Answer 2

Can be gravity or electric field for charged particle

Question 3

Z electrical mobility

Answer 3

Proportionality factor between particle velocity and electrical field strength. V=ZE. Derived from dragforce and depends on temperature, pressure and kind of gas.

Question 4

Why are particles charged?

Answer 4

Often charged when produced. Charge can change due to transport of ions to the particle.

Question 5

Wiedensohler approximate model

Answer 5

Probability that a particle has a particular charge. Probability of charge increases with diameter.

Question 6

Differential mobility analyser (DMA)

Answer 6

Measurement instrument that uses the particles electrical mobility in an electric field to sort out a certain size.

Question 7

Tandem differential Mobility Analyser

Answer 7

Measures size of particles after changing the diameter somehow

Question 8

Hygroscopic Growth Measurements

Answer 8

Uses a tandem differential mobility analyser to measure both the dry and wet size of a particle. Show how hygroscopic a particle is which can have a large impact on health, climate and other things. Depends on chemical composition.