sampling the environment

Question 1

4 particulate sampling techniques

Answer 1

Filters
impactors
dry cyclones
wetted wall cyclones

Question 2

3 gas sampling techniques

Answer 2

absorption
adsorption
Condensation

Question 3

4 key air sampling questions

Answer 3

Why are you sampling
what are you sampling
where are you sampling
how long are you sampling for

Question 4

7 main analytes

Answer 4

aural
bio
chem
magnetic
optical
radiological
thermal

Question 5

define an analyte

Answer 5

a substance who’s chemical constituents are being identified and measured

Question 6

what is the prerequisite for detection of a stimulus?

Answer 6

must be present in sufficient CONCENTRATION or INTENSITY so it can be DETECTED and DIFFERENTIATED from the environment

Question 7

4 routes of entry to the human body

Answer 7

respiratory
percutaneous
ocular
ingestions

Question 8

2 features of the air we breathe

Answer 8

Highly diverse
Ambient aerosol

Question 9

Define highly diverse

Answer 9

already contains bacteria, viruses and toxins
infections are from an aerosol route

Question 10

Define ambient aresol

Answer 10

contains naturally occurring aerosolised particles
physically identical to threat particles
present at continually fluctuating levels

Question 11

6 particulate sampling techniques

Answer 11

filtration
impingement/impaction
sedimentation
precipitation
thermal
electrostatic

Question 12

4 stages of air sampling

Answer 12

pre-separator
filter/collection media
airflow controller
pump

Question 13

Features of PM10 high volume air sampler

Answer 13

Flow rate between 1-1.7 m^3/min
size selective inlet allow for particles of pre determined range to be captured on a quartz filter (usually less than 10 microns and filter paper determines the minimum size)
filter weighted before and after use to determine the mass of particulates caught
controlled by mass flow controller or volumetric flow controller

Question 14

types of filter (8)

Answer 14

glass fibre
quartz fibre
borosilicate fibre
cellulose and mixed cellulose esters (MCE)
PTFE PM 2.5
Glass fibre tape
Andersen impactor filters
Polycarbonate filter

Question 15

Concentration calculation

Answer 15

concentration = mass of pollutant / volume of air

Question 16

gravimetric concentration formula

Answer 16

SP = (Wf-Wi)/V(T) x 10^6

SP = mass concentration of suspended particulate
Wf = final weight of filter
Wi = initial volume of filter
V(T) = total volume of air sampled
10^6 = conversion of g to ug

Question 17

Define aerodynamic diameter of a particle

Answer 17

a sphere, whose density is 1 g cm^-3 which settles in still air at the same velocity as the particle in question

Question 18

Define Mass Median Aerodynamic Diameter

Answer 18

is defined as the diameter at which 50% of the particles by mass are larger and 50% are smaller.

Question 19

Define Geometric Standard Deviation (GSD)

Answer 19

is a measure of the spread of an aerodynamic particle
size distribution. Typically calculated as follows:
GSD = (d84 /d16)^1/2
where d84 and d16 represent the diameters at which 84% and 16% of the aerosol mass are contained, respectively, in diameters less than these diameters.

Question 20

Types of air sampler

Answer 20

Cyclone
3 piece cassette
swirling aerosol collector
AGI 30
Slit sampler
Andersen sampler