L27

Question 1

examples of aerobiology

Answer 1

-covid19, chickenpox, flu
-aerosols from flushing toilets
-mold on buildings

Question 2

characteristics of the atmosphere

Answer 2

• troposphere- lowest layer of atmosphere, has large amounts of turbulsnce + decrease in temp. as go up
• about 10km+ from surface
• has layers including
• laminar boundary later (1mm-2mm)
  turbulent boundary layer (up to 150m)
  transitional layer
  convection layer (extends fro 1 km above group to top of troposphere)

Question 3

what is aerobiology

Answer 3

dispersion fo airborne particles via
- liberation
-dispersion in air current
-deposition on surface

Question 4

explain liberation

Answer 4

-requires overcoming adhesion forces to enter turbulent layer, is difficult for bacteria + viruses but ideal for fungi
-energy required for liberation, supplied by:

• passive release mechanisms
  -air movements/mechanical disturvances (air currents moving voer cup shaped structures projecting into turbulent layer)
  - water (breaking of water films leading to droplets)
• violent discharge mechanisms (widespread in fungi, involving breaking turgid cells

Question 5

explain dispersion

Answer 5

• dependant on atmospheric features + spore characteristics
  stokes law- msot spores fall at speed of <10mm/s
• spores deposited close to source unless turbulence + convection are operating

Question 6

explain deposition

Answer 6

• final stage
• on plants, inorganic surfaces, respiratory tracts, soil etc.
  -mechanisms
• at 60% of drops, settle into a laminar flow (across then down)
  -at 10% of drops, settling into turbulent air (goes everywhere)
• at 100% of drops, setting into calm air (fall straight down)
  -sedimentation (calm conditions- fall under gravity)
  
  • boundary layer exchange (deposition under gravity, downward molecular diffusion)
    -impaction (more efficient with large microbes- hitting surfaces with loss of kinetic energy)
  • wash out of spores (rain- spores combines with water for greater mass)
    -electrostatic changes (attraction + repulsion)

Question 7

explain outside air spora

Answer 7

• contains propagules of msot spore producing organisms
• is not static (differs day/night, humdiitt, mosture, seasonal patterns, geographical considerations etc.)
• has to survive in atmospherere which is NOT a netural environment (temp., radiation, dehydration, chemicals, pH)

Question 8

explain inside air spore

Answer 8

consists of
- outdoor air spore (lower no. then outdoors)
-air spora from indoors

dependent on
- macroorganisms (pets + humans)
-respiratory tract organisms released
-air humidifcation + condition systems releasing roganisms
-stored vegetation (mold)

can be responsible for allergies

Question 9

explain allergic reactions

Answer 9

allergic alveolitis- expsoure to actinomycetes + fungal spores, avian, and animals erum proteins
-can lead to occupation disease by predisposition (repeated exposure leading to permanent damage, e.g. around kangroos all th etime, may develop a allergy)

• allergic rhinitis + asthma- everyday exposure to airborne allergens, predisposing conditions constitutional, syptoms: acute, very rapid repsonses

Question 10

explain infection by inhalation

Answer 10

-extramural (outdoor) environment
- few inhalant diseases important
- Q fever, foot + mouth virus, some fungal pathognes

• intramural (indoor) environment
  
  • particle size significant for uptake + destination
  • a no. fo bacteiral + viral organisms
  • highly contaminated air near the ground is inhaled by humans

Question 11

how to control aerobiology

Answer 11

-ventilation- reduces conc., less deposition (mixes indoor + outdoor atmosphere, lowers indoor only conc.)

• filtration of air (HEPA) or less effective filters- masks air supply
• biocidal treatment- UV germicidal treatment of air into/out of contaminated areas
• isolation: neg. pressure in infected area, pos. pressure (clean area)- air flow also cleaned with HEPA filters