Slide Show Chapter 07 27-03-2013

7/28/2019 Slide Show Chapter 07 27-03-2013

http://slidepdf.com/reader/full/slide-show-chapter-07-27-03-2013 1/30

1



2



3

Divided into three regions Figure 7.1



4

split

repeatedly

flow

rate

decreases

different

flows

at

different

parts

of

the

respiratory

system

This is important for the deposition of particles



5

aerodynamic characteristics

gases depends on their solubility

particlesdepends on their sizes



Note that they all affect flow rate



7



Impaction occurs mostly in the case of larger particles that are very

close to airway walls

greatest in the bronchial region



grow

in the

smaller airways of the bronchioles

and alveoli

deposition of particles with

lar ge aerodynamic diameters



most likely to occur in small airways

most significant for fibers

when a particle contacts an

airway surface due to its physical

size

do not

deviate from their air str eamlines



primary mechanism of deposition

for particles less than 0.5 microns

net transport of particles from a region of high

concentration to a region of lower concentration due to Brownian

motion

mostly at the pulmonary(alveolar)

region



12



13

solubilities

Note: for both gases and particles the ones that are held in the upper parts of the respiratory system (at the

pulmonary region or even at the tribronchial parts) is not bad. The ones that are dangerous are the ones that

reaches to pulmonary region



14

When you inhale pollutants show discomfort by sneezing, coughing etc.

This happens because such irritant gasses stimulate

neurotransmitters.

The gases that enter to the body either are;

removed by biochemical processes, or

diffuses into the circulatory system.

Mostly for gases



15

IMPACT OF AIR POLLUTION ON HUMANS

Young children

Elderly

preexisting diseases



16

Table 7.1



17

Advantages

Conditions can be controlled carefully

Results can be quantified.

Disadvantages:

Exposures are not under natural conditions

Exposures should be kept low

Can be performed on a limited number of people.



18



19

Advantages:

Subjects are exposed to pollutants in their natural environment.

Disadvantages:

Difficulty in quantifying the results.

You must compare two populations differing only in their exposure

to air pollution.

It is not easy to find two groups of people with identical living

habits.

E.g., NIH performs such studies. In one of their studies they used

100,000 people to compare.



20

Advantages

Disadvantages



21

Table 7.2



22

Air pollutants are generally regulated because they are harmful.

You can not state wether a substance harmful or not unless you know how

much is taken.

In order to comment on the harm of a pollutant, the DOSE taken should be

known.

DOSE = conc of pollutant in air breathed x d(time)

Dose – response curve can provide info on how harmful a pollutant is

Dose-response relation is given for individual pollutants (not for general air pollution)

Synergic effects: Combine effect of two seperate pollutnts. Generally

combined effect is higher than the sum of individual erffects



23

no-treshold

Treshold

Dose (conc of pollutant to whichthe public is exposed)

R e s p o n s e

( s u c h

a s p o l l u t i o

n

d e m a g e

t o p u b l i c )

treshold limit

values



24



25



26Figure 7.1. Anatomy of the human respiratory system



27

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

Mass median diameter (um)

D e p o s i t i o n

f r a c t i o n

100101.00.10.01

0.1



28

Table 7.1. Three disciplinary for obtaining health information



29

Table 7.2. Specific air pollutants and associated health effects



30

Slide Show Chapter 07 27-03-2013

Documents

Transcript of Slide Show Chapter 07 27-03-2013