Monitoring air pollution in

swedishstreakMécanique

22 févr. 2014 (il y a 3 années et 3 mois)

63 vue(s)

Monitoring air pollution in
protected areas

Md.
Humauin

Kabir

Mountain Forestry

BOKU

Air pollution?


Changing the natural
composition of the air
both by men as well as
natural process


Effect of air pollution

-
Direct toxic

-
Indirect toxic






Types of air pollutants

-
Primary pollutants



exam: dust, smoke,
aerosols, haze etc.

-
Secondary pollutants


ozone, acid rain,
photochemical smog
etc.

Air pollution


Way of deposition

-
Dry deposition (
dust,
aerosols, gases
)

-
wet deposition (rain,
snow, hail
)

-
occult deposition (fog
deposition, rime
).


Deposition process

-
Sedimentation

-
Interception

-
Turbulent diffusion

-
D
iffusion


Air monitoring


To monitor the quality and quantity of air
pollutants how they behave in a particular
area.

Purpose and use of monitoring system.


Data collection


Determination of air pollution trend


Origin of the air pollution


Determination of the effect of pollution

Method of air monitoring


Manual method



-

Passive sampler



-

Paper tape sampler



-

Bubbler system



Instrumental method



-

Non
-
dispersive infra
-
red (NDIR
)



-

Chemiluminescence



-

Flame photometric analyser:



-

Suspended particulate monitoring
methods



others








Manual methods


Passive sampler:

-
air
pollutants are collected by a chemically treated surface or
material

-
when air pollutants come in contact with collectors, the pollutant is
trapped by chemical reaction.



Paper tape sampler

-
air
is pushed through the treated surface by means of pump

-
then the tape, which is automatically advanced at defined intervals;
produce a series of discrete spots or samples
.

-
H
2
S, HCN, NH
3
, NO
2
, SO
2,
Cl
2
, COCL
2
, amines and
isocyanates

Take
-
up spool

pump

Paper tape

Air inlet

Fig : 1 Paper Tape Sampler

Manual method


Bubbler method

-
Concerning with collection of gaseous pollutants

-
To bubble the air through a solution developed to
absorb or react with the pollutants.

Instrumental methods


Non
-
dispersive infra
-
red (NDIR
):


mainly
designed to monitor those gases, for
example,
SO
2
,
NOx
, CO,
CO
2
,
hydrocarbons
which absorb in the
infra
-
red

Beam
chopper

source

Sample cell

Reference cell

detector

Signal output

Fig2: NDIR analyzer

Instrumental methods


Chemiluminescence
:


-

the emission of light energy that is generated from
some chemical
reaction, example;



NO
+ O
3

= NO
2

+ O
2



NO
2

= NO
2

+
hv



used
to monitor for
NOx

and
O
3
.




NO + O
3


NO
2

+ O
2


NO
2

NO

Ozone generator

Clean air

Sample in

catalyst

Filter

hv

Photo
-
multiplier

output

Fig3:
Chemilunminenscence

Detector for
NOx

Instrumental methods


Flame photometric analyser:

-
used
for the analysis of sulphur
compounds

-
samples from a gas chromatographers column are
passed through a flame rich in hydrogen
.

-
If there is any sulphur containing compounds are
present, the sulphur will be reduced to a diatomic
molecule,
S
2
.

Fig 4: Flame photometric detector

H
2

Sample air

Filter

electrometer

p.m.t

Instrumental methods


Suspended particulate monitoring methods:

-
Traditionally
this dust is collected for measurement
by sucking air through a filter and weighting the
collecting
dust

-
High volume air sampler is used to determine this
sort of suspended particles mainly

Others indicators


Forest

-
Quality of bark, leaf, bole,

-
Water


Lichen

-
small
grey or yellow plants formed by a fungus and a
green alga and /or a blue
-
green bacterium, which
scatter over surface of rocks and trees
.

-
low level of sulphur, nitrogen, and fluorine
-
containing
pollutants affect adversely many species, modifying the
lichen community composition, growth rates,
reproduction, physiology, and morphological
appearance.

Conclusion

particulates

SO2

CO

NOx

Benzene

H2S

fluorides

O3

Passive

samplers















Paper tape





Bubbler

systems





v



NDIR



Chemilumin
escence





FPD





Fluoresence

monitors





T慢汥㨠獵浭慲礠潦o慩a 浯湩m潲o湧 syst敭

Conclusion


Challenging job


Climatic change


Protected area are getting under threat to air
pollutants, so data from monitoring is essential to
take the necessary steps.