Topic 7 Basic Air Pollution Modelling .ppt

8/19/2019 Topic 7 Basic Air Pollution Modelling .ppt

1/21


2/21

22

Point Source Gaussian PluePoint Source Gaussian Plue

Mo!elMo!el


3/21

""


Mo!elMo!el


4/21

##


Mo!elMo!el

Mo!el Structure an! Assu$tionsMo!el Structure an! Assu$tions $ollutants release! %ro a &'irtual $oint$ollutants release! %ro a &'irtual $oint

source(source( a!'ecti'e trans$ort )* +in!a!'ecti'e trans$ort )* +in!

!is$ersi'e trans$ort ,s$rea!in-. %ollo+s!is$ersi'e trans$ort ,s$rea!in-. %ollo+s

noral ,Gaussian. !istri)ution a+a* %ronoral ,Gaussian. !istri)ution a+a* %ro

traector*traector* constant eission rateconstant eission rate


5/21

00


Mo!elMo!el

Mo!el Structure an! Assu$tions ,cont.Mo!el Structure an! Assu$tions ,cont. +in! s$ee! constant +it1 tie an! ele'ation+in! s$ee! constant +it1 tie an! ele'ation

$ollutant is conser'ati'e ,no reaction.$ollutant is conser'ati'e ,no reaction. $ollutant is &re%lecte! )* -roun!($ollutant is &re%lecte! )* -roun!(

terrain is %lat an! uno)structe!terrain is %lat an! uno)structe!

uni%or atos$1eric sta)ilit*uni%or atos$1eric sta)ilit*


6/21


Mo!elMo!el

31ere31ere χ χ 4 !o+n+in! concentration at4 !o+n+in! concentration at

-roun! le'el ,-/-roun! le'el ,-/""..

E E == eission rate o% $ollutant ,-/s.eission rate o% $ollutant ,-/s.

s s y y ,s ,s z z == $lue stan!ar! !e'iations ,.$lue stan!ar! !e'iations ,.

uu 4 +in! s$ee! ,/s.4 +in! s$ee! ,/s.

x, y, z, H x, y, z, H 4 !istances ,.4 !istances ,.

( )

−

−

=

22

2

1exp

2

1exp,0,,

z y z y s

H

s

y

u s s

E H y x

π χ


7/21


8/21


9/21


10/21

=>=>


Mo!el 5 ori?ontal Dis$ersionMo!el 5 ori?ontal Dis$ersion


11/21

====


Mo!el 5 @ertical Dis$ersionMo!el 5 @ertical Dis$ersion


12/21

=2=2


Mo!el 5 3in! S$ee! CorrectionMo!el 5 3in! S$ee! Correction Unless t1e +in! s$ee! at t1e 'irtual stac6 1ei-1tUnless t1e +in! s$ee! at t1e 'irtual stac6 1ei-1t

is 6no+n it ust )e estiate! %ro t1e -roun!is 6no+n it ust )e estiate! %ro t1e -roun!

+in! s$ee!+in! s$ee!

+1ere+1ere uu x x 4 +in! s$ee! at4 +in! s$ee! at

ele'ationele'ation z z x x

p p 4 e$irical constant4 e$irical constant

p

z

z uu

=

1

212


13/21

="="

Ea$le =Ea$le =

A stac6 in an ur)an area is eittin- 8> -/s A stac6 in an ur)an area is eittin- 8> -/s

o% NO It 1as an e%%ecti'e stac6 1ei-1t o%o% NO It 1as an e%%ecti'e stac6 1ei-1t o%

=>> T1e +in! s$ee! is # /s at => =>> T1e +in! s$ee! is # /s at =>

It is a clear suer !a* +it1 t1e sunIt is a clear suer !a* +it1 t1e sun

nearl* o'er1ea! Estiate t1e -roun!nearl* o'er1ea! Estiate t1e -roun!

le'el concentration at a. 2 6 !o+n+in!le'el concentration at a. 2 6 !o+n+in!

on t1e centerline an! ). 2 6 !o+n+in!on t1e centerline an! ). 2 6 !o+n+in!>= 6 o%% t1e centerline>= 6 o%% t1e centerline


14/21

=#=#

Ea$leEa$le

== Deterine sta)ilit* classDeterine sta)ilit* class

Assue +in! s$ee! is # 6 at -roun! Assue +in! s$ee! is # 6 at -roun!sur%ace Descri$tion su--ests stron-sur%ace Descri$tion su--ests stron-solar ra!iationsolar ra!iation

Sta)ilit* class BSta)ilit* class B


15/21

=0=0

Ea$leEa$le

22 Estiate t1e +in! s$ee! at t1e e%%ecti'e stac6Estiate t1e +in! s$ee! at t1e e%%ecti'e stac6

1ei-1t1ei-1t

Note e%%ecti'e stac6 1ei-1t -i'en 5 no nee! toNote e%%ecti'e stac6 1ei-1t -i'en 5 no nee! to

calculate usin- ollan!9s %orulacalculate usin- ollan!9s %orula

/s65.510

1004

15.0

1

212 =

=

=

p

z

z uu


16/21

==

Ea$leEa$le"" DeterineDeterine σ σ y y andand σ σ z z

σ σ y y 4 24 2

σ σ z z 4 22>4 22>

2

22>


17/21

=7=7

Ea$leEa$le

## Deterine concentration usin- E ==F=2Deterine concentration usin- E ==F=2

aa 4 2>>> * 4 > 4 2>>> * 4 >

−

−=

22

220

100

2

1exp

290

0

2

1exp

)6.5)(220)(290(

80)0,2000(

π C

"" G-/-/ 3.641043.6)0,2000( 5 =×= −C


18/21

=8=8

Ea$leEa$le

4 2>>> * 4 >= 6 4 =>> 4 2>>> * 4 >= 6 4 =>>

−

−=

22

220

100

2

1exp

290

100

2

1exp

)6.5)(220)(290(

80)100,2000(

π C

C,2>>>=>>.C,2>>>=>>. 4 > H -/4 > H -/""

4 >4 > -/-/""


19/21

=


20/21

2>2>

Stac6 1ei-1tStac6 1ei-1t

Recentl* t1is $ractice 1as )ecoe un!er attac6 on t1e )asis t1atRecentl* t1is $ractice 1as )ecoe un!er attac6 on t1e )asis t1at!isc1ar-e %ro t1e tall stac6 is ore li6el* to result in lon- ran-e!isc1ar-e %ro t1e tall stac6 is ore li6el* to result in lon- ran-etrans$ort +it1 associate! $ro)les o% interre-ional an! internationaltrans$ort +it1 associate! $ro)les o% interre-ional an! internationaltrans$ort %ui-ation an! aci! !e$ositiontrans$ort %ui-ation an! aci! !e$osition

It is ar-ue! t1at to $re'ent t1ese $ro)les $ollutants ust )eIt is ar-ue! t1at to $re'ent t1ese $ro)les $ollutants ust )ereo'e! %ro t1e e%%luent -ases so t1at e'en i% $lue arereo'e! %ro t1e e%%luent -ases so t1at e'en i% $lue aretrans$orte! %or lon- !istances t1e* +ill not cause 1ar +1en t1eirtrans$orte! %or lon- !istances t1e* +ill not cause 1ar +1en t1eirconstituent e'entuall* reac1e! -roun! le'elconstituent e'entuall* reac1e! -roun! le'el

I% suc1 cleanFu$ o% t1e eission ta6es $lace t1e nee! %or suc1 tallI% suc1 cleanFu$ o% t1e eission ta6es $lace t1e nee! %or suc1 tall

stac6s !isa$$eare! Des$ite t1ese ar-uents t1e taller t1e stac6sstac6s !isa$$eare! Des$ite t1ese ar-uents t1e taller t1e stac6st1e )etter t1e closerFin rece$tor surroun!in- t1e source aret1e )etter t1e closerFin rece$tor surroun!in- t1e source are$rotecte! %ro its e%%luents$rotecte! %ro its e%%luents


21/21

2=2=

Stac6 1ei-1tStac6 1ei-1t

T1e a)ilit* o% tall stac6 to inect its $lue into t1e u$$er air an!T1e a)ilit* o% tall stac6 to inect its $lue into t1e u$$er air an!!is$erse its $ollutants +i!el* !e$en!s u$on $re'alent!is$erse its $ollutants +i!el* !e$en!s u$on $re'alenteteorolo-ical con!itions Soe con!itions ai! !is$ersion ot1erseteorolo-ical con!itions Soe con!itions ai! !is$ersion ot1ersretar! it Since t1ese con!itions are easura)le an! $re!icta)leretar! it Since t1ese con!itions are easura)le an! $re!icta)leinterittent an! su$$leentar* control s*ste ,ICS/SCS. 1a'einterittent an! su$$leentar* control s*ste ,ICS/SCS. 1a'e)een !e'elo$e! to utili?e t1ese release! %ro t1e stac6 )e%ore)een !e'elo$e! to utili?e t1ese release! %ro t1e stac6 )e%ore

-roun! le'el liits ecee!e!-roun! le'el liits ecee!e!

T1is lea!s to t1e sae o)ections to ,ICS/SCS. as +ere note!T1is lea!s to t1e sae o)ections to ,ICS/SCS. as +ere note!a)o'e to t1e use o% tall stac6s +it1out a 1i-1 le'el o% $ollutanta)o'e to t1e use o% tall stac6s +it1out a 1i-1 le'el o% $ollutantreo'al )e%ore eission T1ere%ore 1ere a-ain it is ar-ue! t1at i% areo'al )e%ore eission T1ere%ore 1ere a-ain it is ar-ue! t1at i% a1i-1 le'el o% cleanu$ is use! t1e nee! to $roect t1e e%%luent into t1e1i-1 le'el o% cleanu$ is use! t1e nee! to $roect t1e e%%luent into t1e

u$$er air is re!uce! an! t1e )ene%its o% an o$eratin- ICS/SCSu$$er air is re!uce! an! t1e )ene%its o% an o$eratin- ICS/SCS,+1ic1 is costl*. in lieu o% installin- ore e%%icient $ollutant reo'al,+1ic1 is costl*. in lieu o% installin- ore e%%icient $ollutant reo'aleui$ent !isa$$eareui$ent !isa$$ear

Topic 7 Basic Air Pollution Modelling .ppt

Documents

Transcript of Topic 7 Basic Air Pollution Modelling .ppt