We athe r Impac ts on Air Dispe r sion Pr e par e d for : SMC - - PowerPoint PPT Presentation

We athe r Impac ts on Air Dispe r sion

Pr e par e d for : SMC St. Mar ys Ce me nt Plant Community L iaison Committe e Me e ting Pr e se nte d by: Winnie Song, M.Sc ., P.E ng. BCX E nvir

• nme ntal Consulting

Mar c h 14, 2020

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Ope ning

We a the r c o nditio ns ha ve sig nific a nt impa c ts o n a ir dispe rsio n. Wind dire c tio n is no t the o nly fa c to r. Air dispe rsio n is a lso impa c te d b y ho w sta b le the a tmo sphe re is (i.e . a tmo sphe ric sta b ility).

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Outline

Atmo sphe ric Sta b ility a nd L a pse Ra te s Air Dispe rsio n unde r Diffe re nt We a the r Co nditio ns Air Dispe rsio n in the T

• wn o f St. Ma rys

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

Outline

Atmosphe r ic Stability and L apse Rate s

Air Dispe rsio n unde r Diffe re nt We a the r Co nditio ns Air Dispe rsio n in the T

• wn o f St. Ma rys

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

Atmo sphe ric Sta b ility a nd L a pse Ra te s

T he drive r fo r a ir mo ve me nt is te mpe ra ture va ria nc e . Air te mpe ra ture va rie s with he ig ht. T his ve rtic a l te mpe ra ture va ria nc e dire c tly impa c t a ir sta b ility. T he ve rtic a l te mpe ra ture g ra die nts a re c a lle d “L a pse Ra te s”. L a pse ra te s a re use d to de sc rib e ho w sta b le the a tmo sphe re is (i.e . a tmo sphe ric sta b ility). T he two impo rta nt la pse ra te s a re

Adiabatic L apse Rate (AL R) a nd E nvir

• nme ntal L

apse Rate (E L R).

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L H

Adia b a tic L a pse Ra te (AL R) - Be nc hma rk

Adiabatic L apse Rate (AL

R) is the ra te a t whic h the te mpe ra ture c ha ng e s/ de c re a se s with he ig ht in a n “ide a l” e nviro nme nt. T he AL R is a ppro xima te ly -1˚C e ve ry 100m o r -10 ˚C/ km. T he ide a l e nviro nme nt a ssume s tha t the a ir pa rtic le s a re “isolate d” fro m the e nviro nme nt a nd wa rm o r c o o l witho ut lo sing o r g a ining a ny e ne rg y.

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100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30 E le vation Above Se e L e ve l (m) T e mpe r atur e (˚C)

T e mpe r atur e Change s with He ight Dr y Adiabatic L apse Rate

• 10 ˚C/ km

Adia b a tic L a pse Ra te (AL R) - Be nc hma rk

T he c lo se st a na lo g y to de sc rib e AL R is a ho t a ir b a llo o n. T he a ir in the ho t a ir b a llo o n is “iso la te d”. Whe n the ho t a ir b a llo o n shrinks it do e s no t wo rk o n its surro unding s o r do e s it re q uire a ny wo rk to stre tc h. T he he a t tra nsfe r b e twe e n b a llo o n a nd the e nviro nme nt is slo w e no ug h to b e ig no re d. 7

E nviro nme nta l L a pse Ra te (E L R)

E nvir

• nme ntal L

apse Rate (E

L R) is the ra te a t whic h the te mpe ra ture c ha ng e s/ de c re a se s with he ig ht in a c tua l e nviro nme nt. T he E L R is influe nc e d b y pa tte rns o f he a ting , c o o ling a nd mixing a nd the pa st histo ry o f the a ir ma ss. T he diffe re nc e b e twe e n E L R a nd AL R de te rmine s ho w sta b le the a tmo sphe re is. 8

Outline

Atmo sphe ric Sta b ility a nd L a pse Ra te s

Air Dispe r sion unde r Diffe r e nt We athe r Conditions

Air Dispe rsio n in the T

• wn o f St. Ma rys

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

Air Dispe rsio n unde r Unsta b le Co nditio ns - L

• o ping

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Atmo sphe ric Sta b ility: Unsta b le , stro ng ve rtic a l mixing Wind spe e d: L

• w

T ime / We a the r o f o c c urre nc e : Sunny Da y Air Dispe rsio n Co nditio n: Go o d, do mina te d b y the rma lly induc e d turb ule nc e

L

• w wind 

inte nsive ve rtic a l mixing

100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Temperature Changes with Height

Dry Adiabatic Rate "Balloon" Superadiabatic Lapse Rate "Unstable"

Amb ie nt a ir is c o o ling fa ste r with he ig ht tha n the “b a llo o n”

Air Dispe rsio n unde r Sta b le / Ne utra l Co nditio ns - Co ning

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Atmo sphe ric Sta b ility: Sta b le , OK ve rtic a l mixing Wind spe e d: Mo de ra te to stro ng T ime / We a the r o f o c c urre nc e : Clo udy da ys, da y/ nig ht tra nsitio ns Air Dispe rsio n Co nditio n: OK , do mina te d b y me c ha nic a lly induc e d turb ule nc e (winds)

Stro ng wind  little turb ule nc e

100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Temperature Changes with Height

Dry Adiabatic Rate "Balloon" Subadiabatic Lapse Rate "Stable/Neutral" Subadiabatic Lapse Rate "Stable/Neutral"

Amb ie nt a ir is c o o ling with he ig ht a t simila r ra te s a s the “b a llo o n”

Air Dispe rsio n unde r Sta b le / I nve rsio n Co nditio ns - F a nning

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Atmo sphe ric sta b ility: Ve ry Sta b le , ve ry little mixing Wind spe e d: no t spe c ific T ime / we a the r o f o c c urre nc e : Cle a r nig ht the surfa c e c o o ls Air dispe rsio n c o nditio n: Suppre sse d turb ule nc e

100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Temperature Changes with Height

Dry Adiabatic Rate "Balloon" Inversion Lapse Rate "Strongly Stable"

no turb ule nc e

Amb ie nt a ir te mpe ra ture inc re a se s with he ig ht. Stro ng ve rsio n re sults in ve ry sta b le a tmo sphe re .

100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Temperature Changes with Height

Dry Adiabatic Rate "Balloon" Inversion Layer below Stack

Air Dispe rsio n unde r Sta b le / I nve rsio n Co nditio ns – L

• fting

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Atmo sphe ric Sta b ility: Sta b le b e lo w the inve rsio n la ye r Wind spe e d: no t spe c ific T ime / we a the r o f o c c urre nc e : L a te a fte rno o n a nd e a rly unde r c le a r skie s Air dispe rsio n c o nditio n: F a vo ra b le fo r g ro und le ve l fo r ta ll sta c ks.

T he a ir is wa rme r b e lo w the inve rsio n la ye r, whic h “a lo fts” the plume .

Air Dispe rsio n unde r Sta b le / I nve rsio n Co nditio ns – Ca pping (F umig a tio n)

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Atmo sphe ric sta b ility: Sta b le a b o ve the inve rsio n la ye r Wind spe e d: no t spe c ific T ime / we a the r o f o c c urre nc e : E a rly mo rning a fte r a sta b le nig ht Air dispe rsio n c o nditio n: Poor. Plume tra ppe d b y inve rsio n a b o ve sta c k he ig ht.

100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Temperature Changes with Height

Dry Adiabatic Rate "Balloon" Inversion Layer Above Stack

T he a ir is wa rme r a b o ve the inve rsio n la ye r, whic h “c a ps” the plume b e lo w.

Diurna l Cyc le o f Surfa c e He a ting a nd Co o ling

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100 200 300 400 500 600 700 800 900 1000 5 10 15 20 25 30

Elevation Above See Level (m) Temperature (˚C)

Mid Day Night Morning

Nig ht Mo rning Mid-Da y Ra dia tio n I nve rsio n

Outline

Atmo sphe ric Sta b ility a nd L a pse Ra te s Air Dispe rsio n unde r Diffe re nt We a the r Co nditio ns

Air Dispe r sion in the T

• wn of St. Mar

ys

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

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Que e n Stre e t Are a Kiln Stac k

• T

he kiln sta c k is lo c a te d in a fo rme r q ua rry b e lo w g ra de . T he sta c k is sho rt re la tive to the e le va te d re c e pto rs in to wn.

• T

he rive r va lle y runs thro ug h to wn.

• Ra dia tio n inve rsio ns a re

inte nsifie d in the va lle y to re sult in ve ry sta g na nt a ir.

• Sho rt sta c k + va lle y

c lima te = Po o r a ir dispe rsio n.

Air Dispe rsio n in the T

• wn o f St. Ma rys

Outline

Atmo sphe ric Sta b ility a nd L a pse Ra te s Air Dispe rsio n unde r Diffe re nt We a the r Co nditio ns Air Dispe rsio n in the T

• wn o f St. Ma rys

What will the Stac k E xte nsion Do for Air Dispe r sion

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n unde r Go o d/ Ok Dispe rsio n Co nditio ns

 T

he sta c k e xte nsio n will e le va te the plume fro m the g ro und a nd pro vide mo re vo lume fo r mixing a nd dilutio n.

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SMC K iln Sta c k E xisting SMC K iln Sta c k with 30m E xte nsio n

Wha t will the Sta c k E xte nsio n Do fo r Air Dispe rsio n unde r Po o r Dispe rsio n Co nditio ns

 T

he sta c k e xte nsio n will ra ise the plume (a po rtio n o f it if no t a ll) a b o ve the inve rsio n la ye r to minimize fumig a tio n.

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SMC K iln Sta c k with 30m E xte nsio n SMC K iln Sta c k E xisting

I n Summa ry:

Atmo sphe ric Sta b ility ha s sig nific a nt impa c ts o n a ir dispe rsio n Air dispe rsio n c a n b e ve ry po o r whe n inve rsio n o c c urs I nve rsio n c a n o c c ur in the mo rning o r e a rly e ve ning Sta c k e xte nsio n c a n minimize g ro und le ve l c o nc e ntra tio ns b y pro viding mo re mixing vo lume / he ig ht a nd lifting the plume (a t le a st a po rtio n o f it) a b o ve the inve rsio n la ye r

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Co urte sy o f BCX Sta ff, BCX Pa int Nig ht, Oc to b e r 2019

T ha nk yo u ~ Que stio ns?

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