+ O - Freie Universität Berlin

geofuberlin

+ O - Freie Universität Berlin

Block-Kurs

Luftchemie

16 – 20 Februar 2009

Freie Universität Berlin, FB Geowissenschaften

Institut für Meteorologie

Arbeitsgruppe TRUMF – TRoposphärische UMweltForschung

9.00 - 13.00 / Nachmittag Selbststudie

Peter Builtjes


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Fokus des Kurses

Atmosphärische chemische Zusammensetzung der Troposphäre

und der Stratosphäre

Welche Phenomäne bestimmen die chemische

Zusammensetzung

Geowissenschaften – Meteorologie – Atmosphärische Chemie

Atmosphärische Chemie ist wichtig für:

− Strahlungsbilanz und Klimaänderung

− Luftqualität

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Berlin, 16-20 Februar 2009


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Ziel von der Block-Kurs

Einführung in Atmosphärische Chemie

Lesen/Studieren zwei algemeine - kurze - Artikeln

Studieren/Verstehen von ein ausgewählte Artikel

Kurze Presentation am Freitag über dieses Artikel

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Berlin, 16-20 Februar 2009


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Struktur des Kurses (1)

Montagmorgen : Entwicklung Erdatmosphäre/Basisprinzipen

Chemie/Stratosphäre 1

Montagnachmittag : “Aerosols Before Pollution” Meinrat Andreae,

Science Jan. 2007

Dienstagmorgen : Stratosphäre II / Troposphäre I

Dienstagnachmittag : “On avoiding dangerous anthropogenic interference

with the climate system”.

V.Ramanathan and Y.Feng, PNAS, vol 105, 38,

14245-14250, Sept.23, 2008

Mittwochmorgen : Troposphäre II und III

Mittwochnachmittag : Anfang studieren ausgewählte Artikel

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Struktur des Kurses (2)

Donnerstagmorgen : Aerosolen

Donnerstagnachmittag : Weiter studieren ausgewählte Artikel

Freitag : Präsentationen

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Erst Stratosphäre/Ozonschicht, dann Troposphäre

Fokus: Luftqualität, aber auch Bemerkungen über Klima

Fokus: Feinstaub/Aerosolen

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I) Entwicklung der Zusammensetzung

der Erdatmosphäre

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Literatur

Peter Warneck, Chemistry of the Natural Atmosphere, Acadamic Press,

Inc., 1988

E. Meszaros, Atmospheric Chemistry, Elsevier, 1981

John Seinfeld and Spyros Pandis, Atmospheric Chemistry and Physics,

John Wileyd Sons, 1998

Detlev Möller, Luft, Chemie Physik Biologie Reinhaltung Recht,

Walter de Gruyter, 2003

Richard Wayne, Chemistry of Atmospheres, Clarendon Press, 1993

Peter Hobbs, Basic physical Chemistry for the Atmospheric Sciences, Cambridge

Univ. Press, 1995

Junge, Air Chemistry and Radioactivity, Academic Press, 1963

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Formation and evolution of the atmosphere

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Richard Wayne


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Io : a satellite of Jupiter. Active volcano’s, atmosphere with

SO 2 and O-atoms

Titan : a satellite of Saturn. Possibly pools of liquid CH 4 ,

< 91 K

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Development of the earth atmosphere

1) Proto-planet, gasphase H 2 , He (little CH 4 , H 2 O, NH 3 , H 2 S)

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followed by dissipation of the leighter atoms

Development of gravitation field and of temperature

(by radioactive heating + solar radiation)

followed by condensation of H 2 O, binding of H

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2) Solid surface, secondairy elements: gases from the solid earth,

outgassing + volcano’s

CH 4 , NH 3 , H 2 O, a reducing atmosphere with H

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proof: Old (3.000 - 1000 million years) Fe-layers are

reduced, not oxidised

vulcano’s lead to CO 2 , H 2 O, N 2 , an oxidising atmosphere

with O

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Averaged composition of volcanic gas

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H 2 O 20 - 97 %

CO 2 1-48 %

N 2 1-38 %

SO 2 1-30 %

SO 3 0- 8 %

H 2 0- 4 %

Cl 2 0- 4 %

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3) Surface temperature at the edge between reducing and

oxidysing atmosphere: T ~ -10 / -15 °C

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With increasing amount of CO 2 and H 2 O

(greenhouse effect) T increases to above 0 °C,

liquid water

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Formation of O 2 in the atmosphere

H 2 O + hν →H + OH λ < 195 nm

H 2 O + hν →H 2 + O

O + O + M → O 2 + M

But, O 2 absorbs at λ < 195 nm, blocking

Estimated equilibrium at O 2 ~ 0.02 %, 10 -3 PAL

(present atmospheric level)

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O 2 + hv → O + O

O+ O 2 → O 3

Mehr in Detail später

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Live on earth started in a reduced atmosphere

Photosynthesis:

2H 2 O + CO 2 + hν →CH 2 O + H 2 O + O 2 + energy

live in the sea, or in mudded areas because of lack of O 3 -layer

gradual increase of O 2 level to 0.01 - 0.1 PAL

formation of O 3 -layer makes live on the surface possible

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Respiration:

C n H m O p + O 2 → H 2 O + CO 2 + energy

(more energy than by photosynthesis)

Fermentation:

C n H m O p → C 2 H 5 OH + CO 2 + energy

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Possible fluctuations in concentration levels

1) Higher O 2 levels in the past, upto 25 %

Proof. Current insects about 10 cm

In the past about 50 cm

Probability of forest-fires increases by 70 % with every percent

increase in O 2 -concentration, leading to decrease in O 2 -levels

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Air

Ocean

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The chemical composition of the

atmosphere is far from equilibrium

CO 2

N 2

O 2

Ar

H 2 O

NaCl

NaNO 3

Present world

0.03

78

21

1

96

3.5

~ O

Equilibrium world

99

0

~ 0

1

63

35

1.7

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Live is the deviation from equilibrium,

the living planet

Gaia hypothesis : James Lovelock

Homeostasis : The eco-system creates the atmosphere,

the environment, in which it feels well

Capacity of control

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The system contains numerous (delicate)

feed-back mechanisms to keep the balance

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Figures from:

The revenge of Gaia James Lovelock Penguin Books 2006

Question: What is the best temperature for life on earth?

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Figure 1: Distribution of Life

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Figure 2: Algal life in the oceans: blue: ocean deserts

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Doom-scenario I

New micro-organisms appear:

They kill the plants/forests

CO2 rises

T > 100 °C

H2O-vapour to stratosphere

H2O + hν →H2 + O

H2 escapes to space

3O + N2 → 2NO3 NO3 desolves in the sea, before evaporation

Results in CO 2 -atmosphere at high temperatures: Venus

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Doom-scenario II

New micro-organisms appear:

They consume nearly all CO 2

CO 2 decreases

T decreases to ~ -10 / -15 °C

Atmosphere with some CO 2 , some H 2 O: Mars

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Current composition of the earth atmosphere

N 2

O 2

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78.09 %

Ar 0.93 %

CO 2

Ne 18.2 ppm

He 5.24 ppm

CH 4

Kr 1140 ppb

20.95 %, very minor decrease by increase of CO 2

0.0038 %, equals 380 ppm, pre-industrial 270 ppm

pre-industrial 270 ppm; increase 2 ppm/year

1.8 ppm = 1800 ppb, pre-industrial 600 ppb

Composition of the dry atmosphere, H 2 O-vapour between 0.02-4 % in the

troposphere

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Wissenschaftliche Frage

Wie wahr der Chemische Zusammensetzung von der natürliche

Erdatmosphäre?

Für CO 2 und CH 4 : Eiskernbohren, zurück ca. 150.000 Jahr

Was mit Aerosolen/Feinstaub??

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Natural Aerosols

Soil Dust

Sea Spray

Smoke from Wildfires

Biological Particles

Biogenic Dimethyl Sulfide

Vulcano’s

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Aerosols and Cloud Condensation Nuclei-CCN

Paper Andreae “Aerosols before Pollution”

CCN: size 60-90 nm = 0.06-0.09 um

Cloud formation

Aerosols disappear mainly from the atmosphere by rain-out

Aerosols before pollution over the ocean and over land

about 100 particles/cm3 about 5 µgr/m3 Block-Kurs Luftchemie

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Units

ppm : parts per million : 10 -6

ppb : parts per billion : 10 -9

ppt : parts per trillion : 10 -12

Nearly always : volume ratio: ppm (ν)

Sometimes : mass ratio

Example : O 2 : 20.95 % is volume ratio (ν)

Moleculair weight O2 : 32

Averaged moleculair weight air : 29

O2 mass-ratio : 20.95 x 32/29 = 23.1 % (m)

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Also used, especially in air quality: mass/volume:

gr/m 3 , or µgr/m 3 (10 -6 gr)

ppm (ν) = RT/pMi x conc. in µgr/m 3

Mi is moleculair weight

So, µgr/m 3 is function from T and p

Often µgr/m 3 STP = standard temperature and pressure:

1013 hPa and 20 °C (293 K)

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Atmospheric residence time

The earth + atmosphere is a (nearly) closed system

(only not for H 2 , but the sun-wind contains protons~

no effective loss of H 2 )

Definition: The mean residence time of a gasmolecule:

t = mass of gas in the atmosphere / emission per time-unit

= mass ... / sink per time unit

In case of equilibrium

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Emission : Anthropogenic and/or biogenic and/or natural

(geogenic)

Sink : dry deposition and/or wet deposition and/or

chemical conversion

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Example

Total mass of the atmosphere : 5.15 10 18 kg

(total mass of the oceans:

1.4 10 21 kg, mass of the earth : 6.0 10 24 kg)

N 2 . 78 % 3.9 10 18 kg

N 2 -emission . biogenic : 10 12 kg/year

anthropogenic : 0.06 10 12 kg/year

t = 3.9 10 6 year

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Junge’s law

C = C + C* (fluctuation)

C1 = √ C *2 ⎯

C 1

⎯ = a.T -b

C

T in years; a = 2.16.10 -2 ; b = 0.95

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Relative Standard Deviation

10 2

10 0

10 -2

10 -4

10 -6

Rn

10-3 100 103 106 Tropospheric Residence Time/yr

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O 3

H 2 O

CH 4

CO

CO 2

H 2

N 2 O

O 2

He

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Atmospheric mixing time scales

Troposphere, zonal average ≈ 2 weeks

Troposphere, global ≈ 1-2 years

Troposphere + stratosphere, global ≈ 2-5 years

Small τ: large variation in concentration in time and place

Large τ: constant (not at sources/sinks)

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Turbulent diffusion / Eddy diffusion is essential to describe the

concentration patterns

Kz ~ 1-10 m 2 /s

Ky ~ 2.10 +6 m 2 /s

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II) Basisprinzipen von Chemie

und Strahlung

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Chemical reactions occur by adding energy to the system:

By – elevated – temperature or by radiation.

In the atmosphere the strongest driving force is radiation, sunlight,

so photo-chemistry. Thermal reactions are less important.

Some aspects: Mass-conservation. Stoichiometry

Example: CH 4 + 2O 2 → CO 2 + 2H 2 O (only at T > 400 °C)

This is the overall reaction

Chemical reaction rate k

-dCH 4 /dt = k CH 4

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Energy →

AB + C

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E act

∆H

(ABC) + +

Reaction Path →

E: Activatie Energy

Exotherme reactie

Depiction of the transition state for a bimolecular reaction

A + BC

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AB + hν →A + B (dissociation)

dn ab

dt

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= n ab . j i

j i = photo-dissociation constant

ji = ∫ ∅i (λ) σab (λ) I (λ) d λ

∆λ

∅ i (λ) : Quantum yield

= product molecules formed/cm3 s

photons absorbed/cm3 s

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σ ab (λ) : Absorption cross-section

I (λ) : Local photo flux

I total =I direct (taking into account absorption)

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+I diffuse

+ I reflected (at earth surface and clouds)

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Attenuation of solar radiation in the atmosphere

UV-A 100 - 280 nm

UV-B 280 - 315 nm

UV-C 315 - 400 nm

Visible light 400 - 800 nm

Infra-red > 800 nm

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III) Stratospheric chemistry and other trace

gases

First, some observations

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At 55 ° N January 360 DU

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March 400 DU

May 370 DU

July 360 DU

September 310 DU

November 320 DU

DU = Dobson Unit = equivalent column height at standard pressure

and temperature, in units of 10 -2 mm

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Formation of stratosphere O 3

O 2 + hν O + O j a

O + O 2 + M O 3 + M k b

O 3 + hν O 2 + O j c

O + O 3 O 2 + O 2 k d

Role of stratospheric O 3 :

Absorption λ < 300 nm

Temperature increase in the stratosphere

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O 2 + hV O + O (‘D) λ 180-240 nm

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50 km 30 km 15 km

J (O 2 ) [s -1 ] 10 -9 5.10 -11 10 -14

Photo-dissociation of O 3

O 3 + hV O 2 + O (‘D) λ 200-300 nm

50 km 30 km 15 km

J (O 3 ) [s -1 ] 8.10 -3 10 -3 7.10 -4

Remark: O (‘D) + H 2 O OH

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Mehr Detail über Chemie

O (‘D) usw: Angeregte Zustand: Spin, Verbotene Schale (shell)

Energy levels, „Spin-forbidden Transitions“ etc.

For example in Physical Chemistry, P.W.Atkins, 1994

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n 1 : conc. O

n 2 : conc. O 2

n 3 : conc. O 3

n m : conc. (N 2 + O 2 )

dn 1

dt

dn 2

dt

dn 3

dt

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=2 j a n 2 –k b n 1 n 2 n m

+ j c n 3 –k d n 1 n 3

=–j a n 2 –k b n 1 n 2 n m

+ j c n 3 + 2k d n 1 n 3

=k d n 1 n 2 n m + j c n 3

–k d n 1 n 3

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In addition:

n 2 (O 2 ) >> n 1 (O) + n 3 (O 3 )

dn 2

⇒ = 0

dt

n 1 (O) in equilibrium in 10-20 sec

dn 1

⇒ = 0

dt

As result:

B 1 – exp. [-2 (AB) ½ t]

n3 (O3 ) = .

A 1 + exp. [-2 (AB) ½ ½

t]

A = 2 k d j c / k b n 2 n m

B = 2 j a n 2

In equilibrium:

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Theory of Chapman (1932)

From the 4 reactions follows:

conc. O 3 = conc. O 2

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( )

K b .j a .conc (N 2 + O 2 ) 0.5

K d .j c

(for equilibrium, long time scales)

Qualitative correct, but factor 2 too high compared

to measurements

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Possible explanation of the overestimation of stratospheric

ozone by Chapman Theory:

Dynamics, transport. However, this should not influence the total

budget

Chemistry, missing loss-processes

Remark: This explanation should hold for the natural,

undisturbed stratospheric ozone layer!

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Other stratospheric trace gases

N 2 O, H 2 O, CH 4 , (CH 3 Cl etc.)

Origin: the troposphere

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N 2 O (ca. 90 % of biogenic origin)

N 2 O + hV N 2 + O ('D) λ ≈ 200 nm

O ('D) + N 2 O N 2 + O 2

2NO

from O 3 -photo-dissociation

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Followed by: NO + O3 NO2 + O2 NO2 + hV NO + O

O + O2 + M O3 + M

(NO + NO2 = constant)

O + NO2 NO + O2 (O + O3 2O2 )

Leading to: O3 + hV O + O2 O + NO2 O2 + NO

NO + O3 NO2 + O2 Netto: O 3 + O 3 3O 2

With NO x = NO + NO 2 as catalyst

Paul Crutzen: 1970

“The influence of nitrogen oxides on the atmospheric ozone content”

Quart. J.R.Met.Soc. (1970), 320-325

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The paper by Paul Crutzen shows:

Impact of NO and NO 2 , but also of:

OH

HO 2

No explanation where NO/NO 2 comes from,

mentiones “photodissociation” of N 2 O

But main source is N 2 O + O → 2NO

Nobel Prize for Chemistry in 1995 with Molina and Rowland

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H 2 O troposphere: 0.02 - 4%

stratosphere: 2 - 7 ppm

O ('D) + H 2 O 2OH

CH 4 in the stratosphere

CH 4 + OH H 2 O + CH 3 (lower stratosphere)

CH 4 + O ('D) OH + CH 3 (higher stratosphere)

CH 4 + Cl HCl + CH 3

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O + H 2 O → 2 OH

OH in Stratosphäre und Troposphäre

OH reagiert mit sehr viel Komponenten, nur nicht mit N 2 , O 2 und

CO 2

OH ist "cleansing agent", und bestimmt der Oxidation Capacity

von der Atmosphäre

Is the cleansing capacity of the atmosphere changing?

Guy Brasseur and Ron Prinn

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Für viele Spezies bestimmt OH die

“Chemical Lifetime” in der Atmosphäre

In der Troposphäre:

O3 + hv → O2 + O

O+ H2O → OH

Und CH4 +OH

CO + OH

Frage : Ändert sich OH ??

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Die gestörte O 3-Schicht

Freonen, F11, F12 usw

CF2CL2: F12

CFCL3:F11

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Stratospheric chlorine

Methylchloride: CH 3 Cl (biogenic)

F 11 : CFCl 3 (antropogenic)

F 12 : CF 2 Cl 2 (antropogenic)

Carbontetrachloride: CCl 4 (antropogenic)

Methylchloroform: CH 3 CCl 3 (antropogenic)

Example: CFCl3 + hV Cl + CFCl2 λ 170-190 nm

CFCl2 + O2 COFCl + ClO

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Followed by: Cl + O 3 ClO + O 2

O + ClO Cl + O 2

O 3 + hV O + O 2

Netto: O 3 + O 3 3O 2

With Cl as catalyst

Molina and Rowland: 1974

“Stratospheric sink for chlorofluormethanes:

chlorine atom-catalysed destruction of ozone”

Nature, vol.249, June 28, 1974, 810-812

Nobel Preis zusammen mit Paul Crutzen

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O 3 “residence time”

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50 km 5 - 20 hours

30 km ≈ 1 week

20 km 1 - 3 years

Residence time is the time needed to replace O3 when

stratospheric O3 is taken away/destroyed.

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CFC-11 : CFCl 3 : last number amount of F

fore-last number amount of H+1

first number amount of C-1

CF C-22 : HCF 2 Cl

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Loss reactions for Cl

Cl + CH4 HCl + CH3 Cl + HO2 HCl + O2 Cl + H2 HCl + H

CH4 most important reaction

OH + HCl H2O + Cl: slow

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Important:

Binding Cl in less reactive compounds

Cl + CH 4 → HCl + CH 3

ClO + NO 2 → ClONO 2

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Photo-dissociation in the stratosphere

N 2 O, CFCl 3 , CF 2 Cl 2 , CCl 4

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(all λ > 175 nm)

No photo-dissociation of CH 4 , NH 3

Components without H-atoms: photo-dissociation

Components with H-atom: reaction with OH and O ('D)

Photo-dissociation in the troposphere

NO 2 λ 175 - 240 nm

240 - 307 nm

CH 2 O λ < 300 nm

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Stratospheric ozone budget

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X + O3 XO + O2n+1 XO + O2 X + (n+1) O2 Netto: O 3 + O 2n+1 (n+2) O 2

n: 0 or 1

X: H, OH, NO, Cl, O

Model calculations, Crutzen & Schmailzel, 1983

Stratosphere, 2-D model

O + O3 2O2 20%

NO + O3 NO2 + O2 30%

H + O3 OH + O2 30%

Cl + O3 ClO + O2 20% anthropogenic

Also: ClO + NO2 ClONO2 Berlin, 16-20 Februar 2009


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104

Erste synthese CFC’s 1929 Thomas Midgley,

General Motors

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F 11: DuPont, 1932, for cooling

Production F 11 + F 12

1960 150.10 3 ton/year

1974 800

1982 600

1986 750

spray-can war

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105

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Concentrations

1975 1986 1991

F 11 0.1 ppb 0.23 0.30

F 12 0.1-0.2 ppb 0.40 0.50

Residence time

Estimates F 11 F 12

Sze & Wu (1974) 10 year 10-20 years

Singh (1979) 40 70

Crutzen (1987) 75-100 75-100

Elkins (1993) 55 140

Berlin, 16-20 Februar 2009


106

British Antartic Survey; 1982

TOMS instrument NASA

Ozone hole: fully unexpected

Normal chemistry can not explain this

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Berlin, 16-20 Februar 2009


107

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Berlin, 16-20 Februar 2009


108

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‘Om het behoud van de ozonlaag’

John Gribbin, DuPoc, Wageningen, 1992

Berlin, 16-20 Februar 2009


109

Der Zusammenhang zwischen Ozon und ClO in das Chemisch Zerstörte Gebiet

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Berlin, 16-20 Februar 2009


110

Situation

Polar night: polar vortex ≈ 60 o S

temperature: < -83 o C

HNO 3 + H 2 O polar stratospheric

clouds, PSC’s

In the polar night, at the surface of PSC’s:

ClONO 2 + HCl Cl 2 + HNO 3

ClONO 2 + H 2 O HOCl + HNO 3

Inactive Cl becomes potential active Cl

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Berlin, 16-20 Februar 2009


111

At sunrise

Cl 2 + hV 2Cl

HOCl + hV OH + Cl

O 3 increase after October:

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breaking of polar vortex mixing

T > - 83 o C, no polar clouds

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112

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PSC: Polar Stratospheric Clouds

Key Role

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113

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Berlin, 16-20 Februar 2009


114

Stratospheric ozone worldwide

Seasonal variation ≈ 50 DU

Solar cycle ≈ 6 DU

Quasi-biennal oscillations ≈ 8 DU

Vulcano’s ≈ ...

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Berlin, 16-20 Februar 2009


115

Weniger O3 in der Stratosphäre gibt weniger

Absorption von UV-B (280-315 nm)

in der Stratosphäre

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116

Increase of UV-B leads to

Increase in melonomia, skin cancer

1% less O 3 leads to 4 % more skin cancer

Eye-problems

Damage to protection-system at the skin-surface

Damage to plancton

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117

1) Ozone depletion potential-ODP

mean O 3 -depletion due to kg. of species X, divided by:

mean O 3 -depletion due to kg. CFC-11

2) Global warming potential-GWP

increase radiative forcing due to kg of species X, divided by:

increase radiative forcing due to kg.CO 2 (or CFC-11)

3) Atmospheric residence time

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Berlin, 16-20 Februar 2009


118

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Berlin, 16-20 Februar 2009


119

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Berlin, 16-20 Februar 2009


120

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Berlin, 16-20 Februar 2009


121

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Berlin, 16-20 Februar 2009


(WMO, 2007)

122

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CFC Trends 1978 - 2006

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123

(WMO, 2007)

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Trends HCFC

Berlin, 16-20 Februar 2009


124

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(WMO, 2007)

Trends CH 3ClCH 3 and CCl 4

Berlin, 16-20 Februar 2009


125

(WMO, 2007)

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Trend CH 3Br

Berlin, 16-20 Februar 2009


126

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ODP and GWP of different CFC’s

Berlin, 16-20 Februar 2009


127

Effects of the emission reduction of CFC’s

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Berlin, 16-20 Februar 2009


128

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Ozone in Earth’s stratosphere

Berlin, 16-20 Februar 2009


129

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Pollution of the stratosphere

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130

Koplung Klima-änderung und

Stratosphärische O 3-Schicht

Erhöhte CO 2 usw.:

Erhöhte Temperatur in der Troposphäre

So, Abkühlung in der Stratosphäre

Mehr Polar Stratospheric Clouds

J. Austin et al.

“Possibility of an Artic ozone hole in a double-CO 2 climate”,

Nature, vol. 360, Nov. 19, 1992, 221-225

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Berlin, 16-20 Februar 2009


131

Modelberechnungen mit ein 3-D Nord-

Hemisphärisch Circulations Modell,

UK Met-Office

Present Day CO 2 level

Present Day CO 2 level+ calculated O 3 -concentrations

Double CO 2 -level + climatological O 3 -concentrations

Double CO2-level + calculated O 3 -concentrations

Look to areas with < 195 K

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Berlin, 16-20 Februar 2009


132

Koplung Klima-änderung und Luftqualität

Aerosolen/Feinstaub

“On avoiding dangerous anthropogenic interference with the

climate system”.

V.Ramanathan and Y.Feng, PNAS, vol 105, 38, 14245-14250,

Sept. 23, 2008

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133

Aerosols lead to cooling, accept Black Carbon

Green House Gases and Atmospheric Brown Clouds

Committed Equilibrium Warming, without, and with aerosols

Coal, Oil, Gas

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134

IV Tropospheric chemistry

Gasphase chemistry: tropospheric ozone and related

components

Heterogeneous chemistry: Aerosol physics and chemistry

Dry and wet deposition

Chemical Transport Modelling - CTM

Emissions

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135

Tropospheric ozone

90 % of all ozone is in the stratosphere, only about 10 % is in the troposphere

Ozone concentration in the troposphere increases with height above the surface

Basic question in 1970: What is the origin of ozone in the troposphere and at groundlevel??

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Diffusion from the stratosphere (Junge)

Current insight: In the Northern hemisphere:

Produced by anthropogenic emissions (Crutzen)

Total troposphere: 50 % of the ozone from stratosphere

50 % anthropogenic

At ground level : 90-95 % anthropogenic

Berlin, 16-20 Februar 2009


136

Ozone and summersmog

Los Angeles, 1945, Haagen-Smit

Photochemical smog : (smoke + fog = smog) in summer

Wintersmog : London ‘fog’ 1940-1950: SO 2 and Sulfate-aerosols

Summersmog : LA: NOx and Reactive Hydro-carbons

Effects : Eye-irritation, breathing problems (asmatics)

Forest

Plants (tomato’s, tabacco)

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Berlin, 16-20 Februar 2009


137

Surface-near ozone at Montsouris 1876-1905

(Volz et al., 1986) compared to the Arkona series

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Berlin, 16-20 Februar 2009


138

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Open symbols : Before 1950

Closed symbols : After 1990

Berlin, 16-20 Februar 2009


139

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Berlin, 16-20 Februar 2009


140

Tropospheric chemistry

Stratospheric chemistry: mostly gasphase

Tropospheric chemistry: gasphase, aquous phase, aerosols

Formation of tropospheric ozone

NO 2 + hV NO + O λ < 410 nm

O + O 2 + M O 3 + M

O 3 + NO NO 2 + O 2

NO2 + O2 Photo-stationairy state

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NO + O 3

Berlin, 16-20 Februar 2009


141

Increase of tropospheric ozone: shift in

photo-stationairy state:

NO 2 + O 2

Reactive hydrocarbons:

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NO + O 3

RH + OH + O2 RO2 + H2O RO2 + NO RO + NO2 R: CH 3 , C 2 H 5 etc. etc.

RO + O2 Aldehydes + HO2 H2O + NO NO2 + OH

Aldehydes Beispiele: Formaldehyde: HCHO

Acetaldehyde: CH 3 CHO

CH 3 CHO+OH → PAN: Peroxyacethylnitrate

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142

Example

CH4 + OH H2O + CH3 CH3 + O2 + M CH3O2 + M

CH3O2 + NO CH3O + NO2 CH3O + O2 HCHO + HO2 stable product

CO + OH CO 2 + H

H + O 2 + M HO 2 + M

HO 2 + NO NO 2 + OH

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143

Netto:

CH 4 + 8 O 2 → CO + 4 O 3 + 2 OH + H 2 O

CO + 2 O 2 → CO 2 + O 3

Also:

P (O 3 ) = k 1 [NO] [RO 2 ]

+ k 2 [NO] [HO 2 ]

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144

Reactive Hydrocarbons: RH's transform NO in NO 2 without a loss

of O 3 , so leads to increase in O 3 concentration

Different RH's have a different Photochemical Ozone Creation

Potential: POCP

Ethene

Propene

1-Butene

Ethane

Propane

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Initial NO-NO 2

2

2

2

2

3

Total, including products

4

7

10

6

8

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145

RH : Reactive Hydrocarbons

VOC : Volatile Organic Compounds

NMVOC : Non Methane VOC

Alkanes : Saturated Compounds

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Examples : Ethane C 2H 6 atmospheric life-time : 80 days

Alkenes : Unsaturated Compounds

Propane C 3H 8 15 days

Examples : Ethene C 2H 4 2 days

Propene C 3H 6 15 hours

Isoprene C 5H 8 5 hours (biogenic)

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146

Alkynes : Example: Acethylene C 2H 2 30 days

Aromatics : Example: Benzene C 6H 6 20 days (carciogenic)

Tolueen : C 6H 5CH 3 3.6 days

Terpenes : C 10H 16 2 hours (biogenic)

Aldehydes and ketones : Example: Formaldehyde HCHO 1.6 days

Alcohols : Example: Methanol: CH 3OH 20 days

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147

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O 2

ην

O 3

NO 2

NO

OH

RH

Aldehydes

Berlin, 16-20 Februar 2009


148

NO → NO 2 → O 3

RH → Aldehyden

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Messungen in L.A.

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149

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150

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151

Policy for tropospheric O 3

RH versus NO x abatement,

Non-lineair: NO + O 3 NO 2 + O 2

lowering of NO leads to increase in O 3

high RH/NO x -ratio: NO x -strategy

low RH/NO x -ratio: RH-strategy

Biogenic RH-emissions

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152

Biogenic RH/VOC Emissions

From Decidious and Coniferous Forest:

Isoprene and Terpene

Strong dependence on Temperature and Radiations

(PAR+ Photosynthetic Active Radiation)

Biogenic NO Emissions

From surface, bacteria

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153

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154

Normal reactions in Northern Hemisphere,

for NOx > 50 ppt

RH + OH + O 2 → RO 2 + H 2 O

RO 2 + NO → RO + NO 2

RO + O 2 → aldehydes

HO 2 + NO → NO 2 + OH

For NOx < 50 ppt

HO 2 + HO 2 → H 2 O 2 + O 2

O 3 + HO 2 → 2O 2 + OH

O 3 + OH → O 2 + HO 2

Leads to decrease on O 3 -concentration

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155

The formation of the OH-radical,

the hydroxyl-radical

O 3 + hν →O 2 + O ('D)

O ('D) + H 2 O → 2 OH

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156

In free troposphere (> 2/3 km):

reaction OH with CH 4 , CO most important

In the polluted boundary layers:

reaction OH with NO 2 and HCHO most important

residence time OH ≈ 0.3 - 25 sec

mean concentration: 5.10 5 molecules/cm 3

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157

OH-radical 'discovered' by Levy, 1971

OH reactes with CH 4 , CO, with NO 2 , HCHO, H 2 , O 3 , NH 3 , SO 2 , RH

OH is the cleansing agent of the atmosphere, and determines the

atmospheric life time of species

OH does not react with N 2 , O 2 , H 2 O, CO 2

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158

Atmospheric Chemistry and the OH Radical

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159

OH Daytime summer : 5-10 x 10 6 molecules/cm 3

Daytime winter : 1-5 x 10 6 molecules/cm 3

Night time : < 2 x 10 5 molecules/cm 3

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160

Trends in the OH-concentration

Increase in O 3

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Increase in OH

Increase in hv Increase in OH

Increase in H 2O Increase in OH

Increase in CH 4

Decrease in OH

Increase in CO Decrease in OH

But: increase in CH 4, CO leads to increase in O 3 also …

Guy Brasseur and Ron Prinn: “Is the ‘cleansing capacity’ of the atmosphere

changing?”

IGBP Newsletter 43, 2002.

Conclusion: Relatively constant since 1850, may be about 20 % less.

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161

Studies to analyse the Budget of a Species

Emissions

Chemical formation and destruction

Dry and Wet Deposition

Can I understand the resulting concentrations?

Are emissions in balance with the loss terms?

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162

Dry Deposition

Flux = Fs [conc. m/s]

Fs = Kz (z)

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∂C

∂ z

- Fs = ( C (z)ref – C (o) ) /

o

= ( C (z)ref – C (o) ) / ra (z)

zref : reference hight, within the constant flux-layer

ra (z) : atmospheric resistance

rb : viscous sublayer

rc : surface resistance


z

d z

K z (z)

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163

-F s = [ C (z ref ) – c (o) ] / r a + r b + r c

with C (o) : concentration at z = 0, often zero:

-F s = V d C (z ref )

V d : Deposition velocity

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164

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165

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166

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Dry deposition velocity V d in cm/ s

SO 2

O 3

HNO 3

NO 2

Grassland

0.8

0.8

2.5

0.5

Water

0.4

0.05

1.0

0.02

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167

Dissolve in water

∆z g

∆z l

F s = ( C gi –C g )

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D g

∆z g

D l

= ( C l –C li )

∆z l

C l

C gi

C g

C li

air

interface

water

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168

Dg, Dl = Moleculair Diffusion Coefficient in gasphase

and liquid phase

Cgi = H . Cli

H : Henry Constant

Fs = ( Cl – Cgi / H ) / ( 1/kg H + 1/kl )

D g

∆z g

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D l

= kg = kl

∆z l

kg, kl : fct (windspeed)

Fs = l ( Cl – Cgi / H )

r

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169

SO 2

O 3

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Dry deposition to watersurfaces

Kg, K l , V d in cm/s

Kg

0.44

0.51

K l

9.6

0.049

H

0.02

3

V d

0.4

0.05

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170

Wet Deposition

Two processes:

In cloud processes: Gases absorped in droplets followed by

deposition when it rains:

Rain Out

Below cloud processes:

Wash out

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171

Below cloud scavenging of species C is given by

dC bc

dt

=

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Λ * P

∆z

Λ bc = Below-cloud scavenging coefficient

P = precipitation rate [m/s]

z = scavenging scale depth [=1000 m]

The scavenging coefficients

Component

SO 2

HNO 3

NH 3

H 2 O 2

HCHO

Λ bc (*10 6 )

0.15

0.5

0.5

0.5

0.05

Overview of below cloud scavenging coefficients for gases

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172

For particles the wet deposition is calculated by:

dC

dt

A = 5.2 m 3 kg -1 s -1

P = precipitation rate [m/s]

V rd = Fall speed of rain droplet [m/s]

E = Collection efficiency

SO 4

NO 3

NH 4

=

PPM fine

PPM coarse

Collection efficiency for aerosol particles

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A*

P

* E

V

rd

0.1

0.1

0.1

0.1

0.4

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173

Global CH 4 -budget

Emission sources in Tg/ year

Animals 100-220

Rice-paddies 280

Swamp 130-260

Termites 150

Biomass-burning 30-100

Natural gas leakage 20

Coal mines 40

Total ~ 500

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174

Loss term

CH 4 + OH ~ 400 Tg/ year

CH 4 -flux to the stratosphere ~ 60

Total ~ 460

Concentration CH 4

Atmospheric life-time ~ 8 years

Terra 10 12

Giga 10 8

Mega 10 6

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~ 1800 ppb Northern Hemisphere

~ 1700 ppb Southern Hemisphere

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175

Biogenic: Anaerob : 2 H 2 + CO 2 → CH 4 + O 2

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Aerob : CH 4 + 2O 2 → CO 2 + 2H 2 O

Biogenic/Anthropogenic distinction by

14 C production by cosmic radiation t ~ 5700 year

So, 14 C content biogenic emissions = 14 C content trees

14 C content fossil fuel = 0

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176

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177

Trend increase CH 4-concentration

1970-1985 : 1.5 % / year

1985-1989 : 0.8 % / year

around 1993 : 0 %

1995-2003 : 0.3 % / year

Reason : CH 4 -emission changes ??

OH increase ??

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178

M. Khalil et al

“Atmospheric Methane: Trends and Cycles of Sources and Sinks”,

Draft Paper 01/2007

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179

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180

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181

Conclusions

Global CH4-emissions and life time (OH) constant over the last

20 years

Result: No further increase in CH 4 -concentrations

Fluctuations due to temporary increases in CH4-emissions on the

northern hemisphere

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182

I) Eiszeit Methan

Vor 38.000/14.500/11.500 Jahre :

Erwärmung in weniger hundert Jahren

Als reaction steigt auch CH 4 an-verstärkt Temperatur Erhöhung

Quelle unklar:

Im Eiskristalle gelagert CH 4 .H 2 O, vielleicht nicht??

Mehr bei Bacterien?

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183

II) Nature Artikel, Januar 2006

Frank Keppler et al:

Methane emissions from terrestial plants under aerobic conditions

A lot of discussions!

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184

Tropospheric O 3-budget

A. Inflow from the stratosphere

B. Dry deposition at the surface

C. Chemical production

D. Chemical destruction

No wet deposition, O 3 does not desolves in water

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185

Ad A. Stratosphere-Troposphere exchange

Change in tropopause height

Tropopause folding

Turbulent transport by jet-streams

Small scale turbulence

Estimate: NH 300-500 Tg/ year

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SH 150-250 Tg/ year

(jet-streams stronger in NH)

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186

ad B. Deposition flux

V d deposition velocity

Oceans/snow 0.001 m/s

Grassland 0.005 m/s

Forest 0.006 m/s

Result: NH 425 Tg/ year

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SH 275 Tg/ year

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187

Ozone Production: NOx and RH

Ozone Destruction: by hν

Somewhat by O 3+ OH → HO 2 +O 2

O 3 + HO 2 → 2O 2 + OH

Conc. O 3 NH tropics 35 ppb

> 30 ° N 45 ppb

Total: NH 140 Tg

SH 120 Tg

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SH tropics 30 ppb

< 30 ° S 40 ppb

Atmospheric life time NH 100 days

SH 120 days

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188

Anthropogenic

Combustion:

C + O 2 → CO 2

C x H y + O 2 → xCO 2 + 0.5y H 2 O

Incomplete Combustion:

VOC, CO, CH 4 , Dust (BLACK CARBON!!)

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189

Contained in fuels

S → SO 2

Heavy metals

N → NO x

in gas N about 0 %

in coal about 0.5- 3 %

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190

Thermic NO x

N 2 + O 2 → NO x

High T + high O 2 → NO high

Low T + low O 2 → NO low

Industrial processes:

HF, CFC’s, heavy metals, pesticides, particles etc.

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191

Emissie benzine-auto’s

N 2 78 %

CO 2 12 %

H 2 O 5 %

O 2 1 %

CO 2 %

H 2 2 %

NO 0.06 %

RH 0.08 %

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192

Biogenic Emissions

Animals: CO 2 , CH 4 , NH 3

Forests: VOC

Soil/Bacteria: NO, N 2 O

Wetlands: CH 4

Plancton: DMS, H 2 S

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193

Natural emissions

Sea-salt (NaCl)

Wind-blown dust (sahara-sand)

Lightning (NO)

Natural forest fires (CO 2 , CH 4 , CO, VOC, NO, particles)

Meteorites (particles)

Vulcano's (CO 2 , SO 2 , H 2 S, HCl, particles)

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194

Anthropogenic PM2.5 emissions over Europe

in 2000 including shipping

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195

Resolution needed?

Emission Test file TNO Europe NOX total at ~ 6 x 6 km

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196

A more refined Budget Analysis

By the development and use of Chemical Transport

Models-CTM’s

CTM’s describe the relation between emissions and

concentrations/deposition

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197

∂C i

∂t


∂y

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The basis of atmospheric

transport-chemistry modelling

∂C i

∂C i

∂C i

+ u + v + w =

∂x ∂y ∂z ∂x

(K h

∂C i )

∂y

+


∂z

(K z

∂C i ) +


(K h

∂C i ) +

chemistry + emissions – dry deposition – wet deposition

∂z

∂x

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198

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Examples of the use of

Chemical Transport Models

Global Models

− Troposphere + Lower Stratosphere

− Horizontal grids of ca. 2.5 x 2.5 latlong

Regional Models, for example covering Europe

Urban Models

Local Models, Street scale

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CTM’s are 3-D Eulerian Grid Models

Horizontal grids globally 2.5 x 2.5 latlong, down to 1 x 1

Europe 25 x 25 km2 down to 10 x 10 km2 Vertical layers 10-30 upto 5 - 10 km

Concentrations calculated in boxes

Local models: Plume models and line source/street canyon models

Often empirical models

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200

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Some examples of global

modelling with the TM-5 Model

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201

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202

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203

G.J.Roelofs, J. Lelieveld and R.van Dorland

“A three-dimensional chemistry/general circulation model

simulation of anthropogenically derived ozone in the troposphere

and its radiative climate forcing”

J. of Geoph. Res. 102, D19, 23389-23401, 1997

Model calculations with the European Center Hamburg Model-

ECHAM, with pre-industrial and contemporary emissions

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204

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ECHAM

Berlin, 16-20 Februar 2009


205

O 3 Tropospheric Budget

By anthropogenic emissions : 30 %

By biogenic emissions : 30 %

From stratosphere : 40 %

Radiative forcing by O 3

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:0.5 W/m 2 NH

0.3 W/m 2 SH

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206

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Radiative forcing sensitivity of global

surface temperature to changes in

vertical ozone distribution. The heavy

solid line is a least squares fit to onedimensional

model radiative-convective

equilibrium results computed for 10

Dobson unit ozone increment added to

each atmospheric layer. Ozone

increases in region I (below ≈ 30 km)

warm the surface temperature. No

feedback effects are included in the

radiative forcing. From: Lacis et al., 1990

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207

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Atmospheric Chemistry

and Greenhouse Gases

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208

Increase in surface ozone from transatlantic

transport of North American pollution

(July 1997)

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209

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210

3-D Eulerian grid modelling

Global scale, continental scale, urban scale.

Model system at TRUMF : REM/CALGRID ( continental)

+ urban version

Model system at TNO : LOTOS ( continental)

and LOTOS –zoom ( urban)

Characteristics of the model –systems:

Horizontal grid resolution 0.25 x 0.5 latlong, with nesting down to about

4 x 4 km2 Vertical layers: 5-10 upto about 3-5 km

Gasphase chemistry (O 3 ) and aerosol physics and chemistry

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211

Required input data

Boundary conditions from observations, or global modelling

(TM-5)

Anthropogenic and biogenic and natural emissions

Land use data base

Diagnostic meteorological fields (by Eberhard Reimer)

Prognostic meteorological fields:

− DWD-LM

− NWP

− MM5-reanalysis

− ECMWF-ERA 40

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212

Model calculations hour-by-hour for

one year, or more

Computer demand : several days on a PC

Purpose of modelling : Understanding the phenomena that

control the chemical composition

Policy applications : emission reduction strategies

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213

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214

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215

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216

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217

Model evaluation:

How reliable present the model the ‘reality’

Aspects:

Model calculates volume averaged concentrations, observations are at

a specific point

Observations (might) contain errors, and their spatial representativity is

(often) not well known

Uncertainty and errors in input data: emissions

Weak parts of the model as description of vertical exchange processes

and the treatment of clouds

Chemistry is non-linear: Right for the wrong reasons

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Berlin, 16-20 Februar 2009


218

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219

Waldhof: Tagesmittelwerte Ozon 1997

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220

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Waldhof: Tagesmaxima Ozon 1997

Berlin, 16-20 Februar 2009


221

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REM3-CBM4: Station Waldhof

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222

Acidification / Eutrophication

and Ground level ozone

Protection of the Ecos-systems: Freshwater, Forests, Vegetation

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223

Critical loads of S- and N- deposition,

depending on the character of the soil

S-Deposition: Acidification

N-Deposition: Acidification and Eutrophication

Ground level Ozone, averaged over the growing season

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224

Policy based on

− Average Accumulated Exceedance: AAE

− Accumulation over Threshold of 40 ppb O3 of forest: AOT40f

AAE and AOT40f are weighted with sensitive areas, resp. forest

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Berlin, 16-20 Februar 2009


225

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226

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227

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228

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229

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230

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231

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232

Aerosols, fine particles, particle matter

Definition:

Dispersed system containing solid or liquid particles suspended in

air (cloud droplets are not considered to be aerosols)

Aerosols : Size-spectrum

Chemical composition

Aerosols : Radius > radius molecules

Mass > mass molecules

Aerosols : > 10 -3 µm

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233

Aitken particles : r < 0.1 µm

Fine particles : 0.1 < r < 2.5 µm

Coarse particles : 2.5 < r < 10 µm

Fine particles : r ~ wavelenght of light

Block-Kurs Luftchemie

Particle size < wavelenght of light: Rayleigh scattering

~ wavelenght of light: Mie scattering

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234

II) Konzentrationen und Grenzwerten.

Bemerkung:

Die Grenzwerten gibt es für PM 10 und PM 2.5

Basiert auf Epidemiologische Studien/Cohort usw.

Nicht basiert auf Toxicologische Studien, deswegen kein

Grenzwert für Russ/Black Carbon

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235

Grenzwerten

PM 10:

− Jahresmittelwert 40 µgr/m 3

− Tagesmittelwert 50 µgr/m 3 , nicht mehr als 35 Tagen pro Jahr

Grenzwert gillt „überall“ /hot-spots, und von 1-1-2005

Mann darf das Anteil natürliches Feinstaub (wie Seesalz) separat

melden

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236

PM 2.5

Umgebungs Jahresmittelwert 20 µgr/ 3 (exclusief hot-spots), in 2015

Allgemeine Jahresmittelwert 25 µgr/m3 (inclusief hot-spots) in 2015

20 µgr/m3 (inclusief hot-spots) in 2020

Exposure Reduction Target: In 2020 eine Reduktion relatief zu

2008-2010

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237

Indikator f. durchschnittliche Exposition (AEI-Average Exposure

Indicator) ist der PM2.5-Jahresmittelwert des Referenzjahres =

Ausgangskonzentration AK

Ableitung von 5 Immissionsklassen aus dem PM2.5-Jahresmittelwerten: Reduzierungsziel bis 2020 in %

Klasse 1: AK = AK < 13 µg/m 3 10

Klasse 3: 13 µg/m 3 >= AK < 18 µg/m 3 15

Klasse 4: 18 µg/m 3 >= AK < 22 µg/m 3 20

Klasse 5: AK >= 22 µg/m3 Alle angemessenen Maßnahmen

um 18 µg/m3 zu erreichen

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238

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239

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240

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241

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242

Removal of aerosols by:

Coagulation + Accumulation

Wet precipitation

Sedimentation

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243

Block-Kurs Luftchemie

Coalescence by Brownian motion


N

k

l

r

µ :

A

:

:

dynamic gas

:

dN

dt

:

:

=

numbers of

Bolzmann−constant

mean free path

radius

Stokes

kT ⎛

+

µ


4

3 ⎜1

particles

viscosity

Al


⎟ N

r ⎠

− Cunningham correction

2

Berlin, 16-20 Februar 2009


244

Wet deposition and aqueous phase chemistry

Cloud-formation by Cloud Condensation Nucleii-CCN

CCN’s are aerosol, size ~ 0.05 µm

In-cloud scaveging : Rain out

Below-cloud scaveging : Wash out

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245

Example for in-cloud scaveging:

SO 2 , gas + H 2 O ↔ SO 2 .H 2 O

In droplets:

SO2 .H2O ↔ H + -

+ HSO3 -

HSO3 +

↔ H

2-

+ SO3

2- 2-

SO3 + ½ O2 → SO4 Block-Kurs Luftchemie

Berlin, 16-20 Februar 2009


246

Cloud-drops can evaporate Aerosols ”back”, called: processing

Cloud-drops can grow and precipitate

Wash out by raindrops

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Berlin, 16-20 Februar 2009

Block-Kurs Luftchemie

247

aerosol

of

radius

:

r

ion

concentrat

number

:

(r)

N

)

(

:

mass

Total

)

:

(

:

drop

of

Radius

:

R

:

out

Wash

3

3

4

2

2


=

r

o

dr

r

N

r

h

R

m

surface

the

above

height

h

h

R

π

π

π


248

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249

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Berlin, 16-20 Februar 2009


Berlin, 16-20 Februar 2009

Block-Kurs Luftchemie

250

s

m

V

m

kg

m

r

for

g

r

V

s

p

s

/

1

.

0

/

10

.

2

30

viscosity

gas

dynamic

:

µ

density

particle

:

ρ

radius

:

r

law

Stokes'

n

Gravitatio

3

3

p

2

9

2







=

ρ

µ

µ

ρ


251

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252

Messungen von Aerosolen

Zusammensetzung:

– primär, anthropogen und natürlich

– sekundär anorganisch

– sekundär organisch-biogen und anthropogen

PM 10 und PM 2.5

Chemie sekundärer Aerosole

Anzahl Messungen + Zusammensetzung sehr gering

– AFO-2000 Projekt FU-Berlin-Reimer

– Messungen Stadt Berlin-Lutz

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253

Voerde, Germany, PM10

Metals

1%

Na

4%

UD

26%

NH4

9%

Figure 1 Composition of PM10 expressed in relative units at three sites in Europe.

Block-Kurs Luftchemie

NO3

19%

BC

7%

Barcelona, PM10

Ca

7%

Na

3%

Cl

3%

EC

11%

NH4

9%

NO3

19%

SO4

21%

OC

12%

SO4

22%

OC

27%

BC

OC

SO4

NO3

NH4

Na

Metals

UD

EC

OC

SO4

NO3

NH4

Ca

Na

Cl

Po Valley, PM10

Elements

16%

NH4

11%

NO3

18%

UD

7%

EC

3%

OC

24%

SO4

21%

EC

OC

SO4

NO3

NH4

Elements

UD

Berlin, 16-20 Februar 2009


254

Satelliet-messungen von

Aerosol Optical Depth-AOD

Grosse Verteilung, Ångström Coefficient

Versuch um mit LOTOS-EUROS und Data assimilation PM2.5

zu bestimmen

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255

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256

Mean Ångström coefficient (a) and its variance (b) for August 1997 computed from the

Ångström law using all possible combination of wavelengths.

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257

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Preliminary estimate of the average PM2.5 (µg/m3 )concentration

for August 1997, based on ATSR-2 data.

0 to 5

5 to 10

10 to 15

15 to 20

20 to 25

25 to 35

35 to 45

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258

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259

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260

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261

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262

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263

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264

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265

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266

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267

Secondary inorganic aerosol

NO 2 + OH → HNO 3

HNO 3 + NH 3 ↔ NH 4 NO 3

SO 2 + 2OH → H 2 SO 4

H 2 SO 4 + 2NH 3 → (NH 4 ) 2 SO 4

secondary organic aerosol

ROG + OH → Σ α i C i

Block-Kurs Luftchemie

+ NO 3

+ O 3

Berlin, 16-20 Februar 2009


268

Example PM10 consists of

Secondary Inorganic Aerosol: SIA

Biogenic Secondary Organic Aerosol: BSOA

Anthropogenic Secondary Organic Aerosol: ASOA

Primary Aerosol, BC = Black Carbon and OC + Organic Carbon

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269

Erste Ergebnisse Modellierung von

Aerosolen

REM-Calgrid/RCG und LOTOS und erste Validierung

Additionelle Information AOD mit ATSR

Hauptbeschränkungen Modellierung:

Zu wenig gute Beobachtungen

Wolkenbeschreibung / Chemie / CCN

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270

Average PM 2.5 28 July - 13 August 1997

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271

Average BSOA 28 July - 13 August 1997

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272

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Primary part of the PM 10 concentrations in 1995 (µg/m 3 )

as modeled by the LOTOS model

Berlin, 16-20 Februar 2009

20

17.5

15

12.5

10

7.5

5

2.5

0


273

Average computed (LOTOS) wind blown dust concentration (µg/m 3 ) in 1995

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Berlin, 16-20 Februar 2009

7

6

5

4

3

2

0


274

Windgeblasenen Sand

Funktion von

Landnutzung

Bodenfeuchte

Windgeschwindigkeit + Grenzwert

Agrar bodenbearbeitung

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275

Soot ( Russ) is the same as Black Carbon – BC- or Elementary

Carbon-EC

It is produced by burning, so is part of the primary emissions of PM

PM 2.5 exists to a large extent of BC and Organic Carbon-OC

BC might be the health relevant part of PM 2.5

BC is a greenhouse “gas”, it absorbs light

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276

MODELLING BLACK CARBON OVER EUROPE

Overview of the total European BC and non-BC emissions per source category

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Berlin, 16-20 Februar 2009


277

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Figure 2 European BC emission (tonnes) derived in this study

Berlin, 16-20 Februar 2009


278

Average computed (LOTOS) Black Carbon concentration (µg/m 3 ) in 1995

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Berlin, 16-20 Februar 2009

2

1.5

1.25

1

0.75

0.5

0.25

0


279

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Figure 4

Annual average distribution of BC,

APPM, SO 4, NO 3 and NH 4 over

Europe (µg/m 3 ).

Berlin, 16-20 Februar 2009


280

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Figure 5

Annual average distribution of

PM2.5 (µg/m 3 ) over Europe in the

upper left panel and the associated

fractions of BC, APPM, SO 4, NO 3

and NH 4 in the other panels.

Berlin, 16-20 Februar 2009


281

Block-Kurs Luftchemie

SO 3 Scatter Diagram

Berlin, 16-20 Februar 2009


282

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TNO 3 Scatter Diagram

Berlin, 16-20 Februar 2009


283

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BC to measurements

Berlin, 16-20 Februar 2009


284

Modellierte PM10 über Europa (2003)

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Total Anthropogen (ohne See-Saltz)

Berlin, 16-20 Februar 2009


Model

285

60

50

40

30

20

10

0

Verifikation von Modell-Ergebnisse: PM10

Block-Kurs Luftchemie

PM10 Model vs Airbase metingen

0 10 20 30 40 50 60

Meting

45

40

35

30

25

20

15

10

5

0

Holland:

PM10 wird 45 %

unterschätzt

Korrelation: 0.52-0.62

NL0007R

NL0010R

NL0220A

NL0223A

NL0226A

NL0227A

NL0249A

NL0250A

NL0252A

Berlin, 16-20 Februar 2009

Meting

Model


286

Verifikation von Modell-Ergebnisse: Sulfaat

Modelled concentration (mg/m 3 Modelled concentration (mg/m) 3 )

6

5

4

3

2

1

0

Block-Kurs Luftchemie

SO2

SO4

0 1 2 3 4 5 6

Observed concentration (mg/m 3 Observed concentration (mg/m )

3 )

Unsicherheit: Nicht-Lineare Trend in SO 2 -SO 4 umsetzung

(Wolken/Mist, heterogene Reaktion, usw

Berlin, 16-20 Februar 2009


Modelled concentration ( µg/m 3 Modelled concentration ( µg/m )

3 Modelled concentration ( µg/m )

3 )

287

6

5

4

3

2

1

0

TNO3

NO3

Block-Kurs Luftchemie

Verifikation von Modell-Ergebnisse:

Nitraat en ammonium

0 1 2 3 4 5 6

Observed concentration (µg/m 3 Observed concentration (µg/m )

3 Observed concentration (µg/m )

3 )

Modelled concentration ( µg/m 3 Modelled concentration ( µg/m )

3 Modelled concentration ( µg/m )

3 )

5

4

3

2

1

0

TNH4

NH4

0 1 2 3 4 5

Observed concentration (µg/m 3 Observed concentration (µg/m )

3 Observed concentration (µg/m )

3 )

Berlin, 16-20 Februar 2009


288

A model intercomparison study

focussing on episodes of elevated

PM10 concentrations

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289

Das Ziel von das Projekt war das verstehen von die hohe

gemessene PM-werte, mit Hilfe von Modellen

Benützte Modellen: RCG, LOTOS-EUROS, CHIMERE, EURAD,

LM-MUSCAT

Episode von Jan-April 2003

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290

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291

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Berlin, 16-20 Februar 2009


292

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293

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294

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295

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296

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297

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298

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299

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300

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301

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302

Ergebnis

Das Modellieren von Anorganisch Aerosol geht gut (nicht bei EURAD)

Das Modellieren von hohe PM10 werte geht nicht gut (nur bei EURAD,

aber da “right for the wrong reasons”)

Empfindlichkeit für Meteorologie ist Gross

Untersätzung von PM10 bei Modellen bei:

Fehlende Emissionen wie Windblown Dust

Schwierigkeiten bei Modellierung von BSOA

Meteorologische Beschreibung bei stabiele Wetterlagen/Vertikal

Austausch

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Berlin, 16-20 Februar 2009


303

Die EU-Rahmenrichtlinien und andere

Massnahmen

Massnahmen in Brussel : Focus auf Gesundheit – Stadt

Massnahmen in Genf : Focus auf Eco-system – Laendliche

Gebiete

Bruessel : EU-Rahmenrichtlinien, NEC-Directive

(National Emission Ceilings)

Genf : UNECE-Grenzueberschreitende

Luftverschmutzung-Gothenburg Protokoll

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304

EU-Rahmenrichtlinien

Fuer SO 2 , NO 2 , NO x , PM 10 (PM 2.5 ), Pb, O 3

In der Zukunft: PAK und Schwermetalle

Fuer Stadtgebiete sind NO 2 und PM 10 /PM 2.5 die wichtigsten Stoffen

(Im allgemeinen ist O 3 in der Stadt niedrig)

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305

Grenzwerte

NO 2 40 µg/m 3 Jahresmittelwert

200 µg/m 3 Stundenmittel, max. 18 x pro Jahr

PM 10 40 µg/m 3 Jahresmittelwert

50 µg/m 3 Tagesmittel, max. 35 x pro Jahr

In Grossstaedten: Ueberschreitungen, auch in Berlin

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306

Konzentrationen in der Stadt sind bestimmt

durch

Grossraeumigen Hintergrund

Allgemeinen Stadt-Hintergrund

Lokale Situation: Hot spots

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307

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308

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Berlin, 16-20 Februar 2009


CALCULATED RCG

309

80

70

60

50

40

30

20

10

0

NOV10_01

NOV10_07

NO 2 Berlin-Buch (Hourly in microgr/m 3 )

NOV10_13

NOV10_19

NOV11_01

Block-Kurs Luftchemie

NOV11_07

NOV11_13

NOV11_19

NOV12_01

NOV12_07

NOV12_13

NOV12_19

NOV13_01

NOV13_07

NOV13_13

NOV13_19

NOV14_01

NOV14_07

NOV14_13

NOV14_19

NOV15_01

OBSERVED

OBSERVATIONS REM/CALGRID

NOV15_07

NOV15_13

NOV15_19

NOV16_01

NOV16_07

NOV16_13

NOV16_19

NOV17_01

NOV17_07

NOV17_13

NOV17_19

NOV18_01

NOV18_07

NOV18_13

Berlin, 16-20 Februar 2009

NOV18_19


CALCULATED RCG

310

45

40

35

30

25

20

15

10

5

0

NOV10_01

NOV10_07

NOV10_13

PM10 ZARTOU (Hourly in microgr/m 3 )

NOV10_19

NOV11_01

NOV11_07

Block-Kurs Luftchemie

NOV11_13

NOV11_19

NOV12_01

NOV12_07

NOV12_13

NOV12_19

NOV13_01

NOV13_07

NOV13_13

NOV13_19

NOV14_01

NOV14_07

NOV14_13

NOV14_19

NOV15_01

OBSERVED

OBSERVATIONS REM/CALGRID

NOV15_07

NOV15_13

NOV15_19

NOV16_01

NOV16_07

NOV16_13

NOV16_19

NOV17_01

NOV17_07

NOV17_13

NOV17_19

NOV18_01

NOV18_07

Berlin, 16-20 Februar 2009

NOV18_13

NOV18_19


311

RCG: Zartau: PM10 COMPOSITION 1999

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312

Modellierung von PM10 über Berlin

Hauptfrage

Wie gut kann ich PM10 in Berlin modellieren?

Wieviel von PM10 ist verursacht durch Emissionen in Berlin?

Paper

R. Stern et al. “Analyzing the response of a chemical transport

model to emission reductions utilizing various grid resolutions”,

ITM, Leipzig, May 2006

Block-Kurs Luftchemie

Berlin, 16-20 Februar 2009


RCG modelling domains. Upper left: European scale grid with resolution of 0.25° Lat., 0.5° Lon. Upper right:

Nest 1, national scale (Germany) grid with resolution of 0.125° Lat., 0.25° Lon. Lower left: Nest 2, the

Federal State (Brandenburg) grid with resolution of 0.03125° Lat., 0.0625° Lon., embedded in Nest 1. Lower

right: Nest 3, urban grid Berlin with resolution of 0.0078125° Lat., 0.015625° Lon., embedded in Nest 2 (and

Nest 1) and also showing the major “ring” motorway around Berlin.

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Scatter diagram of observed and calculated NO 2 and PM10 annual means in the greater Berlin area at four

scales, including regression lines and correlation coefficients. Dashed lines indicate the range of +/- 50% of

the observations. For further explanations see text.

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IV) Ursachen Analyse und Massnahmen in

Deutschland

Präsentation von PM 10 über Deutschland bei Kombination von

Messungen und Modellergebnisse

Data-assimilation ist der Kombination von Messungen und

Berechnungen:

− Passief: Kriging, Optimal Interpolation

− Aktief: 4-D var, Ensemble Kalman Filter

Massnahmen Analyse: UBA-project PAREST:

Particle Reduction Strategies: www.parest.de

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Many problems in understanding /

modelling of PM10 and PM2.5

In observations : PM2.5 1/3 Anorganic

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1/3 Organic

1/3 Primary

Coarse Particles : PM10- PM2.5

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In general: Modelled concentrations of especially

PM10 are lower than observations

Possible explanations :

Missing emission-sources : Wind-blown dust

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Road abrasion

Tyres and brakes

Resuspension : Treatment of Agricultural Soil

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Atmospheric Chemistry / Air quality and

Climate Change are coupled phenomena

Example: High ozone concentrations in the hot period of August

2003

Tropospheric ozone is a greenhouse gas

Most aerosols are cooling, BC is warming

Research question:

Air quality/atmospheric chemistry situation over Europe in

2050/2100, so in a modified climate.

Detailed question: OH-radical in 2050/2100 ???

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DEM with climate change

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Impact of climate change on

regional air pollution budgets

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Climate Change is not only due to CO 2

Importance

of Tropospheric ozone

of aerosols

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Radiative Forcing Components

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Aerosols are also relevant for Climate Change

Most aerosols are cooling (reflection)

Estimate over Europe ~ -2 W/m 2

Black Carbon is warming (absorption)

Estimate over Europe ~ +1 W/m 2

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Modelling Black Carbon over Europe

Radiative forcing (W/m 2 ) of BC over Europe

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M.Schaap et al.

“Anthropogenic black carbon and fine aerosol distribution over

Europe.

J. of Geoph. Res. 109, D 18207, 2004

Model calculations over 1995 over Europe using the LOTOSmodel,

overview paper.

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Four areas of current research

Data assimilation

Ensemble approach

Impact of climate change on air quality, and vice versa

Use of satellite observations for air quality and climate

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Data assimilation by combining models and observations

(Kalnay, E (2003). Atmospheric modelling, data assimilation and

predictability.

Cambridge Univc. Press, UK)

Concept:

Model calculated and observed concentrations represent different

sources of information about air quality concentration levels.

Necessary: Estimation of uncertainties in model calculated and

observed concentrations

Necessary: Decision of weighting these uncertainties

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Different methods

Optimal Interpolation-OI

3-D Var and 4-D Var

Kalman filtering

M.van Loon, P.Builtjes and A.Segers

“Modelling and data assimilation of ozone”

Air Pollution Modelling and its Application XIV

Kluwer/Plenum, 2001

Preliminary results of applying Kalman filtering for combining

observed and modelled ozone concentrations over Europe

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Ensemble using different CTM’s to

determine the spread of models

Example for O3 using EMEP, RCG, MATCH, LOTOS-EUROS,

CHIMERE, TM-5, DEHM

Loon, van M. et al “Evaluation of long-term ozone simulations

from seven regional air quality models and their ensemble”

Accepted Atm. Env. 2007

Ensemble is a method to determine uncertainty

(Science florishes by uncertainty, policy freeces by uncertainty)

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Yearly mean diurnal cycle of ozone, in µg.m -3 , as a function of hour, for all models,

averaged over all monitoring stations.

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Yearly mean diurnal cycle of ozone, in µg.m -3 , as a function of hour, for all models,

averaged over all monitoring stations, relative to the average of each data set.

In order to obtain values in this figure, values of Figure 1 are divided by their

Average over hours for each model.

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Schlussbemerkungen

Weitere Untersuchung notwending in der Messung von

PM 10/2.5 mit chemische Aufsplittung

Weitere Untersuchung notwending in der Modellierung

von PM 10 /PM 2.5 , einschliesslich der Emissionen

Herausforderung: Kombination von Messungen und

Modellierung bei Data-assimilation / Optimale Interpolation

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PM10 MEAN 1999 BERLIN/BRB

Jahresmittelwert der PM10-Konzentration für Berlin\Brandenburg aus der kleinräumigen Modellrechung

(links, oben), der OI-Methode aus Modell und Beobachtung (links unten) und der Beobachtung

(rechts oben) und der OI-Methode ausschließlich aus Messungen für das Jahr 1999.

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Data assimilatie AOD en PM in LOTOS-EUROS

23-5-2000

Exp 2.

Retrieved

Model

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geässimileerd

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Validatie AOD → systeem werkt!

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Diplomthemen/Batchelor-Masters (1)

Weitere Modell-Evaluierung REM-CALGRID (RCG)

Budget Analyse PM über Berlin mit RCG

(Dr. Arbeit Andreas Kerschbaumer)

Verbesserung Depositions Modul in RCG

Prognoseverifizierung für PM10 und PM2.5

Statistische Auswertung PM10 usw im Vergleich zu

Meteorologische Grössen

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Diplomthemen/Batchelor-Masters (2)

Verwendung von Wolkenanalyse, Wolken Top und -Basis,

Einbau in TRAMPER

Source/Receptor Statistik für Pollenmessungen, Einbau in RCG

Verbesserung Aerosol-Modellierung, mit TNO

Data Assimilation, mit TNO

Analyse Satelliet-Data für Luftqualität, mit TNO

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Diplomthemen/Batchelor-Masters (3)

Analyse von Seesalzmessungen (in Deutschland)

Seesalzmodellierung mit RCG

Modellierung Basische Kationen (TNO)

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Danke für die Interesse !!!

Block-Kurs Luftchemie

Berlin, 16-20 Februar 2009

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