THE COMPUTATIONAL INVESTIGATION THE COMPUTATIONAL INVESTIGATION OF THE INFLUENCE OF WEATHER OF THE INFLUENCE OF WEATHER

CONDITIONS ONCONDITIONS ON OZONE FORMATION IN URBAN OZONE FORMATION IN URBAN

ATMOSPHEREATMOSPHERE

Dmitry A. Belikov, Alexander V. StarchenkoDmitry A. Belikov, Alexander V. StarchenkoTomsk State University, Russia, TomskTomsk State University, Russia, Tomsk

Institute of Atmospheric Optics of the SB RAS, Russia, TomskInstitute of Atmospheric Optics of the SB RAS, Russia, Tomske-mail: e-mail: belikov@iao.rubelikov@iao.ru, e-mail: , e-mail: starch@math.tsu.rustarch@math.tsu.ru

Photochemical smog in world towns Photochemical smog in world towns

The annual American Lung Association study says about 159 million Americans -- 55 percent of the population -- reside in counties where the air is heavily polluted with ozone.

For many large cities in the world (e.g., Los Angeles) the presence in the daylight hours in the atmospheric surface layer of high concentrations of ozone, one of most widely spread pollutants, is an inevitable reality.

Simplified scheme of photochemical ozone formation Simplified scheme of photochemical ozone formation

NO NO2

h

O3

RO RO2

NOx

emission

VOC

emission

O2 OH

OH HNO3

deposition

O2

Tropospheric ozone is formed by photochemical reactions involving volatile organic compounds (VOC) and the oxides of nitrogen.

It has been proved that the major source of ozone precursors (nitrogen oxide and dioxide, hydrocarbon radicals) is automobile exhausts.

According to the researches by Mage, performed in 1996, for the megapolises with the population of more than ten million, automobiles are the primary source of atmospheric pollution, and for a half of them are the only one.

A significant contribution of emissions from industrial and power plants should also be noted. By having been transferred from coal to gas, they have substantially reduced emissions of sulfur, dust, and soot, but increased those of nitrogen and carbon

Model formulationModel formulation

– is concentration of the i-th admixture component;

In this work, calculation of admixture concentration, taking into account chemical reactions between components, is realized on the basis of the model, represented in the photochemical Hurley’s scheme (Hurley P.J. The Air Pollution Model (TAPM) Version 1: Technical Description and Examples //CSIRO Atmospheric Research Technical Paper No.43. Aspendale: CSIRO. 1999. 39p.):

zyxtCi ,,,

wcvcuc iii ,, – are turbulent correlations of concentration with wind velocity constituents;

iS – stands for pollution discharge into the atmosphere or its settling onto the underlying surface;

iR – refers to chemical reactions between admixture components;

)1(iiiiiiiii RSwc

zvc

yuc

xz

CW

y

CV

x

CU

t

C

Reactions and reaction rates of Harley’s modelReactions and reaction rates of Harley’s model

N Reactions Reaction rates 1 SNGOCRRPhvR smogsmog

RsmogCkR 11 2 2NONORP NORPCCkR 22 3 32 ONOhvNO 233 NOCkR

4 23 NOONO 344 ONOCCkR

5 22OHRPRPRP RPRPCCkR 55 6 SGNNORP 2 266 NORPCCkR

7 SNGNNORP 2 277 NORPCCkR

8 SNGSSORP 2 288 SORPCCkR

9 SNGSSOOH 222 22299 SOOH CCkR

10 SNGSSOO 23 231010 SOO CCkR

– are introduced into the system in order to provide effectiveness. APM include SNGOC, SNGN, SNGS as a result, the terms of Ri of equation (1) for 8 pollutants will have the form:

Reactions and reaction rates of Harley’s modelReactions and reaction rates of Harley’s model

1. smog reactivity Rsmog,

2.

nitric oxide NO,3. radical pool RP,

4.

nitrogen dioxide NO2, 5. hydrogen peroxide H2O2,

6.

ozone O3,7. sulfur dioxide SO2,

8. stable non-gaseous organic carbon SGOC, 9. stable gaseous nitrogenated substances SGN,10. stable non-gaseous nitrogenated substances SNGN, 11. stable non-gaseous sulfurous substances SNGS,12. airborne particulate matter (APM) that includes secondary particulate

concentrations consisting of SNGOC, SNGN, SNGS

Species of Seinfeld’s modelSpecies of Seinfeld’s model

In model of Seinfeld 12 equation with 11 species are considered:

• ozone O3,• nitric oxide NO,• nitrogen dioxide NO2 ,• atomic oxygen O,• hydrocarbon RH,• hydroxyl radical OH,• aldehydes RO2, • peroxide radical HO2 ,• hydrocarbon substances RCHO, RCHOO2, RCHOO2NO2

Reactions and reaction rates of Seinfeld’s modelReactions and reaction rates of Seinfeld’s model

N Reactions Reaction rates 1 ONOhvNO 2

211 NOCkR

2 32 OOO OCkR 22

3 23 NOONO 333 ONOCCkR

4 2ROOHRH OHRHCCkR 44

5 2RCOOOHRCHO OHRCHOCCkR 55

6 22 HOROhRCHO RCHOCkR 66

7 22 NOHONO 277 HONOCCkR

8 222 HONONORO NORO CCkR288

9 222 RONONORCOO NORCOO CCkR 299

10 OHNOOHNO 22 OHNO CCkR21010

11 2222 NORCOONORCOO 2299 NORCOO CCkR

12 2222 NORCOONORCOO 2299 NORCOOCkR

One dimensional model of atmospheric One dimensional model of atmospheric boundary layerboundary layer

K-l model of turbulence:K-l model of turbulence:

;gVVfuwzt

U

;gUUfvwzt

V

wzt

wqzt

q

,l

EC

z

klE

zw

g

z

Vvw

z

Uuw

t

E De

2

3

E

lw

g

z

Vvw

z

UuwC

t

lL 1 ,1

2

2

z

lEC

z

llE

z Le

zz

V

z

UlEFwvwuw hm ,,,, ,

112*111

*1

*

01

;;;;sin;cos

:

lk

obsobsuu zflfvEtqqtf

vVf

vU

zzz

Initial and boundary conditionsInitial and boundary conditions

0

:

z

q

z

l

z

E

z

V

z

U

Hz

z

The boundary conditions for model of atmospheric boundary layer are:

1. The results of height distributioneight distribution obtained due to weather balloon are used as initial conditions for wind velocity, air temperature and moisture and also for correction of this variables.

2. For turbulence characterizations the initial profiles are generated on the basis of above model at fast averaged dynamic and temperature parameters of atmosphere.

3.3. At upper boundary wind velocity equals to the velocity of geostrophic wind which At upper boundary wind velocity equals to the velocity of geostrophic wind which are calculated on the basis of atmosphere pressure (data of are calculated on the basis of atmosphere pressure (data of http:http:////mmeteo.infospace.rueteo.infospace.ru););

Aria of investigationAria of investigation Conditions of calculationsConditions of calculations

- urban area;

- point sources of pollution

2 -ecological observation station

1. Station №2; 2. Academic city;

Tomsk

1

2

N

E W

S

1. Spatial time-dependent equations (1) were solved numerically for a parallelepiped with 119 linear (roads), 12 point and area 338 emission sources;

2. The typical diurnal evaluation of the traffic ratio are used;

0 5 10 15 20 252.5 7.5 12.5 17.5 22.5

tim e , h

0

20

40

60

80

100

traf

fic

rati

o in

%

Method of computation Method of computation

1. In the investigated area that covers a town and its neighborhood, the finite-difference grid was built with the cells having constant horizontal sizes and variable vertical sizes, the latter decreasing when approaching the surface:

50x50x100 for meteorology; 12x12x100 for pollution;

2. Approximation of differential operators in Eqs.(1) was accomplished with the second accuracy order over coordinates and with the first accuracy order over time;

3. Advective terms of transport equations (1) are approximated using the monotoned antistreaming Van Leer scheme that does not allow appearance of “non-physical” values of the concentration;

4. In the computations high-performance calculation resources were used, namely, multiprocessors of Tomsk State University (http://cluster.tsu.ru) and Institute of Atmospheric Optics SB RAS (http://cluster.iao.ru);

5. Parallelization of numerical method of solution of Eqs.(1) was executed using geometric principle, i.e. data decomposition.

Fig. 1. Results of model calculation over two days (27-28 08 2003) and measurement data. Negative values on the time scale correspond to the first day, positive values refer to the second day. Dots indicate measurement data, curves are calculation results (red line – 1d (Hurley) calculation, blue line – 3d (Hurley), firm line indicates the district of Akademgorodok, dotted line refers to the center of Tomsk).

Results of model calculationResults of model calculation

-10 0 10 20

tim e , h

0

20

40

60

O3,

ppb

-10 0 10 20

tim e , h

0

0.5

1

1.5

2

2.5

win

d sp

eed,

ì/s

-10 0 10 20

tim e , h

0

100

200

300

400

win

d di

rect

ion,

deg

r

-10 0 10 20

tim e , h

0

4

8

12

16

20

NO

, ppb

-10 0 10 20

tim e , h

0

20

40

60

80

NO

2, pp

b

-10 0 10 20

tim e , h

0

200

400

600

800

sola

r ra

diat

ion,

Wt/

m2

Fig. 2. Results of model calculation over two days (27-28 08 2003) and measurement data. Negative values on the time scale correspond to the first day, positive values refer to the second day. Dots indicate measurement data, curves are calculation results (red line – 1d (Hurley) calculation, blue line – 3d (Hurley), firm line indicates the district of Akademgorodok, dotted line refers to the center of Tomsk).

Results of model calculationResults of model calculation

-10 0 10 20

tim e , h

0

0.5

1

1.5

2

2.5

win

d sp

eed,

ì/s

-10 0 10 20

tim e , h

0

100

200

300

400

win

d di

rect

ion,

deg

r

-10 0 10 20

tim e , h

0

200

400

600

800

sola

r ra

diat

ion,

Wt/

m2

-10 0 10 20

tim e , h

0

2

4

6

8

10

AP

M,

g/m

3

-10 0 10 20

tim e , h

0

0.0004

0.0008

0.0012

0.0016

0.002

RP

, ppb

-10 0 10 20

tim e , h

0

1

2

3

4

5

Rsm

og, p

pb

-10 0 10 20

tim e , h

0

0.5

1

1.5

2

2.5

win

d sp

eed,

ì/s

-10 0 10 20

tim e , h

0

100

200

300

400

win

d di

rect

ion,

deg

r

-10 0 10 20

tim e , h

0

200

400

600

800

1000

sola

r ra

diat

ion,

Wt/

m2

-10 0 10 20

tim e , h

0

0.0004

0.0008

0.0012

0.0016

0.002

RP

,RO

2, pp

b

-10 0 10 20

tim e , h

0

1

2

3

4

5

6

Rsm

og, R

H, p

pb

Fig. 3. Results of model calculation over two days (26-27 08 2003) and measurement data. Negative values on the time scale correspond to the first day, positive values refer to the second day. Dots indicate measurement data, curves are calculation results (red line – 1d (Hurley) calculation, blue line – 1d (Seinfeld), firm line indicates the district of Akademgorodok, dotted line refers to the center of Tomsk).

Results of model calculationResults of model calculation

Fig. 3. Results of model calculation over two days (26-27 08 2003) and measurement data. Negative values on the time scale correspond to the first day, positive values refer to the second day. Dots indicate measurement data, curves are calculation results (red line – 1d (Hurley) calculation, blue line – 1d (Seinfeld), firm line indicates the district of Akademgorodok, dotted line refers to the center of Tomsk).

Results of model calculationResults of model calculation

-10 0 10 20

tim e , h

0

0.5

1

1.5

2

2.5

win

d sp

eed,

ì/s

-10 0 10 20

tim e , h

0

100

200

300

400

win

d di

rect

ion,

deg

r

-10 0 10 20

tim e , h

0

200

400

600

800

1000

sola

r ra

diat

ion,

Wt/

m2

-10 0 10 20

tim e , h

0

20

40

60

O3,

ppb

-10 0 10 20

tim e , h

0

10

20

30

40

NO

, ppb

-10 0 10 20

tim e , h

0

20

40

60

80

100

120

NO

2, pp

b

ConclusionConclusion

At this workAt this work::

1.1. The model of spreading pollution The model of spreading pollution taking into account chemical reactions taking into account chemical reactions between substances at the atmosphere surface layer was used for investigation between substances at the atmosphere surface layer was used for investigation of ozone formation and transformation;of ozone formation and transformation;

2.2. The result of calculation with observation data were compared. Well The result of calculation with observation data were compared. Well agreement was received;agreement was received;

3.3. The comparison with 3d meteorological and Seinfeld’s photochemical models The comparison with 3d meteorological and Seinfeld’s photochemical models are conducted; are conducted;

4.4. Some Some features of generation and spreading ozone in Tomsk area for different features of generation and spreading ozone in Tomsk area for different weather conditions were revealed; weather conditions were revealed;

The research was founded by grant RFBR 04-07-90219 and grant of RF Ministry of Education.

Thank you Thank you

for attention!for attention!