Aplinkos tyrimai, inžinerija ir vadyba, 2009. Nr. 3(49), P. 21-28 Environmental Research, Engineering and Management, 2009. No. 3(49), P. 21-28

ISSN 1392-1649

Ground-level Ozone Air Pollution in Vilnius City Dovilė Laurinavičienė Department of Environmental sciences, Vytautas Magnus University, Lithuania

(received in July, 2009; accepted in September, 2009) This study aspires to assess distribution of the ground-level ozone concentration in Vilnius city. A portable Aeroqual series 300 ozone monitor has been used for measuring purposes. Sampling was carried out in Vilnius city during four seasons in the period of 2006-2007. Results of this study have revealed that annual mean of ground-level ozone concentration in Vilnius city was 30.3 µgm-3. The highest ground-level ozone concentration was in Viršuliškiai district (43.1 µgm-3), the lowest - at a highway of Eišiškės (17.9 µgm-3). The highest average seasonal concentration was determined in summer (49.6 µgm-3) and the lowest - in autumn (16.9 µgm-3). The ground-level ozone concentration has also a clear diurnal cycle - with higher values in the day-time and notably lower values at night. A minimal ground-level ozone concentration was at 06 am (4.0 µgm-3), the maximal one - at 01 pm (87.0 µgm-3). During the measurement period the concentration of ground-level ozone in Vilnius has never exceeded the stated value (120.0 µgm-3). Meteorological conditions are known to influence the formation and dispersion of ground-level ozone. The results of this work show that the ground-level ozone concentration noticeably correlates with the temperature (r=0.554 p= 0.000) and the wind speed (r= -0.785 p= 0.000). Keywords: air pollution, ground-level ozone concentration, seasonal and diurnal variation of groundlevel ozone concentration, meteorological parameters.

1.

Introduction

Ground-level ozone air pollution is of great concern because of its adverse effects on human health and ecosystems (Poupkou et al. 2008, Cristofanelli & Bonasoni 2009). Ground-level ozone is not emitted directly into the atmosphere. It results from photochemical reactions between oxides of nitrogen (NOx) and volatile organic compounds (VOCs) in the presence of sunlight (Pudasainee et al. 2006, Vingarzan & Taylor 2003, Clapp & Lenkin 2001, Sillman 1999). Emissions of NOx are produced primarily in motor vehicle engines, power plants, industrial boilers and at burning of fossil fuels. Main sources of VOCs emissions are motor vehicle emissions, gasoline vapors, chemical solvents (Parra et al. 2009, Westmoreland et al. 2007). Big concentrations of ground-level ozone become a greater and greater problem each year because it constitutes the main part of photochemical smog. Photochemical ground-level ozone formation depends on a number of natural and anthropogenic

factors. Typical summer fair weather conditions are responsible for an increase in ground-level ozone production (Jacob & Winner 2009). The most efficient ozone formation reactions are driven by solar radiation and its precursors (Chudzynski et al. 2001). Meteorological parameters (temperature, wind speed and direction, solar radiation, humidity) highly influence the formation and dispersion of pollutants, the concentration varying widely from region to region, with the time of year, and the time of day (Hunova et al. 2004). This study intends to assess the ground-level ozone concentration in Vilnius city. To determine the ground-level ozone concentration a portable Aeroqual series 300 ozone monitor has been used. The latter has been of great assistance in estimating the concentration of ground-level ozone in places where there are no permanent measurements: close to streets, in catchment areas, also in resorts, in relatively clean places and suburbs.

D. Laurinavičienė

2.

An Aeroqual series 300 ozone monitor is constructed to measure low and high ozone levels. Its low concentration ozone head measures the ozone concentration from 0.000 to 0.500 ppm, and a high concentration ozone head measures the ozone concentration from 0.50 to 20.00 ppm. Accuracy of a low concentration ozone head is +/- 0.010 ppm (from 0 to 0.100 ppm); +/- 10% (0.100 to 0.500 ppm), while that of a high concentration ozone head is +/10% (from 0.20 to 2.00 ppm); +/- 15% (from 2.00 to 20.00 ppm), the measurement units being either ppm or mg/m3. The operating temperature range is from 5°C to 50°C, relative humidity limits are 5% and 95%. A sensor type - gas sensitive semiconductor (GSS) is described in (www. ozoneapplications). Sampling was carried out during four seasons in the period of 2006-2007. 15 measurement places were selected in the whole city (Table 1, Fig. 2). In each measurement place the ground-level ozone concentration was measured three times at noon (at 12 am-01 pm) and in the evening (at 05-06 pm).

Methods

Ground-level ozone concentration measurements were carried out in Vilnius city. A portable Aeroqual series 300 ozone monitor was used (Fig. 1).

Fig. 1.

Ground-level ozone concentration measurement Aeroqual series 300 ozone monitor

Table 1.

Measurement places of the ground-level ozone concentration

No. 1. 2. 3. 4. 5. 6. 7. 8. 9.

Measurement place Crossroad of Kareivių and Kalvarijų str. Sapieginės pinewood Geležinkelio str. City hall Dariaus and Girėno str. New Vilnia Cathedral square Sausio 13 th str. Supermarket “Akropolis“

10.

Savanorių av.

11. 12. 13. 14. 15.

Sereikiškių park Arsenalo str. Tauras hill Viršuliškių str. Eišiškių highway

Description of measurement place Intensive traffic Recreation zone Intensive traffic Lots of people and vehicles, valley Residential district, many vehicles Suburb area, many people, intensive traffic, hill Many people and vehicles, valley Residential district, intensive traffic Many people, intensive traffic, many vehicles, hill Residential district, intensive traffic, stationary air pollution source „Vilniaus energija“ Recreation zone, valley Many people , hill Residential district, hill Residential district, intensive traffic Suburb area, housing, many vehicles

According to the measured concentration the average seasonal and annual concentration of groundlevel ozone in Vilnius city was calculated. To assess the relation to the meteorological parameters, the correlation coefficients between the ground-level ozone concentration and meteorological variables (temperature and wind speed) were calculated. Meteorological data were obtained from a meteorological station (www.meteo.lt).

3. 3.1.

Results Seasonal variation of the ground-level ozone concentration

Study results show that the annual mean ground-level ozone concentration in Vilnius city was 30.3 µgm-3. Distribution of the ground level ozone concentration in the whole city is presented in Fig.3. The highest ground level ozone concentration was in Viršuliškiai district (43.1 µgm-3) and Lazdynai district near Television Tower (42.4 µgm-3). The lowest ground-level ozone concentration was at the highway of Eišiškės (17.9 µgm-3).

22

Ground-level Ozone Air Pollution in Vilnius City

•2

•1 •9 • 14

•8

• 10 • 7 • 13 • 4

• 12 • 11

•6

•3 •5

• 15

Fig. 2.

Measurement places of the ground-level ozone concentration in Vilnius

50.0

O3, μgm

-3

40.0

43.1

42.4

37.3

36.1

33.4

33.1

31.8

30.0

29.9

27.9

26.6

25.1

24.4

23.5

19.6

20.0

17.9

10.0

Fig. 3.

wa y hig h

os tr. eli

Ei š išk ių

žin k

yh all

Ge le

Cit

N.V iln ia ų# Ka lva rijų str Ca . th e dra l sq uar e Se rei kiš kių p ar k Ta ura Da sh ria ill us and Gi rėn os tr. ivi

Ka re

Vi ršu lišk ių str . Sa usi o1 3t hs tr. Sa v a Su no per rių ma str . rke t "A kro po lis" Ar sen alo Sa str pie . gin ės pin ew ood

0.0

Annual mean of the ground-level ozone concentration in Vilnius

found in summer (49.6 µgm-3, Fig.4) and the lowest – in autumn (16.9 µgm-3). In winter season the ozone concentration was 23.6 µgm-3, in spring – 31.1 µgm-3.

Meteorological conditions and anthropogenic exhaustion made a basic impact on seasonal distribution of the concentration of ground-level ozone. The highest mean seasonal concentration was

23

D. Laurinavičienė

49.6

50.0 40.0 O3, μgm

-3

31.1

30.0 20.0

23.6 16.9

10.0 0.0 autumn

Fig. 4.

winter

spring

summer

Seasonal distribution of the ground-level ozone concentration in Vilnius

(25.0 µgm-3, Fig. 5), the lowest at the highway of Eišiškės (8.0 µgm-3).

In autumn season the highest ground-level ozone concentration was determined at Viršuliškių street 50.0

O3, μgm

-3

40.0 25.0

30.0

22.5

22.0

21.0

21.0

20.0

20.0

17.5

17.0

16.0

14.5

14.0

12.0

11.5

11.0

10.0

8.0

Fig. 5.

iln A ia rs en al Sa o str us io . 13 th st r Sa . va Sa no pi rių eg Su in str ės pe . pi rm n ar ew ke oo t" K d A ar kr ei op vi ų# ol is" K al va rij Se ų re str ik . i sk ių G pa el rk ež in ke lio Ca th str ed . ra ls qu ar e Ci ty ha D ll ar Ta ia ur us as an hi d ll G irė Ei no šiš str ki . ų hi gh w ay

N .V

V irš

ul

išk

ių

str

.

0.0

Ground-level ozone concentration in autumn season in Vilnius

In winter season the highest ground-level ozone concentration was at Sausio 13th str., Savanorių av. and Arsenalo str.( 29.5 µgm-3, Fig. 6) the lowest at

Dariaus and Girėno str. and Geležinkelio str. (15.5 µgm-3). The situation in autumn and winter seasons was similar.

50.0

O3, μgm

-3

40.0

29.5

30.0

29.5

29.5

28.5

28.5

26.0

26.0

25.5

23.0

20.0

23.0

19.5

18.0

16.0

15.5

15.5

10.0

alo Vi str ršu . liš ki ų str . Ci ty ha ll N. V Ca iln th ia ed ra ls qu Se ar Su re e ik pe išk rm i ar ų pa ke rk t" Ka A kr re iv op ių ol #K is" a lv Sa ar pi ijų eg in str ės . pi n ew Ei šiš oo ki d ų hi gh wa y Da T ria au ra us sh an ill d Gi rė no Ge str le . žin ke lio str .

Ar se n

rių

Sa v

an o

th 13 sio Sa u

Fig. 6.

str

str .

.

0.0

Ground-level ozone concentration in winter season in Vilnius

In spring season the ground-level ozone concentration was considerably higher than in autumn and winter seasons. The highest ground-level ozone

concentration was at supermarket “Akropolis” ( 47.0 µgm-3, Fig. 7) the lowest - at the highway of Eišiškės (16,. µgm-3).

24

Ground-level Ozone Air Pollution in Vilnius City

47.0 45.8

50.0

42.3

-3

40.0

38.3

36.5

34.5

32.5

31.5

O3, μgm

30.0

28.8

26.5

24.8

22.8

20.5

20.0

18.8

16.0

10.0

Su pe rm

ar

ke t

"A

kr op V ol irš is" ul išk Sa ių us str io Sa . 13 pi eg t h in s tr ės . pi ne w oo Sa d va no rių str A . rs en al o str K ar . ei N vi . V ų# iln K D ia al ar va ia us rij ų an str d . G irė Ca no th str ed . ra ls qu ar e Ta ur Se as re hi ik ll išk ių pa rk Ci ty Ge ha le ll ži nk e Ei l i o šiš str ki . ų hi gh wa y

0.0

Fig. 7.

Ground-level ozone concentration in spring season in Vilnius

(77.0 and 73.0 µgm-3, Fig. 8) the lowest at the highway of Eišiškės and Geležinkelio str. (29.5 µgm3 ).

O3, μgm

-3

In summer the ground-level ozone concentration was the highest compared to the other seasons. The highest ground-level ozone concentration was determined at Sausio 13th str.and Viršuliškių str. 77.0

80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0

io us Sa

Fig. 8.

13

73.0 62.0

th

. str

ršu Vi

57.0

57.0

54.5

48.0

48.0

46.0

45.0

42.5

42.0

33.0

29.5

29.5

. . . . " e d ll ll ia rk ay str str str ar str lis hi oo ha iln pa o hw w io y qu lo jų po as l n V t i ų s e g a r . i o i r e i ė l r n u r a in k h C N n ra išk se lv ų Gi Ta Ak žn sp va ed ki d Ar le ei k Ka t" š h nė n r e Sa i t e # i a š k G ių Se Ca Ei ieg ar us iv ap re rm ria S a e a p K D Su

ų ki liš

. str

ių or

. str

Ground-level ozone concentration in summer season in Vilnius

level ozone concentration were at Sausio 13th Viršuliškių streets, supermarket “Akropolis” and Savanorių avenue in all seasons.

Variation in the seasonal ground-level ozone concentration in each measurement place is presented in Fig.9. This Figure shows that the highest groundautumn

winter

spring

summer

Fig. 9.

Sa p

K ar ei

vi ų# K al va rij ie gi ų nė str sp . in ew G el oo ež d in ke lio st r D ar . ia Ci us ty an ha d ll G irė no str . N .V Ca iln th ia ed ra ls Sa qu Su us ar pe e i o rm 13 ar t h ke st r t" . A kr op ol Sa is" va no rių Se re str ik . i šk ių pa A rk rs en al o str . Ta ur a sh V irš ill ul išk Ei ių šiš str ki . ų hi gh w ay

O3, μgm

-3

80,0 70,0 60,0 50,0 40,0 30,0 20,0 10,0 0,0

Seasonal variation in the ground-level ozone concentration in Vilnius

25

D. Laurinavičienė

In the measurement period the concentration of ground-level ozone had not exceeded the stated value (120.0 µgm-3).

3.2. Diurnal variation in the ground-level ozone concentration To determine diurnal variation in the groundlevel ozone concentration, measurements were made each hour from 06 am to 09 pm (Fig. 10). The minimal ground-level ozone concentration was at 06 am (4.0 µgm-3), the maximal at 01 pm (87.0 µgm-3). Fig. 10 shows that two peaks of the groundlevel ozone concentration are clearly expressed. The first peak of the ground-level ozone concentration was formed from 12 am to 01 pm, the second - at 05 pm.

3.3.

86.0

80.0 -3

ozone with

87.0

77.0

75.0

66.0

60.0

60.0

62.0

39.0

40.0

concentration meteorological

To assess the relation with meteorological parameters the correlation coefficients between the ground-level ozone concentration and meteorological variables (temperature and wind speed) have been calculated.

100.0

O3, μgm

Ground-level relationship parameters

58.0

56.0 54.0

37.0

38.0

26.0

20.0

8.0

4.0

0.0 5

6

7

8

9

10

11

12

13

14

15

16

17

18

19

20

21

Hour Fig. 10.

Diurnal variation in the ground-level ozone concentration

r = -0.785, p=0.000

80

80

70

70

60

60 -3

90

50

O3, mcgm

O3 , mcgm

-3

r = 0.554, p=0.000 90

40

50 40

30

30

20

20

10

10 0

0 -15

-10

-5

0

5

10

15

20

25

2

30

3

O

a) Fig. 11.

5

6

7

8

-1

b) Correlation between the ground-level ozone concentration and meteorological variables: a) correlation between the ground-level ozone concentration and temperature; b) correlation between the ground-level ozone concentration and wind speed

oxides (NOx) and volatile organic compounds (VOCs) as main precursors. Main sources of nitrogen oxides and volatile organic compounds in urban areas are transport and industrial activities (Cristofanelli & Bonasoni, 2009). In polluted urban areas high groundlevel ozone levels are frequently reported. Results of this study show the same situation i.e. that the highest ground-level ozone concentration is in urban residential districts close to supermarkets (with intensive traffic at a supermarket „Akropolis) and around the stationary pollution sources (“Vilniaus

Results of this research have revealed that the ground-level ozone concentration is markedly correlated with the temperature (r= 0.554 p= 0.000, Fig. 11 a). The ground-level ozone concentration is also strongly correlated with the wind speed (r= 0.785 p= 0.000, Fig. 11 b). 4.

4

Wind speed, ms

Temperature, C

Conclusions

Ground-level ozone is known as a product of complex photochemical processes involving nitrogen 26

Ground-level Ozone Air Pollution in Vilnius City

Jacob D.J., and Winner D.A. Effect of climate change on air quality. Atmospheric Environment, 2009, Vol. 43, p. 51-63. Lee S.H., Sung K.H., Lee H.W. Impact of regional trans-boundary ozone associated with complex terrain on urban air quality. Atmospheric environment, 2008, Vol. 42, p. 7384-7396. ELSEVIER. ISSN 1352-2310. Lietuvos hidrometeorologijos tarnyba. www.meteo.lt Luria M., Valente R.J., Bairai S., Parkhurst J., Tanner R.L. Airborne study of ozone formation over Dallas, Texas. Atmospheric Environment, 2008, Vol. 42, p. 6951-6958. ELSEVIER. ISSN 1352-2310. Millan M.M., Mantilla E., Salvador R., Carratala A., Sanz M.J., Alonso I., Gangoiti G., Navazo M. Ozone cycles in the Western Mediterranean Basin: interpretation of morning data in complex coastal terrain. Journal of Applied Meteorology, 2000, Vol. 39, p. 487-508. Allen Press Inc. ISSN 1520-0450. Olszyna K.J., Luria M., Meagher J.F. The correlation of temperature and rural ozone levels in southeastern USA. Atmospheric Environment, 1997, Vol. 31, p. 3011-3022. ELSEVIER. ISSN 1352-2310. Pace G., Meloni D., di Sarra A. Forest fire aerosol over Mediterranean basin during summer 2003. Journal of Geophysical Resarch, 2005, Vol. 110, D21202, doi:10.1029/2005JD005986. AGU. ISSN 0148-0227. Parra M.A., Elustando D., Bermejo R., Santamaria J.M. Ambient air levels of volatile organic compounds (VOC) and nitrogen dioxide (NO2) in a medium size city in Northern Spain. Science of the Total Environment, 2009, Vol. 407, p. 999-1009. ELSEVIER. ISSN 0048-9697. Poupkou A., Symeonidis P., Lisaridis I., Melas D., Ziomas I., Yay O.D., Balis D. Effects of anthropogenic emission sources on maximum ozone concentrations over Greece. Atmospheric Research, 2008, Vol. 89, p. 374381.ELSEVIER. ISSN 1352-2310. Pudasainee D., Sapkota B., Manohar L.S., Kaga A., Kondo A., Inoue Y. Ground level ozone concentrations and its association with NOx and meteorological parameters in Katmandu valley, Nepal. Atmospheric Environment, 2006, Vol. 40, p. 8081-8087. ELSEVIER. ISSN 1352-2310. Sanz M.J., Calatayud V., Sanchez-Pena G. Measures of ozone concentrations using passive sampling in forests of South Western Europe. Environmental Pollution, 2007, Vol. 145, p. 620-628. ELSEVIER. ISSN 0269-7491. Sillman S. The relation between ozone, NOx and hydrocarbons in urban and polluted rural environments. Atmospheric Environment, 1999, Vol. 33, p. 1821-1845. ELSEVIER. ISSN 1352-2310. Tressol M., Ordonez C., Zbinden R., Brioude J., Thouret V., Mari C., Nedelec P., Cammas J.P., Smit H., Patz H.W. Volz-Thomas A. Air pollution during the 2003 European heat wave as seen by MOZAIC airliners. Atmospheric Chemistry and Physics, 2008, Vol. 8, p. 21332150. Copernicus Publications. ISSN 1680-7316. Vingarzan R., Taylor B. Trend analysis of ground level ozone in the greater Vancouver/Fraser Valley area of British Columbia. Atmospheric Environment, 2003, Vol. 37, p. 2159-2171. ELSEVIER. ISSN 1352-2310. Westmoreland E. J., Carslaw N., Carslaw D., Gillah A., Bates E. Analysis of air pollution within a street canyon using statistical and dispersion modeling techniques. Atmospheric Environment, 2007, Vol. 41, p. 9195-9205. ELSEVIER. ISSN 1352-2310. www.ozoneapplications.com/ozone monitors

energija“, Fig. 2). Similar results are reported by other authors (Tressol et al. 2008, Pace et al. 2005). The ground-level ozone concentration is characterized by the specific seasonal variation. The highest ground-level ozone concentration is spring and summer seasons (Jacob and Winner, 2009). In this case the highest seasonal ground-level ozone concentration was determined during the summer season, too (49,. µgm-3, Fig. 3). These results are similar to those of other authors (Sanz et al. 2007). The ground-level ozone concentration has also a clear diurnal cycle, with higher values in the day-time and notably lower values at night (Millan et al. 2000). This study has also revealed that at the day-time the ground-level ozone concentration values were considerably higher than at an early morning or evening (Fig. 9). Lee et al. also reported that ozone concentration gradually increased after the sunrise and decreased in the evening (Lee et al. 2008). The ground-level ozone concentration depends on meteorological conditions (temperature, solar radiation, wind speed and direction). Olszyna et al. have demonstrated that ozone concentration correlate reasonably well with the temperature (Olszyna et al. 1997). We have also found a significant positive correlation between the ground-level ozone concentration and temperature (r= 0.554 p= 0.000, Fig. 11 a). The other authors have reported an inverse correlation between the wind speed and ozone concentration (Luria et al. 2008). Our results present the same relationship (r= -0.785 p= 0.000, Fig. 11 b).

Acknowledgement Many thanks to Laura Buce who assisted in the field sampling and otherwise contributed to this work. References Chudzynski S., Czyzewski A., Ernst K., Pietruczuk A., Skubiszak W., Stacewicz T., Stelmaszczyk K., Szymanski A., Sowka I., Zwozdziak A., Zwozdziak J. Observation of ozone concentration during the solar eclipse. Atmospheric Research, 2001, Vol. 57, p. 43-49. ELSEVIER. ISSN 0169-8095. Clapp L. J., Jenkin M., E. Analysis of the relationship between ambient levels of O3, NO2 and NO as a function of NOx in the UK. Atmospheric Environment, 2001, Vol. 35, p. 6391-6405. ELSEVIER. ISSN 1352-2310. Cristofanelli P. and Bonasoni P. Background ozone in the southern Europe and Mediterranean area: Influence of the transport and processes. Environmental Pollution, 2009, Vol. 157, p. 1399-1406. ELSEVIER. ISSN 0269-7491. Hunova, I., Santroch, J. and Ostatnická, J. Ambient air quality and deposition trends at rural stations in the Czech Republic during 1993-2001. Atmospheric Environment, 2004, Vol. 38, p. 887-898. ELSEVIER. ISSN 1352-2310.

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D. Laurinavičienė

Dovilė Laurinavičienė – assoc. prof. of Vytautas Magnus University, Department of Environmental Sciences. Main research areas: assessment of environmental quality and air pollution. Address: Vileikos str. 8, LT-44404 Kaunas, Lithuania Tel.: +370 37 327904 Fax: +370 37 327904 E-mail: [email protected]

Oro tarša priežemio ozonu Vilniaus mieste Dovilė Laurinavičienė Aplinkotyros katedra, Vytauto Didžiojo universitetas

(gauta 2009 m. liepos mėn.; atiduota spaudai 2009 m. rugsėjo mėn.)

Darbo tikslas – nustatyti oro taršą priežemio ozonu Vilniaus mieste. Priežemio ozono koncentracija buvo matuojama naudojant „Aeroqual Series 300” ozono kontrolės prietaisą. 2006 – 2007 m. Vilniaus mieste buvo atlikti sezoniniai priežemio ozono koncentracijos matavimo tyrimai. Gauti matavimų rezultatai buvo naudojami apskaičiuoti vidutinę sezoninę ir vidutinę metinę priežemio ozono koncentraciją Vilniaus mieste. Tyrimų rezultatai parodė, kad vidutinė metinė priežemio ozono koncentracija Vilniuje buvo 30,3 µgm–3. Didžiausia vidutinė metinė priežemio ozono koncentracija nustatyta Viršuliškių g. (43,1 µg/m3), mažiausia – Naujininkuose prie Eišiškių plento (17,9 µg/m3). Vidutinė sezoninė priežemio ozono koncentracija svyravo nuo 16,9 µgm–3 rudenį iki 49,6 –3 µgm vasarą. Priežemio ozono koncentracija pasižymi aiškia kaita paros metu, didesnės reikšmės fiksuojamos dieną, mažesnės – naktį. Mažiausia priežemio ozono koncnetracija buvo nustatyta 6:00 val. ryto (4,0 µgm–-3), didžiausia – 13:00 val. dienos (87,0 µgm–3). Priežemio ozono koncnetracija nei vienoje tyrimo vietoje neviršijo nustatytos ribinės vertės (120,0 µgm–3). Žinoma, kad meteorologinės sąlygos turi įtakos ozono susidarymui ir sklaidai. Gauti rezultatai parodė, kad yra ryšys tarp priežemio ozono koncentracijos ir temperatūros (r = 0,554, p = 0,000) bei tarp priežemio ozono koncentracijos ir vėjo greičio (r = -0,785 p = 0,000).

28