KAZALCI OKOLJA

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Key message
Good

Concentrations of sulphur dioxide in ambient air are no longer harmful for human health. Also, the critical annual value for the protection of vegetation is no longer exceeded. The improvement of the situation in the last decade is a result of the use of low-sulphur fuels in industry and the operation of desulphurisation facilities in thermal power plants.


This indicator shows the frequency of exceeding of the hourly limit value for sulphur dioxide (SO2) concentration (350 μg/m3), the frequency of exceeding of the 24-hour limit value for SO2 concentration (125 μg/m3), the mean annual SO2 concentration and exceeding of annual critical SO2 concentration for vegetation protection (20 μg/m3) in Slovenia from 1992 onwards.

The health protection limit value is the limit concentration set on the basis of scientific knowledge. The objective of compliance with the limit value is to avoid, prevent or reduce harmful effects of SO2 on human health and ecosystems. The limit value must be met within the set time limit determined by the legislation. Once the goal is achieved, the limit value may not be exceeded again.

The plant protection critical value is the concentration set on the basis of scientific knowledge. Its being exceeded may result in direct harmful effects on certain receptors, such as trees, other plants or natural ecosystems, but not on humans.

The main sources of SO2 are large thermal power plants and heat production plants and, in some urban areas, small and medium-sized coal-burning boiler facilities. SO2 is also generated in certain industrial processes (e.g. cellulose production) and in combustion of fuels containing sulphur. Due to its acidic properties, it causes the formation of acids that are deposited on waters and the ground (acid deposition). Acidification may adversely affect the water ecosystems of rivers and lakes as well as forests, crops and other vegetation. Due to the acidity of sulphur dioxide, damage to buildings and cultural monuments may also occur. Emissions of SO2 contribute to the formation of particulate matter in the atmosphere.

.


Charts

Figure ZR05-1: No. of hours with exceeded 1-hour limit value of SO2 (350 μg/m3) in Slovenian cities (not to be exceeded more than 24 times calendar year)
Sources: 
Air quality monitoring database (DMKZ), Slovenian Environment Agency (2018)
; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar (2018)
Chart note: 

Note to picture ZR5-1:* measurments were discontinued

Show data

Urban background

Ljubljana Bežigrad

Hrastnik

Velenje

Celje

Nova Gorica

Suburban background

Topolšica

Trbovlje

Škale

Rural background

Kum

Urban-traffic type

Zagorje

- Maribor center

Suburban - industrial type

Šoštanj

Rural/Industrial type

- Zavodnje

- Kovk

- Vnajnarje

Veliki Vrh

Graška Gora

Ravenska vas

Dobovec

Rural/Agricultural type

Murska Sobota - Rakican

permitted exceedance

1993

66

51

82

27

104

0

178

194

162

0

10

10

72

137

7

318

318

208.57

196

315

13

315

248

50

323

0

0

24

1994

18.75

13

24

16

22

0

72

83

61

0

13

13

35.50

71

0

218

218

205.43

233

448

5

246

293

61

152

0

0

24

1995

10.25

16

14

0

11

0

27.50

9

46

0

25

25

11

22

0

131

131

129.43

54

260

7

179

80

149

177

0

0

24

1996

14.25

32

23

2

0

0

21.50

26

17

0

22

22

15.50

31

0

175

175

117.86

90

151

11

200

64

122

187

0

0

24

1997

26

39

58

3

4

0

45

38

52

0

68

68

24

48

0

127

127

241.71

158

486

11

200

107

390

340

0

0

24

1998

12

14

24

6

4

0

40.33

62

14

45

19

19

19

38

0

289

289

210.71

152

262

10

273

102

399

277

0

0

24

1999

16.75

14

40

13

0

0

31.33

33

18

43

23

23

24.50

49

0

249

249

202.86

152

323

9

400

131

178

227

0

0

24

2000

4.50

0

11

6

1

0

27.67

47

12

24

16

16

7.50

15

0

324

324

141.43

96

218

0

279

120

131

146

0

0

24

2001

3.75

0

14

0

1

0

8.33

2

20

3

13

13

12.50

25

0

334

334

108.43

18

159

1

250

17

125

189

0

0

24

2002

8.80

0

43

1

0

0

10.67

13

10

9

0

0

7.50

15

0

228

228

110.29

45

26

0

269

34

249

149

0

0

24

2003

2

0

8

1

1

0

11.33

5

28

1

0

0

16.50

33

0

108

108

128

23

288

0

246

7

193

139

0

0

24

2004

10

0

49

0

1

0

0

0

0

0

6

6

36

72

0

47

47

96.86

1

278

0

90

2

139

168

0

0

24

2005

2.40

0

12

0

0

0

5.67

0

17

0

12

12

8.50

17

0

22

22

70.71

9

94

0

56

2

205

129

0

0

24

2006

0

0

0

0

0

0

0.33

0

1

0

0

0

0

0

0

12

12

5.14

1

3

0

28

0

1

3

0

0

24

2007

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

11

11

2.14

0

1

0

9

2

0

3

0

0

24

2008

0

0

0

0

0

0

0

0

0

0

0

0

1

2

0

1

1

1

0

0

0

6

0

1

0

0

0

24

2009

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1.83

2

1

0

0

0

1

7

0

0

24

2010

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

0.14

0

0

0

0

0

1

0

0

0

24

2011

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1.29

1

0

0

3

0

3

2

0

0

24

2012

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

2

2

1

0

3

0

4

0

0

0

0

0

24

2013

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.57

1

2

0

1

0

0

0

0

0

24

2014

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

24

2015

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

0

0

0

0

0

0

0

0

0

0

24

2016

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Figure ZR05-2: No. of days with exceeded 24-houly limit value of SO2 (125 μg/m3) (not to be exceede more than 3 times a calendar year)
Sources: 
Air quality monitoring database (DMKZ), Slovenian Environment Agency (2018)
; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar (2018)
Chart note: 

Note to picture ZR5-2:* measurments were discontinued

Show data

Urban background

Ljubljana Bežigrad

Hrastnik

Velenje

Celje

Nova Gorica

Suburban background

Topolšica

Trbovlje

Škale

Rural background

Kum

Urban-traffic type

Zagorje

- Maribor center

Suburban - industrial type

Šoštanj

Rural/Industrial type

- Zavodnje

- Kovk

- Vnajnarje

Veliki Vrh

Graška Gora

Ravenska vas

Dobovec

Rural/Agricultural type

Murska Sobota - Rakican

permitted exceedance

1992

35.50

38

50

4

50

0

44

29

59

0

1

1

41.50

61

22

41

41

31.17

37

36

0

63

27

14

10

0

0

3

1993

23.25

28

28

1

36

0

41.50

30

53

0

0

0

27.50

48

7

37

37

29.29

29

55

0

45

32

11

33

0

0

3

1994

6.25

2

4

1

18

0

18.50

12

25

0

0

0

14.50

28

1

25

25

31.86

34

71

0

37

46

16

19

0

0

3

1995

3.75

3

4

0

8

0

11

1

21

0

2

2

7

14

0

14

14

21.57

11

47

0

26

14

33

20

0

0

3

1996

1

1

3

0

0

0

4

1

7

0

1

1

3

6

0

22

22

18.71

13

19

1

32

13

29

24

0

0

3

1997

2.75

1

4

2

4

0

5

2

8

0

6

6

0

0

0

17

17

37

26

65

0

28

13

80

47

0

0

3

1998

0.25

1

0

0

0

0

5

5

4

6

0

0

2.50

5

0

34

34

39.14

28

48

1

47

18

90

42

0

0

3

1999

0.75

0

2

1

0

0

5.33

6

3

7

1

1

2

4

0

30

30

32

27

53

0

67

17

35

25

0

0

3

2000

0.75

0

1

0

2

0

2

4

1

1

1

1

1.50

3

0

44

44

26.14

18

49

0

41

23

30

22

0

0

3

2001

0.25

0

1

0

0

0

0.67

0

2

0

2

2

1.50

3

0

52

52

17.57

2

38

0

32

1

29

21

0

0

3

2002

1

0

5

0

0

0

1

1

1

1

0

0

0.50

1

0

29

29

19.14

9

6

0

44

4

55

16

0

0

3

2003

0

0

0

0

0

0

0

0

0

0

0

0

0.50

1

0

9

9

17.57

1

39

0

21

0

47

15

0

0

3

2004

0.80

0

4

0

0

0

0

0

0

0

0

0

4

8

0

1

1

13.71

0

50

0

5

0

23

18

0

0

3

2005

0

0

0

0

0

0

0.33

0

1

0

0

0

0.50

1

0

0

0

10.57

1

21

0

4

0

35

13

0

0

3

2006

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

0.14

0

0

0

0

0

0

1

0

0

3

2007

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0.14

0

0

0

0

0

0

1

0

0

3

2008

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2009

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2010

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2011

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2012

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2013

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2014

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2015

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

3

2016

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

Figure ZR05-3: Average annual concentration of SO2 and exceedances of critical annual level for the protection of vegetation (20 μg/m3)
Sources: 
Air quality monitoring database (DMKZ), Slovenian Environment Agency (2018)
; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar (2018)
Chart note: 

Note to picture ZR5-3: Critical yearly concentration of SO2 for vegetation protection is valid only outside of urban sampling aresa, those sampling aresa are: Murska Sobota – Rakičan, Iskrba, Veliki Vrh, Zavodnje, Graška Gora, Kovk, Dobovec, Kum, Ravenska vas, Vnajnarje.

Show data

Urban background

Ljubljana Bežigrad

Hrastnik

Velenje

Celje

Nova Gorica

Suburban background

Topolšica

Trbovlje

Škale

Rural background

Iskrba

Kum

Urban-traffic type

Zagorje

- Maribor center

Suburban - industrial type

Šoštanj

Rural/Industrial type

- Zavodnje

- Kovk

- Vnajnarje

Veliki Vrh

Graška Gora

Ravenska vas

Dobovec

Rural/Agricultural type

Murska Sobota - Rakičan

annual critical conc. for vegetation protection

1992

44

38

62

19

57

0

61.50

54

69

0

17

0

17

59

71

47

49

49

53.33

51

73

0

71

39

56

30

0

0

20

1993

42.25

45

51

19

54

0

61

51

71

0

13

0

13

51

60

42

48

48

47.17

44

59

0

54

42

34

50

0

0

20

1994

31.50

33

32

12

49

0

40.50

32

49

0

11

0

11

39

48

30

38

38

45.83

46

70

0

49

47

34

29

0

0

20

1995

22

21

29

6

32

0

34

20

48

0

13

0

13

34.50

41

28

29

29

41

26

58

0

49

27

50

36

0

0

20

1996

22.75

33

24

10

24

0

28.50

20

37

0

18

0

18

29

34

24

34

34

37.71

33

35

19

57

28

51

41

0

0

20

1997

24.75

34

27

11

27

0

29

18

40

0

25

0

25

27

31

23

29

29

53.43

42

76

19

53

36

82

66

0

0

20

1998

21.25

27

25

10

23

0

26

20

32

0

16

0

16

22.50

27

18

44

44

49.57

43

55

18

63

32

82

54

0

0

20

1999

16.25

15

21

10

19

0

18.67

17

23

16

14

0

14

19

21

17

42

42

45

42

57

14

72

32

57

41

0

0

20

2000

14.25

10

23

7

17

0

18.33

18

18

19

10

0

10

15.50

18

13

52

52

37.14

31

53

6

56

34

45

35

0

0

20

2001

12

11

17

5

15

0

11.67

11

14

10

18

0

18

14

18

10

51

51

32.14

21

40

7

52

15

51

39

0

0

20

2002

11

9

22

8

10

6

14.67

15

15

14

0

0

0

12

16

8

43

43

32.14

23

10

8

56

21

67

40

5

5

20

2003

8.80

11

8

8

10

7

14.67

16

16

12

0

0

0

15

21

9

24

24

31.29

15

52

10

45

10

59

28

5

5

20

2004

9.40

8

15

6

11

7

7.67

6

9

8

4

0

4

14

20

8

13

13

29.83

8

61

0

30

6

43

31

5

5

20

2005

7

5

10

4

9

7

9.33

5

15

8

6

0

6

10

12

8

11

11

22

12

30

8

33

6

42

23

5

5

20

2006

6.40

4

9

5

7

7

4.67

4

7

3

2.50

1

4

5.50

6

5

8

8

10.43

8

12

4

20

6

17

6

6

6

20

2007

4.80

3

6

3

5

7

3

3

3

3

4

1

7

4

5

3

9

9

8.43

6

9

4

14

5

14

7

5

5

20

2008

4.80

2

5

4

5

8

2.67

2

2

4

5

1

9

3

4

2

6

6

6.71

3

12

3

8

4

9

8

6

6

20

2009

3.80

4

4

2

5

4

4.33

3

5

5

3

1

5

5

0

5

4

4

6

6

8

0

5

3

8

6

0

0

20

2010

3.50

2

4

2

6

0

3.33

3

3

4

4.50

1

8

8

8

0

7

7

5.71

6

8

3

6

2

9

6

0

0

20

2011

4.25

3

5

3

6

0

5.67

3

7

7

2.50

1

4

5

7

3

5

5

6.43

4

11

3

6

2

11

8

0

0

20

2012

5.50

6

5

4

7

0

5.33

3

6

7

3.50

1

6

3

2

4

7

7

6

4

10

3

7

2

9

7

0

0

20

2013

3.75

4

6

1

4

0

4.33

2

4

7

3

1

5

5

5

0

7

7

6

4

10

3

7

2

9

7

0

0

20

2014

3

3

3

3

3

0

4.33

3

4

6

2.50

1

4

5

5

0

5

5

5.14

3

7

6

4

3

7

6

0

0

20

2015

4

4

4

3

5

0

5.33

5

6

5

2.25

0.50

4

3

3

0

4

4

4.57

2

6

4

4

4

6

6

0

0

20

2016

5.25

6

6

3

6

0

5

3

7

5

2.65

0.30

5

5

5

0

2

2

4.43

2

5

3

3

4

6

8

0

0

20


Goals

Compliance with limit values for sulphur dioxide (SO2) for human health and vegetation protection that have been in force since 1 January 2005:

  • 1-hour limit value for human health protection: 350 μg/m3 (permitted overage: 24-times within a calendar year),
  • 24-hour limit value for human health protection: 125 μg/m3 (permitted overage: 3-times within a calendar year),
  • critical value for the protection of vegetation in wintertime (1 October– 31 March): 20 μg/m3,
  • critical annual value for vegetation protection: 20 μg/m3.

The alert threshold for sulphur dioxide concentrations measured over three consecutive hours at locations representative for air quality in an area of at least 100 km2, an entire area or an agglomerated area may not exceed 500 µg/m3.


In urbanised areas in Slovenia that were heavily polluted by sulphur dioxide due to the large number of small and medium-sized boiler facilities using coal, limit values have not been exceeded since 2006. This is partially due to further expansion of district heating provided by large combined heat and power plants, a switch to gas as a heating source and the use of cleaner fuels for heating in general, and largely a result of the installation of a flue gas desulphurisation plant at the Trbovlje power plant and gradual connection of lower stacks to a flue gas desulphurisation plant at the Šoštanj power plant.

Occasionally, slightly elevated SO2 concentrations still occur at higher altitudes within the impact areas of the Šoštanj and Trbovlje thermal power plants as a result of direct transmission of flue gases from the power plants and during periods of pronounced temperature inversion in the colder part of the year. Also, elevated SO2 concentrations in the vicinity of the Šoštanj thermal power plant are a consequence of a limited capacity of the flue gas desulphurisation plant. Elevated SO2 concentrations in the Zasavje region are partially a result of an unfavourable settlement pattern at the bottom of narrow valleys with low-wind conditions in wintertime when the impact of emissions from small heating units and industry is greater. The impact of SO2 emissions from the Trbovlje power plant was greater in elevated areas of the Zasavje region during failures in the operation of the flue gas desulphurisation plant.

The critical annual SO2 concentration for vegetation protection (20 μg/m3) that is relevant at measuring sites in rural areas was last exceeded in 2006 at the Veliki Vrh measuring site.