KAZALCI OKOLJA

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.

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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)
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)
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)
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.


Methodology

Date of data source summarization