[ZR05] Air pollution by sulphur dioxide

Key message

Concentrations of sulphur dioxide in ambient air no longer represent a hazard for human health in settled areas. 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 implemented measures in industry and thermal power plants and the introduction of low-sulphur fuels.

This indicator shows the frequency of exceeding of the hourly limit value for sulphur dioxide (SO_{2}) concentration (350 μg/m^{3}), the frequency of exceeding of the 24-hour limit value for SO_{2} concentration (125 μg/m^{3}), the mean annual SO_{2} concentration and exceeding of annual critical SO_{2} concentration for vegetation protection (20 μg/m^{3}) 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 SO_{2} 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 SO_{2} are large thermal power plants and heat production plants and, in some urban areas, small and medium-sized coal-burning boiler facilities. SO_{2} 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 SO_{2} contribute to the formation of particulate matter in the atmosphere.

.

Sources:

Air quality monitoring database (DMKZ), Slovenian Environment Agency; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar, 2016.

Note to table ZR5-1: * measurements are canceled, np=no data

1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | ||
---|---|---|---|---|---|---|---|---|---|---|---|

Urban background | number of hours | 66 | 19 | 10 | 14 | 26 | 12 | 17 | 5 | 4 | 9 |

Ljubljana Bežigrad | number of hours | 51 | 13 | 16 | 32 | 39 | 14 | 14 | 0 | 0 | 0 |

Hrastnik | number of hours | 82 | 24 | 14 | 23 | 58 | 24 | 40 | 11 | 14 | 43 |

Velenje | number of hours | 27 | 16 | 0 | 2 | 3 | 6 | 13 | 6 | 0 | 1 |

Celje | number of hours | 104 | 22 | 11 | 0 | 4 | 4 | 0 | 1 | 1 | 0 |

Nova Gorica | number of hours | np | np | np | np | np | np | np | np | np | 0 |

Suburban background | number of hours | 178 | 72 | 28 | 22 | 45 | 40 | 31 | 28 | 8 | 11 |

Trbovlje | number of hours | 162 | 61 | 46 | 17 | 52 | 14 | 18 | 12 | 20 | 10 |

Škale | number of hours | np | np | np | np | np | 45 | 43 | 24 | 3 | 9 |

Rural background | number of hours | 10 | 13 | 25 | 22 | 68 | 19 | 23 | 16 | 13 | np |

Kum | number of hours | 10 | 13 | 25 | 22 | 68 | 19 | 23 | 16 | 13 | np |

Urban-traffic type | number of hours | 72 | 36 | 11 | 16 | 24 | 19 | 25 | 8 | 13 | 8 |

- Maribor center | number of hours | 7 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Suburban - industrial type | number of hours | 318 | 218 | 131 | 175 | 127 | 289 | 249 | 324 | 334 | 228 |

Šoštanj | number of hours | 318 | 218 | 131 | 175 | 127 | 289 | 249 | 324 | 334 | 228 |

Rural/Industrial type | number of hours | 209 | 205 | 129 | 118 | 242 | 211 | 203 | 141 | 108 | 110 |

- Zavodnje | number of hours | 196 | 233 | 54 | 90 | 158 | 152 | 152 | 96 | 18 | 45 |

- Kovk | number of hours | 315 | 448 | 260 | 151 | 486 | 262 | 323 | 218 | 159 | 26 |

- Vnajnarje | number of hours | 13 | 5 | 7 | 11 | 11 | 10 | 9 | 0 | 1 | 0 |

Veliki Vrh | number of hours | 315 | 246 | 179 | 200 | 200 | 273 | 400 | 279 | 250 | 269 |

Graška Gora | number of hours | 248 | 293 | 80 | 64 | 107 | 102 | 131 | 120 | 17 | 34 |

Ravenska vas | number of hours | 50 | 61 | 149 | 122 | 390 | 399 | 178 | 131 | 125 | 249 |

Dobovec | number of hours | 323 | 152 | 177 | 187 | 340 | 277 | 227 | 146 | 189 | 149 |

Rural/Agricultural type | number of hours | np | np | np | np | np | np | np | np | np | 0 |

Murska Sobota - Rakičan | number of hours | np | np | np | np | np | np | np | np | np | 0 |

permitted exceedance | number of hours | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | 2012 | ||

Urban background | number of hours | 2 | 10 | 2 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Ljubljana Bežigrad | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Hrastnik | number of hours | 8 | 49 | 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Velenje | number of hours | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Celje | number of hours | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Nova Gorica | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | * | * |

Suburban background | number of hours | 11 | 0 | 6 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Trbovlje | number of hours | 28 | np | 17 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |

Škale | number of hours | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Rural background | number of hours | np | 6 | 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Kum | number of hours | np | 6 | 12 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Urban-traffic type | number of hours | 17 | 36 | 9 | 0 | 0 | 1 | 0 | 0 | 0 | 0 |

- Maribor center | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | 0 | 0 |

Suburban - industrial type | number of hours | 108 | 47 | 22 | 12 | 11 | 1 | 0 | 1 | 0 | 2 |

Šoštanj | number of hours | 108 | 47 | 22 | 12 | 11 | 1 | 0 | 1 | 0 | 2 |

Rural/Industrial type | number of hours | 128 | 97 | 71 | 5 | 2 | 1 | 2 | 0 | 1 | 1 |

- Zavodnje | number of hours | 23 | 1 | 9 | 1 | 0 | 0 | 2 | 0 | 1 | 0 |

- Kovk | number of hours | 288 | 278 | 94 | 3 | 1 | 0 | 1 | 0 | 0 | 3 |

- Vnajnarje | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | np | 0 | 0 | 0 |

Veliki Vrh | number of hours | 246 | 90 | 56 | 28 | 9 | 6 | 0 | 0 | 3 | 4 |

Graška Gora | number of hours | 7 | 2 | 2 | 0 | 2 | 0 | 0 | 0 | 0 | 0 |

Ravenska vas | number of hours | 193 | 139 | 205 | 1 | 0 | 1 | 1 | 1 | 3 | 0 |

Dobovec | number of hours | 139 | 168 | 129 | 3 | 3 | 0 | 7 | 0 | 2 | 0 |

Rural/Agricultural type | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | * | * | * | * |

Murska Sobota - Rakičan | number of hours | 0 | 0 | 0 | 0 | 0 | 0 | * | * | * | * |

permitted exceedance | number of hours | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 | 24 |

2013 | 2014 | 2015 | |||||||||

Urban background | number of hours | 0 | 0 | 0 | |||||||

Ljubljana Bežigrad | number of hours | 0 | 0 | 0 | |||||||

Hrastnik | number of hours | 0 | 0 | 0 | |||||||

Velenje | number of hours | 0 | 0 | 0 | |||||||

Celje | number of hours | 0 | 0 | 0 | |||||||

Nova Gorica | number of hours | * | * | * | |||||||

Suburban background | number of hours | 0 | 0 | 0 | |||||||

Trbovlje | number of hours | 0 | 0 | 0 | |||||||

Škale | number of hours | 0 | 0 | 0 | |||||||

Rural background | number of hours | 0 | 0 | 0 | |||||||

Kum | number of hours | 0 | 0 | 0 | |||||||

Urban-traffic type | number of hours | 0 | 0 | 0 | |||||||

- Maribor center | number of hours | * | * | * | |||||||

Suburban - industrial type | number of hours | 0 | 0 | 1 | |||||||

Šoštanj | number of hours | 0 | 0 | 1 | |||||||

Rural/Industrial type | number of hours | 1 | 0 | 0 | |||||||

- Zavodnje | number of hours | 1 | 0 | 0 | |||||||

- Kovk | number of hours | 2 | 0 | 0 | |||||||

- Vnajnarje | number of hours | 0 | 0 | 0 | |||||||

Veliki Vrh | number of hours | 1 | 0 | 0 | |||||||

Graška Gora | number of hours | 0 | 0 | 0 | |||||||

Ravenska vas | number of hours | 0 | 0 | 0 | |||||||

Dobovec | number of hours | 0 | 0 | 0 | |||||||

Rural/Agricultural type | number of hours | * | * | * | |||||||

Murska Sobota - Rakičan | number of hours | * | * | * | |||||||

permitted exceedance | number of hours | 24 | 24 | 24 |

Sources:

Air quality monitoring database (DMKZ), Slovenian Environment Agency; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar, 2016.

Note to table ZR5-2: * measurements are canceled, np=no data

1992 | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | ||
---|---|---|---|---|---|---|---|---|---|---|---|

Urban background | number of days | 36 | 23 | 6 | 4 | 1 | 3 | 0 | 1 | 1 | 0 |

Ljubljana Bežigrad | number of days | 38 | 28 | 2 | 3 | 1 | 1 | 1 | 0 | 0 | 0 |

Hrastnik | number of days | 50 | 28 | 4 | 4 | 3 | 4 | 0 | 2 | 1 | 1 |

Velenje | number of days | 4 | 1 | 1 | 0 | 0 | 2 | 0 | 1 | 0 | 0 |

Celje | number of days | 50 | 36 | 18 | 8 | 0 | 4 | 0 | 0 | 2 | 0 |

Nova Gorica | number of days | np | np | np | np | np | np | np | np | np | np |

Suburban background | number of days | 44 | 42 | 19 | 11 | 4 | 5 | 5 | 5 | 2 | 1 |

Trbovlje | number of days | 59 | 53 | 25 | 21 | 7 | 8 | 4 | 3 | 1 | 2 |

Škale | number of days | np | np | np | np | np | np | 6 | 7 | 1 | 0 |

Rural background | number of days | 1 | 0 | 0 | 2 | 1 | 6 | 0 | 1 | 1 | 2 |

Kum | number of days | 1 | 0 | 0 | 2 | 1 | 6 | 0 | 1 | 1 | 2 |

Urban-traffic type | number of days | 42 | 28 | 15 | 7 | 3 | 0 | 3 | 2 | 2 | 2 |

- Maribor center | number of days | 22 | 7 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Suburban - industrial type | number of days | 41 | 37 | 25 | 14 | 22 | 17 | 34 | 30 | 44 | 52 |

Šoštanj | number of days | 41 | 37 | 25 | 14 | 22 | 17 | 34 | 30 | 44 | 52 |

Rural/Industrial type | number of days | 31 | 29 | 32 | 22 | 19 | 37 | 39 | 32 | 26 | 18 |

- Zavodnje | number of days | 37 | 29 | 34 | 11 | 13 | 26 | 28 | 27 | 18 | 2 |

- Kovk | number of days | 36 | 55 | 71 | 47 | 19 | 65 | 48 | 53 | 49 | 38 |

- Vnajnarje | number of days | np | 0 | 0 | 0 | 1 | 0 | 1 | 0 | 0 | 0 |

Veliki Vrh | number of days | 63 | 45 | 37 | 26 | 32 | 28 | 47 | 67 | 41 | 32 |

Graška Gora | number of days | 27 | 32 | 46 | 14 | 13 | 13 | 18 | 17 | 23 | 1 |

Ravenska vas | number of days | 14 | 11 | 16 | 33 | 29 | 80 | 90 | 35 | 30 | 29 |

Dobovec | number of days | 10 | 33 | 19 | 20 | 24 | 47 | 42 | 25 | 22 | 21 |

Rural/Agricultural type | number of days | np | np | np | np | np | np | np | np | np | np |

Murska Sobota - Rakičan | number of days | np | np | np | np | np | np | np | np | np | np |

permitted exceedance | number of days | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |

2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | ||

Urban background | number of days | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Ljubljana Bežigrad | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Hrastnik | number of days | 5 | 0 | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Velenje | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Celje | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Nova Gorica | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | * |

Suburban background | number of days | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Trbovlje | number of days | 1 | 0 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |

Škale | number of days | 1 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Rural background | number of days | np | np | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Kum | number of days | np | np | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Urban-traffic type | number of days | 1 | 1 | 4 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |

- Maribor center | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | 0 |

Suburban - industrial type | number of days | 29 | 9 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |

Šoštanj | number of days | 29 | 9 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 |

Rural/Industrial type | number of days | 19 | 18 | 14 | 11 | 0 | 0 | 0 | 0 | 0 | 0 |

- Zavodnje | number of days | 9 | 1 | 0 | 1 | 0 | 0 | 0 | 0 | 0 | 0 |

- Kovk | number of days | 6 | 39 | 50 | 21 | 0 | 0 | 0 | 0 | 0 | 0 |

- Vnajnarje | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | np | 0 | 0 |

Veliki Vrh | number of days | 44 | 21 | 5 | 4 | 0 | 0 | 0 | 0 | 0 | 0 |

Graška Gora | number of days | 4 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 | 0 |

Ravenska vas | number of days | 55 | 47 | 23 | 35 | 0 | 0 | 0 | 0 | 0 | 0 |

Dobovec | number of days | 16 | 15 | 18 | 13 | 1 | 1 | 0 | 0 | 0 | 0 |

Rural/Agricultural type | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | * | * |

Murska Sobota - Rakičan | number of days | 0 | 0 | 0 | 0 | 0 | 0 | 0 | * | * | * |

permitted exceedance | number of days | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 | 3 |

2012 | 2013 | 2014 | 2015 | ||||||||

Urban background | number of days | 0 | 0 | 0 | 0 | ||||||

Ljubljana Bežigrad | number of days | 0 | 0 | 0 | 0 | ||||||

Hrastnik | number of days | 0 | 0 | 0 | 0 | ||||||

Velenje | number of days | 0 | 0 | 0 | 0 | ||||||

Celje | number of days | 0 | 0 | 0 | 0 | ||||||

Nova Gorica | number of days | * | * | * | * | ||||||

Suburban background | number of days | 0 | 0 | 0 | 0 | ||||||

Trbovlje | number of days | 0 | 0 | 0 | 0 | ||||||

Škale | number of days | 0 | 0 | 0 | 0 | ||||||

Rural background | number of days | 0 | 0 | 0 | 0 | ||||||

Kum | number of days | 0 | 0 | 0 | 0 | ||||||

Urban-traffic type | number of days | 0 | 0 | 0 | 0 | ||||||

- Maribor center | number of days | 0 | * | * | * | ||||||

Suburban - industrial type | number of days | 0 | 0 | 0 | 0 | ||||||

Šoštanj | number of days | 0 | 0 | 0 | 0 | ||||||

Rural/Industrial type | number of days | 0 | 0 | 0 | 0 | ||||||

- Zavodnje | number of days | 0 | 0 | 0 | 0 | ||||||

- Kovk | number of days | 0 | 0 | 0 | 0 | ||||||

- Vnajnarje | number of days | 0 | 0 | 0 | 0 | ||||||

Veliki Vrh | number of days | 0 | 0 | 0 | 0 | ||||||

Graška Gora | number of days | 0 | 0 | 0 | 0 | ||||||

Ravenska vas | number of days | 0 | 0 | 0 | 0 | ||||||

Dobovec | number of days | 0 | 0 | 0 | 0 | ||||||

Rural/Agricultural type | number of days | * | * | * | * | ||||||

Murska Sobota - Rakičan | number of days | * | * | * | * | ||||||

permitted exceedance | number of days | 3 | 3 | 3 | 3 |

Sources:

Air quality monitoring database (DMKZ), Slovenian Environment Agency; Air quality monitoring database of Thermal power plant Šoštanj, Trbovlje and TE-TO Ljubljana, Insitute Milan Vidmar, 2016.

Note: Critical annual value of SO_{2} for the protection of vegetation should be considered at non-urban monitoring sites like Murska Sobota – Rakičan, Iskrba, Veliki Vrh, Zavodnje, Graška Gora, Kovk, Dobovec, Kum, Ravenska vas, Vnajnarje.

Note to table ZR5-3: * measurements are canceled, np=no data

1992 | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | ||
---|---|---|---|---|---|---|---|---|---|---|---|

Urban background | µg/m3 | 44 | 42 | 32 | 22 | 23 | 25 | 21 | 16 | 14 | 12 |

Ljubljana Bežigrad | µg/m3 | 38 | 45 | 33 | 21 | 33 | 34 | 27 | 15 | 10 | 11 |

Hrastnik | µg/m3 | 62 | 51 | 32 | 29 | 24 | 27 | 25 | 21 | 23 | 17 |

Velenje | µg/m3 | 19 | 19 | 12 | 6 | 10 | 11 | 10 | 10 | 7 | 5 |

Celje | µg/m3 | 57 | 54 | 49 | 32 | 24 | 27 | 23 | 19 | 17 | 15 |

Nova Gorica | µg/m3 | np | np | np | np | np | np | np | np | np | np |

Suburban background | µg/m3 | 62 | 61 | 41 | 34 | 29 | 29 | 26 | 19 | 18 | 12 |

Trbovlje | µg/m3 | 69 | 71 | 49 | 48 | 37 | 40 | 32 | 23 | 18 | 14 |

Škale | µg/m3 | np | np | np | np | np | np | np | 16 | 19 | 10 |

Rural background | µg/m3 | 17 | 13 | 11 | 13 | 18 | 25 | 16 | 14 | 10 | 18 |

Iskrba | µg/m3 | np | np | np | np | np | np | np | np | np | np |

Kum | µg/m3 | 17 | 13 | 11 | 13 | 18 | 25 | 16 | 14 | 10 | 18 |

Urban-traffic type | µg/m3 | 59 | 51 | 39 | 35 | 29 | 27 | 23 | 19 | 16 | 14 |

- Maribor center | µg/m3 | 47 | 42 | 30 | 28 | 24 | 23 | 18 | 17 | 13 | 10 |

Suburban - industrial type | µg/m3 | 49 | 48 | 38 | 29 | 34 | 29 | 44 | 42 | 52 | 51 |

Šoštanj | µg/m3 | 49 | 48 | 38 | 29 | 34 | 29 | 44 | 42 | 52 | 51 |

Rural/Industrial type | µg/m3 | 53 | 47 | 46 | 41 | 38 | 53 | 50 | 45 | 37 | 32 |

- Zavodnje | µg/m3 | 51 | 44 | 46 | 26 | 33 | 42 | 43 | 42 | 31 | 21 |

- Kovk | µg/m3 | 73 | 59 | 70 | 58 | 35 | 76 | 55 | 57 | 53 | 40 |

- Vnajnarje | µg/m3 | np | np | np | np | 19 | 19 | 18 | 14 | 6 | 7 |

Veliki Vrh | µg/m3 | 71 | 54 | 49 | 49 | 57 | 53 | 63 | 72 | 56 | 52 |

Graška Gora | µg/m3 | 39 | 42 | 47 | 27 | 28 | 36 | 32 | 32 | 34 | 15 |

Ravenska vas | µg/m3 | 56 | 34 | 34 | 50 | 51 | 82 | 82 | 57 | 45 | 51 |

Dobovec | µg/m3 | 30 | 50 | 29 | 36 | 41 | 66 | 54 | 41 | 35 | 39 |

Rural/Agricultural type | µg/m3 | np | np | np | np | np | np | np | np | np | np |

Murska Sobota - Rakičan | µg/m3 | np | np | np | np | np | np | np | np | np | np |

annual critical conc. for vegetation protection | µg/m3 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 |

2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 | 2011 | ||

Urban background | µg/m3 | 11 | 9 | 9 | 7 | 6 | 5 | 5 | 4 | 4 | 4 |

Ljubljana Bežigrad | µg/m3 | 9 | 11 | 8 | 5 | 4 | 3 | 2 | 4 | 2 | 3 |

Hrastnik | µg/m3 | 22 | 8 | 15 | 10 | 9 | 6 | 5 | 4 | 4 | 5 |

Velenje | µg/m3 | 8 | 8 | 6 | 4 | 5 | 3 | 4 | 2 | 2 | 3 |

Celje | µg/m3 | 10 | 10 | 11 | 9 | 7 | 5 | 5 | 5 | 6 | 6 |

Nova Gorica | µg/m3 | 6 | 7 | 7 | 7 | 7 | 7 | 8 | 4 | * | * |

Suburban background | µg/m3 | 15 | 15 | 8 | 9 | 5 | 3 | 3 | 4 | 3 | 6 |

Trbovlje | µg/m3 | 15 | 16 | 9 | 15 | 7 | 3 | 2 | 5 | 3 | 7 |

Škale | µg/m3 | 14 | 12 | 8 | 8 | 3 | 3 | 4 | 5 | 4 | 7 |

Rural background | µg/m3 | 4 | 6 | 3 | 4 | 5 | 3 | 5 | 3 | ||

Iskrba | µg/m3 | np | np | np | np | 1 | 1 | 1 | 1 | 1 | 1 |

Kum | µg/m3 | 4 | 6 | 4 | 7 | 9 | 5 | 8 | 4 | ||

Urban-traffic type | µg/m3 | 12 | 15 | 14 | 10 | 6 | 4 | 3 | 5 | 8 | 5 |

- Maribor center | µg/m3 | 8 | 9 | 8 | 8 | 5 | 3 | 2 | 5 | * | 3 |

Suburban - industrial type | µg/m3 | 43 | 24 | 13 | 11 | 8 | 9 | 6 | 4 | 7 | 5 |

Šoštanj | µg/m3 | 43 | 24 | 13 | 11 | 8 | 9 | 6 | 4 | 7 | 5 |

Rural/Industrial type | µg/m3 | 32 | 31 | 30 | 22 | 10 | 8 | 7 | 6 | 6 | 6 |

- Zavodnje | µg/m3 | 23 | 15 | 8 | 12 | 8 | 6 | 3 | 6 | 6 | 4 |

- Kovk | µg/m3 | 10 | 52 | 61 | 30 | 12 | 9 | 12 | 8 | 8 | 11 |

- Vnajnarje | µg/m3 | 8 | 10 | np | 8 | 4 | 4 | 3 | np | 3 | 3 |

Veliki Vrh | µg/m3 | 56 | 45 | 30 | 33 | 20 | 14 | 8 | 5 | 6 | 6 |

Graška Gora | µg/m3 | 21 | 10 | 6 | 6 | 6 | 5 | 4 | 3 | 2 | 2 |

Ravenska vas | µg/m3 | 67 | 59 | 43 | 42 | 17 | 14 | 9 | 8 | 9 | 11 |

Dobovec | µg/m3 | 40 | 28 | 31 | 23 | 6 | 7 | 8 | 6 | 6 | 8 |

Rural/Agricultural type | µg/m3 | 5 | 5 | 5 | 5 | 6 | 5 | 6 | np | * | * |

Murska Sobota - Rakičan | µg/m3 | 5 | 5 | 5 | 5 | 6 | 5 | 6 | np | * | * |

annual critical conc. for vegetation protection | µg/m3 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 | 20 |

2012 | |||||||||||

Urban background | µg/m3 | 6 | |||||||||

Ljubljana Bežigrad | µg/m3 | 6 | |||||||||

Hrastnik | µg/m3 | 5 | |||||||||

Velenje | µg/m3 | 4 | |||||||||

Celje | µg/m3 | 7 | |||||||||

Nova Gorica | µg/m3 | * | |||||||||

Suburban background | µg/m3 | 5 | |||||||||

Trbovlje | µg/m3 | 6 | |||||||||

Škale | µg/m3 | 7 | |||||||||

Rural background | µg/m3 | 4 | |||||||||

Iskrba | µg/m3 | 1 | |||||||||

Kum | µg/m3 | 6 | |||||||||

Urban-traffic type | µg/m3 | 3 | |||||||||

- Maribor center | µg/m3 | 4 | |||||||||

Suburban - industrial type | µg/m3 | 7 | |||||||||

Šoštanj | µg/m3 | 7 | |||||||||

Rural/Industrial type | µg/m3 | 6 | |||||||||

- Zavodnje | µg/m3 | 4 | |||||||||

- Kovk | µg/m3 | 10 | |||||||||

- Vnajnarje | µg/m3 | 3 | |||||||||

Veliki Vrh | µg/m3 | 7 | |||||||||

Graška Gora | µg/m3 | 2 | |||||||||

Ravenska vas | µg/m3 | 9 | |||||||||

Dobovec | µg/m3 | 7 | |||||||||

Rural/Agricultural type | µg/m3 | * | |||||||||

Murska Sobota - Rakičan | µg/m3 | * | |||||||||

annual critical conc. for vegetation protection | µg/m3 | 20 |

Compliance with limit values for sulphur dioxide (SO_{2}) 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/m
^{3}(permitted overage: 24-times within a calendar year), - 24-hour limit value for human health protection: 125 μg/m
^{3}(permitted overage: 3-times within a calendar year), - critical value for the protection of vegetation in wintertime (1 October– 31 March): 20 μg/m
^{3}, - critical annual value for vegetation protection: 20 μg/m
^{3}.

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 km^{2}, an entire area or an agglomerated area may not exceed 500 µg/m^{3}.

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 SO_{2} 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 SO_{2} concentrations in the vicinity of the Šoštanj thermal power plant are a consequence of a limited capacity of the flue gas desulphurisation plant. Elevated SO_{2} 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 SO_{2} 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 SO_{2} concentration for vegetation protection (20 μg/m^{3}) that is relevant at measuring sites in rural areas was last exceeded in 2006 at the Veliki Vrh measuring site.