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The main national sources of SO2 are energy supply and industry; these each emit more that 35% of annual SO2 emissions. The residential, commercial and institutional sector is also relevant (EEA, 2025a).
The EEA has received valid 2024 SO2 data from 37 of the reporting countries (all, excluding Albania and Liechtenstein). Preliminary data for 2025 were received from all the countries except the Member State of Luxembourg as well as Albania, Kosovo, Liechtenstein, Serbia and Türkiye.
The EU and the WHO have set different air quality standards and AQG levels for both short- (hourly and daily) and long-term (annual) concentrations. They are presented in Table 5.
Table 5. EU limit values and WHO AQG levels for SO2
Current EU standard | 2030 EU standard | WHO 2021 AQG level | ||||
|---|---|---|---|---|---|---|
Averaging period | Limit value | Not to be exceeded more than | Limit value | Not to be exceeded more than | AQG level | Comments |
1 hour | 350μg/m3 | 24 hours/year | 350μg/m3 | 3 hours/year | ||
24 hours | 125μg/m3 | 3 days/year | 50μg/m3 | 18 days/year | 40μg/m3 | 99th percentile (3-4 days/year) |
1 calendar year | 20μg/m3 |
Country status for SO2 in 2024:
- 0.9% of all the reporting stations registered levels above the current EU HLV: ten in Bosnia and Herzegovina, three in Türkiye and one in Iceland.
- 1.1% of all the reporting stations registered levels above the current EU DLV. These were all located in three non-EU countries: Bosnia and Herzegovina (11), Türkiye (four) and Iceland (one).
- 4.7% of the reporting stations located across seven different EU Member States (Bulgaria, Czechia, France, Germany, Ireland, Poland and Spain) and five other countries (Bosnia and Herzegovina, Iceland, Montenegro, Serbia and Türkiye) registered levels above the WHO daily AQG level of 40µg/m3 (instead of the 99th percentile, the 99.18th percentile was used for the daily values, equating to three days of exceedance per year).
- 97.5% of the reporting stations recorded concentrations below the 2030 HLV. The 38 stations with levels above the HLV were located in the Member States of Czechia (four), Bulgaria (three), Austria, France, Germany, Italy and Poland (one each) as well as Bosnia and Herzegovina (14), Türkiye (six), Iceland (four), Montenegro and Serbia (one each).
- 98.4% of the reporting stations recorded concentrations below the 2030 DLV. The 24 stations with concentrations above the 2030 DLV were located in the Member States of Bulgaria and Spain (one each) as well as in Bosnia and Herzegovina (13), Türkiye (eight) and Montenegro (one).
- 98.8% of reporting stations recorded concentrations below the new 2030 ALV. The 19 stations with concentrations above the 2030 ALV were located in Bulgaria (one), an EU member state, and also Bosnia and Herzegovina (12), Türkiye (five) and Montenegro (one).
In 2025, six stations in Bosnia and Herzegovina and one in Montenegro reported concentrations above the current EU HLV. Eight reporting stations registered concentrations of SO2 above the current EU DLV: seven in Bosnia and Herzegovina and one in Montenegro. In the same year, concentrations above the WHO daily AQG level (again, the 99.18th percentile, instead of the 99th percentile) were registered at 42 stations (3.5% of total stations) located in 10 different EU Member States and four other reporting countries.