Sulphur Dioxide (SO₂)
A colorless gas with a sharp, irritating smell. Once a major cause of acid rain, SO2 levels have dropped dramatically in Europe but remain problematic near industrial facilities.
Regulatory Limits (µg/m³)
WHO Guideline
40
Most protective standard
EU 2030 Target
50
Directive 2024/2881
EU Current Limit
125
Being replaced in 2030
0 out of 688 tracked European cities currently exceed the EU 2030 SO₂ target.
Where Does SO₂ Come From?
- •Burning coal and oil (power generation)
- •Industrial processes (metal smelting, chemical manufacturing)
- •Shipping (heavy fuel oil)
- •Volcanic emissions
- •Petroleum refining
Health Effects of SO₂
Short-Term Exposure
- •Bronchoconstriction (airway narrowing)
- •Wheezing and shortness of breath
- •Eye and throat irritation
- •Particularly dangerous for asthmatics
Long-Term Exposure
- •Chronic bronchitis
- •Aggravation of existing cardiovascular disease
- •Contributes to particulate formation (secondary PM2.5)
- •Environmental damage (acid rain)
How to Protect Yourself
- 1.Monitor readings if you live near industrial areas or ports
- 2.Keep rescue inhalers accessible if you have asthma
- 3.Avoid outdoor exercise downwind of industrial facilities
- 4.Support clean energy transitions to reduce SO2 at source
Highest SO₂ Levels in Europe
| # | City | Country | PM2.5 | AQI |
|---|---|---|---|---|
| 1 | Blagoevgrad | Bulgaria | - | |
| 2 | Zabrze | Poland | - | |
| 3 | Pleven | Bulgaria | - | |
| 4 | Kalisz | Poland | 17.7 | 18 |
| 5 | Burgas | Bulgaria | - | |
| 6 | Pernik | Bulgaria | 16.8 | 17 |
| 7 | Gliwice | Poland | 21.2 | 21 |
| 8 | Râmnicu Vâlcea | Romania | - | |
| 9 | Gela | Italy | 14.8 | 15 |
| 10 | Zielona Góra | Poland | 19.9 | 20 |
| 11 | Stara Zagora | Bulgaria | 17.0 | 17 |
| 12 | Craiova | Romania | - | |
| 13 | Nowy Sacz | Poland | 18.8 | 19 |
| 14 | Pila | Poland | - | |
| 15 | Zory | Poland | 20.1 | 20 |