Nitrogen Dioxide (NO₂)
A reddish-brown gas produced primarily by burning fossil fuels. Nitrogen dioxide is a major indicator of traffic-related air pollution and a precursor to ground-level ozone and PM2.5.
Regulatory Limits (µg/m³)
WHO Guideline
10
Most protective standard
EU 2030 Target
20
Directive 2024/2881
EU Current Limit
40
Being replaced in 2030
44 out of 96 tracked European cities currently exceed the EU 2030 NO₂ target.
Where Does NO₂ Come From?
- •Vehicle exhaust (the primary source in cities)
- •Power plants burning fossil fuels
- •Industrial boilers
- •Gas stoves and heaters (indoor source)
- •Shipping emissions in port cities
Health Effects of NO₂
Short-Term Exposure
- •Airway inflammation
- •Increased susceptibility to respiratory infections
- •Worsened asthma symptoms (especially in children)
- •Reduced lung function
Long-Term Exposure
- •Development of asthma in children
- •Chronic respiratory disease
- •Reduced lung development in children
- •Increased cardiovascular mortality
How to Protect Yourself
- 1.Choose walking and cycling routes away from busy roads
- 2.Keep car windows closed in heavy traffic
- 3.Ensure good ventilation when using gas stoves
- 4.Support low-emission zones in your city
- 5.Consider electric vehicles to reduce personal contribution
Highest NO₂ Levels in Europe
| # | City | Country | PM2.5 | AQI |
|---|---|---|---|---|
| 1 | Turin | Italy | 18.2 | 18 |
| 2 | Milan | Italy | 17.9 | 18 |
| 3 | Katowice | Poland | 23.0 | 23 |
| 4 | Krakow | Poland | 22.1 | 22 |
| 5 | Plovdiv | Bulgaria | 22.5 | 23 |
| 6 | Bologna | Italy | 14.2 | 14 |
| 7 | Palermo | Italy | 14.2 | 14 |
| 8 | Genoa | Italy | 14.2 | 14 |
| 9 | Naples | Italy | 13.3 | 13 |
| 10 | Bucharest | Romania | 18.8 | 19 |
| 11 | Sofia | Bulgaria | 20.0 | 20 |
| 12 | Budapest | Hungary | 15.2 | 15 |
| 13 | Split | Croatia | 15.2 | 15 |
| 14 | Debrecen | Hungary | 15.2 | 15 |
| 15 | Lodz | Poland | 17.2 | 17 |