SmogRank / Countries / Ireland / September 2026

Most polluted cities in Ireland, September 2026

21 cities in Ireland ranked by their average PM2.5 over the 30 days. Worst: Letterkenny at 6.3 µg/m³, #1,124 of 2,332 cities in the world. Cleanest: Bray at 4.1. A city needs measurements on 70% of the days to be ranked.

  1. 1LetterkennyUlster
    6.3
  2. 1GalwayConnacht
    6.3
  3. 3WaterfordMunster
    5.8
  4. 4WexfordLeinster
    5.7
  5. 4SligoConnacht
    5.7
  6. 6EnnisMunster
    5.5
  7. 7TraleeMunster
    5.3
  8. 7AthloneLeinster
    5.3
  9. 9DublinLeinster
    5.2
  10. 9DroghedaLeinster
    5.2
  11. 11NavanLeinster
    5.0
  12. 11CarlowLeinster
    5.0
  13. 13LimerickMunster
    4.9
  14. 13CorkMunster
    4.9
  15. 15DundalkLeinster
    4.8
  16. 15Cluain MealaMunster
    4.8
  17. 17Dún LaoghaireLeinster
    4.7
  18. 18LeixlipLeinster
    4.6
  19. 19GreystonesLeinster
    4.3
  20. 20NaasLeinster
    4.2
  21. 21BrayLeinster
    4.1
Good0–9.0
Moderate9.1–35.4
Sensitive groups35.5–55.4
Unhealthy55.5–125.4
Very unhealthy125.5–225.4
Hazardous225.5+

All cities in the world, September 2026 · Ireland now