Basel ozone hits 161 µg/m³, sixth highest in past year.
July 15, 2026On July 14, 2026, Basel experienced unusually high ozone levels, with a maximum concentration of 161.0 µg/m³ that exceeded the regulatory threshold and ranked as the sixth highest in the past year. While nitrogen dioxide and PM10 remained within safe limits, the ozone spike was significant compared to historical and seasonal averages, likely driven by summer conditions like strong sunlight and heat.
On July 14, 2026, air quality in Basel was characterized by elevated ozone levels. The maximum ozone concentration of 161.0 µg/m³ was the sixth highest recorded in the past 365 days. This value exceeded the regulatory threshold of 120.0 µg/m³, triggering an exceedance. The average ozone concentration for the day was 117.7 µg/m³, which is also above the threshold.
Nitrogen dioxide and PM10 levels remained within regulatory limits. The maximum NO₂ concentration was 22.8 µg/m³, and the average was 10.9 µg/m³, both well below the daily average limit of 80.0 µg/m³. For PM10, the maximum was 30.4 µg/m³ and the average was 21.8 µg/m³, also below the daily average limit of 50.0 µg/m³.
Compared to historical data since 2018, the maximum ozone concentration of 161.0 µg/m³ is well below the all-time maximum of 206.3 µg/m³ recorded on June 27, 2019. The average ozone concentration of 117.7 µg/m³ is higher than the seasonal average of 82.9 µg/m³ and the 30-day average of 91.5 µg/m³, indicating a significant spike. The maximum NO₂ and PM10 concentrations are far below their all-time records of 83.2 µg/m³ and 165.1 µg/m³, respectively.
Overall, the air quality on this day was unusual due to the notably elevated ozone levels. The high ozone concentration, ranking sixth in the past year and exceeding the regulatory standard, suggests conditions favorable for ozone formation, such as strong sunlight and high temperatures. This is a typical summer phenomenon, but the degree of elevation on this day was significant.
Table 1: Statistics for Air Quality Parameters on 2026-07-14
| Constituent | Average µg/m³ | Maximum µg/m³ | Standard | Comments |
|---|---|---|---|---|
| NO2 | 7.3 | 26.4 | 80.0 | daily average may not exceed standard |
| Ozone | 92.8 | 161.0 | 120.0 | maximum hourly average may exceed standard only one time per year |
| PM10 | 12.6 | 30.4 | 50.0 | daily average may not exceed standard |
Table 2: Statistics for Air Quality Parameters for the Month of July, since 2018
| Constituent | Average µg/m³ | Max µg/m³ | Exceedances |
|---|---|---|---|
| NO2 | 7.8 | 56.2 | 0 |
| Ozone | 76.7 | 181.9 | 95 |
| PM10 | 11.4 | 43.3 | 0 |
Figure 1: NO2 Concentrations in Basel, last 90 Days
Figure 2: Ozone Concentrations in Basel in the last 90 Days
Figure 3: PM10 Concentrations of last 90 Days at Binningen/Basel
Additional resources: Umweltbericht beider Basel, Luftqualität Nordwestschweiz, Luftreinhalte-Verordnung (LRV)
🤖 This text was generated with the assistance of AI. All quantitative statements are derived directly from the dataset listed under Data Source.