Basel ozone peaked at 153 µg/m³, 10th highest in 362 days.
July 14, 2026On July 13, 2026, Basel experienced unusually high ozone levels that exceeded the regulatory threshold and ranked among the highest in the past year, while nitrogen dioxide and fine particulate matter remained within normal ranges.
On July 13, 2026, the most notable air quality issue in Basel was elevated ozone. The maximum ozone concentration of 153.1 µg/m³ ranked 10th highest out of the last 362 days. This value exceeded the regulatory threshold of 120 µg/m³ for the maximum hourly average, which is permitted only once per year. The average ozone concentration for the day was 111.6 µg/m³, which is higher than the 30-day average of 89.3 µg/m³ and the seasonal average of 82.0 µg/m³. The maximum ozone concentration was below the all-time maximum of 206.3 µg/m³ recorded on June 27, 2019.
Nitrogen dioxide and fine particulate matter (PM10) levels were not elevated. The maximum NO2 concentration was 18.2 µg/m³, well below the daily average threshold of 80 µg/m³, and its rank of 232 out of 362 days indicates a typical low value. The average NO2 of 8.3 µg/m³ was slightly above the 30-day average of 7.3 µg/m³ and the seasonal average of 6.4 µg/m³. The maximum PM10 concentration was 25.8 µg/m³, also well below the daily average threshold of 50 µg/m³, with a rank of 79 out of 362 days. The average PM10 of 16.1 µg/m³ was similar to the 30-day average of 15.8 µg/m³ but above the seasonal average of 13.1 µg/m³.
Overall, the air quality on this day was characterized by unusually high ozone levels, which were significantly above the historical average for the season and ranked among the highest in the past year. This elevation is typical for summer conditions with strong sunlight and high temperatures, which promote ozone formation. The levels of NO2 and PM10 remained within normal ranges.
Table 1: Statistics for Air Quality Parameters on 2026-07-13
| Constituent | Average µg/m³ | Maximum µg/m³ | Standard | Comments |
|---|---|---|---|---|
| NO2 | 7.1 | 26.4 | 80.0 | daily average may not exceed standard |
| Ozone | 90.9 | 159.8 | 120.0 | maximum hourly average may exceed standard only one time per year |
| PM10 | 11.9 | 27.0 | 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 | 76.5 | 181.9 | 94 |
| 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.