On August 8, 2025, Basel experienced unusually high ozone levels, reaching 140.9 µg/m³, significantly surpassing historical averages, while other pollutants remained within normal ranges; this deviation suggests specific meteorological conditions or increased emissions and requires further investigation to assess potential health and environmental impacts.
This report on air quality in Basel for August 8, 2025, is published because the daily maximum concentration of ozone (O₃) exceeded the 95th percentile of all values measured in August. On this day, the air quality showed notable characteristics. The maximum concentration of ozone reached 140.9 µg/m³, with an average of 87.5 µg/m³. Nitrogen dioxide (NO₂) had a maximum of 20.1 µg/m³ and an average of 10.4 µg/m³. Particulate matter (PM₂.₅) recorded a maximum of 10.8 µg/m³, averaging 8.0 µg/m³. The particle count (CPC) peaked at 20,117.8 particles/cm³, with an average of 8,532.0 particles/cm³. Elemental carbon (EC) had a maximum of 0.5 µg/m³ and an average of 0.3 µg/m³. Solar radiation peaked at 849.2 W/m², averaging 302.4 W/m². Sulfur dioxide (SO₂) reached a maximum of 5.7 µg/m³, with an average of 1.6 µg/m³. Nitrogen oxides (NOx) had a maximum of 27.0 µg/m³, averaging 12.4 µg/m³.
Comparing these values to historical data since 2018, the ozone levels were unusually high, with the maximum significantly surpassing the recent 30-day maximum of 128.9 µg/m³ and the seasonal average of 73.1 µg/m³. NO₂ levels were within the normal range, below the recent 30-day maximum of 27.4 µg/m³ and the seasonal maximum of 31.9 µg/m³. PM₂.₅ concentrations were typical, below the recent maximum of 31.6 µg/m³. The particle count was within historical norms, below the recent maximum of 24,328.1 particles/cm³. EC levels were consistent with historical averages. Solar radiation was typical, below the historical maximum of 953.8 W/m². SO₂ levels were within normal ranges, matching the seasonal maximum. NOx levels were below historical peaks, with the recent maximum being 40.0 µg/m³.
The air quality on August 8, 2025, showed a significant deviation from historical norms due to the unusually high ozone levels. This could be attributed to specific meteorological conditions or increased emissions. The elevated ozone levels are noteworthy and warrant further investigation to understand their cause and potential impact on health and the environment.
| Constituent | Average µg/m³ | Maximum µg/m³ | Standard | Comments |
|---|---|---|---|---|
| NO2 | 8.5 | 31.2 | 80.0 | daily average may not exceed standard |
| Ozone | 73.7 | 171.1 | 120.0 | maximum hourly average may exceed standard only one time per year |
| PM10 | 14.4 | 46.8 | 50.0 | daily average may not exceed standard |
| Constituent | Average µg/m³ | Max µg/m³ | Exceedances |
|---|---|---|---|
| NO2 | 8.7 | 49.6 | 0 |
| Ozone | 70.2 | 192.4 | 84 |
| PM10 | 11.4 | 162.7 | 0 |
🤖 This text was generated with the assistance of AI. All quantitative statements are derived directly from the dataset listed under Data Source.