In July 2026, the air quality at the NBCN station in Binningen showed a mixed picture. There were 3 days with low pollution, corresponding to a Kurzzeit-Belastungs-Index (KBI) of 1, and 9 days with moderate pollution, a KBI of 2. However, the month also experienced 19 days with elevated pollution levels: 5 days reached a KBI of 3, indicating marked pollution, and 14 days reached a KBI of 4, signifying significant pollution. No days fell into the high or very high categories. The KBI combines the concentrations of ozone, nitrogen dioxide, and particulate matter into a single, easy-to-understand index of short-term exposure. The mean concentrations for the month were 96.3 µg/m³ for ozone, 7.5 µg/m³ for nitrogen dioxide, and 14.1 µg/m³ for PM10. Maximum daily values reached 175.3 µg/m³ for ozone, 26.4 µg/m³ for nitrogen dioxide, and 63.2 µg/m³ for PM10. All values are listed in Table 1, and regulatory thresholds are listed in Table 3.

Compared to previous Julys since 2018, the air quality in July 2026 was notably worse in several respects. The 3 days with a KBI of 1 tied for the highest rank in the nine-year period, yet this was overshadowed by the high number of days with significant pollution. The mean ozone concentration ranked second highest, and the maximum ozone concentration ranked third highest. Most strikingly, both the mean and maximum PM10 concentrations ranked first, with the maximum of 63.2 µg/m³ being substantially higher than in any other July on record. In contrast, nitrogen dioxide levels were unremarkable, with the maximum daily value ranking as the lowest observed. The monthly average and maximum values for July are reported in Table 2 and are also displayed in Figures 1 to 3.