In August 2026, the air quality at the NBCN monitoring station in Binningen showed no days with low pollution (KBI = 1) and 14 days with moderate pollution (KBI = 2). There were 5 days with marked pollution (KBI = 3) and 12 days with significant pollution (KBI = 4), while no days reached high or very high KBI levels. The Kurzzeit-Belastungs-Index (KBI) combines the concentrations of ozone, nitrogen dioxide, and particulate matter into a single short-term exposure index, where higher values indicate greater air pollution. The mean concentrations for August 2026 were 86.6 µg/m³ for ozone, 8.4 µg/m³ for nitrogen dioxide, and 15.2 µg/m³ for PM10. The maximum concentrations reached 168.0 µg/m³ for ozone, 30.9 µg/m³ for nitrogen dioxide, and 580.2 µg/m³ for PM10. All values are listed in Table 1, and regulatory thresholds are listed in Table 3.

Compared with previous Augusts from 2018 to 2025, August 2026 had the highest mean ozone concentration on record for this month, ranking first out of nine years. The mean PM10 concentration ranked second highest, while the maximum PM10 value was the highest ever recorded for August, driven by an extreme event. The number of days with KBI = 1 ranked sixth, tied with several other years that also had zero such days, and the number of days with KBI = 2 ranked sixth as well. The maximum ozone concentration ranked fifth, and the maximum nitrogen dioxide concentration ranked sixth among the nine years. Overall, August 2026 was generally more polluted than most previous Augusts, particularly for ozone and particulate matter. The monthly average and maximum values for August are reported in Table 2 and displayed in Figures 1 to 3.