The European Air Quality Directive, updated in 2024, requires systematic measurements of ultrafine particles (UFPs) – yet there are currently no binding limit values for the protection of public health. Our study defines a virtual UFP limit value and analyses instances where this limit is exceeded on an hourly and daily average basis at 13 locations in Germany. The result: daily values exceed the limit more frequently than hourly values, particularly at locations affected by traffic.
Bußkamp, M., Kramer, T., Weinhold, K., Wiedensohler, A., Weber, S., 2026. A virtual limit value for ultrafine particles: Frequency of threshold exceedances across Germany based on data from the German Ultrafine Aerosol Network. Atmospheric Environment 386, 122390, doi.org/10.1016/j.atmosenv.2026.122390