Kelsterbach Stops Air Quality Monitoring Despite High Ultrafine Particle Risks

Air quality monitoring in Kelsterbach has ended following a new EU directive on ultrafine particles. The Hessian Agency for Nature Conservation, Environment, and Geology (HLNUG) stopped its measurements after the rule was introduced, though no binding limits for these pollutants yet exist. The town's pollution is heavily linked to nearby Frankfurt Airport, with high particle levels recorded on many days.

Ultrafine particles—those smaller than 100 nanometres—pose a potential health risk. They can penetrate deep into the lungs and even enter the bloodstream. The EU's updated Air Quality Directive now requires continuous monitoring of these particles by the end of 2026, though unlike PM₂.₅ or nitrogen dioxide, no legal limits have been set.

Over a 12-month period, Kelsterbach recorded an average of 11,500 ultrafine particles per cubic centimetre. On days with southerly winds, this figure spiked to 21,100 particles, affecting nearly a third of measurements. The World Health Organization (WHO) flags exposure risks when daily averages exceed 10,000 particles—something Kelsterbach surpassed on over half the days monitored. The pollution stems largely from aircraft operations at Frankfurt Airport. When winds blow from the south, emissions drift toward the town. HLNUG's data from Kelsterbach aligns closely with readings from a permanent station in Frankfurt-Schwanheim, confirming the airport's impact. This station will now serve as a reference for Kelsterbach's air quality.

The EU's directive means ultrafine particle monitoring will become mandatory, but without enforceable limits. Kelsterbach's high particle levels, driven by airport emissions, will continue to be tracked via the Frankfurt-Schwanheim station. The town's exposure remains a concern, with readings frequently exceeding WHO thresholds.