This report presents the results of the 2025 plume‑chase measurement campaign, conducted by TNO on Dutch motorways, with a focus on Dutch and international heavy-duty vehicles and light-duty delivery vans. For the first time, particulate matter emissions were also measured by plume chasing.
The results show that international road tractors are found to have higher average NOx-emissions and a significantly larger share of high-emitters compared to Dutch road tractors. While Dutch road tractors show a high-emitter share of only 9.0%, international road tractors were found to have a high-emitter share of 17.6%. This difference is statistically significant and is primarily driven by road tractors registered in Eastern European countries, which show a high‑emitter share of 20%.