The current experimental study presents particulate emissions from 30 Euro 1-4 L-category vehicles (i.e. 2-, 3- and 4-wheelers such as mopeds, motorcycles, quads and minicars, registered in Europe between 2009 and 2016) tested on a chassis dynamometer. The objectives were to identify those sub-categories with high emissions, to assess whether the measures prescribed in the Euro 5 legislation will effectively control particulate emissions and finally to investigate the need for additional measures. The results showed that 2-stroke (2S) mopeds and diesel minicars comprised the vehicles with the highest particulate mass (PM) and solid particle number above 23 nm (SPN23) emissions (up to 64 mg/km and 4.5 × 10 13 km −1, respectively). It is uncertain whether the installation of diesel particulate filters (DPF) is a cost-effective measure for diesel mini-cars in order to comply with Euro 5 standard, while advanced emission controls will be required for 2S mopeds, if such vehicles remain competitive for Euro 5. Regarding 4-stroke mopeds, motorcycles and quads, PM emissions were one order of magnitude lower than 2S ones and already below the Euro 5 limit. Nevertheless, SPN23 emissions from these sub-categories were up to 5 times higher than the Euro 6 passenger cars limit (6 × 10 11 km −1). Even recent Euro 4 motorcycles exceeded this limit by up to 3 times. These results indicate that L-category vehicles are a significant contributor to vehicular particulate emissions and should be further monitored during and after the introduction of the Euro 5 step. Moreover, including SPN in the range 10–23 nm increases emission levels by up to 2.4 times compared to SPN23, while volatile and semi-volatile particle numbers were even higher. Finally, cold engine operation was found to be a significant contributor on SPN23 emissions, especially for vehicles with lower overall emission levels. These results indicate that a specific particle number limit may be required for L-category to align emissions with passenger cars.
L-category is becoming a major contributor to vehicular particulate emissions.
2-Stroke mopeds and diesel minicars comprise the highest emitters.
High particle number emissions are observed even if particulate mass is low.
Particulate emissions of latest technology vehicles much higher than passenger cars.
A revision of particulate emissions regulation for L-category shall be investigated.