Particulate matter has been considered an indicator for the pollution of urban stormwater runoff for quite some time. There are only few studies that have investigated the contamination with organic micropollutants and metals both in the dis-solved and particulate phase as well as across different particle size classes. Yet, this distribution plays an important role in better understanding and optimising urban stormwater treatment measures. Therefore, this work aimed at assessing the composition of particulate matter in urban stormwater in terms of the physico-chemical properties (particle size distribution and organic content), as well as the occurrence of organic micropollutants and metals, their association to particulate matter and their removal from urban runoff. An intensive long term monitoring campaign at a centralised stormwater treatment facility of an industrial area was conducted. The stormwater runoff was sampled with large volume sampling tanks filled volume-proportional to the runoff at the two outlets of the facility. This allowed the determination of the event mean concentrations as well as the load-related removal efficiencies of the treatment facility for different parameters. Within each sample the concentrations of total suspended solids across different particle size fractions (< 63 µm, 63 – 125 µm, 125 – 250 µm, 250 – 2000 µm) were measured as well as their organic content. Furthermore, the concentrations and the phase distribution of 5 metals (Chromium, Copper, Zinc, Cadmium, Lead) and 29 organic micropollutants including polycyclic aromatic hydrocarbons, industrial chemicals (e.g. organophosphates, alkyphenols) and biocides were ana-lysed across different particle size fractions. In this study, over a period of almost 2.5 years, a total of 36 sampling events were recorded and investigated within two sampling periods (2015 – 2016 and 2017 – 2019) at the rainwater treatment facility in Freiburg Haid. The occurrence of organic micropollutants was determined in 22 of these events and the occurrence of metals in 17. The evaluation of the event mean concentration of total suspended solids showed that the fine fraction of the solids is of particular importance, as it showed an event mean concentration more than twice as high (34 mg \(L^{-1}\)) as the coarser particle fraction (14.9 mg \(L^{-1}\)). Regarding the occurrence of total suspended solids in terms of the transported solid load, the solids < 63 µm accounted for a mean proportion of 61 %, the fraction 63 – 125 µm for 13 %, the fraction 125 – 250 µm for 6 % and the fraction 250 – 2000 µm for 9 % of the total solid mass. In terms of the organic content of the solids, the results showed a clear increase of the organic content with increasing particle size (measured as loss on ignition). As in the case of solids, the highest concentrations of the organic micropollutants and metals investigated were found in the particle size fraction < 63 µm. This fine fraction of the particles also accounted for the largest load of organic micropollutants and metals. Therefore, the particle loading with organic micropollutants or metals respectively the particle-bound micropollutant/metal concentration was calculated in this study. For most substances, a rather equal distribution over the smallest three particle size fractions was found. A certain correlation of the organic content with the occurrence of organic micropollutants and metals could be shown, therefore it can be assumed that the particle-bound concentration is certainly influenced by the organic content of the particulate matter. However, due to the fact that, among other things, the largest particle-bound pollutant loads are transported with particles < 63 µm, the fine fraction represents the relevant particle size in urban stormwater runoff. Regarding the total treatment efficiency (including sedimentation efficiency and volume retention), the investigated facility in this study was able to reduce the load of fine particles by only a quarter. The larger particle size classes were reduced by far more than half in most cases. If total suspended solids in its entire particle size range were used as a proxy to estimate the removal efficiency of metals and organic micropollutants, the efficiency would be overestimated and the actual pollutant load released into the environment would thus be underestimated. However, the investigation, weather the particle size fraction < 63 µm would be more suitable, showed that even for substances with a high tendency to adsorb onto particles (e.g. Cr, Cu, IND, GHI), the total treatment efficiency was still overestimated by the fine fraction.