Abstract Airborne ultrafine particles (UFPs) potentially have adverse health effects for the exposed population both in life and work environments. Main objective of this study is to propose a strategy to measure multiple parameters that may influence human exposure to UFPs and apply it in a case study at the university site of “La Sapienza” in Rome (Italy). The measurements allow the characterization of UFPs in terms of particle number concentration (PNC), particle size distribution (PSD), lung deposited surface area (LDSA), geometric mean diameter (GMD) and polycyclic aromatic hydrocarbons concentration (PAHs), using data collected in indoor and outdoor conditions by real-time instruments with high time resolution. The study design includes: i) inter-comparison of devices based on different principles of operation to harmonize the outputs in relation to a reference instrument; ii) case study site description and sampling points identification to allow indoor vs outdoor relations at different height; iii) extensive measurement campaigns to provide a dataset useful to data comparison; iv) statistical data series analysis. The preliminary results reported here are related to the values of PNC and calculated average diameter (D_avg) for airborne UFPs, obtained in three different sampling points of the research workplaces at the university site: auditorium (about 300 places - ground floor), computer science laboratory (about 50 workstations - first floor) and external roof (top of the building). Major relations between PNC and D_avg have been highlighted in daily trends.