## 1 Introduction
Several SPME sorbent coatings have been developed, such as divinylbenzene/polydimethylsiloxane (DVB/PDMS), which is used especially for the adsorption of semi-volatile analytes and larger volatile compounds, carboxen/polydimethylsiloxane (CAR/PDMS), suitable for small volatile molecules, and DVB/CAR/PDMS, which is indicated for the adsorption of an extended molecular weight range of analytes [30]. For this reason, in our study, we utilized the DVB/CAR/PDMS coating. In this study, DVB/CAR/PDMS fibers have been included in a dynamic sampling system characterized by a controlled and constant air flux, which allowed the adsorption of BVOCs on the fibers and the ability to reach the equilibrium retaining analytes with different molecular weights uniformly [38]. Our Dynamic BVOC Sampling System (DBSS), based on a previous study [36], was improved in the material used for the instrument to make it cheaper and easier to assemble. Our choice was to use aluminum instead of polyacetal plastic. Using this metal, all the components are easily available in any hardware store, and no glue was used for its assembly to avoid possible interferences in BVOCs analysis. The choice of aluminum was guided by the need to have a light and resistant instrument for field campaigns. Furthermore, the DBSS shape and its low weight allow it to be easily set up on a metal picket in the forest, while the metal net in front of the chamber provides a physical barrier to insects or debris, additionally creating a swirling flow. The DBSS was positioned at a height of 45 cm from the ground, which is optimal to limit wind action and manage the sampling operations [39]. Finally, the sampling duration of 4 h was chosen to obtain the best compromise between a long exposition time of SPME fibers [40] and an operationally feasible sampling time in the field. In this work, we present a methodology for BVOC collection as specified above. Our technique for BVOC collection was tested under field conditions for qualitative and semi-quantitative analyses of BVOCs emitted from _Q.__i.e_ plants at the atmospheric level. The study was carried out on two sampling sites: the first one was located in the experimental fields of CNR (National Research Council of Italy, Sesto Fiorentino, FI, Italy), where BVOCs were collected from three-year-old _Q. alex_ L. potted plants; the second experimental site consisted of a Mediterranean sclerophyll forest located in the Maremma Regional Reserve (Alberese, GR, Italy). The forest was dominated by _Q. alex_, while other woody species were also present in a lower percentage, such as _Rubus_ spp., _Phillirea latifolia_, _Cistus sulviofilus_, _Quercus cerris_, _Pistacia lentiscus_, _Acer monspessulanum_, _A. campestre_ and _Fraxinus ornus_. Mediterranean forests are important for their ecological and socio-economic value providing several ecosystem services and goods to society [41; 42; 43]. To test our sampling method, we selected _Quercus lex_ as the most representative species of the Mediterranean forest ecosystem that, in recent years, has been subjected to repeated drought events [44]. Thus, the main aim of our study was to develop and test a new, rapid and simple sampling strategy to obtain reliable data on BVOC emission at the environmental level.