## 2 Materials and Methods
### The Case Study  
The defined methodology was implemented and validated in selected rooms of the Uffizi Gallery Museum in Florence, Italy. This is a large museum that is among the most famous in the world. The Uffizi Gallery hosts priceless artwork collections that include paintings by Italian artists from the 14 th-century and the Renaissance (e.g., [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], [PERSON], and [PERSON]). Numerous precious works by European painters from the same historic period (mainly Dutch, Flemish, and German), and a collection of ancient statues and busts [35] from the [PERSON] family, are also displayed in the museum. The latter are ancient Roman copies of lost Greek sculptures that adorn the corridors of the Uffizi Gallery. The museum is located on the first and second floors of a valuable historical building in the city center of Florence, designed by [PERSON] and dating back to 1560-1580. According to the results of phase (i), and due to the insights obtained from the interviews with the technical staff, some Gallery rooms characterized by poor air quality were identified. Therefore, the investigation was carried out for nine representative rooms that are highlighted in Figure 1 and described in detail below. With respect to the HVAC system serving the building, the Uffizi Gallery is mainly equipped with HVAC systems which recirculate the air, for the control of air temperature and relative humidity, all year. Moreover, the system is managed by a remote monitoring and control system, positioned in a technical room, that also controls the fire system, the security system, and the electrical system. As an example, Figure 2 shows the air handling unit (AHU) control system of Room 2 and some pictures of the room. On the first floor of the museum, three rooms were considered (Figure 3). The Verone I floor (Figure 3a) has views from every orientation with large windows and mainly hosts ancient statues and busts. Sampling was performed near the north-facing window. The Verone I floor has a floor area of 201.04 m\({}^{2}\), a height of 8.17 m and a volume of 1642.50 m\({}^{3}\). It is equipped with an HVAC system for control all year of temperature  
Figure 1: Plan of the first (**a**) and the second (**b**) floor of the Uffizi Gallery pointing out the analyzed rooms. and relative humidity, managed by a remote monitoring and control system. The primary ventilation air comes from the AHU, using supply fans with variable flow (nominal air flow rate of 1400 m\({}^{3}\)/h), and enters the room through floor inductors. There is no recirculated air. Figure 3: Analyzed rooms on the first floor of the Uffizi Gallery: (**a**) Verone I floor, (**b**) Room 41 and (**c**) Room 160. Figure 2: (**a**) AHU control system scheme, (**b**) AHU in the attic room, (**c**) air inlet grids from the top of the roof, and (**d**) air outlet grids at the bottom of the opposite wall of Room 2. Room 71 (Figure 3b) has non-external walls. Inside the room, the \"Scudo con testa di Medusa\" of [PERSON] from Caravaggio is displayed, an oil painting on canvas (1597). Samplings were carried out near the painting. The room has a floor area of 69.28 m\({}^{2}\), a height of 8.02 m and a volume of 555.62 m\({}^{3}\). It is equipped with an HVAC system for the control all year of temperature and relative humidity, managed by a remote monitoring and control system. The AHU, housed in an attic room, allows for centralized air treatment in summer mode, while, in winter mode, there is also the possibility of post-heating by means of zone batteries; the outdoor air intake is on the roof and there are variable flow fans (nominal air flow rate of 9000 m\({}^{3}\)/h). Air inlet and outlet takes place through floor grids with adjustable nozzles. Room 160 (Figure 3c) has a north-west oriented windowless external wall and a skylight. It houses the collection donated by Contini-Bonacossi, with paintings and marble statues. Samplings were carried out near the precious paintings.