## 3 Results  
Figure 3 shows the results related to the overall profile of the trial participants. In total, 245 professionals participated in the study; Hospital Arena Fonte Nova (Field Hospital for COVID-19) was the health unit with the highest number of participants (\(n=98\)), followed by Hospital Espanhol (\(n=74\)) (Field Hospital for COVID-19), and Hospital Ernesto Simoes (\(n=73\)), (Figure 3a). Most participants who answered the questionnaire were women (\(71\%\) or \(n=174\)), whereas men accounted for \(29\%\) (or \(n=71\)) of the total participants (Figure 3b). The percentage between men and women who participated in the study according to the hospital is shown in Table S2. The highest frequency of participation was observed for nursing technicians (36.73% or \(n=90\)), followed by nurses (13.06% or \(n=32\)) (Figure 3c and Table S2). The lowest frequency of participation was observed for receptionists, social workers and biomedical professionals (0.41% or \(n=1\), 0.41% or \(n=1\), and 0.82% or \(n=2\), respectively) (Figure 3c and Table S2). Healthcare professionals represented \(72.24\%\) (\(n=177\)) of the population that was investigated in this study. In addition, it is important to note that the selection of participants was not directed to any specific occupation, respecting only the eligibility criteria. The opinion of professionals from different areas can minimize any kind of bias of a specific professional class. Figure 4 presents the results pertaining to two questions associated with the history of contact (familiarity) of the professionals with the biocidal agent used in the disinfection chamber (sodium hypochlorite at a concentration of 0.25% (2500 ppm)). Of the participating professionals, 92% (\(n=225\)) answered that they used sodium hypochlorite in the cleaning/disinfection processes of surfaces in domestic activities (Figure 4a and Table S2). Of the professionals who answered yes to this question, 49.60% (\(n=124\)) stated that they were concerned about the dilution of the hypochlorite solution; 32.80% (\(n=82\)) answered that they handled the disinfect agent using gloves; and 16.40% (\(n=41\)) answered that they did not have concerns about handling the sodium hypochlorite solution (Figure 4a). Regarding reactions during previous contact with sodium hypochlorite, 79.59% (\(n=195\)) of the participants answered that they did not experience any type of reaction to the biocidal  
agent, and although 20.41% (\(n=50\)) of the participants answered that they experienced some type of reaction (Figure 4b), they did not oppose the use of the chamber or refuse to participate in the study. Among the previous reactions reported, 35.14% (\(n=26\)) referred to skin irritation or itching, 36.49% (\(n=27\)) to eye irritation or itching, and 25.68% (\(n=19\)) to difficulty in breathing (Figure 4b). Figure 3: The profile of professionals participating in the survey: (**a**) total number of participants according to hospital or healthcare unit; (**b**) sex; and (**c**) profession according to hospital or healthcare unit. Responses to the next three questions regarding the history of contact with the biocidal agent are presented in Figure 5. Figure 5a presents the opinion of professionals regarding the efficiency of sodium hypochlorite, where 85.31% (\(n=209\)) of the participants considered it as a good disinfectant, 3.27% (\(n=8\)) did not consider it as a good disinfectant, and 11.43% (\(n=28\)) did not know, with significant difference between responses (\(p<0.05\)). The percentage of professionals who knew that sodium hypochlorite is effective for the inactivation of SARS-CoV-2 and that it is recommended by the WHO for the disinfection of home and hospital environments was 85.71% (\(n=210\)), and that of professionals who were not aware of this information was 14.29% (\(n=35\)), with significant difference between responses (\(p<0.05\)) (Figure 5b).