# Development of Far-UVC-Based Surface Disinfection Prototype for Public Buses
## 1 Introduction
Numerous studies have been conducted to investigate the efficacy and practicality of UVC disinfection robots in diverse settings, especially hospitals. A summary of these studies is provided in Table 1. \begin{table}
\begin{tabular}{c c c c} \hline \hline
**Scheme** & **UV Wavelength** & **Objective** & **Findings** \\ \hline Tru-DTM room & Not specified & Assess the efficacy of a Tru-D UVC room & The successful eradication of organisms in an unoccupied operating theatre was accomplished. The robot was not found suitable for integration into hospital’s cleaning procedures; it had an insufficient UVC irradiation cycle for pathogens with enhanced environmental resilience; it was effective in reducing the microbial burden on hospital surfaces. & _Bacillus atrophanes_ spores serve as suitable model organisms for testing the influence of shadows on the inactivation efficacy of mobile whole-room UVGI devices. & on the inactivation efficacy of mobile whole-room UVGI devices. \\ UV-C Disinfection & 254 nm & Evaluate the effectiveness and usability of a UVC disinfection robot in hospital setting & & \\  & & Investigate the effectiveness of whole-room UVGI devices in controlling surface-borne pathogens & & \\ COVID-19 Disinfection & 254 nm & Develop a robot specifically designed for disinfecting COVID-19 in complex indoor settings & & \\  & & & \\ UVC-PURGE Robot & 254 nm & Evaluate the performance of the UVC-PURGE robot in combating COVID-19 & & \\  & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Summary of robotic UVC disinfection research. Despite the extensive research conducted on UVC disinfection systems, recent studies have shifted their focus towards investigating the effects of UVC radiation exposure on various materials. For example, one study examined the effects of UVC radiation exposure on materials (fabric and plastic) commonly used in aircraft cabins. The study found that cumulative damage from frequent UVC radiation application has no significant effect on flame retardancy up to 269 J/cm\({}^{2}\) of dose, and no effect on tensile or tear strength up to 191 J/cm\({}^{2}\). However, changes in color or appearance can occur at lower doses, and a limit of 40 J/cm\({}^{2}\) was proposed to avoid perceptible changes in appearance [26]. Another investigation on UVC's effect on materials was conducted in our previous research [27], where we found that the use of far-UVC radiation with a specific wavelength of 222 nm for disinfection can have significant negative effects on the mechanical and visual properties of the surfaces to be disinfected. The results of the study showed that far-UVC radiation at 222 nm causes significant color degradation in all the polymeric materials tested. The degree of color degradation varies depending on the type of polymeric material and the duration of exposure to far-UVC radiation. As ongoing research and development continues to refine UVC disinfection robot systems, these technologies are expected to play an increasingly important role in public health and infection control strategies. The collective findings from these studies will guide the deployment and optimization of UVC disinfection robots, leading to safer and healthier environments for people worldwide. The aim of this scientific article is to present a comprehensive evaluation of the reliability and functionality of a specially developed prototype of a public transport disinfection system using 222 nm far-UVC light. The investigation and evaluation focus on the critical aspect of efficient surface disinfection with minimal energy consumption. By analyzing these factors, we aim to provide insight into the system's practicality and its potential to effectively protect public health while ensuring sustainable operation in the face of ongoing infectious disease challenges.