# Development of Far-UVC-Based Surface Disinfection Prototype for Public Buses
## 4 Discussion  
The prototype of the disinfection system based on 222 nm wavelength far-UVC light proposed in this study offers significant contributions to the field of public transport disinfection. By addressing multiple aspects, the system provides a comprehensive approach to enhance the effectiveness and efficiency of disinfection processes while ensuring passenger safety. This paper has emphasized the importance of disinfection effectiveness by investigating the optimal far-UVC light angle and has reported a bus seat irradiation study. These efforts ensure that the disinfection system achieves the desired radiant exposure of 2 m/cm\({}^{2}\), which is crucial for effectively eliminating pathogens including the SARS-CoV-2 virus. This knowledge enables the development of disinfection protocols that maximize the system's efficiency in reducing microbial contamination on various surfaces within public buses.  
Figure 16: Electrical power consumption according for disinfection scenario 3 using two far-UVC lamps (**a**) and four far-UVC lamps (**b**).  
Figure 15: Electrical power consumption according for disinfection scenario 2 using two far-UVC lamps (**a**) and four far-UVC lamps (**b**).  
From the previous studies, it is known that the long-term use of far-UVC radiation at a distinct wavelength of 222 nm for disinfection purposes can considerably impair the mechanical and visual characteristics of the surfaces intended for disinfection [27]. Energy efficiency is another key consideration in the design of a disinfection system. The proposed energy efficiency assessment model enables the simulation and optimization of electrical energy demand during the disinfection process. By accurately forecasting energy consumption, public transport authorities and operators can implement energy-saving measures and ensure the sustainable operation of a disinfection system. This will not only reduce operational costs but also contribute to environmental conservation and the overall sustainability of public transport services. Therefore, minimum disinfection durations were chosen to ensure minimum disinfection doses and energy consumption during the development of the prototype.  
The analysis of different disinfection scenarios, including factors such as bus zone, disinfection time, and energy demand, provides valuable insights for practical implementation. By identifying the optimal placement of far-UVC light sources, such as in the fixed vertical position specified in the study, the disinfection system can fulfil the most efficient disinfection time and energy requirements. These findings facilitate the effective deployment of the system in real-world settings, maximizing its impact on reducing the spread of pathogens within public transport environments.  
It is also important to mention that a light source with reflectors ensures that UVC radiation does not affect a person, and scenarios are analyzed when there are empty disinfected seats or the bus is empty at the end stops. When considering other scenarios that would include disinfection with people, it is necessary to evaluate the overall expected exposure limits of far-UVC in the context of legal regulations. Additionally, it should be noted that according to the manufacturer's specifications, the far-UVC lamps used in the prototype emit a minimum amount of ozone. The accumulation of ozone in an enclosed space can have adverse effects on air quality and potentially pose health risks to passengers and drivers. Therefore, additional studies are needed in the future that would allow to assess whether this ozone concentration is not excessive according to regional standards.