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. 2022 Jan 29;19(3):1559.
doi: 10.3390/ijerph19031559.

Airborne Microorganism Inactivation by a UV-C LED and Ionizer-Based Continuous Sanitation Air (CSA) System in Train Environments

Giulia Baldelli  1 , Mattia Paolo Aliano  2 , Giulia Amagliani  1 , Mauro Magnani  1 , Giorgio Brandi  1 , Carmelo Pennino  3 , Giuditta Fiorella Schiavano  4
Affiliations

Airborne Microorganism Inactivation by a UV-C LED and Ionizer-Based Continuous Sanitation Air (CSA) System in Train Environments

Giulia Baldelli et al. Int J Environ Res Public Health. .

Abstract

Improving indoor air quality present in environments where people live is important to protect human health. This particularly applies to public transportation, where air quality may affect the health and safety of passengers, workers and staff. To provide better air quality, many buildings and transports are provided with heating, ventilation and air conditioning (HVAC) systems, which are always equipped with filters to retain the particulate present in the airflow, but they lack continuous air sanitization systems. In this study, a new UV-C LED and ionizer-based continuous sanitation air (CSA) system to be installed in a train HVAC was developed (international patent: N.PCT/IB2021/054194) and its sanitation efficacy against various microbial species (bacteria and fungi) was assessed. The device proved to be very effective at the microbial killing of aerodispersed microorganisms, both in its experimental configuration (ISO 15714:2019) and in a train setting. The installation of this CSA system on public transportation appears to be a promising solution to guarantee high microbiological air quality with a very low environmental impact due to its eco-friendly components.

Keywords: SARS-CoV-2; UV-C LED; air sanitation; heating, ventilation and air conditioning (HVAC); public transportation.

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Conflict of interest statement

MPA is an employee of and holds shares in the start-up STE-Sanitizing Technologies and Equipments Srl. The company develops air sanitation systems with innovative and eco-sustainable technologies. All the other authors do not have any conflict of interest.

Figures

Figure 1
Figure 1
Front view (A) and sub-ducts posterior view (B) of CSA system.
Figure 2
Figure 2
(A) LED UV-C ray reflections; (B) simulation of LED UV-C ray reflections inside sub-ducts. The color scale is representative of the radio frequency exposure power (mW/cm2) and to the refraction.
Figure 3
Figure 3
Test rig configuration. ① Air-intake/air inlet/inflow/entrance; ② variable flow rate blower; ③ HEPA filter; ④ upstream duct; ⑤ UVGI device mounting duct; ⑥ downstream duct; ⑦ off-gas pipe; ⑧ nebulizer; ⑨ upstream microorganism sampling port; ⑩ CSA system; ⑪ downstream microorganism sampling port.
Figure 4
Figure 4
Experimental setting in the Vivalto train. Sampling sites: proximal (A), central (B) and distal (C) air vent panels of the upper central section of the train car (red arrows); the proximal (D), central (E) and distal (F) air vent panels of the lower central section of the train car (green arrows); the proximal (G) and distal (H) air vent panels in the terminal section of the train car (blue arrows). Point of determination of E. coli starting concentration after nebulization (yellow).
Figure 5
Figure 5
Contribution of each CSA system component to air sanitation efficiency in the test rig configuration.
See this image and copyright information in PMC

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