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The presence of airborne viruses in bioaerosols is a significant and ongoing public health concern. In this context, this study aimed to develop a new filter that integrates nanosilver into a TiO 2 -chitosan matrix (nano-Ag/TiO 2 -CS) to inactivate the non-enveloped bacteriophage MS2 as a viral aerosol surrogate. The materials were characterized using various techniques, such as X-ray diffraction (XRD), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM), and X-ray photoelectron spectroscopy (XPS). The SEM images showed that the nano-Ag particles were spheres with a high surface area for virus interactions and that the fiber surfaces were covered by nano-Ag, which enhanced contact with viruses. The optimal 5 wt% nano-Ag/TiO 2 -CS filter combined with a negative air ionizer (NAI) showed the highest viral aerosol removal efficiency, which reached 97 %. The use of an NAI during filtration enhanced the inactivation of the viral aerosols. A long-term antiviral efficacy assessment showed that the nano-Ag/TiO 2 -CS filter demonstrated robust durability, which is vital for real-world applications. The nanofilter proposed in this work is simple, safe, and cost-effective for inactivating viral aerosols to improve indoor air quality. • Simple and eco-friendly processed nano-Ag/TiO 2 -CS filters. • Synergetic effect of NAI on nano-filters for viral aerosol removal. • Remarkable antiviral activity was achieved by 5 wt% nano-Ag/TiO 2 -CS filters. • Inviability of the viral aerosol adsorbed on the nano-filter surface. [ABSTRACT FROM AUTHOR]

Waterborne pathogenic bacteria and viruses are of great concern to environmental and public health. This study focused on the impact of dissolved organic matter (DOM) on photocatalytic inactivation of bacteriophage MS2 by utilizing a visible-light-responded photocatalyst composed of rGO-supported g-C 3 N 4 (7.5%GCN). The results showed that the inactivation rate of MS2 by 7.5%GCN photocatalysis was 3.20 log at λ > 400 nm and 3.27 log at λ > 305 nm within 120 min. The presence of humic acid (HA) in the water matrix led to a decline in the inactivation rate of 2.19 log at λ > 400 nm and 2.08 log at λ > 305 nm, representing a reduction of 31.56% and 36.4%. During an 8 h inactivation process in ultrapure water using 7.5%GCN photocatalysis under λ > 400 nm, steady-state concentrations of 1O 2 , •OH, •O 2 - and H 2 O 2 were measured to be 5.67 × 10-13, 8.56 × 10-7, 1.21 × 10-5 and 7.08 × 10-5 mol/L, respectively; When in presence of HA, the concentrations of ROSs were inhibited except for 1O 2. The order of ROS steady-state concentration was found to be H 2 O 2 > •O 2 -> •OH> 1O 2 during 7.5%GCN photocatalysis, both within and without HA. Transmission electron microscopy (TEM) analysis revealed that the distortion in the morphology of MS2, potentially leading to the disclosure of RNA. Furthermore, protein analysis indicated that the protein structure was damaged, resulting in a decrease of approximately 90% in its concentration. This study may shed light on the impact of DOM during solar light-driven photocatalysis, offering a green, environment-friendly, and sustainable water treatment process. [Display omitted] • The HA can inactivate MS2 in water under light irradiation by generating 3DOM*. • The HA inhibits the 7.5%GCN inactivation rate of MS2 due to its quenching effect. • The H 2 O 2 and •O 2 - mainly contribute to MS2 inactivation in 7.5%GCN with HA system. • The ROSs distorted the morphology of MS2 and damaged the protein structure. [ABSTRACT FROM AUTHOR]

• Contaminated writing utensils are a potential source for transmission of pathogens. • Colonized patients transfer methicillin-resistant Staphylococcus aureus to pens. • A novel ultraviolet light device was effective in reducing microorganisms on pens. • The device could be used to reduce the risk of transmission by shared writing utensils. Shared pens and styluses are a potential source for transmission of health care–associated pathogens and respiratory viruses in health care facilities. A novel ultraviolet light-emitting diode device was effective in reducing bacteria and viruses inoculated on pens and in reducing methicillin-resistant Staphylococcus aureus transferred to pens by colonized patients. The device could be useful in reducing the risk of transmission of pathogens by shared writing utensils. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic has raised awareness in the spread of disease via airborne transmission. As a result, there has been increasing interest in technologies that claim to reduce concentrations of airborne pathogens in indoor environments. The efficacy of many of these emerging technologies is not fully understood, and the testing that has been done is often conducted at a small scale and not representative of applied settings. There is currently no standard test method for evaluating air treatment technologies, making it difficult to compare results across studies or technology types. Here, a consistent testing approach in an operational-scale test chamber with a mock recirculating heating, ventilation, and air conditioning (HVAC) system was used to evaluate the efficacy of bipolar ionization and photocatalytic devices against the non-enveloped bacteriophage MS2 in the air and on surfaces. Statistically significant differences between replicate sets of technology tests and control tests (without technologies active) are apparent after 1 h, ranging to a maximum of 0.88 log 10 reduction for the bipolar ionization tests and 1.8 log 10 reduction for the photocatalytic device tests. It should be noted that ozone concentrations were elevated above background concentrations in the test chamber during the photocatalytic device testing. No significant differences were observed between control and technology tests in terms of the amount of MS2 deposited or inactivated on surfaces during testing. A standardized, large-scale testing approach, with replicate testing and time-matched control conditions, is necessary for contextualizing laboratory efficacy results, translating them to real-world conditions, and for facilitating technology comparisons. • Large-scale testing useful for evaluating technology efficacy against bioaerosols. • Time-matched control tests (no technology active) critical for assessing efficacy. • Replicate experiments at each condition essential for characterizing efficacy. • Devices can demonstrate marginal benefit that generally increases with time. • Elevated ozone concentrations observed in photocatalytic device experiments. [ABSTRACT FROM AUTHOR]