Airborne-mediated microbial diseases such as influenza and tuberculosis represent major public health challenges. A direct approach to prevent airborne transmission is inactivation of airborne pathogens, and the airborne antimicrobial potential of UVC ultraviolet light has long been established; however, its widespread use in public settings is limited because conventional UVC light sources are both carcinogenic and cataractogenic. By contrast, we have previously shown that far-UVC light (207–222 nm) efficiently inactivates bacteria without harm to exposed mammalian skin. This is because, due to its strong absorbance in biological materials, far-UVC light cannot penetrate even the outer (non living) layers of human skin or eye; however, because bacteria and viruses are of micrometer or smaller dimensions, far-UVC can penetrate and inactivate them. We show for the first time that far-UVC efficiently inactivates airborne aerosolized viruses, with a very low dose of 2 mJ/cm²of 222-nm light inactivating >95% of aerosolized H1N1 influenza virus. Continuous very low dose-rate far-UVC light in indoor public locations is a promising, safe and inexpensive tool to reduce the spread of airborne-mediated microbial diseases.

Far‐UVC radiation, typically defined as 200–235 nm, has similar or greater anti‐microbial efficacy compared with conventional 254‐nm germicidal radiation. In addition, biophysical considerations of the interaction of far‐UVC with tissue, as well as multiple short‐term safety studies in animal models and humans, suggest that far‐UVC exposure may be safe for skin and eye tissue. Nevertheless, the potential for skin cancer after chronic long‐term exposure to far‐UVC has not been studied. Here, we assessed far‐UVC induced carcinogenic skin changes and other pathological dermal abnormalities in 96 SKH‐1 hairless mice of both sexes that were exposed to average daily dorsal skin doses of 400, 130 or 55 mJ cm⁻² of 222 nm far‐UVC radiation for 66 weeks, 5 days per week, 8 h per day, as well as similarly‐treated unexposed controls. No evidence for increased skin cancer, abnormal skin growths or incidental skin pathology findings was observed in the far‐UVC‐exposed mice. In addition, there were no significant changes in morbidity or mortality. The findings from this study support the long‐term safety of long‐term chronic exposure to far‐UVC radiation, and therefore its potential suitability as a practical anti‐microbial approach to reduce airborne viral and bacterial loads in occupied indoor settings.

Recent research using UV radiation with wavelengths in the 200–235 nm range, often referred to as far-UVC, suggests that the minimal health hazard associated with these wavelengths will allow direct use of far-UVC radiation within occupied indoor spaces to provide continuous disinfection. Earlier experimental studies estimated the susceptibility of airborne human coronavirus OC43 exposed to 222-nm radiation based on fitting an exponential dose–response curve to the data. The current study extends the results to a wider range of doses of 222 nm far-UVC radiation and uses a computational model coupling radiation transport and computational fluid dynamics to improve dosimetry estimates. The new results suggest that the inactivation of human coronavirus OC43 within our exposure system is better described using a bi-exponential dose–response relation, and the estimated susceptibility constant at low doses—the relevant parameter for realistic low dose rate exposures—was 12.4 ± 0.4 cm²/mJ, which described the behavior of 99.7% ± 0.05% of the virus population. This new estimate is more than double the earlier susceptibility constant estimates that were based on a single-exponential dose response. These new results offer further evidence as to the efficacy of far-UVC to inactivate airborne pathogens.

Tinnitus has high prevalence and a wide range of etiologies and of impacts on sufferers. Our objective was to develop understanding of the role of personality in the perception of tinnitus in the general population. As a theoretical basis for this, we combined elements of a general model of signal detection with the ideas of ignition (development) and promotion (neural transmission) of tinnitus, and considered plausible roles for personality factors within this conceptual framework. We interviewed a birth cohort of 970 people aged 32 yr sampled from the general population. On the basis of questioning, we divided them into three groups, those without tinnitus, those with occasional tinnitus (including those with transient tinnitus of very brief duration), and those who experienced tinnitus most of the time. We also established how annoying or distressing the tinnitus was, and assessed personality using the Multidimensional Personality Questionnaire. Tinnitus was experienced rarely by 38.2% and half the time or more by 6.8% of those studied. Men and women did not differ in the amount of tinnitus reported, but women were more likely to find it annoying. People from lower socioeconomic backgrounds were more likely to report tinnitus. People with tinnitus were more socially withdrawn, reactive to stress, alienated, and less Self-Controlled. People who were more annoyed by tinnitus were more socially withdrawn, and men were more stress reactive and alienated. Our interpretation of the findings is that personality influences the persistence of tinnitus by influencing the tendency to be aware of it. Consideration of personality factors may improve the ability to tailor tinnitus therapies, and the concept of awareness may benefit treatment outcomes by showing tinnitus sufferers a means of internalizing the locus of control over their symptoms.

The effectiveness of UVC to reduce airborne‐mediated disease transmission is well established. However, conventional germicidal UVC (~254 nm) cannot be used directly in occupied spaces because of the potential for damage to the skin and eye. A recently studied alternative with the potential to be used directly in occupied spaces is far UVC (200–235 nm, typically 222 nm), as it cannot penetrate to the key living cells in the epidermis. Optimal far‐UVC use is hampered by limited knowledge of the precise wavelength dependence of UVC‐induced DNA damage, and thus we have used a monochromatic UVC exposure system to assess wavelength‐dependent DNA damage in a realistic 3‐D human skin model. We exposed a 3‐D human skin model to mono‐wavelength UVC exposures of 100 mJ/cm², at UVC wavelengths from 215 to 255 nm (5 nm steps). At each wavelength, we measured yields of DNA‐damaged keratinocytes, and their distribution within the layers of the epidermis. No increase in DNA damage was observed in the epidermis at wavelengths from 215 to 235 nm, but at higher wavelengths (240–255 nm) significant levels of DNA damage was observed. These results support use of far‐UVC radiation to safely reduce the risk of airborne disease transmission in occupied locations.

To investigate associations between personality traits in early adulthood (and changes in them) and change in smoking status. Prospective, longitudinal study of a general-population birth cohort. We measured smoking at ages 18, 26, and 32, and personality at ages 18 and 26 using the Multidimensional Personality Questionnaire (Tellegen & Waller, in press). We assessed personality's ability to predict future smoking, and assessed how changes in personality traits relate to change in smoking status. Higher aggression and alienation at age 18 predicted smoking at 26; higher self-control and traditionalism at age 18 predicted nonsmoking at 26; and higher alienation at age 26 predicted persistence of smoking to age 32. Personality change between 18 and 26 was associated with change in smoking behavior; those who stopped smoking decreased more than others in negative emotionality and increased more in constraint. These findings suggest that interventions fostering personality change may be effective in reducing smoking and indicate appropriate targets for such antismoking interventions in young people. In particular, high alienation predicted smoking persistence, perhaps due to resistance to existing antismoking messages; we discuss approaches that may overcome this.