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The application of 222 nm light from KrCl excimer lamps (GUV222 or far-UVC) is a promising approach to reduce the indoor transmission of airborne pathogens, including the SARS-CoV-2 virus. GUV222 inactivates airborne pathogens and is believed to be relatively safe for human skin and eye exposure. However, UV light initiates photochemical reactions which may negatively impact indoor air quality. We conducted a series of experiments to assess the formation of ozone ( ${\text{O}}_3$), and resulting formation of secondary organic aerosols (SOA), induced by commercial far-UVC devices in an office environment (small conference room) with an air exchange rate of $1.3{\text{h}}^{-1}$. We studied scenarios with a single far-UVC lamp, corresponding to the manufacturer’s recommendations for disinfection of a space that size, and with four far-UVC lamps, to test conditions of greater far-UVC fluence. The single lamp did not significantly impact ${\text{O}}_3$or fine particulate matter levels in the room. Consistent with previous studies in the literature, the higher far-UVC fluences lead to increases in ${\text{O}}_3$of 5 to 10 ppb above background, and minor increases in particulate matter (16% ± 10 % increase in particle number count). The use of far-UVC at minimum intensities required for disinfection, and in conjunction with adequate ventilation rates (e.g. ANSI/ASHRAE recommendations), may allow the reduction of airborne pathogen levels while minimizing the formation of air pollutants in furnished indoor environments. 

Electrolyte ions have a profound impact on the reaction environment of electrochemical systems and can be key drivers in determining the reaction rate and selectivity of electro-organic reactions. We combine experimental and computational approaches to understand the individual effect of the size and concentration of supporting alkali cations, as well as their synergies with other electrolyte ions on the electrosynthesis of adiponitrile (ADN). The size of supporting alkali cations influences the surface charge density, availability of water molecules, and stability of reaction intermediates. Larger alkali cations can help limit hydrogen evolution and the early protonation of intermediates by lowering the availability of water molecules in the near electrode region. A selectivity of 93% towards ADN was achieved at −20 mA cm⁻²in electrolytes containing cesium phosphate salts, ethylenediaminetetraacetic acid, and tetraalkylammonium ions (TAA ions). Electrolytes containing only supporting phosphate salts promote the early hydrogenation of intermediate species leading to low ADN selectivities (i.e., <10%). However, the combined effect of alkali cations and selectivity-directing ions (i.e., TAA ions) is essential in the enhancement of ADN synthesis. The insights gained in this study provide guidelines for the design of aqueous electrolytes that improve selectivity and limit hydrogen evolution in organic electrosynthesis.