Evaluating the Gaseous Chlorine-containing Byproducts from the Use of an HOCl-derived Disinfectant

Abstract

This study investigates the gas-phase chlorine-containing byproducts generated from HOCl solutions under controlled conditions using Time-of-Flight Chemical Ionization Mass Spectrometry (TOF-CIMS). We analyzed how delivery flow rate, ambient humidity, and nebulization time influence the speciation and concentration of volatile Cl₂, HOCl, and NCl₃ within a sealed Teflon environment using relatively clean, compressed house air as the medium. Our results show that increasing the delivery flow rate enhances the detection of volatile HOCl while suppressing Cl₂ levels, suggesting that in the absence of strong delivery flow, Cl₂ dominates the headspace composition. Humidification of the carrier air substantially increased Cl₂ formation while accelerating the decomposition of HOCl. The use of clean house air led to minimal NCl₃ levels under the majority of conditions. These findings demonstrate the capability of TOF-CIMS to identify and quantify gaseous chlorinated byproducts with high time resolution and highlight the potential hazards of using HOCl-based disinfectants in poorly ventilated environments. Future experiments will focus on localized HOCl application to authentic laboratory / office furniture near the IMR inlet and refined stepwise dosing protocols to support calibration curve development and health risk estimation.