Factors Affecting\nChlorinated Product Formation from\nSodium Hypochlorite Bleach and Limonene Reactions in the Gas Phase

During use of sodium hypochlorite bleach, gas-phase hypochlorous\nacid (HOCl) and chlorine (Cl<sub>2</sub>) are released, which can\nreact with organic compounds present in indoor air. Reactivity between\nHOCl/Cl<sub>2</sub> and limonene, a common constituent of indoor air,\nhas been observed. The purpose of this study was to characterize the\nchemical species generated from gas-phase reactions between HOCl/Cl<sub>2</sub> and limonene. Gas-phase reactions were prepared in Teflon\nchambers housing HOCl, Cl<sub>2</sub>, and limonene. The resulting\nchemical products were analyzed using gas-phase preconcentration,\nfollowed by gas chromatography and high-resolution mass spectrometry.\nSeveral chlorinated products were detected, including limonene species\ncontaining one, two, and three chlorines and limonene chlorohydrin.\nProduct concentrations and yields were estimated for the most abundant\nproducts, and greater than 80% of transformed limonene was represented\nin the detected products. Temporal sampling of the reactions allowed\ntime courses to be plotted for limonene decay and chlorinated limonene\nproduct generation under different conditions, including the treatments\nof HOCl/Cl<sub>2</sub>, Cl<sub>2</sub> only, high vs low relative\nhumidity, and ± ozone. These experiments add product speciation,\nyield estimates, and an understanding of environmental factors affecting\nproduct formation to previous studies, further highlighting the chemical\ntransformations initiated by sodium hypochlorite bleach in indoor\nair.