Atmospheric Fate of a New Polyfluoroalkyl Building Block, C3F7OCHFCF2SCH2CH2OH.

Many per- and polyfluoroalkyl substances (PFAS) have been regulated or phased-out of usage due to concerns about persistence, bioaccumulation potential, and toxicity. We investigated the atmospheric fate of a new polyfluorinated alcohol 2-(1,1,2-trifluoro-2-heptafluoropropyloxy-ethylsulfanyl)-ethanol (C3F7OCHFCF2SCH2CH2OH, abbreviated FESOH) by assessing the kinetics and products of the gas-phase reaction of FESOH with chlorine atoms and hydroxyl radicals. Experiments performed in a stainless-steel chamber interfaced to an FTIR were used to determine reaction kinetics and gas-phase products. We report reaction rate constants of k(Cl + FESOH) = (1.5 ± 0.6) × 10-11 cm3 molecule-1 s-1 and k(OH + FESOH) = (4.2 ± 2.0) × 10-12 cm3 molecule-1 s-1. This leads to a calculated FESOH gas-phase lifetime of 2.8 ± 1.3 days with respect to reaction with OH, assuming [OH] = 106 molecule1 cm-3. Gas-phase products of FESOH oxidation included at least two aldehydes, likely C3F7OCHFCF2SCH2C(O)H and C3F7OCHFCF2SC(O)H, and secondary products including COF2, SO2 and C3F7OC(O)F. Additional gas-phase experiments performed in a Teflon chamber were used to assess aqueous products by collecting gaseous samples offline into an aqueous sink prior to analysis with ultrahigh performance liquid chromatography-tandem mass spectrometry, resulting in four acidic products: C3F7OCHFCF2SCH2C(O)OH, C3F7OCHFCF2S(O)(O)OH, C3F7OCHFC(O)OH, and perfluoropropanoic acid (C2F5C(O)OH).

Formation and emission of hydrogen chloride in indoor air.

To improve our understanding of chlorine chemistry indoors, reactive chlorine species such as hydrogen chloride (HCl) must be analyzed using fast time-response measurement techniques. Although well studied outdoors, sources of HCl indoors are unknown. In this study, mixing ratios of gaseous HCl were measured at 0.5 Hz in the indoor environment using a cavity ring-down spectroscopy (CRDS) instrument. The CRDS measurement rate provides a major advance in observational capability compared to other established techniques. Measurements of HCl were performed during three types of household activities: (a) floor exposure to bleach, (b) chlorinated and nonchlorinated detergent use in household dishwashers, and (c) cooking events. Surface application of bleach resulted in a reproducible increase of 0.1 ppbv in the affected room. Emissions of HCl from automated dishwashers were observed only when chlorinated detergents were used, with additional HCl emitted during the drying cycle. Increased mixing ratios of HCl were also observed during meal preparation on an electric element stovetop. These observations of HCl derived from household activities indicate either direct emission or secondary production of HCl via chlorine atoms is possible. Calculations of photolysis rate constants of chlorine atom precursors provide evidence that photolysis may contribute to indoor HCl levels.