Oxygenated VOCs, aqueous chemistry, and potential impacts on residential indoor air composition

Abstract

Dampness affects a substantial percentage of homes and is associated with increased risk of respiratory ailments; yet, the effects of dampness on indoor chemistry are largely unknown. We hypothesize that the presence of water-soluble gases and their aqueous processing alters the chemical composition of indoor air and thereby affects inhalation and dermal exposures in damp homes. Herein, we use the existing literature and new measurements to examine the plausibility of this hypothesis, summarize existing evidence, and identify key knowledge gaps. While measurements of indoor volatile organic compounds (VOCs) are abundant, measurements of water-soluble organic gases (WSOGs) are not. We found that concentrations of total WSOGs were, on average, 15 times higher inside homes than immediately outside (N = 13). We provide insights into WSOG compounds likely to be present indoors using peer-reviewed literature and insights from atmospheric chemistry. Finally, we discuss types of aqueous chemistry that may occur on indoor surfaces and speculate how this chemistry could affect indoor exposures. Liquid water quantities, identities of water-soluble compounds, the dominant chemistry, and fate of aqueous products are poorly understood. These limitations hamper our ability to determine the effects of aqueous indoor chemistry on dermal and inhalation exposures in damp homes. K E Y W O R D Saqueous chemistry, damp homes, human exposure, interfacial chemistry, OVOC, water-soluble organic compounds | INTRODUCTIONDampness in buildings is common in the United States, with estimates ranging from 18% to 50% percent of buildings affected, where buildings were defined as "damp" based on observation of standing water, water-damaged materials, presence of mold, and/ or high measured relative humidity (RH). WSOGs are emitted from indoor sources and formed through oxidation. They will be taken up into liquid water, when present, and subsequently react. Thus, aqueous chemistry could affect exposure by acting as a sink for certain water-soluble gases in indoor air and a source of other volatile products (altering inhalation exposure) and condensed phase products (altering particle inhalation and dermal exposure).This study provides insights into WSOGs likely to be in residential indoor air and examines the potential for aqueous chemistry indoors to alter the chemical composition of this air, with the motivation of further understanding dermal and inhalation exposure

Modeling the formation and growth of organic films on indoor surfaces

“…[1][2][3][4] These manufactured compounds exist alongside a wide range of naturally occurring and chemically formed SVOCs 2,5 and water-soluble gases 6 as a result of cooking, the use and chemical transformation of consumer products, microbial processes, 7 and volatilization of particulate matter. [1][2][3][4] These manufactured compounds exist alongside a wide range of naturally occurring and chemically formed SVOCs 2,5 and water-soluble gases 6 as a result of cooking, the use and chemical transformation of consumer products, microbial processes, 7 and volatilization of particulate matter.…”

“…Semi-volatile organic compounds (SVOCs), with vapor pressures sufficiently low to partition between gas-and condensed-phases under typical ambient conditions, are present in thousands of materials and products found indoors. [1][2][3][4] These manufactured compounds exist alongside a wide range of naturally occurring and chemically formed SVOCs 2,5 and water-soluble gases 6 as a result of cooking, the use and chemical transformation of consumer products, microbial processes, 7 and volatilization of particulate matter. 8 SVOCs, defined here as having vapor pressures in the range of 10 −9 to 10 1 Pa following Weschler and Nazaroff, 2 can migrate out of and back into manufactured materials.…”

The atmospheric chemistry of indoor environments

“…Condensed-phase water molecules are present in surface reservoirs in a variety of forms, 113 with measurements of roughly 10 À6 g cm À2 present on surfaces in a house. 114 It is well known that water sorbs to the interfaces of typical indoor materials, such as metal oxides (e.g.…”

Characterizing sources and emissions of volatile organic compounds in a northern California residence using space‐ and time‐resolved measurements

“…More than half of the air breathed is residential indoor air. One major concern regarding residential indoor air quality is elevated concentrations of volatile organic compounds (VOCs) . Indoor VOCs encompass a broad range of chemical species, including saturated and unsaturated hydrocarbons, carbonyls, alcohols, organic acids, ethers, esters, furanoids, amines, siloxanes, sulfides, etc .…”