Semi-volatile organic compounds in French dwellings: An estimation of concentrations in the gas phase and particulate phase from settled dust

Abstract

Semi-volatile organic compounds (SVOCs) are present in the gas phase, particulate phase and settled dust in the indoor environment, resulting in human exposure through different pathways. Sometimes, SVOCs are only measured in a single phase because of practical and/or financial constraints. A probabilistic method proposed by Wei et al. for the prediction of the SVOC concentration in the gas phase from the SVOC concentration in the particulate phase was extended to model the equilibrium SVOC concentrations in both the gas and particulate phases from the SVOC concentration measured in settled dust. This approach, based on the theory of SVOC partitioning among the gas phase, particulate phase, and settled dust incorporating Monte Carlo simulation, was validated using measured data from the literature and applied to the prediction of the concentrations of 48 SVOCs in both the gas and particulate phases in 3.6 million French dwellings where at least one child aged 6 months to 6 years lived. The median gas-phase concentration of 15 SVOCs, i.e., 5 phthalates, 2 organochlorine pesticides, 4 polycyclic aromatic hydrocarbons (PAHs), 2 synthetic musks, dichlorvos, and tributyl phosphate, was found to be higher than 1 ng/m 3. The median concentration of 5 phthalates in the particulate phase was higher than 1 ng/m 3. The impacts of some physical parameters, such as the molar mass and boiling point, on the SVOC partitioning among the different phases were quantified. The partitioning depends on the activity coefficient, vapor pressure at the boiling point, entropy of evaporation of the SVOCs, and the fraction of organic matter in particles. Thus, the partitioning may differ from one chemical family to another. The empirical equations based on regressions allow quick estimation of SVOC partitioning among the gas phase, particulate phase, and settled dust from the molar mass and boiling point.

Semivolatile organic compounds in French schools: Partitioning between the gas phase, airborne particles and settled dust

“…It can take between several minutes and days to reach the equilibrium partitioning for SVOCs with a log K oa < 13 and particles with a diameter < 2.5 µm 2 . Despite the possible variations of the partitioning scenario in a specific environment, the probabilistic method based on the equilibrium partitioning assumption can provide reliable estimations of SVOC distributions for field studies covering a large data set of different environments 21,22 . Moreover, the method took into account the influence of indoor air temperature on the value of K p according to the following Equation 28 where K p2 and K p1 are the K p values at temperatures T 2 (K) and T 1 (K), respectively; ΔH (J/mol) is the phase‐change enthalpy; and R (8.314 J/(mol K)) is the gas constant.…”

“…According to the SVOC partitioning theory under the equilibrium partitioning conditions, 2 the SVOC partitioning between dust and indoor air can be described by where C d (ng/g) is the SVOC concentration in the dust and K d (m 3 /g) is the dust/gas partition coefficient. The K p value can be theoretically calculated from the K oa 32 or from the boiling point 21 of the SVOC using the following equations. where f om is the mass fraction of organic matter in the particles; M o (g/mol) and M om (g/mol) are the molecular weight of octanol and the mean molecular weight of the organic matter phase, respectively; γ o and γ om are the activity coefficients of the chemical in octanol and in the organic matter phase, respectively; T b (K) and T (K) are the boiling point of the SVOC and the indoor air temperature, respectively; p b is the SVOC vapor pressure at its boiling point; and β is a constant.…”

“…Based on Equation (7), Wei et al developed the following equation to describe the SVOC partitioning between the gas phase and airborne particles 21 where A 3 and B 3 are regression constants depending on the chemical family.…”

“…Studies have shown that the indoor SVOC partitioning between the gas and particle phases and between the gas phase and settled dust can be predicted assuming that the indoor SVOC concentrations have reached steady state in the different phases 2,20 . This assumption is valid for studies of large data sets from buildings 21,22 . The characterization of SVOCs in the gas phase, airborne particles, and settled dust allows studies of SVOC exposure through different pathways including inhalation, dust ingestion, and dermal exposure 2 .…”

Calcium Chloride (CaCl2) : Characteristics and Molecular Interaction in Solution

“…Kalsium klorida ini juga memiliki beberapa sifat baik itu sifat fisika maupun sifat kimia (222)(223)(224)(225) . Dimana yang termasuk sifat fisika yaitu densitas, massa molar (91)(92)(93)(94)(95)(96)(97)(98)(99)(100) , titik didih, titik lebur, bau, dan viskositas. Sedangkan yang termasuk sifat kimia yaitu kelarutan dalam air.…”