Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

Won, Youngbo; Lakey, Pascale S. J.; Morrison, Glenn; Shiraiwa, Manabu; Rim, Donghyun

doi:10.1111/ina.12700

Cited by 24 publications

(29 citation statements)

References 50 publications

(125 reference statements)

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“…Using ozone again for comparison, measured and modeled values of h range from 2•10 −4 m/s to greater than 5•10 −3 m/s. [287][288][289][290][291][292] In the absence of significant surface resistance to uptake or emissions, greater rates of gaseous contaminant exchange (66)…”

Section: Thermal Gradients Convection and Mass Transportmentioning

confidence: 99%

Temperature and indoor environments

Salthammer

Morrison

2022

Indoor Air

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From the thermodynamic perspective, the term temperature is clearly defined for ideal physical systems: A unique temperature can be assigned to each black body via its radiation spectrum, and the temperature of an ideal gas is given by the velocity distribution of the molecules. While the indoor environment is not an ideal system, fundamental physical and chemical processes, such as diffusion, partitioning equilibria, and chemical reactions, are predictably temperature‐dependent. For example, the logarithm of reaction rate and equilibria constants are proportional to the reciprocal of the absolute temperature. It is therefore possible to have non‐linear, very steep changes in chemical phenomena over a relatively small temperature range. On the contrary, transport processes are more influenced by spatial temperature, momentum, and pressure gradients as well as by the density, porosity, and composition of indoor materials. Consequently, emergent phenomena, such as emission rates or dynamic air concentrations, can be the result of complex temperature‐dependent relationships that require a more empirical approach. Indoor environmental conditions are further influenced by the thermal comfort needs of occupants. Not only do occupants have to create thermal conditions that serve to maintain their core body temperature, which is usually accomplished by wearing appropriate clothing, but also the surroundings must be adapted so that they feel comfortable. This includes the interaction of the living space with the ambient environment, which can vary greatly by region and season. Design of houses, apartments, commercial buildings, and schools is generally utility and comfort driven, requiring an appropriate energy balance, sometimes considering ventilation but rarely including the impact of temperature on indoor contaminant levels. In our article, we start with a review of fundamental thermodynamic variables and discuss their influence on typical indoor processes. Then, we describe the heat balance of people in their thermal environment. An extensive literature study is devoted to the thermal conditions in buildings, the temperature‐dependent release of indoor pollutants from materials and their distribution in the various interior compartments as well as aspects of indoor chemistry. Finally, we assess the need to consider temperature holistically with regard to the changes to be expected as a result of global emergencies such as climate change.

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Section: Thermal Gradients Convection and Mass Transportmentioning

confidence: 99%

Temperature and indoor environments

Salthammer

Morrison

2022

Indoor Air

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“…To address such questions, it may be required to integrate the KM‐FILM model with a large‐scale indoor model such as computational fluid dynamics (CFD) simulations that explicitly resolve indoor air flow. The combination of our kinetic modeling approach with the CFD model has been done in our previous work to investigate ozone reactions with human skin and clothing 59,60 and we intend to apply a similar approach in future studies.…”

Section: Conclusion and Research Needsmentioning

confidence: 99%

Kinetic multi‐layer model of film formation, growth, and chemistry (KM‐FILM): Boundary layer processes, multi‐layer adsorption, bulk diffusion, and heterogeneous reactions

et al. 2021

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Large surface area‐to‐volume ratios indoors cause heterogeneous interactions to be especially important. Semi‐volatile organic compounds can deposit on impermeable indoor surfaces forming thin organic films. We developed a new model to simulate the initial film formation by treating gas‐phase diffusion and turbulence through a surface boundary layer and multi‐layer reversible adsorption on rough surfaces, as well as subsequent film growth by resolving bulk diffusion and chemical reactions in a film. The model was applied with consistent parameters to reproduce twenty‐one sets of film formation measurements due to multi‐layer adsorption of multiple phthalates onto different indoor‐relevant surfaces, showing that the films should initially be patchy with the formation of pyramid‐like structures on the surface. Sensitivity tests showed that highly turbulent conditions can lead to the film growing by more than a factor of two compared to low turbulence conditions. If surface films adopt an ultra‐viscous state with bulk diffusion coefficients of less than 10−18 cm2 s−1, a significant decrease in film growth is expected. The presence of chemical reactions in the film has the potential to increase the rate of film growth by nearly a factor of two.

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“…The mixing conditions of room air may have some effect on the fitted results. Since emissions from the human envelope can be viewed as a "point" source, 80 if the room air is not well mixed, the proposed material balance model may not represent realistic conditions. The rapid changes in occupancy may result in uneven distributions in local SOOP concentrations.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Influence of Mechanical Ventilation Systems and Human Occupancy on Time-Resolved Source Rates of Volatile Skin Oil Ozonolysis Products in a LEED-Certified Office Building

Tasoglou

Huber³

et al. 2021

Environ. Sci. Technol.

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Building mechanical ventilation systems are a major driver of indoor air chemistry as their design and operation influences indoor ozone (O 3 ) concentrations, the dilution and transport of indoor-generated volatile organic compounds (VOCs), and indoor environmental conditions. Real-time VOC and O 3 measurements were integrated with a building sensing platform to evaluate the influence of mechanical ventilation modes and human occupancy on the dynamics of skin oil ozonolysis products (SOOPs) in an office in a LEEDcertified building during the winter. The ventilation system operated under variable recirculation ratios (RRs) from RR = 0 (100% outdoor air) to RR = 1 (100% recirculation air). Time-resolved source rates for 6-methyl-5-hepten-2-one (6-MHO), 4-oxopentanal (4-OPA), and decanal were highly dynamic and changed throughout the day with RR and occupancy. Total SOOP source rates during high-occupancy periods (10:00−18:00) varied from 2500−3000 μg h −1 when RR = 0.1 to 6300−6700 μg h −1 when RR = 1. Source rates for gas-phase reactions, outdoor air, and occupant-associated emissions generally decreased with increasing RR. The recirculation air source rate increased with RR and typically became the dominant source for RR > 0.5. SOOP emissions from surface reservoirs were also a prominent source, contributing 10−50% to total source rates. Elevated per person SOOP emission factors were observed, potentially due to multiple layers of soiled clothing worn during winter.

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Spatial distributions of ozonolysis products from human surfaces in ventilated rooms

Cited by 24 publications

References 50 publications

Temperature and indoor environments

Temperature and indoor environments

Kinetic multi‐layer model of film formation, growth, and chemistry (KM‐FILM): Boundary layer processes, multi‐layer adsorption, bulk diffusion, and heterogeneous reactions

Influence of Mechanical Ventilation Systems and Human Occupancy on Time-Resolved Source Rates of Volatile Skin Oil Ozonolysis Products in a LEED-Certified Office Building

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