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The purpose of this study was to investigate the clinical efficacy of lateral circumflex femoral artery embedded with fascia lata flap in the repair of skin and tendon defects in hand, foot, and ankle. From January 2020 to June 2021, 32 patients with skin and tendon defects of the hand, foot, and ankle admitted to our hospital were selected as the study subjects. According to the random number table method, they were divided into the observation group (16 cases, treated with rotational lateral femoral vascular inlay broad fascial flap repair) and the control group (16 cases, treated with conventional skin flap repair) and followed up for 6 months. The postoperative tendon midactivity measurement scale (TAM), ankle-hindfoot scoring system (AOFAS), and lower limb functional evaluation scale (LEFS) scores were all higher in the observer group than in the control group The number of people with infection, implant necrosis, and subcutaneous hematoma in the observation group (total incidence 6.25%) was less (lower) than that in the control group (50.00%), and the total number of people with significant and fair clinical efficacy in the observation group (total effective rate 100.00%) was more (higher) than that in the control group (68.75%). The application of early plastic surgery to the clinical treatment of patients with deep burns on the hand can reduce the patient's pain and promote the healing of the wound. It is of great significance to reduce the risk of complications such as necrosis of the skin graft and improve the efficacy of the surgery.

The COVID-19 pandemic has caused millions of deaths and great economic loss globally. There has been substantial evidence supporting the airborne transmission of SARS-CoV-2. Airborne route has been...

Exposure to bioaerosols poses important health effects on occupants. To elucidate seasonal and room variations of household airborne bacteria, this study investigated 30 residential homes during summer and winter throughout Nanjing, Southeast China, with a humid subtropical climate. Culturing and 16S rDNA sequencing methods were combined in this study. Results showed that the community structure and composition in the same season but different homes show similarity, however, they in the same home but in different seasons show a huge difference, with Sphingomonas (25.3%), Clostridium (14.8%), and Pseudomonas (7.6%) being the dominant bacteria in summer, and Pseudomonas (57.1%) was dominant bacteria in winter. Culturable concentrations of bacteria were also significantly higher in summer (854 ± 425 CFU/m3 ) than in winter (231 ± 175 CFU/m3 ), but difference by home or room was relatively minor. More than 80% of culturable bacteria (

Activities such as household cleaning can greatly alter the composition of air in indoor environments. We continuously monitored hydrogen peroxide (H2O2) from household non-bleach surface cleaning in a chamber designed to simulate a residential room. Mixing ratios of up to 610 ppbv gaseous H2O2 were observed following cleaning, orders of magnitude higher than background levels (sub-ppbv). Gaseous H2O2 levels decreased rapidly and irreversibly, with removal rate constants (kH2O2) 17-73 times larger than air change rate (ACR). Increasing the surface-area-to-volume ratio within the room caused peak H2O2 mixing ratios to decrease and kH2O2 to increase, suggesting that surface uptake dominated H2O2 loss. Volatile organic compound (VOC) levels increased rapidly after cleaning and then decreased with removal rate constants 1.2-7.2 times larger than ACR, indicating loss due to surface partitioning and/or chemical reactions. We predicted photochemical radical production rates and steady-state concentrations in the simulated room using a detailed chemical model for indoor air (the INDCM). Model results suggest that, following cleaning, H2O2 photolysis increased OH concentrations by 10-40% to 9.7 × 105 molec cm-3 and hydroperoxy radical (HO2) concentrations by 50-70% to 2.3 × 107 molec cm-3 depending on the cleaning method and lighting conditions.

A modular-based Green Design Studio (GDS) platform has been developed in this study for fast and accurate performance analysis for early stage green building design. The GDS platform aims to simplify the design and analysis process by embedding performance parameters into design elements in modules and employing near-real-time model for whole building performance simulation as well as by providing an easy-to-use and intuitive user interface to assist users without extensive knowledge on building physics. The platform consists of building modules as fundamental building blocks, performance predicting models, and a user interface for visualization and interactive design. In the platform, a whole building is composed of modules organized in a hierarchical structure, including spaces, enclosures, service systems, sustainable resource systems and sites. Both physics-based and data-driven models can be used to simulate the building performance and optimize building systems. A simplified physics-based model, the Resistance–Capacitance (RC) model, has been proposed as a generic simulation model for the flows of heat, air, moisture and pollutants, which is significantly faster than conventional simulation tools such as EnergyPlus, and hence more practical for use in real-time design interaction and optimization. A pilot case study is conducted to illustrate the modular-based design approach using a section of an office building. Compared to conventional building performance analysis tools, the GDS platform can provide fast and reliable feedback on performance prediction for early design. The modular approach makes it easier to modify the building design and evaluate the potentials and contributions of various green design features and technologies.

Public attention has been drawn to the commercial restaurant cooking emission since it can cause health and hygiene risks, reduction of the efficiency of the ventilation system, and even fire accid...

In order to evaluate the impacts of volatile organic compounds (VOCs) emissions from building materials on the indoor air quality beyond the standard chamber test conditions and test period, mechanistic emission source models have been developed in the past. However, very limited data are available for the required model parameters including the initial concentration (Cm0), in-material diffusion coefficient (Dm), partition coefficient (Kma), and convective mass transfer coefficient (km). In this study, a procedure was developed for estimating the model parameters by using VOC emission data from standard small chamber tests. In the procedure, initial values of the model parameters were refined by multivariate regression analysis of the measured emission data. To verify the procedure and estimate its uncertainty, simulated chamber test data were generated by adding 10% experimental uncertainties on the theoretical curve from the analytical solution to a mechanistic emission model. Then the procedure was applied to the generated data to estimate the model parameters. Results indicated that estimates converged to the original parameter values used for the data generation and the error of estimated parameters Dm, Cm0 and Kma were within ±10%, ±23%, and ±25% of the true values, respectively. The procedure was further demonstrated by applying it to estimate the model parameters from real chamber test data. Wide application of the procedure would result in a database of mechanistic source model parameters for assessing the impact of VOC emissions on indoor pollution load, which are essential input data for evaluating the effectiveness of various indoor air quality (IAQ) design and control strategies as well as the energy required for meeting given IAQ requirements.

The effects of moisture content, temperature and pollutant mixture on atmospheric corrosion of copper and silver were investigated by exposing test specimens to different environmental conditions, ...

Micro-environment control system has been proved to be able to provide local thermal comfort control. It also has the potential to save building energy by relaxing the control on the unoccupied space. This work aims at designing an efficient heating delivering device (HDD) to locally warm the person to restore thermal comfort when the unoccupied space temperature is reduced from 70.0 °F to 66.0 °F to save the energy. A three-stage approach was developed for designing the HDD including the initial stage of developing by CFD simulation, the second stage of manikin test verification and final stage of human subject test confirmation. The results of the first two stages were presented and discussed in this work. It was shown that convective heating was not efficient enough unless a confinement box was used to hold the hot air around the legs and feet. A more ergonomically friendly design of using a foot warmer was finally proved to be a better solution for individually heating by both simulation and experiments since it can heat the occupant sufficiently. The ability of using CFD to predict heat loss from the clothed human body and its limitation was also investigated. It was found that with proper clothing insulation, the CFD can give a reasonable prediction, although simulating the clothing as a layer of certain thermal resistance might be problematic regarding the structure and permeability of the clothing material. A more appropriate method for simulating the clothing was needed for better prediction in the future.

Chemical contamination is ubiquitous in the indoor environment, but measurement options are often limited outside of research studies. This is especially true for formaldehyde, a known carcinogen and irritant. The goal of this project was to develop a novel screening tool: a smartphone-based app that can be paired with low-cost colorimetric badges for detection of indoor formaldehyde. The target users include citizen scientists, concerned citizens, public health nurses visiting homes, and researchers with relevant measurement needs. The user interface was designed using a collaborative development model. Badges were exposed to air for 72 h, and the user takes images that are analyzed in the phone. The app itself measures illumination (lightness) to determine color change, which was associated with formaldehyde concentration (R2 = 0.8811, P 80%) relative humidity. Co-exposure to acetaldehyde or a VOC mixture did not interfere with measurement (P = 0.93, P = 0.07, respectively). Overall, this screening tool can provide inexpensive, accessible information to users about their formaldehyde exposure, which can inform further testing and potential remediation activities.

Many people spend most of their time in an indoor environment. There is a positive relationship between indoor environmental quality and the health, wellbeing, and productivity of occupants in buildings. The indoor environment is affected by pollutants, such as gases and particles. Pollutants can be removed from the indoor environment in various ways. Air cleaning devices are commonly marketed as benefitting the removal of air pollutants and consequently, improving indoor air quality. Depending on the type of cleaning technology, air cleaners may generate undesired and toxic by-products. Different air filtration technologies such as electrostatic precipitators have been introduced to the market. The electrostatic precipitator (ESP) has been used in buildings because it can remove particles while only causes low pressure drops. Electrostatic precipitators can be either in-duct or standalone units. This review aims to give an overview of ESP use, methods for testing this product, the performance of existing ESPs in removing pollutants, their by-products, and the existing market for ESPs.

The IEA EBC Annex 68 project on “Indoor Air Quality Design and Control in Low Energy Residential Buildings” has been recently completed. The project considered indoor air pollution loads in dwellings, particularly how such pollutants are emitted in dependency of the hygrothermal conditions: temperature, moisture and air flows. Thus, a proper understanding of the mutual interactions between hygrothermal conditions and pollutants was needed to obtain optimal paradigms for demand-controlled ventilation. The project adopted a similarity approach for modelling the transports of moisture and volatile organic compounds (VOCs) in materials, and thereby it was possible to provide a comprehensive set of data and tools whereby the indoor atmospheric conditions of buildings can be optimized, e.g. with respect to the need for ventilation. The paper explains the experimental and modelling approach and presents a summary of the results.

Respiratory diseases such as COVID-19 can be spread through airborne transmission, which is highly dependent on the airflow pattern of the studied room. Indoor air is typically not perfectly mixed even using a mixing ventilation, especially in large spaces. Airflow patterns in large open spaces such as hotel banquet rooms and open plan offices, are of particular concern, as these spaces usually accommodate more occupants and thus have the potential to spread diseases more rapidly leading to outbreaks. Therefore, understanding airflow patterns in large open spaces can help to estimate the detailed infection risk at certain locations in the space, which can prevent the spread of virus and track the potential new infections. This study estimated airflow patterns in a typical banquet room under theatre and banquet scenarios, and a large open plan office using computational fluid dynamics (CFD) simulations. Typical ventilation and air distribution approaches, as well as room layouts and occupant configurations in these scenarios were studied and applied in simulations. According to current results, the air distribution in a typical hotel banquet room with mixing ventilation can be very complicated, particularly for the banquet scenario. For a typical theatre scenario, under typical ventilation design, people sitting in the middle and lateral area were exposed to the highest infection risk. The front rows may be exposed to short-range transmission as well. For a banquet scenario, people sitting on the same table were more likely to be cross contaminated. But cross-table infection was still possible. The results can provide guidance on designing ventilation and air distribution approaches in large spaces with similar settings.

As more megacities emerge owing to urbanization and industrialization, the subway has become the main public transportation mode worldwide, providing punctuality and convenience. The subway environment, including its ventilation, thermal comfort, air quality, and energy consumption, remains an area of great focus for scientists and passengers. In addition to theoretical and experimental methods, computational fluid dynamics (CFD) has been used in past decades to predict 3D airflows, temperatures, and pollutant dispersion in subway tunnels, stations, and cabins. In this review, recent applications of CFD involving three scenarios—subway tunnels, stations, and passenger cabins—and two objective parameters—particulate matter, and energy savings till 2021—are systematically presented. The boundary conditions, validation methods, turbulence models, and mesh information are summarized. Finally, the possibilities regarding novel models, open-source CFD codes, and best practice guidelines are discussed with the aim to predict future perspectives on the subway environment.

Occupant behavior is identified as one of the key factors influencing the energy use and indoor environmental quality of the building. Occupancy-centric control is famous for its potential to save building energy without sacrificing occupants’ comfort. This study utilized two identical lab spaces, configured as typical open-plan offices, to investigate the performance of the occupancy-centric control in terms of energy-saving, indoor air quality, and thermal comfort. The results have demonstrated that occupancy-centric control could save around 28% total energy, including fan, cooling, and heating energy, with minimal impact on the air quality and thermal comfort.

The unprecedented coronavirus disease 2019 (COVID-19) pandemic caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has made more than 125 million people infected and more than 2.7 million people dead globally. Airborne transmission has been recognized as one of the major transmission routes for SARS-CoV-2. This paper presents a systematic approach for evaluating the effectiveness of multi-scale IAQ control strategies in mitigating the infection risk in different scenarios. The IAQ control strategies across multiple scales from a whole building to rooms, and to cubical and personal microenvironments and breathing zone, are introduced, including elevated outdoor airflow rates, high-efficiency filters, advanced air distribution strategies, standalone air cleaning technologies, personal ventilation and face masks. The effectiveness of these strategies for reducing the risk of COVID-19 infection are evaluated for specific indoor spaces, including long-term care facility, school and college, meat plant, retail stores, hospital, office, correctional facility, hotel, restaurant, casino and transportation spaces like airplane, cruise ship, subway, bus and taxi, where airborne transmission are more likely to occur due to high occupancy densities. The baseline cases of these spaces are established according to the existing standards, guidelines or practices. Several integrated mitigation strategies are recommended and classified based on their relative cost and effort of implementation for each indoor space. They can be applied to help meet the current challenge of ongoing COVID-19, and provide better preparation for other possible epidemics and pandemics of airborne infectious diseases in the future., Graphical abstract Image 1

This work quantitatively investigated the concentration relationships between indoor and outdoor bioaerosols in residence. We measured bacteria and fungi from air in 28 residential homes throughout Nanjing, southeast China during summer and winter. The culture-based method was applied and the ratios of indoor to outdoor concentrations, expressed in I/O, were calculated. Results revealed that concentrations of indoor bioaerosols were significantly associated with outdoor bioaerosols, and their size distributions showed similar single-peak pattern. Spearman correlation analysis indicated that I/O ratios were positively related to indoor microbial concentration. The I/O ratios differed insignificantly from seasons, but significantly higher I/O ratios were observed in airborne bacteria rather than airborne fungi during the same season. For bacteria, as much as 89% of homes in summer and 67% of homes in winter have I/O ratios >1, while for fungi, more than half of homes have I/O ratios 1 was observed in smaller size of bacteria and greater percentage of I/O

Micro-environment is hereby defined as the air space and environment around a person that directly impacts his/her thermal sensation. Most existing HVAC systems condition the air of the entire room including the unoccupied space, which leaves a big potential to save energy. This study aims at evaluating the performance of three existing air terminal devices (ATDs) to locally remove enough heat from the micro-environment to manage the thermal balance so as not to sacrifice thermal comfort when the ambient unoccupied space temperature is increased by 2.2 °C from 23.9 °C to 26.1 °C in the summer to reduce the external cooling load. A computational fluid dynamics (CFD) model was developed, validated by full-scale chamber tests and applied to evaluate different configurations of the ATDs for local cooling. Results show that the predicted performance agreed well with the measurements, and the selected ATD, with only 50 W cooling power, was always able to remove a sufficient amount of heat from the micro-environment in a room of raised temperature, when the manikin was moved inside a semicircle movement range. The cooling performance of the jet was increased more by increasing the supply air flow rate than reducing the supply temperature and was highly dependent on the shooting angle. The heat flux from the manikin surface is very sensitive to the surface temperature and furniture placement, and proper specification of the surface temperature is crucial for the CFD simulation to match the measured results.

Micro-cogeneration or micro-combined heat and power, which can meet both the electrical and thermal needs of the residential sector, is growing and can offer reduced energy usage and emission. Micr...

Several studies have analyzed the heat flow impact of green roofs in hot weather, but few studies have examined the thermal performance during cold climate conditions. This study presents an experimental and numerical investigation of a large extensive green roof on the Onondaga County Convention Center in Syracuse, NY in both summer and winter conditions. Measured temperatures across the multilayers of the roofing system reveal the spatial and temporal variation of thermal conditions in the roofing system and the impact of the green roof. The CHAMPS-BES model (coupled heat, air, moisture and pollutant simulations for building envelope systems) has been applied to simulate the temperature profile through the layers of the green roof in which a new approach is developed to account for the evapotranspiration in the vegetation. In late fall without snow, the temperatures of the growth medium and roof membrane follow the diurnal cycle of ambient air temperatures but with smaller amplitude. Under extremely cold weather in winter with snow on the roof, the snow acts as an insulator, and heat flux is dominated by the temperature gradient between interior space and the snow layer. During the summer, the green roof significantly reduces the daily peak temperature of the membrane. In addition, the green roof moderates the heat flow through the roofing system and reduces the amount of air conditioning needed. This work also shows that the CHAMPS-BES model can be used to inform green roof design decisions.

The aim of this article is to present a validated model to study the influence of humidity on formaldehyde sorption of building material and the effect of formaldehyde and moisture buffering capacity of hygroscopic porous material on indoor air environment. New empirical formulas proposed to describe the diffusion and partition coefficients as functions of humidity based on previous experimental data are incorporated in a coupled moisture and pollutants transport simulation model. The numerical model that takes into account the effect of RH (or moisture) in building materials on VOC diffusion can be used to simulate VOC emissions/sorption from building materials. The developed model is implemented in the environment SPARK (Simulation Problem Analysis and Research Kernel) using finite difference technique. The model is then applied to study the hygric and formaldehyde (FOR, a water soluble VOC) behavior of calcium silicate (CS) subjected to different dynamic conditions of RH and formaldehyde. The results obtained in this paper help to emphasize the importance of moisture and formaldehyde buffering capacity as a new key parameter when selecting clean and hygroscopic building materials in building design because they can contribute to dampen indoor RH and formaldehyde variations. In addition, the impact of RH variation is significant and needed to be taken into account in the simulation to correctly predict the indoor formaldehyde concentration. The model developed in this paper can also be used to optimize the hygric performance and IAQ in building.

Controlling and understanding indoor humidity and pollutants can help reduce the risk of health concerns. The experimental results suggested that there is a similarity relationship between water vapor and Volatile Organic Compounds (VOC) in diffusion through porous media. In this paper, the similarity between the moisture and pollutant transport and storage coefficients of porous building materials has been clearly established and explained. In addition, two similarity coefficients have been defined for VOC storage and diffusion to estimate the VOC properties from the moisture properties of the same material. A coupled hygric-pollutant (VOC) model which can be used to simulate VOC and hygric behavior of building materials under dynamic conditions is presented. The model which is implemented in the environment SPARK (Simulation Problem Analysis and Research Kernel) suited to complex problems using finite difference technique with an implicit scheme, has been validated with the experimental data. It is then applied to study the effect of toluene and moisture buffering capacities of a hemp concrete wall on indoor toluene concentration and relative humidity (RH). Hemp concrete was chosen in this study because it is an environmentally-friendly material that is used more and more in building construction. The toluene (TOL, selected VOC for this study) transport and storage properties obtained from hygrique properties of hemp concrete based on the assumption of the similarity between toluene and moisture transport have been modelled and investigated. At the room level, the results obtained show that taking into account the sorption capacity toward moisture and toluene has a significant effect on indoor RH and IAQ because hemp concrete contributes to dampen indoor RH and toluene variations. The numerical model presented is very useful for the building design optimization and can be used for a fast estimation of indoor pollution and hygrothermal conditions in building.

Population growth is forcing people to build near highways. Outdoor air quality affects the indoor environment. Highway traffic-generated ultrafine particles (UFPs) carry toxic substances, posing a serious threat to pedestrians and residents. Existing literature has shown that the primary sources of UFPs are vehicle emissions, combustion sources, and atmospheric transformation. Particle number concentration and size distribution are mainly influenced by the type of vehicle, traffic volume, wind speed and direction, atmospheric dilution and coagulation or distance from the road. The toxicological relationship between UFPs and human health needs to be further investigated. Prediction models of UFPs transport include line source dispersion, street canyon, and Gaussian models. Line source diffusion models can be used in open streets and highways. Street canyon models are mainly used in metropolitan areas. Gaussian models can be used on flat roads. The results of these three models have randomness and uncertainty and are suitable for short-term models. Numerical models can handle diffusion problems of complex street patterns. Commonly used non-numerical models include the STREET, CPBM, and OSPM models. The CPBM model had higher accuracy and practical value than the STREET model. The OSPM model considered the effect of street geometry and weather conditions in the calculation of pollution diffusion. In addition, coupling CFD and GIS technology has become a promising approach in recent years.

The coupling air organizations between supplying air jets and platform piston winds prevail on the platforms of the subway stations without platform screen doors (PSD) all over the world. The thermal comfort characteristics under the vent are studied in this paper. Firstly, the coupling mechanism of these two airflows is described based on the cross-flow theory. Secondly, Relative Warmth Index (RWI) is selected to evaluate human thermal comfort level with dynamic coupling airflows in the transitional areas. Calculated by the RWI theory model, it can be concluded that air velocities can be enhanced to compensate the supplying air temperature increasing without affecting human thermal sensations with RWI within 0-0.15. Thirdly, experimental studies are carried out and it can be seen that the average RWI values of vertical points under the vent increase from [−0.29, −0.03] in uncoupled conditions to [0.23, 0.14] in coupling conditions, leading to human thermal sensations greatly improved. The experimental RWI values of horizontal points move into the comfort zone a lot under coupling airflows conditions, compared with the uncoupled conditions. In conclusion, the coupling airflows of supplying air jets and cross-flows can improve the transitional thermal comfort and bring forward huge energy-saving potential in air-conditioning systems by allowing the supplying air temperature to be increased in transitional subway stations.

Solar Chimney is a potentially effective low carbon technique that uses solar energy to heat and cool buildings or to enhance ventilation. Proper design of a solar chimney requires a reliable model to estimate the airflow rate generated by the heat of solar irradiation. Existing analytical models ignore density variations either for the whole channel or across the channel gap. This paper presents a plume model based on energy balances and the thermal boundary theory and thus considered density variations in both horizontal and vertical directions. This plume model, expressed implicitly as a function of heat flux, can be solved easily through simple iterations. The performance of the model was verified by using experimental data in the literature. Results show that the plume model outperformed existing analytical models. Recognizing the challenges in airflow measurement, we suggest that further tests and calibrations of this plume model be done by using more concrete and accurate experimental data. Simple in form, the plume model has its potential in building simulation programs.

The objective of this study was to compare the life-cycle cost of using a dedicated hood exhaust and replacement air system versus the cost of removing heat and moisture by the kitchen's general HVAC system. With measured sensible and latent heat generation data from Part I of the RP-1631, whole-building energy performance simulations and cost–benefit analysis were conducted for a generic prototype model of restaurants/cafeteria that included a dining and kitchen zone. Simulations were performed for 12 climate zones in the United States and different amounts of transfer air from the dining to the cooking zone. For most of the climates simulated, the hooded cases resulted in an increase in energy consumption, particularly for the heating-dominated regions, since the heat from the appliance was not used for space heating. In the cooling dominated regions, the hooded cases had about the same or less energy consumption due to reduced cooling loads. However, after integrating the initial cost, maintenance cost...

The main objectives of this research were to improve the understanding of the characteristics of the grease emission and heat generation from electric countertop appliances, and to determine the amount of grease particulate/vapor production as well as sensible and latent heat gains from 20 commercial electric countertop appliances under cooking conditions. The grease particulate and vapor were captured by a Type II hood, and the concentrations were measured using EPA Method 5 in the exhaust duct under an exhaust flowrate of 0.24 m3/s (500 cfm). An energy balance protocol was used to determine the heat generation of these appliances during both idle and cooking conditions. The results indicate that the rate of grease particle and vapor emissions concentration for the 20 appliances tested ranged from 0.12 to 8.27 mg/m3. Only three appliances, the hot plate range, rapid cook oven (cooking with chicken wings or pizzas), and hot dog roller, generated more than 5 mg/m3 of grease at 0.24 m3/s (500 cfm) exhaust f...

This study aims to explore the clinical effectiveness of a combination therapy of transarterial chemoembolization (TACE) and percutaneous microwave coagulation therapy (PMCT) in treating hepatocellular carcinoma (HCC) abutting the diaphragm.Six cases with HCC were treated with TACE followed by PMCT one month later with the aid of artificial pneumothorax.CT/MRI revealed complete necrosis in the tumor lesions and the treated tumor margins (≥ 5 mm). Serum alpha-fetoprotein (AFP) levels markedly declined in patients who originally had higher serum AFP levels. Postoperative complications such as fever, mild hepatic dysfunction and pleural effusion were alleviated within a short period of time. All patients were closely monitored through follow-up; all patients survived, except for one patient who received a liver transplantation.As lesions are either invisible or poorly visible in sonography, determining an effective treatment for HCC abutting the diaphragm remains a particular challenge. TACE and PMCT combined therapy with the aid of artificial pneumothorax proved to be an available treatment option.

This study investigated phthalate emissions from vinyl flooring in a large-scale chamber. Vinyl flooring materials were examined for their phthalates content; one with high contents of diisononyl phthalate (DINP) and di(2-ethylhexyl) phthalate (DEHP) was selected for emissions testing in a small chamber at two different temperatures. Using the same type of vinyl flooring, large-scale chamber experiments were then conducted in three testing phases. In the first phase, the gas-phase concentrations of DINP and DEHP in the large chamber at 36 °C were about three times lower than those in the small chamber under the same temperature, which is consistent with its lower area/volume ratio. In the second phase, when a large air mixing fan inside the chamber was replaced with a small fan, the gas-phase concentrations of DINP and DEHP in the large chamber were reduced slightly, due to the decease of mass transfer coefficient and emission rate. During the last phase, when the temperature of the chamber was reduced to 25 °C, phthalate concentrations dropped instantly and steeply due to the significantly reduced emissions. However, they did not decrease as quickly thereafter because of desorption of phthalates from the internal surfaces of the large chamber. A fundamental mechanistic model was developed to interpret the experimental results in the large chamber based on the emission characteristics obtained in the small chamber measurements. Reasonable agreement was obtained between the model calculation and experimental data. Further model simulations show that temperature and air mixing above the source material have important effects on the fate of phthalates, while the impact of air change rate (ACH) is not significant.

The paper is aimed at building an appropriate computational fluid dynamics (CFD) model for simulating the flow field in the office cubicle with and without personalized ventilation (PV) and using it to investigate the flow field in the cubicle. A computational model was first constructed by using a commercial CFD code (STAR-CCM). In this process, different approaches to represent manikins, boundary conditions, geometries, and gridding were tested, and a proper approach was selected for simulating the air and contaminant movement in the cubicles and their interactions with the remaining room space. A comparison between the simulation and the experimental results are made to show how accurate the CFD model can be. A brief evaluation of the environmental quality was conducted for both cases with PV and underfloor air diffuser (UFAD). This comparison showed a significant advantage in the PV system, indicating how the PV system performed under different airflow rates. This verified CFD model will be utilized in the future to investigate the performance of the partitioned cubicle collaborating with personalized ventilation systems.

Outdoor particles can penetrate through wall assemblies and influence the indoor air quality (IAQ). In this study, a computational fluid dynamics (CFD) model was developed for predicting the particle penetration through wood-framed residential wall assemblies. The model included a simplified approach to account for the particle loss due to the fiberglass insulation material layer in the wall assemblies. Particles ranging from 0.001 to 10 μm in diameter were studied. Particle movement was modeled following an Eulerian approach, while particle deposition in the fiberglass insulation was accounted for by an additional sink term in the governing equation, derived from the classical filtration theory. The model was applied to a typical residential wall assembly, assuming crack heights of 1 mm in the vertical direction and 3 mm in the horizontal direction and a fiberglass insulation width of 0.14 m. The results showed that 0.05–1 μm particles were the most penetrable particles. The fiberglass insulation media r...

This paper presents a co-simulation method using EnergyPlus and CHAMPS-Multizone for combined energy efficiency and indoor air quality (IAQ) analysis. The energy simulation estimates the energy consumption of HVAC systems, lights, and electrical equipment. The Indoor Environmental Quality (IEQ) simulation predicts the indoor contaminate concentrations for IAQ, the zone air temperature and relative humidity for controlled zone conditions, the Predicted Mean Vote (PMV) and Predicted Percentage Dissatisfied (PPD) for thermal comfort, and the illumination for daylighting performance. The energy, thermal comfort, and daylighting simulation are performed by EnergyPlus while the CHAMPS-Multizone is used for the IAQ simulation. In each time step, the CHAMPS-Multizone simulates the pollutant balance, and the ventilation rate required to control the contaminant concentrations under pre-established threshold values. EnergyPlus uses the ventilation rate to simulate the heat, air, and moisture balance, and the energy and daylighting performance. The Building Controls Virtual Test Bed is used for the run-time data exchange. Simulation cases using a 3-zone building are used to validate and demonstrate the benefit of the method. The co-simulation model is developed and implemented in a Virtual Design Studio (VDS) software framework with graphical user interface for integrated building system design. The co-simulation method is found to be especially useful in analyzing the interaction between IAQ and energy efficiency measures.

In thermal environment where occupants stopover, the air supply jet easily dynamical changes due to some cross-flow interferences, influencing the dynamic human thermal comfort. RWI and PD are selected as the human dynamic thermal comfort indexes here. Based on the theory analysis on RWI and PD, the supply air temperature can be increased by improving the velocity in some extends. This will bring obvious energy saving of the air conditioning system. For example, based on RWI and PD within dynamic thermal comfort range, the supply air temperature could be 32 °C with air velocity between 0.6-4 m/s. Experimental studies on the RWI and PD characteristics beneath the vent are developed, affected by the unstable cross-flow. According to the experimental results of typical testing points under the vent in vertical direction and horizontal direction at 1.5 m height, the values of RWI and PD are close to the comfort zone coupling with the dynamic cross-flow and the dynamic thermal comfort below the air conditioning vent is improved.

To guide the selection of gas phase filtration media in the air cleaning devices, it is important to understand and estimate the media performance under usage concentrations. Filters for improving indoor air quality are typically subject to low volatile organic compounds (VOCs) concentration levels (e.g., ∼50 ppb), while the current standard tests per ASHRAE 145.1 (ANSI/ASHRAE 2008). are performed at relatively high challenge concentrations (∼1–100 ppm level). The primary objective of this study was to determine if media that perform well at the high concentration test condition would also perform well under the low concentration. The secondary objective was to investigate if and how existing models of filtration by media bed can be applied to extrapolate the results from the high concentration tests to the low concentration condition. Experiments and simulations were carried out at both high concentrations (100 ppm for toluene and 1 ppm for formaldehyde) and low concentrations (0.05 ppm for toluene and f...