Indoor and Built Environment

A distinct feature of Wuhan is that almost a quarter of the total area of this city is covered with water, leading to its unique hot and humid climate characteristics in summer. However, according to records, water area in built-up zone of Wuhan has been reduced by 130.5 km² from 1965 to 2008, while the annual average air temperature has been increased by more than 3℃. To investigate the quantitative connection between the water area reduction and air temperature increase, three scenarios were simulated in a summer; to evaluate the impact of water reduction on the local thermal environment in different water areas; and to study the impact of water reduction on the urban heat island (UHI) phenomenon. Meso-scale meteorological models of Weather Research and Forecasting model were applied in this study for quantitative assessment and prediction. With the predictions, this study reveals that the decreased water area could affect air temperature, wind velocity and wind flow direction, energy balance and the UHI intensity. The simulations show that areas with significant wind velocity, wind direction and air temperature differences are distributed among the downwind zones. Moreover, the areas with high UHI intensity are wider and farther from the boundary of urban areas because of the reduction of water areas.

Experimental and modeling based assessments of employing reflective wall coatings towards improving the effectiveness of ultraviolet germicidal irradiation in unoccupied hospital rooms were carried out. Measurements of incident radiative fluxes on different surfaces were made in a control room as well as a room whose walls were painted with a nanostructured UV-C reflective wall coating. Employing the reflective paint resulted in up to a 20% increase in the incident radiative fluxes on some surfaces that were directly exposed to the radiation and nearly a 10-fold increase on surfaces that were not directly exposed. Spatially and directionally well-resolved simulations of radiative transfer within the rooms were carried out employing the finite volume radiation model. The measured enhancement in radiative fluxes predicted numerically agreed in general with experimental observations. The volume-averaged incident radiation increased by 60% in the presence of UV reflective walls. Ray effects or the preferential streaming of radiation in the numerical calculations was more pronounced in the control room and was minimized by increasing the angular resolution of the calculations even further. However in the room with UV reflective walls, the diffuse reflections caused the intensity distributions to become more isotropic and minimized the impacts of ray effects.

Roofs surfaces are frequently used to catch water for drinking in many countries, so the presence and mobilisation of material into runoff water can be an important process to consider. This paper investigates the origin and mobilisation of trace elements from roofing tiles. Our work suggests that trace elements can mobilise into roof runoff. However, lead by contrast, appears to have accumulated at the surface of tiles exposed to busy automobile traffic that used leaded fuel (confirmed by X-ray fluorescence). Although lead is relatively immobile on the tile surface, the potential for leaching by acidic rain (pH < 4) means that the guidelines for lead in drinking water may be exceeded during some rainfall events.

The integration of vegetated architecture has evolved from gardening, aesthetic design, or artistic expression, to an indoor element named iVGS providing fashion function for the indoor environment. The aim of this study is to identify characteristics of commonly used indoor plants in tropics, and to determine the advantages and disadvantages of iVGS, criteria in selecting installation methods, layout plans for iVGS and correlation among locations, parameters, types and Pros & Cons. A questionnaire survey and three case studies including (a) Ban Guan Nursery; (b) Yeo Tang Hing Nursery and (c) Absolute Thai Garden were conducted. The three case studies determined characteristics of commonly used indoor plants and installation requirements of iVGS. The questionnaire survey found aesthetic the top benefit of iVGS but denied noise reduction as an effective function of it. The system could improve indoor air quality by filtering contaminates from different pollutants. This research denied allergy as a significant disadvantage of iVGS. High construction and maintenance cost is still the main obstacle for potential users to choose iVGS, but this paper does not cover the cost of iVGS; thus, further analysis on costing aspect for various iVGS are recommended for future research.

Computational fluid dynamics computations were conducted to investigate the particle inhalation characteristics of a thermal manikin standing in a horizontal airflow with different orientations, leg postures, wind speeds and particle sizes. The computations revealed that only when the manikin’s thermal plume moves into the breathing zone (namely, the manikin is facing the lee side) could the body heat affect the characteristics of particle inhalation. Further computations demonstrated that, when facing the lee side, the manikin’s particle inhalation is highly sensitive to its leg posture. When the legs are separated, air can flow through the gap, causing more particle entrainment into the breathing zone from the lower level. Although the thermal effect of body heat is gradually suppressed with increasing wind speed or particle size, different leg postures have different environmental sensitivities.

In this study, effects of the thermophysical properties of the wall masonry layer on the time lag and decrement factor of the composite wall were investigated numerically. For this purpose, the time lag and the decrement factor of six kinds of composite walls were calculated using the software FLUENT. The results show that the time lag would increase with an increase in the heat capacity of the masonry wall layer and would decrease with an increase in the thermal conductivity of the masonry wall; the decrement factor would decrease with an increase in the heat capacity of the masonry wall layer, but would increase with an increase in the thermal conductivity of the masonry wall. In the walls with one insulation layer, the wall with insulation on the outer surface would always have the smallest decrement factor. In the walls with two insulation layers, the wall with the insulation partly in the middle and partly on the outer surface would always have the highest time lag and the wall with the insulation partly on the inner surface and partly on the outer surface would always have the smallest decrement factor.

As energy efficiency concerns grow for building heating, ventilation, and air-conditioning systems, more advanced mathematical models and methods may be needed for implementing more comprehensive building environmental monitoring practices. This work investigates the methodology of applying a coupled proper orthogonal decomposition (POD) and linear stochastic estimation (LSE) technique to provide detailed real-time velocity information for a single-room test environment under either mechanical ventilation or wind-driven cross natural ventilation with the support of limited on-site monitoring measurements. In addition, an example application of the proposed POD–LSE methodology with limited measurements to obtain real-time fluctuating wind-driven ventilation rates using a POD–LSE reconstructed velocity profile across a window opening is presented and shows very good agreement with the measured ventilation rates.

In the present study, newly designed single entry pin hole-based diffusion chambers were used for the first time in a study region to estimate exact ²²²Rn and ²²⁰Rn concentration. These diffusion chambers are independent of high turbulent environmental conditions as well as with same entry rate of ²²²Rn and ²²⁰Rn. The device was calibrated at Bhabha Atomic Research Centre, Mumbai following the standard procedures to correlate the number of tracks registered in the LR-115 detector placed in the two chambers to the ²²²Rn and ²²⁰Rn concentrations in the environment. The average values of ²²²Rn and ²²⁰Rn concentration in the indoor environments were 28.76 ± 13 Bqm⁻³ and 63.08 ± 17.27 Bqm⁻³, respectively. The values were within the recommended level of ICRP, 2010 (200–300 Bqm⁻³). The observed data has provided a good correlation (R²= 0.8618) between ²²²Rn and ²²⁰Rn concentrations in the studied area. A linearity relationship was established between PAEC (²²⁰Rn) and {PAEC (²²²Rn)}^0.4 with R²= 0.9047. These data will provide a good database for ²²²Rn and ²²⁰Rn mapping in India.

Indoor radon-in-air (IR) concentrations in dwellings situated on a fault line passing underneath Muzaffarabad City were measured with a continuous radon monitor. Measurements were taken at half an hour intervals at 11 sites for 48 h. The values ranged from 14 ± 1 to 155 ± 4 Bq.m^− 3 with an average value of 42 ± 2 Bq.m⁻³. The geometric mean (GM), standard deviation (STD) and geometric standard deviation (GSD) were 32 ± 2, 40.2 ± 0.8 and 1.5 Bq.m⁻³, respectively. Annual mean effective doses ranged between 0.35 ± 0.03 and 3.9 ± 0.1 mSv.y⁻¹ with an overall mean value 1.05 ± 0.05 mSv.y⁻¹. The experimental data were analysed by comparing algorithms to extract phase space dynamical information in the radon time series. Such approaches are potentially useful for deriving methods of extrapolation of short-term measurements to annualized average predictions and for earthquake detection. The computed values for Hurst exponent (H) from the rescaled range analysis and the Lyapunov exponent (L) provided estimates of the degree of chaotic regime. The Hurst exponent (0.877) for the radon time series indicates that the radon time series is a persistent time series. The value of Lyapunov exponent (0.0021) shows deterministic chaos in the data. The permutation entropy value was 0.6894 reflecting the irregularity in IR time series. The value of entropy obtained confirmed that the predictability of the IR time series is restricted to approximately one time step into the future. The mean value of IR concentrations corresponds to excess relative risks (ERR) of radon-induced lung cancer for 35- and 55-year-olds at all sites of 0.25 ± 0.01 and 0.205 ± 0.01, respectively. The observed 48-h average level (42 ± 2 Bq.m⁻³) was less than those recommended by the World Health Organization (WHO) (100 Bq.m⁻³), US Environmental Protection Agency (148 Bq.m⁻³) and Health Protection Agency, UK (200 Bq.m⁻³).

This article aims to assess some of the main lighting software programs currently available for architecture. It compares the daylight simulation results from programs, Flamingo nXt rendering, DIVA and Lightscape with the physical measurements carried out on a flat plate surface and in a model box. Identical parameters of geometry and lighting conditions were set. Two strategies were used to investigate the difference and correlation between the measurements and simulations. One test simulated several angles which were identical to the real-time sun position during daytime by rotating the box for both the simulation and field test, and the other test conducted every hour during daytime simulated three typical days (spring equinox, summer solstice and winter solstice). The output from simulation programs was conducted on a set grid of identical surface locations. The simulation programs and physical measurements were used to generate a parametric model. The results suggested that the accuracy of all these inspected simulation programs was acceptable for design exploration and that the parametric model could be used to calibrate the programs to give more accurate, real-time illuminance and luminance.

As an indicator of general indoor air quality in industrial facilities, the concentrations of total volatile organic compounds (TVOC) were determined in the workplaces of 37 industry sectors during the years of 2006–2011. For comparison, the TVOC levels in office-type workplaces were also determined. Based on the results, the TVOC target and guideline values are proposed for industrial workplaces. The geometric mean and median concentrations in the industrial workplaces were 778 and 845 µg/m³, respectively, while the 90th, 25th percentiles were, respectively, 6616 and 270 µg/m³. In the office-type environments, the geometric mean and median concentrations were 55 and 50 µg/m³, and the 90th and 25th percentiles were 230 and 27 µg/m³. Based on the measured TVOC distributions and the target values previously set, we propose a TVOC target value of 300 µg/m³ and guideline value of 3000 µg/m³ for the general indoor air in industrial workplaces. The concentration of 3000 µg/m³ could be achieved with reasonable measures by most industry sectors, but does not guarantee that the inhalation exposure to volatile organic compounds in the occupational environments is free from health concerns or perceived discomfort. Therefore, when reasonably achievable, a TVOC concentration close to or below the target value is recommended. This would make the TVOC levels in industrial facilities similar to those in the non-occupational indoor environments.