Mohd Rodzi Ismail

Double skin façade (DSF) has emerged as a decisive strategy for improving building thermal performance and energy efficiency. In various climatic conditions, DSF will perform differently and accordingly. However, the whole building performance of the DSF has never been studied in a broad climatic condition. As a result, there will be a high risk that the system will underperform conventional façade. This study adopted a quantitative approach with computational simulation software, EnergyPlus, to analyze the thermal behavior and energy efficiency of both single skin façade (SSF) and DSF systems. The investigation focused on an overall Köppen classified tropical climate category, which encompasses tropical rainforest (Af), tropical monsoon (Am), tropical savanna with dry winter (Aw), and tropical savanna with dry summer (As) climates. The primary finding indicates that the SSF in various tropical-classified groups exhibits diverse thermal behaviors throughout the year, from month to month and from orientation to orientation. The climate of each tropical classification distinctly influences the performance of both façades. The air temperature and relative humidity in both SSF and DSF office zones remained within a predictable range throughout the year. Thermal behavior and energy consumption fluctuated considerably on a monthly basis but only marginally on an annual basis. This similarity explains how buildings in the four cities consumed distinctly comparable cooling energy consumptions. The study also indicates that, even without a shading device, the DSF could still outperform the conventional facades. In all climatic contexts, energy consumption for cooling could be diminished by more than 40%, and the air temperature in the office zones was decreased to around 4°C while relative humidity was increased by 1% to 5%. Hence, an appropriate DSF design could be employed on office buildings in the overall classified tropical climates to attain energy efficiency through thermal enhancement from the façade’s second layers.

To obtain optimal efficacy toward energy saving in buildings, numerous approaches have been persistently developed and innovated. Double Skin Façade (DSF), one of the keys to energy efficiency and thermal enhancement, is increasingly drawing attention from designers and researchers in speculating its benefits. Nowadays, there are still some doubts about the performance of DSF as it provides pros and cons. Therefore, this review provides a deep understanding of the composition of DSF and its performance, and its startling gaps among researchers toward green building within the built environment. The research studies present evidence of the potential of DSF in various applications with the proper design scheme. However, location and climatic conditions are the most important factors to consider when it comes to designing DSF for building envelopes. Otherwise, the system not only mandates a higher investment cost on double structuring but also higher demand for energy consumption. The findings additionally indicate that DSF has also left some uncertainties on its positive impact within the extensive tropical climate, since there are inadequate studies conducted, such as lighting, heat transfer and ventilation, etc. Accordingly, the system requires more rigorous investigation to be profoundly employed.

Traffic emissions in developing townships are less studied compared to major townships and cities. The Electrified Double-Track Project (EDTP) rail line is a linear project traversing from south to north of peninsular Malaysia. Construction of this line has somewhat affected the traffic flow in terms of delay and congestion, affecting traffic-related emissions. A study on the emission fluctuations due to traffic flow changes during the electrified double-track rail line construction was carried out in Parit Buntar, a developing township north of Peninsular Malaysia. Currently, not many primary study reports furnish insights into the effect of the project’s construction phase. Sidra 6.1 were used to estimate the traffic flow delay and level of service (LOS) at signalised intersections from traffic surveys of six intersections. These inputs were also used to estimate the fuel consumption and cost of fuel consumption for all three stages of emission contribution, namely before construction, during construction, and after construction (commissioning phase). The respective fuel consumption (L/hr.) before the construction, during construction, and post-construction were (437, 174, and 198) at J1, (-, 1650, and 264) at J2, (475, 2429, and 2384) at J3, (332, 336, and 261) at J4, and (206, 13996, and 452) at J5. This study found that a proper signal phasing post construction has improved delay time and traffic emission. The findings should be relevant for researchers interested in the emissions within the developing townships, especially in enhancing road layouts for the sustainability of life and well-being in the local and broader contexts.

Ground-level ozone (O₃) is mainly produced during daytime in the presence of ultraviolet (UV) light and later destroyed by nitrogen oxides during nighttime. However, light pollution caused by the excessive use of artificial lights may disrupt the chemistry of night-time ground-level O₃ by providing enough energy to initiate nighttime ground-level O₃ production. In this study, nighttime (7 p.m. to 7 a.m.) ground-level O₃, nitrogen oxide (NO), and nitrogen dioxides (NO₂) concentrations were observed for three years (2013, 2014, and 2015). The existence of O₃ was found during nighttime, especially in urban areas with a concentration range of 8–20 ppb. The results suggested that nighttime variations of ground-level O₃ concentrations were higher in urban areas than in suburban areas. The mean nighttime O₃ concentration at urban sites varied, possibly because the distribution of anthropogenic lights around the urban sites is brighter than in suburban locations, as indicated by the data from the light-pollution map. This anthropogenic light has not caused the suspected nighttime photolysis processes, which directly slowed nighttime oxidation. The photochemistry rate of JNO₂/k₃ was supposed to be near zero because of the absence of photochemical reactions at night. However, the minimum concentration in all urban and suburban sites ranged from 2–3 ppb, indicating that O₃ might also form at night, albeit not due to light pollution.

This study observed the influence of different ventilation, indoor and outdoor activities (i.e., cooking, praying, sweeping, gathering, and exhaust from motorcycle) between a bungalow house (i.e., stack and cross ventilation applications) and a terrace house (i.e., one-sided ventilation application). We appraised the indoor air quality (IAQ) and thermal comfort. We monitored the indoor air contaminants (i.e., TVOC, CO, CH2O, PM10, O3, and CO2) and specific physical parameters (i.e., T, RH, and AS) for four days in the morning (i.e., 6.00 a.m. – 9.00 a.m.), morning-evening (i.e., 11.00 a.m. – 2.00 p.m.), and evening-night (i.e., 5.00 p.m. – 8.00 p.m.) sessions. The results found that cooking activities are the major activities that contributed to the increase of the TVOC, CO, PM10, O3, and CO2 concentrations in the bungalow and terrace houses. However, IAQ exceeded the Industry Code of Practice on IAQ (ICOP) limit in the terrace house. The bungalow house applies stack and cross ventilation, double area, and a long pathway of indoor air contaminants movements. Besides that, the results indicated that cooking activities worsen the ventilation system because CO2 exceeded the ICOP limit on Day 2 at 74.1 % (evening-night session) and Day 3 at 13.2 % (morning session), 11% (morning-evening session), and 50.1 % (evening-night session). Moreover, the combination of mechanical (i.e., opened all fans) and natural ventilation (i.e., opened all doors, windows, and fans) is the best application in the house without a cooking ventilator with lower indoor air movement. Furthermore, the temperatures exceeding the ICOP limit of 23-26 °C for both bungalow and terrace houses could be lower indoor air movement, which is less than the ICOP limit of 0.15-0.5 m/s and high outdoor air temperature. Therefore, it is prudent to have an efficient ventilation system for acceptable indoor air quality and thermal comfort in the family house.

Occupants of buildings spent most of their time indoors and posed themselves to the indoor biological contaminants (i.e. bacteria and fungi) in the built environment. However, the factors that influenced the prevalence of suspended bacteria and fungi in the air of the built environment are not well recognised. Authorities must take the growth of biological contaminants seriously to prevent serious health effects among occupants of buildings. This review summarises the factors (i.e. outdoor air, dust, ventilation problems, humidity/moisture surface problems and human occupancy) of indoor biological contaminants and their species in buildings that could worsen the indoor air quality. Bacteria species could exist in various indoor buildings (i.e. schools, cafeterias, mosques, faculties, child day-care centres, hospitals, dwellings, educational buildings, homes, elderly care centres, libraries, restaurants, and factories). The dominant bacteria were Bacillus spp. (24.1 %), Staphylococcus spp. (20.7 %), and Micrococcus spp. (20.7 %) whereas for fungi species were Penicillium spp. (25 %), Cladosporium spp. (21.9 %), and Aspergillus spp. (21.9 %).