PM_2.5 pollution has become a severe problem in China due to rapid industrialization and high energy consumption. It can cause increases in the incidence of various respiratory diseases and resident mortality rates, as well as increase in the energy consumption in heating, ventilation, and air conditioning (HVAC) systems due to the need for air purification. This paper reviews and studies the sources of indoor and outdoor PM_2.5, the impact of PM_2.5 pollution on atmospheric visibility, occupational health, and occupants’ behaviors. This paper also presents current pollution status in China, the relationship between indoor and outdoor PM_2.5, and control of indoor PM_2.5, and finally presents analysis and suggestions for future research.

A climate-responsive landscape design can create a more livable urban microclimate with adequate human comfortability. This paper aims to quantitatively investigate the effects of landscape design elements of pavement materials, greenery, and water bodies on urban microclimate and thermal comfort in a high-rise residential area in the tropic climate of Singapore. A comprehensive field measurement is undertaken to obtain real data on microclimate parameters for calibration of the microclimate-modeling software ENVI-met 4.0. With the calibrated ENVI-met, seven urban landscape scenarios are simulated and their effects on thermal comfort as measured by physiologically equivalent temperature (PET) are evaluated. It is found that the maximum improvement of PET reduction with suggested landscape designs is about 12°C, and high-albedo pavement materials and water bodies are not effective in reducing heat stress in hot and humid climate conditions. The combination of shade trees over grass is the most effective landscape strategy for cooling the microclimate. The findings from the paper can equip urban designers with knowledge and techniques to mitigate urban heat stress.

Corrosion has been found to be the most predominant cause for failures of buried metal pipes. A review of published literature on pipe corrosion reveals that little research has been undertaken on the effect of corrosion on mechanical properties of pipe materials and almost no research has been conducted on corrosion effect on fracture toughness. The intention of this paper is to present a comprehensive test program designed to investigate the effect of corrosion on mechanical properties of metals in soil. Two types of metals, namely, cast iron and steel, are tested under corrosion in three different environments. A relationship between corrosion and deterioration of mechanical property of metals is developed. It is found in the paper that the more acidic the environment is, the more corrosion the metal undergoes and that the corrosion reduces both the tensile strength and fracture toughness of the metal. The results presented in the paper can contribute to the body of knowledge of corrosion behavior and its effect on mechanical properties of metals in soil environment, which in turn enable more accurate prediction of failures of buried metal pipes.

As a global problem for reinforced concrete structures located in a chloride and/or carbon dioxide–laden environment, reinforcing steel corrosion in concrete costs approximately $100 billion per annum worldwide for maintenance and repairs. The continual demands for greater load for infrastructure exacerbate the problem. This paper attempts to examine the whole process of longitudinal cracking in concrete structures under the combined effect of reinforcement corrosion and applied load. A model for residual stiffness of cracked concrete is derived using the concept of fracture energy. It is found that the corrosion rate is the most important single factor that affects both the time-to-surface cracking and crack width growth. The paper concludes that the developed model is one of very few theoretical models that can predict with reasonable accuracy the crack width on the surface of reinforced concrete structures under such a combined effect. The developed model can be used as a tool to assess the serviceabil...

Outdoor environment exchanges heat with indoor environment, enabling pollutants to infiltrate indoors, affecting buildings’ energy efficiency, comfort, and indoor air quality. Investigating the impact of the outdoor environment on the indoor thermal environment is crucial. Firstly, this paper reviews the coupling method to link the outdoor environment with the indoor environment. Secondly, it examines the impact of the outdoor physical environment, including neighboring buildings, greening, road surface, water body, and sky, on the indoor thermal environment. During the hottest summer, an increase of 17% in trees can reduce indoor temperature by 1.1 °C. Thirdly, the impact of weather conditions, including outdoor temperature, outdoor humidity, external wind, global warming, extreme weather conditions, and solar radiation, on the indoor thermal environment is studied. Due to global warming, cooling energy consumption and heating energy consumption in 2050 could increase by 223% to 1050%, and heating demand could decrease by 36% to 58%. Finally, the impact of outdoor air pollution on indoor environment and energy consumption is analyzed. For every 75 μg/m³ increase in PM_2.5 concentration, average power consumption could increase by 11.2%. Recommendations for future research are provided. This study contributes to the understanding of the outdoor–indoor thermal relationship and offers insights into enhancing indoor thermal comfort and reducing building energy consumption.

Outdoor thermal comfort in urban spaces is an important indicator of the quality of life in an urban environment. This paper attempts to investigate the effect of street design on outdoor thermal comfort in an urban street in the central business district in Singapore, focusing on the design variables of street orientation, height-to-width ratio (H/W), and vegetation. A comprehensive field measurement with multiple points is presented and used to validate a widely used computer software holistic microclimate modeling system. The significance of the research is that real field data from multiple measurement points on microclimate parameters are produced and the effect of street design parameters on outdoor thermal comfort is quantified. It is found in the paper that the NW-SE oriented street is more stressful than the NE-SW street in the afternoon in terms of thermal comfort in Singapore, and that a H/W of 3 can be considered a threshold with respect to outdoor thermal comfort. The paper concludes ...