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The significance of global warming is shaping building procurement, with much of the effort aimed at reducing greenhouse gas emissions through a preferential bidding mechanism. However, only a limited number of studies have quantitatively estimated the potential impact of bid preference on the emission reduction from building construction. The aim of this paper is to improve our understanding of how bid discounts change owners' procurement costs and the magnitudes of emission mitigation. A two-stage optimization model is designed to help the owner determine the discount rate that would automatically control the emission of the awarded contract within a desired level. The goal is for bidders to regard emission reduction efforts as an investment, with returns coming in the form of an increased chance of winning the bid. Our results imply that for the building retrofit project studied herein, a discount rate of 0.6 is suggested for every percentage of emission reduction. This discount level reduces greenhouse gas emissions by 28.2% while raising procurement costs by 3.7% relative to a non-preference mechanism. The increased procurement costs can be partially compensated under existing cap-and-trade scheme. The results show that the choice of discount significantly alters bidders' efforts on emission mitigation, and emission control cost can be minimized with the proposed optimization algorithm. [ABSTRACT FROM AUTHOR]

Hot Mix Asphalt (HMA) is used in the construction of highway roads, parking lots and other pavement repairs in the US and worldwide. During asphalt pavement installation, a large amount of asphalt fume containing volatile organic compounds (VOCs) is emitted, causing potential health risks to construction workers. The field data investigation in this paper reports the concentration of VOCs around the workers on site using the Photo Ionization Detection (PID) device. Additionally, this paper presents a health risk evaluation model based on the Monte Carlo simulation to assess the carcinogenic and non-carcinogenic risks of workers during pavement construction. More specifically, distribution and sensitivity analyses illustrate the factors that pose the greatest health risks caused by certain VOCs. The study calls for better health risk controls by targeting the emission sources, propagating pathways, and individual receptors of the VOCs to protect workers' health during pavement construction. This paper contributes to the knowledge of VOCs generated from HMA and the potential health risks to construction workers, as well as suggests the implementation of new requirements for pavement construction codes and safety regulations. [ABSTRACT FROM AUTHOR]

Promoting household energy-saving behaviors requires devising effective messages and selecting appropriate message delivery methods. Meanwhile, the specific psychological factors that shape the effectiveness of interventions remains elusive. Based on an energy conservation intervention program carried out in communities in the city of Hangzhou, China in 2016, this paper investigates the impact of eco-feedback and energy-saving tips delivered to households via an instant messaging platform (i.e., WeChat), stickers combined with leaflets, and face-to-face consultations in promoting energy conservation. Psychological attributes including personal values and aspects of decision-making that affect pro-environmental behavior, as well as social and housing demographics were collected and analyzed to identify relationships between household characteristics and the effectiveness of an intervention. The findings suggest that, coupled with eco-feedback, stickers and leaflets (mean rank 37.54) performed better than other alternatives (mean rank 55.34 for WeChat group, 57.08 for consultation group) in encouraging household energy-saving behaviors. The effectiveness of eco-feedback using an instant messaging platform was revealed to be short-lived. Moreover, the study found that psychological features such as the perception of sufficient non-material incentives and opportunity to perform energy conservation behavior, as well as valuing environmental quality, personal health, and leisure time, are significantly correlated with energy savings. The findings not only contribute to future policymaking in demand-side energy conservation, but also provide insights for the cultivation of long-term behavioral changes at the neighborhood level through the effective design of communications and engagement. Image 1 • Compared the effectiveness of three types of delivering methods. • Sticker with eco-feedback is more effective in saving energy than other methods. • Effectiveness of delivering feedback using an instant message is short-lived. • Household psychological and social attributes are correlated with energy saving. • Households valuing environmental quality and health are likely to save energy. [ABSTRACT FROM AUTHOR]