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A rapidly increasing use of building materials poses threats to resources and the environment. Using novel, localized life cycle inventories and building material intensity data, this study quantifies the resource use of building materials in mainland China and evaluates their embodied environmental impacts. Newly built floor area and related material consumption grew 11% per annum from 2000 to 2015, leveling off at the end of this period. Concrete, sand, gravel, brick, and cement were the main materials used. Spatially, construction activities expanded from east China into the central part of the country. Cement, steel, and concrete production are the key contributors to associated environmental impacts, e.g., cement and steel each account for around 25% of the global warming potential from building materials. Building materials contribute considerably to the impact categories of human toxicity, fossil depletion, and global warming, emphasizing that greenhouse gas emissions should not be the sole focus of research on environmental impacts of building materials. These findings quantitatively shed light on the urgent need to reduce environmental impacts and to conserve energy in the manufacturing processes of building materials on the national scale.

• 4D GIS-MFA-LCA model was used to analyze the characteristic of BMS, BW and ECEs. • The consumption of metallic building materials in construction sector is increasing. • Tourism and entertainment area appears to have the fastest increasing rate of BMS. • Cement can capture about 517 kt CO 2 eq of ECEs, as a carbon sink source. • Economy and population are the driving force for urban BMS in Macao. Enhancing the understanding on the temporal and spatial distribution of urban building material metabolism is crucial for informing urban resource, waste, and environmental management. However, this endeavor is often impeded by inaccuracies and inconsistencies in the typology and material composition data of buildings. Taking Macao as a case, this study established a 4D GIS-MFA-LCA model and compiled a local material composition database to address these gaps, for a detailed characterization of the quantity, quality, and temporal-spatial distribution of the urban building stocks and flows in Macao. The results show that between 1980 and 2020, the building materials stock (BMS) in Macao increased from 6.3 to 55.1 Mt (equaling 1.1 to 14.7 Mt CO 2 eq of embodied carbon emission), accompanied by corresponding increases of 0.03 Mt to 0.7 Mt of building waste (BW). The tourism and entertainment area exhibited the fastest increasing rate of BMS in Macao. IPAT analysis shows that the economy, population growth and demographic changes have been the driving forces for BMS in Macao. The results of this study can help cities take effective measures toward achieving a circular economy and highlight the role of such information and urban planning in urban building resource, waste, and management strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Abstract The tremendous use of building materials poses heavy threats to resources and the environment. In order to better understand the GHG emissions embodied in the abundant building material consumption of Shanghai's buildings and search for approaches to reduce GHG emissions, this study explores the building consumption and the embodied GHG emission in Shanghai's buildings through life cycle assessment. Novel and localized life cycle inventories are applied. Based on our findings, the average annual growth rate of new constructed area in Shanghai was around 10% since 2000 to 2016. Concrete, brick, sand, gravel and cement (non-concrete use) appear as the main materials used. High GHG emission burden materials per kg are revealed to be steel, lime, wood, glass and cement (non-concrete use). Accounting the annual material consumption in 2016, steel, cement (non-concrete use), concrete and brick are found have the highest contribution to embodied GHG emission in Shanghai. The decoupling analysis reveals Shanghai experienced a general trend from non-decoupling to relative decoupling between building material use and GDP in recent 17 years. Findings in this study indicate for the high GHG emission burden materials such as steel and lime, reducing the energy use and using less CO 2 -intensive energy sources during manufacturing are likely to be the most effective approaches. In terms of the highly consumed building materials such as concrete and brick, the focus should be on reducing consumption or looking for substitute materials with lower GHG burden per unit. [ABSTRACT FROM AUTHOR]

With the rapid development of the construction industry in China, a large number of building materials have been consumed and resulted in huge pressure to the resources and environment. Based on localized construction material inventory data, China-specific characterization factors in LIME-3 (Life Cycle Impact Assessment based on Endpoint Modeling) was used to evaluate the environmental impact of human health. It is found that ceramic tiles and steel have high burden of human health impact, which are 2.98E-05 DALY and 1.72E-05 DALY, respectively, while gravel and natural sand have relatively low impact, which are 5.12E-08 DALY and 4.30E-09 DALY, respectively. Among the five midpoint impact categories (climate change, air pollution, photochemical oxidant formation, water consumption and human toxicity) that have effects on "human health", the contribution proportion of different building materials vary significantly. The environmental impact assessment results of different building materials on "human health" under LIME-3 and ReCiPe were compared. Results show that the burden of human health impact for ceramic tile under LIME-3 is nearly 67 times that under ReCiPe, which is mainly due to the different proportion of human toxicity in the endpoint of human health and the difference between the two methods in material characterization factors. For high impact burden materials such as steel and ceramic tiles, impact mitigation strategies have been proposed, such as applying electric arc furnace steel making to improve the productivity of steel and the recycling rate of scrap steel, and promoting new dry powder production processes to reduce alkanes and fluorides emission. This study considered an additional midpoint impact category (human toxicity) based on the LIME-3, directing the impact assessment against indicators located at the end of the impact pathway, such as human health. A database of characterization factors of human toxicity for dozens of substances or components has been constructed. Efforts were made in the direction of developing the application of the most widely used impact assessment methods. [Display omitted] • Ceramic tiles and steel have high burden of human health impact based on China-specific characterization factors in LIME-3. • Human health impact for ceramic tile under LIME-3 are much higher than the results under ReCiPe. • More midpoint impact categories such as human toxicity should be considered in LIME. [ABSTRACT FROM AUTHOR]

In rapidly developing countries, such as China, considerable quantities of construction materials have been mobilized with the fast expansion of urban areas. The rural to urban land use transition, especially the upgrade and redevelopment of original rural areas, is a noted driver of material flows. This rural–urban land transition should be incorporated into material flow and stock analyses to provide a more accurate analysis. In this study, a dynamic material flow and stock model that integrates the historical rural–urban land transition was developed to explore the quantity of material stocks and demolition waste from residential buildings in Shanghai—the largest megacity in China from 1950 to 2100. Our results show that the material stocks from residential buildings in Shanghai increased 41-fold from 1950 to 2010, about 957 MMT (million metric tons), and is estimated to be saturated around 2040. Material stocks have experienced asynchronized growth in rural areas, central urban areas, and rural–urban land transition zones (RULT zones) in Shanghai. Until 2040, the RULT zones in Shanghai will be the largest material repository (62%), followed by central urban areas (20%), and rural areas (18%). The amount of demolition waste, which accounted for 10 MMT in 2010, is expected to peak at 29 MMT in 2060s. This suggests the need for a deliberate investment plan to increase waste treatment capacity. In addition, the dominant component of demolition waste will shift from brick to concrete after 2020s. The RULT zones will contribute two-thirds of demolition waste to Shanghai until the 2060s. If we do not consider the reality of the physical status of buildings in RULT zones, the demolition waste will be underestimated by the maximum of 57% in 2003 in urban areas. The key findings on the trend of construction and demolition (C&D) waste generation and the significant contribution of RULT zones can be used as a reference for the strategic planning of treatment facilities. This research framework can be also used to estimate the amount of C&D waste in other fast-developing cities in China and other countries. UR buildings = urban residential buildings; RR buildings = rural residential buildings. RULT zones = rural–urban land transition zones. Image 1 • A dynamic material flows and stocks model by integrating rural–urban land transition was applied in Shanghai, China. • Material stocks & demolition waste in rural areas, RULT zones, and central urban areas were considered, respectively. • Two-thirds of demolition waste will generate from rural–urban land transition zones by 2060s. • Dominant component of demolition waste will shift from brick to concrete. • Prolonging the buildings' lifetime would be a priority option for waste reduction. [ABSTRACT FROM AUTHOR]