Usage status, potential environmental impacts and sustainable development pathways of garbage bags in China

China's new garbage classification policy introduced in 2017 has increased the classification of household waste from two categories to four categories. This might increase the usage of garbage bags. However, the usage status, potential environmental impact (PEI) and sustainable planning of garbage bags have received little attention. In this paper an exemplary study in Beijing and national prediction were conducted based on the well-developed waste classification system in Beijing. The usage patterns of garbage bags were investigated, the PEI of garbage bag usage were assessed and predicted, and the technological, behavioral and administrative suggestions for manufacturers, consumers and government were proposed. The results showed that the usage of garbage bags in 83.89% of the surveyed households increased after the new policy. High-density polyethylene (HDPE) garbage bag was the most widely used in 46.31% of households. The fully biodegradable (FBD) garbage bags had the highest PEI, 12.85 times that of HDPE; and 81.36% of PEI came from the raw material production stage. Reusing shopping bags and reducing the PEI of FBD were both important for meeting China's environmental protection goals. Research results are essential for the sustainable management of garbage bags.