Role of plastics in decoupling municipal solid waste and economic growth in the U.S. Demetra A. Tsiamis, Melissa Torres, Marco J. Castaldi ⇑ Earth Engineering Center, Department of Chemical Engineering, City College of New York, CUNY, New York, NY 10031, United States article info Article history: Received 18 November 2017 Revised 11 April 2018 Accepted 2 May 2018 Keywords: MSW Decoupling Plastic waste abstract Analysis of data from the US Environmental Protection Agency (EPA) on municipal solid waste (MSW) generation rates correlated to personal consumption expenditure (PCE) uncovers a decoupling event occurring between 1997 and 2000. A comparison of waste generation rates for each material category found in MSW reveals that plastics increased by nearly 84 times from 1960 to 2013 while total MSW increased only 2.9 times. The increase in plastic waste generation coincides with a decrease in glass and metal found in the MSW stream. In addition, calculating the material substitution rates for glass, metal and other materials with plastics in packaging and containers demonstrates an overall reduction by weight and by volume in MSW generation of approximately 58% over the same time period. A quantitative calculation of a scenario where plastics were not used in packaging and containers to replace glass, metal, and other materials demonstrates that MSW generation rate rises equally with PCE. Therefore, this study has determined that the increase of plastic use is a contributing factor to the decoupling of MSW generation from PCE. Ó 2018 Elsevier Ltd. All rights reserved. 1. Introduction There has been a general trend regarding average MSW genera- tion increasing with nominal Gross Domestic Product (GDP) of a region or country. The correlation has given rise to hypotheses that affluent societies consume more materials and resources and there- fore, have a commensurately higher increase in MSW generation rates than less affluent societies. A more detailed inspection of the data indicates that actual MSW generation falls within a range of 2–6 lb per person per day (lb/person/day) over a range of GDP from $5000 to $110,000, respectively (Hoornweg and Bhada, 2012). This suggests that, regardless of region or income, there is a fairly consis- tent rate of material use that eventually is discarded as waste, apply- ing a stress to the environment. Generally, more affluent regions or nations can counteract the environmental impact of development and waste generation by attempting to decouple MSW generation with GDP, productivity, standard of living increase or personal con- sumption expenditure (PCE). Many developed and affluent nations have established material recovery programs (e.g. recycling) to attempt to decouple their continued increase in standard of living with an associated increase in MSW generation (Hopewell et al., 2009). The adaption of the Economic Kuznet Curve (EKC) to waste has resulted in a gen- erally accepted Waste Kuznet Curve (WKC) (Fischer-Kowalski and Amann, 2001; Seppälä et al., 2001). The WKC has developed in the same way as the EKC describing a trajectory where initial increases of income per capita or GDP are directly correlated to increases in pollution or environmental degradation. Eventually, a transition begins where continued rises in per capita income result in a decrease in environmental degradation. Initially, there is a relative decoupling where waste generation rates rise more slowly than per capita income followed by an absolute decoupling where waste generation rates actually decline with a rise in per capita income. A number of studies have been done on waste generation decoupling, mostly in the European Union (EU). In Europe, it is has been observed that decoupling potentially exists due to policy implementation, regulations, and tax penalties. Although the evi- dence is uneven, there does appear to be segments that experience a relative decoupling in recent years. However, a couple of studies (Cole et al., 1997; Seppälä et al., 2001) found no evidence of a tran- sition to the inverted U-curve segment associated with a WKC. A report by Mazzanti and Zoboli concludes that while there is no trend for waste generation (i.e. no observed WKC), policy directives in the early stages of implementation may work. They observe some early positive signals in favor of a relative de-linking for waste gen- eration and associated landfill diversion (Mazzanti et al., 2006; Mazzanti and Zoboli, 2008). In another report by Mazzanti et al., they https://doi.org/10.1016/j.wasman.2018.05.003 0956-053X/Ó 2018 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: mcastaldi@ccny.cuny.edu (M.J. Castaldi). Waste Management 77 (2018) 147–155 Contents lists available at ScienceDirect Waste Management journal homepage: www.elsevier.com/locate/wasman