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1 Introduction

Products and services represent the most basic and key components of an economy and are traded in exchange for currency. In the past few decades, advances in science and technology, and the increasing affordability of consumers and businesses have contributed to the exponential growth in the production and consumption of goods. In this process, natural resources and virgin raw materials have been exploited and wasted irresponsibly due to the existing linear economic model [1, 2]. This has led to unintended environmental impacts such as the depletion of natural resources (almost to an irreversible extent), and environmental pollution on both regional and global scales [3, 4]. Therefore, the way products and services are made, used, and disposed of plays a crucial role in transiting to a CE [5].

In recent years, many large corporations are willingly putting efforts into improving product design and services to create value and become more environmentally sustainable. Some of them are even pursuing certifications from organizations such as the Cradle to Cradle Products Innovation Institute and the Ellen MacArthur Foundation. Various digital tools and sets of indicators such as the CET, the MCI [6], and the CEIP have been made available to businesses/reachers/analysts to measure the circularity of commercial products [7]. Startups around the world championing the CE are coming up with eco-friendly products and services, and innovative business models to reduce the environmental impacts of consumables.Footnote 1,Footnote 2,Footnote 3 However, the eco-friendliness of products and services does not guarantee their circularity. This is why the circularity assessment of products and services that can identify the extent of their circularity and potential avenues for further improvement becomes important.

Through this chapter, we distinguish the circularity assessment of products and services—considered as nano-level in the economic hierarchy, from the micro-level (businesses), in contrast to the prominent prior art [8,9,10]. This chapter begins with a discussion on the need for circularity assessment of the nano-level: products and services. Then, we present a background of the state-of-the-art assessments of products at various stages of a product’s life-cycle such as design, production, use, and end-of-life as well as the list of indicators used in measuring the different aspects of circularity at the nano-level. With this background, a couple of case studies are illustrated for a better understanding of the product’s environmental impact assessment. Since the product circularity directly depends on material circularity, a discussion on the efficient utilization of materials in product design is presented as a logical ending for the chapter.

1.1 The Need for Circularity Assessment at Nano-Level

Many global businesses and start-ups are transiting towards circularity for a sustainable business and with new/upcoming policies of governments on environmental sustainability and the rise in conscious consumerism, every product and service is required to become circular. To do so,

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    the design and manufacturing need to adhere to the principles of the CE [5, 11, 12],

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    the useful phase of products have to be extended for as long as possible [11], and

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    at the end-of-life, products have to be collected for recycling [11].

This will ensure the sustainability of both natural ecosystems and the economic system in the long-term. Moreover, in the short-term, circularity will reduce the stress on scarce material resources and decouples economic growth from volatile commodities. From a financial perspective, although transiting to circularity needs initial investments, circular products and services have the potential to be profitable in the long run [2].

Although there are a few organizations and toolkits providing product circularity assessment, there is a need for a standard methodology for uniform evaluation across products that belong to the same category from different manufacturers. For example, the circularity of laptops/computers produced by various manufacturers across the world, or cosmetics of various commercial brands in the market have to be evaluated using a standard methodology for better comparison of their sustainability. Such an assessment should also identify and provide insights to improve the overall circularity of the product.

2 Circularity Assessment Approach at Nano-Level

When it comes to the transition of a linear product towards circularity or designing of a new circular product, the focus is on the materials involved, both ingredients and other resources needed in the making. Whether the product is technological or biological, the underlying fundamental principles for the transition are the same. The fundamentals established by the pioneer experts such as Stahel, McDonough, and Braungart (as below) concentrate on the efficient utilization of resources in such a way that they can be restored back into the system.

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    Minimizing the usage of resources and increasing the resource efficiency

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    Slowing down the rate of consumption of resources

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    Closing the resource loops

All the practical strategies in transiting towards circular products such as eco-design, life extension, upcycling of resources, innovative business models, and the indicators used to measure the extent of circularity as well as the progress milestones are all based on these principles. With this background, it can be said that the indicators used for the circularity assessment of a product should measure the extent to which its material components are in a restorative flow, the lifespan or the number of uses compared to similar products (from competitors) [2], the economic value of the product (in particular, the ingredient materials) at its end-of-life, and also its social impact. The assessment of this data provides the overall circularity of a product, say a value between 0 and 1 or 1 and 100, and the necessary information to identify various aspects throughout its life-cycle to enhance the product circularity.

In general, a product that is manufactured using only virgin raw materials dumped in a landfill/incinerated at the end-of-life is considered a linear product  [2]. For example, a single-use plastic shopping bag made of petroleum-based virgin plastic disposed of in a landfill is linear, scoring 0 on a scale of 0–1. Contrastingly, a product made of recycled/renewable materials with high recycling efficiency and collected for recycling/component reuse is considered a circular product  [2]. For example, a pair of sports shoes made from 100% recycled plastics, used for a long time and collected back for recycling at the end-of-life, scores nearly 1 as the efficiency of recycling/upcycling is taken into account! However, most commercial products which are chartering towards circularity can be placed between 0 and 1, as they are partially circular.

Assessing the circularity of a product initially requires the understanding and analysis of various phases of the product’s life-cycle, namely, the design phase, the manufacturing phase, the useful phase, and the end-of-life phase (as shown in Fig. 6.1). For this, it is necessary to answer the following questions:

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    How circular is the product by design?

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    How resource-efficient is the manufacturing process?

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    How long or how many times the product can be used?

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    What is the upcycling/recycling/remanufacturing efficiency of the product?

These will provide an overall perspective of how circular the product is and what steps can be implemented to improve its circularity. Measuring the circularity of a product/service requires data obtained using indicators related to the aforementioned influencers.

Fig. 6.1
A table illustration of 4 columns represents stages. The products are listed at all stages. Some of the products are A, the design phase has raw materials and re-use of components. B, Manufacturing has wastage of raw materials and waste products. C, the Use phase has a number of uses. D, End of life has an efficiency of recycling and transportation.

Schematic representation of the factors influencing the circularity of a product at all stages of its life-cycle. Each of the influencers can be quantified using multiple indicators to measure the total circularity of a product considered

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2.1 Measuring Circularity of a Product and Circularity Indicators

In the past decade, many indicators have been proposed and implemented to assess an individual product (nano-level). Most of them are contributions from academic researchers [13] and a few tools/models involving multiple individual indicators presented by groups of experts from various organizations. These indicators can be broadly classified into (i) individual quantitative indicators and (ii) composite sets of indicators (including indexes, tools, and models) combining multiple individual indicators. These indicators generally focus on measuring one or two aspects of a product’s circularity rather than the total circularity throughout its life cycle. To better understand and analyze these indicators, they have been grouped into eight categories based on what they measure, namely, design, resource efficiency, lifetime extension, disassembly, remanufacturing, recycling, end-of-life management, and waste management as shown in Table 6.1.

Table 6.1 Circularity indicators for circularity assessment at the Nano level
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These indicators either measure how circular a phase in the product’s life cycle is concerning its resource/material mass or the economic feasibility of a particular circular process such as disassembly, recycling and remanufacturing. However, there are no indicators measuring the social contributions of a circular product. More importantly, there is a need to combine these indicators into a comprehensive set and close the gaps with new indicators for measuring the total circularity of a product. Besides, attention must be paid to avoid repeated counting of data for multiple indicators. This will ensure accuracy in uptake (for assessing higher levels of the economic hierarchy) or scaling of circularity information. Lastly, standardization of measuring processes (including the methods protocol and how the results must be expressed) and mandatory regulations for following the standards are quintessential in the evaluation of the nano-level.

3 Broadly Applied Methods and Case Studies

Currently, products are majorly being assessed either using MCI [19] or LCA [34] for understanding the circularity and sustainability respectively. Although the two methods seem similar, there are a few major differences. For example, MCI’s focus is on product-centric resource efficiency; whereas LCA concentrates mainly on the environmental impact of the product at all stages of its life-cycle. To elaborate, the LCA considers the environmental impact of the raw material extraction and transportation (inclusive of raw materials, finished products/components, and waste) whereas these factors do not have any weightage in MCI. Another difference between the two is that MCI was designed for mainly technological products, whereas LCA is broadly applicable. However, both methods are dependent on a database created using the MFA.

As discussed earlier, CE is a three-dimensional concept that encompasses environmental, social, and economic aspects. Therefore, for a standard method to assess the circularity of a product, it is necessary to couple the advantages of both MCI and LCA, and also introduce other important factors such as economic competitiveness and social impact (for example, the creation of jobs). The assessment framework must also be universally applicable for products from both technical and biological cycles.

In this section, due to the unavailability of details on MCI analysis and implementation for a specific commercial product [19], we have presented two case studies of commercial products assessed using the LCA method. These case studies clearly show how the assessment is done at every stage of the life-cycle from raw material acquisition to end-of-life using relevant indicators.

Fig. 6.2
A cycle illustration of the phases of the life cycle of a pair of jeans. The phases are cotton production, fabric production, garment manufacturing, transportation and distribution, consumer care, recycling, or end-of-life. If it is recycled, the cycle again starts from fabric production.

Reproduced from [35]; Copyright, 2017 Elsevier

Schematic illustration of the various phases of the life cycle of a pair of Levi’s® 501 jeans and the equivalent environmental impact caused in its entire life-cycle.

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3.1 Case Study I: Levi Strauss & Co. 501 Jeans Wear

Levi Strauss & Co. (LS &Co.), a pioneer in the apparel industry and a global leader in jeanswear, assessed the environmental impacts of their core set of products using LCA. Their first study was focused on the company’s US operations and was further expanded to cover the global scope. During the studies, they analyzed the environmental impacts of a pair of Levi’s® 501® jeans, a pair of Levi’s® Women’s jeans, and a pair of Dockers® Signature Khakis.

To understand how the LCA is applied to a commercial product, the case of the analysis of Levi’s® 501 jeans at every stage of its life cycle is presented. The life cycle of Levi’s® 501 jeans includes 6 phases (as shown in Fig. 6.2) [35, 36] and is listed below along with the key aspects of each phase.

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    Raw material production: Natural fibers agriculture (such as cotton which is 91% of the raw material), synthetic materials manufacturing, regeneration of fibers, extraction of metals (for buttons and zippers), materials derived from livestock (such as leather)

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    Intermediate production of fabric: Extrusion, spinning, weaving, dyeing, finishing, and sundries production (inclusive of molding and forming)

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    Apparel production (inclusive of packaging): Garment assembly (involving cutting, sewing, sundries application), garment finishing, and garment dyeing

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    Transportation and distribution: Transportation of raw materials and intermediate products, distribution of finished apparel to the retail stores, and waste disposal

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    Use phase: Wearing, washing, drying, ironing, and repairing

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    End-of-life/Recycling: Landfilling, incineration, biodegradation, and recycling.

Table 6.2 Categories of environmental impact obtained from the LCA of one pair of Levi’s® 501 jeans, measured and reported by Levi Strauss & Co. [36]
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Every phase of the life cycle consumes energy, water, and chemicals, and generates waste impacting the environment. Therefore, the amount of energy, water, and chemicals consumed and their environmental impact in terms of the carbon footprint are measured. Energy consumption for electricity, heating, and transport is measured in terms of the amount of fossil and renewable resources required for its generation. Measuring water depletion includes consumption of water from freshwater sources and pollution of water resources by the effluents. Regarding chemical footprint in the product’s life cycle, each phase requires different types of chemicals, spanning from fertilizers and pesticides for cotton cultivation, process chemicals such as dyes and detergents, and finishing chemicals, to plastics used in packaging. Hence, each of the chemicals used has to be taken into account with the respective usage quantities and the related environmental impact.

The measured indicators are further segregated into various impact categories to analyze the apparel’s impact on the environment throughout its life cycle. Then, the respective measured values are aggregated to find the total impact of the product in a particular category. The environmental impact categories with their total measured values of one pair of Levi’s® 501 jeans obtained from the LCA are listed in Table 6.2.

The LCA revealed that the major contributor to environmental degradation is the consumption of (i) water and (ii) non-renewable energy resources, for the production of cotton and consumer care (inclusive of washing frequency and drying across the globe) respectively. The other phases of the life cycle have a comparatively lesser impact on the environment.

To address these issues, LS &Co. has devised and implemented programs [36] such as (i) Water<Less® committing to reduce 50% of water being used by 2025, (ii) Better Cotton Initiative to source sustainably produced cotton, (iii) Wellthread to manufacture sustainable alternate raw materials, (iv) Responsible Sourcing inclusive of screening chemicals for Zero Discharge of Hazardous Chemicals (ZDHC) standards, adapting sustainable energy sources, and most importantly, educating consumers about their role in lowering the carbon footprint of their products.

Fig. 6.3
A flow diagram of the life cycle of single-use surgical masks. The stages are raw material acquisition, production, distribution, product usage, and end-of-life. The packaging waste and used face mask end at incineration and landfilling.

Reproduced from [37]; Copyright, 2021 Elsevier

Schematic illustration of the process map including all the stages of the life-cycle of single-use surgical face masks in Singapore. The life cycle of the single-use mask includes the materials input/output, electricity consumption for production, and other processes in the life-cycle contributing to the environmental impact.

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3.2 Case Study II Single-Use Surgical Face Mask

The COVID-19 pandemic, being an airborne infection spreading rapidly, has compelled people around the world to wear face masks as physical protection from the transmission of the infection [38, 39]. This has resulted in increased consumption of face masks, especially the single-use surgical type, as it needs zero maintenance and is economical. Consequently, billions of such masks are being manufactured, used, and disposed of; creating a huge environmental impact due to the resulting waste, compelling researchers across the world to study and assess the impacts.

Table 6.3 Environmental impact categories obtained from the LCA of one functional unit of single-use Surgical Face Mask [37]
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This case study presents the environmental impact of one functional unit (defined as the average number of masks needed per person for one month i.e. 30 masks at an average use of 1 mask/day) of single-use surgical face masks. The assessment was carried out using the LCA and the impacts have been represented in nine different categories. Since this study has been conducted in Singapore, the parameters considered in the analysis, such as the end-of-life treatment and transportation, are specific to this case.

Before discussing the LCA of the mask, its design/construction and end-of-life treatment need to be understood. The single-use surgical face mask is a 3-layered sandwich of melt-blown polypropylene between 2 layers of spun-bond PP with an aluminum nose adapter and polyurethane earloops.Footnote 5 These face masks are considered to be contaminated once worn and are either recycled or disposed of. Due to the absence of mask recycling facilities in Singapore, the used masks are incinerated along with the general municipal waste, and eventually, the residue is landfilled.

The study considered all the life-cycle phases from raw material acquisition to end-of-life as shown in Fig. 6.3, and the assessment process of each stage is explained below.

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    Raw material acquisition: An inventory of the emission factors of the feedstock required for the production and packaging of the masks is created to measure the cumulative emission.

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    Production: The electricity and water usage for the production and packaging processes are accounted for and their equivalent carbon emissions (in Singapore) were calculated.

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    Distribution: The fossil fuels used in transportation are taken into account to calculate the carbon emissions.

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    Product Usage: One functional unit (FU) of masks is defined as the consumption of masks for a person in a month (taken as 31 days) with the duration of usage per day assumed to be less than 12 h. Therefore, 1 FU is considered equivalent to 31 single-use surgical face masks and is used to calculate the consumption.

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    End-of-life: The amount of waste generated (by weight) after use was calculated and the emissions in treating the waste were taken into account.

The emissions measured were further categorized into major environmental impacts and a cumulative value for each category was obtained. These categories with their respective measured values have been listed in the Table 6.3.

These measured values may seem insignificant when perceived for 1 FU, however, they are quite impactful when scaled to the consumption rate of a large population over a long period. Also, it was identified during the study that raw material acquisition is the highest contributor to the carbon emissions and pollution of water bodies. Therefore, an efficient recycling process could lower the long-term environmental impact of single-use surgical face masks.

4 Concluding Opinion: Material Efficiency for Product Circularity

This chapter gives an insight into how most products are currently assessed to understand their environmental impacts. However, circularity assessment does not limit to environmental impacts and extends to social and economic impacts as well, as discussed in Chap. 1. More importantly, the purpose of circularity assessment of products is to slowly close the resource loops using strategies such as redesigning products and introducing new business models [5, 12, 40]. Designing a circular product or refashioning an already existing commercial product into a circular one requires the implementation of multiple strategies.

As we have discussed various circular business models such as extending the lifetime of a product through repairing and IS, we consider design strategies that augur well with the business models. Materials play a vital role when it comes to designing circular products [41, 42]. This means that at the conceptual stage of a product, the ingredient materials chosen should enable circularity and the product design should allow efficient recycling of the used materials. Therefore, the choice of materials should be such that it-

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    allow usage of secondary materials [35] and less material by weight for an efficient product design,

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    is non-hazardous to the environment and the biota,

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    has a low carbon footprint (emissions associated with producing and processing of materials),

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    can be efficiently and economically recycled,

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    promotes the reusability of materials in the form of durable components (for example, hard disks and other electronic components).

Following these strategies in designing products at the nano systemic level can also enable achieving the goal of closing the resource loops at a macro level.