A LifeCycle Analysis and Economic Cost Analysis of Corrugated Cardboard Box Reuse and Recycling in the United States

Abstract

Manufacturing of a product such as a corrugated cardboard box (CCB) includes the extraction of a variety of raw materials in addition to supply chain efforts to get the raw materials to the industry. Conducting a LifeCycle Assessment (LCA) gives the carbon emission of each phase of the product and a quantitative estimate of the overall product carbon footprint and its effect on the environment. This gives impetus to recommendations for improving the phases of the lifecycle to minimize carbon emissions. The proposed waste management method in this paper is the “reuse” method instead of recycling or landfilling the CCB and, in so doing, focusing only on reducing carbon emissions in the manufacturing phase. The paper examines if the incremental cost of reusing the CCBs is less than the environmental and economic cost of reducing the extraction and supply chain of raw materials. This paper uses LCA to evaluate the carbon emission in each phase of the lifecycle of a typical 1 kg corrugated cardboard box in the United States. Carbon emission for the proposed “reuse” phase is also calculated, and the results are compared. This paper also explores the economic feasibility of the proposed “reuse” method that incentivizes the general population to reuse the CCBs instead of recycling or landfilling them. Economic tools such as willingness-to-pay vs. marginal cost curves and benefit-cost analyses are used to evaluate economic feasibility. The results indicate that the “reuse” method for CCBs is economically and environmentally feasible. It also supports the approach of using analytics, economics, and LCA to create a model that can be used for other products and processes as an evaluative process to determine if businesses can benefit from the reduction (or removal) of material extraction costs from the supply chain.

1. Introduction

The current lifecycle of corrugated cardboard boxes (CCB) starts with the manufacturing of the CCBs with raw materials such as hardwood, softwood, and adhesives. These raw materials are collected and transported to the location of the pulp-making operation. The pulp is made out of softwood and hardwood to form fibers which are then combined with recycled fibers to manufacture paper. Next, the manufactured paper is transported to the location of the converting operation. Two types of paper are used in manufacturing the CCBs: liner and medium. CCBs comprise a corrugated board that is made up of three layers of corrugated sheets (an inside liner, an outside liner, and a medium that goes between the two, which is fluted). The corrugated board is formed in the required shape and size of CCBs. Once the CCBs are formed, they are shipped to the required location (e.g., retail stores), where they start their use phase. In this phase, they are mainly used as outer packaging material for the transportation and shipping of goods and products. In the disposal phase, the CCBs are either recycled or landfilled. A huge amount of the supply chain goes into extracting raw materials, such as cutting hardwood and softwood trees and processing them. Additionally, extraction plays a role in the recycling phase, where the recycled fibers are extracted from old CCBs.

Previous work [1] has laid the groundwork for this research paper. This previous work discussed pollution and the current efforts to reduce global warming and climate change. It focused on recycling waste and the two main shortcomings of recycling corrugated cardboard boxes (CCB). First, out of 100 billion boxes produced in the U.S. each year, only 70–75% of the boxes are received for recycling [2,3]. Second, a typical CCB contains only 50% of its fibers from recycled fibers [4,5]. Previous work showed that one of the main reasons for the low recycling rate is the lack of motivation in the general population. In order to address this, the authors proposed a way to “reuse” the CCB instead of recycling it in addition to testing different types of motivation tools. The paper proposed a new motivation means by combining persuasion techniques (ethos, pathos, logos, and aesthetics) and operant condition techniques (positive reinforcement, positive punishment, negative reinforcement, and negative punishment). After conducting two surveys and analyzing the data with various tools, the same paper recommended using “positively-reinforced ethos” as an incentive for the general population to reuse the CCB over recycling or landfilling it. Lastly, the paper also gave the cost of positive reinforcement ($1.81) and the cost of ethos ($1.79). This mean value is used in this study, with the cost of motivating the general population using positive reinforcement ethos being assigned a value of $1.80. The proposed “reuse” cycle includes the general population allocating the CCB they received to “reuse” containers. Then these boxes would be collected by a truck and transported to the location where the CCBs are checked and resold to the general population. When the CCBs are not in a condition to be reused, they are assigned to recycling. Reuse is generally thought to be more sustainable for industries because it will eliminate/decrease certain supply chains and/or extraction of raw materials. Thus, it is important to examine if the environmental and economic cost of reducing the extraction is able to offset the additional cost of recollection and incentives.

Thus, [1] answers questions on motivation and incentives that will work to motivate the general population to reuse and the cost of the incentive to motivate. However, from a systems standpoint, it is also (possibly more) important to determine the amount of carbon that is saved by reusing the CCB instead of recycling it or landfilling it. Moreover, is the reusing process economically feasible? Thus, this paper evaluates the carbon emission of CCB with different disposal scenarios (reusing, recycling, and landfilling). It will also evaluate the economic aspects of the “reuse” process to test its economic feasibility.

2. Materials and Methods

There are many methods to evaluate the carbon emission of a product. Based on the scope, it can be broadly categorized into two types, cradle-to-gate and cradle-to-grave. The cradle-to-gate method includes all the pollution from raw material gathering to packaging and shipping of the final product. It excludes the use phase and disposal phase. The cradle-to-grave method, in contrast, includes all the emissions over the entire life of the product.

2.1. Lifecycle Assessment

Life Cycle Assessment (LCA) was used to calculate the carbon emission of CCB over its life cycle. Ref. [6] defines LCA as “an environmental accounting and management approach that considers all the aspects of resources use and environmental releases associated with an industrial system from cradle-to-grave.” The lifecycle of a corrugated cardboard box can be divided into four parts: pulp-making, converting, use phase, and end of the lifecycle. To calculate the carbon emission in these stages and to estimate total carbon emission over the life cycle of a corrugated cardboard box, LCA is carried out. The LCA methodology used in this research follows the international organization for standardization’s ISO 14040 and ISO 14044. The methodology to conduct an LCA consists of four steps:

• Set Goal and Scope;

• Life Cycle Inventory (LCI) Analysis;

• Life Cycle Impact Assessment (LCIA);

• Interpretation of Results.

2.1.1. Set Goal and Scope

The main product under study is a single-walled corrugated cardboard box. A recent study [5] conducted by Fibre Box Association shows that an average corrugated cardboard box is made up of 50% recycled fibers. Thus, the product that is modeled and considered in this study is assumed to be manufactured with 50% recycled fibers. The function assumed for the product under this study is the domestic use of the average corrugated cardboard box produced in the U.S., namely, that of using the corrugated box mainly as a secondary packaging of products for shipping and transportation. The functional unit is defined as the domestic use of 1 kg of an average single-walled corrugated cardboard box produced in the United States. The goods that the corrugated cardboard box would carry are not considered in this study.

The system boundary includes the following four steps of the lifecycle of the corrugated box, which is set concerning a cradle-to-grave approach, i.e., from raw material extraction to the disposal of the product:

Pulp-making: This includes forest operations (cutting down the trees), transportation of the wood, chipping operation (converting wood into small chips), production of pulp from the chips, paper-making operation from pulp, conversion into a roll, and all the support operations such as steam/heat generation, chemical generation, etc.

Converting: This includes the transportation of paper to converting operations, the converting operation, which includes converting the liner board and corrugated medium into a corrugated box, and all the other supporting operations.

Use: This includes the transportation to use phase and the assumed transportation of the box in its use phase.

End-of-lifecycle (EoL): This includes the transportation of corrugated boxes from the use phase to the EoL phase and the energy and emission from the EoL processes such as landfilling, recycling, and burning.

Capital equipment, maintenance, transport of employees, and operation of support equipment are not included in the scope of this study. The energy required to pack a product in the use phase is also not considered in the scope. Wood and coal ashes are considered residual waste in the production process of CCB. The co-products—turpentine and tall oil—that are produced during the manufacturing process of CCB are very small in number and quality compared to CCB. Thus, co-product allocations are ignored as different allocation procedures are likely to have insignificant effects on the results.

2.1.2. Life Cycle Inventory Analysis

In the Life Cycle Inventory Analysis step, a description of the material used in the lifecycle of the product is expected. It also includes energy flows within the system as well as the system’s interaction with the environment. The life cycle inventory data for a corrugated cardboard box is taken from a report [7] published by NCASI in 2017 as a reference, and the model is built upon it. The reference report has collected data with the help of surveys from corrugated cardboard manufacturing industries in the United States. Inventory data is divided in terms of stages of the lifecycle and are specified below.

Pulp-Making Phase

The pulp-making process consists of many different processes, inputs, and outputs that are outlined in Figure 1.

Thus, the above figure outlines the life cycle process of the corrugated box, from raw materials such as wood logs and wood chips to the end product of the containerboard. It also specifies the energy consumed as well as the byproducts of this process. It is also important to specify the input-output to the production of the containerboard unit process per functional unit, as given in Table 1.

Converting Phase

Converting process consists of many different processes that are outlined in Figure 2.

Thus, the above figure outlines the life cycle process of the corrugated box’s converting process, which gets the containerboard as input from the pulp-making step, which is then converted to a corrugated cardboard box. It also specifies the energy consumed as well as the byproducts of this process. It is also important to specify the input-output to converting unit process per functional unit, as given in Table 2 below.

Use Phase

This phase consists of the use of the corrugated box to ship other products by various consumers. Calculating carbon emission for this phase is very difficult, as it depends on the content inside the corrugated box and distance, as well as the mode of transport used for shipping purposes. Thus, certain assumptions are made to calculate carbon emissions in this phase. The United States Census Bureau’s data on commodity flow is used as the reference data to calculate the shipping distance of a representative corrugated box in the United States. This data was published in 2017 in the CFS preliminary report: Shipment characteristics by total modal activity [8]. Below is the available data in Table 3.

End-of-Lifecycle

The End-of-Lifecycle of the corrugated cardboard box is modeled with respect to the data from the United States Environmental Protection Agency from 2018 as shown in Table 4 [9].

Thus, the end of the life cycle of corrugated cardboard boxes is modeled with respect to the recently available data from 2018. Recycling of CCB is 80.88%, landfill of CCB is 15.37%, and combustion of CCB is 3.75%.

Apart from the material use and energy consumption data, it is also important to specify the reference data on the electricity generation and transportation values used as assumptions for modeling. Data on the U.S. average electricity grid fuel consumption mix used for 2021 is shown in Table 5 below (U.S. Energy Information Administration) [10].

All energy used in the input of the operations is considered electricity. Thus, electricity is modeled in OpenLCA, as given in Table 6 below.

The amount of electricity is based on the national average (mean) in the United States. Since the database did not include electricity produced from solar, other gases, geothermal, and other sources, they are all added to the “average electricity mix”.

Data on transportation distances were modeled using the NCASI report [7] from 2017, which is given in Table 7 below.

2.1.3. Life Cycle Impact Assessment (LCIA)

This step includes describing the selected impact categories for LCA analysis as well as describing the method used to calculate the impact category. There are many impact categories as a list of commonly used categories is specified in ISO 14047 Technical Report (ISO2012a): global warming, human toxicity, stratospheric ozone depletion, depletion of abiotic resources, photo-oxidant formation, nitrification, ecotoxicity, acidification, and the depletion of biotic resources. Since this study focuses on the carbon emission of 1 kg of corrugated cardboard box over its lifecycle, three impact categories are used as follows:

• Global warming, Fossil;

• Global warming, Biogenic, GWP 20 years;

• Global warming, Biogenic, GWP 100 years.

The impact category listed above are custom-made impact categories that are formed by combining the following standard impact categories:

• GHG Protocol;

• Environmental Footprint;

• IPCC 2013 GWP 20;

• IPCC 2013 GWP 100.

Impact categories depend on the impact factors included in their respective category. Impact factors for the three impact categories used in this study can be made available upon request to the authors. It is important to note that the Global Warming Potential (GWP) values for the impact factors are mainly derived from the Fifth Assessment Report (AR5) of IPCC (IPCC 2013, Table 8.A.1) [11].

2.1.4. Interpretation of Results

This step is done in the next two sections (Section 3 and Section 4) of this research paper.

2.2. Economic Model

It is also important to look at the economics of reusing corrugated cardboard boxes instead of landfilling them or recycling them. Two concepts are used in this research to study and model the economics of this proposed “reuse” of corrugated boxes—benefit-cost analysis and marginal cost–willingness-to-pay curve.

Benefit-cost analysis is simply a method to evaluate something by considering its potential cost and benefits. According to Ref. [12], “Benefit-cost analysis is for the public sector what a profit-and-loss analysis is for a business firm or a budget is for a household.” Benefit-cost analysis is a tool used from society’s standpoint to make a public decision instead of a single profit-making firm. The basic framework for benefit-cost analysis is used with reference to Ref. [12], which includes the following four steps:

• Clearly specify the project or program;

• Describe the inputs and outputs of the program quantitatively;

• Estimate the value of social costs and benefits of these inputs and outputs;

• Compare these benefits and costs.

Marginal cost, or willingness-to-pay curves, can simply be imagined as supply and demand graphs with respect to the prediction of demand and ability to supply. According to Ref. [12], a “willingness-to-pay for a given consumption level is the total amount a person would be willing to pay to attain that consumption level rather than go without the good entirely.” In other words, willingness-to-pay is the maximum amount an individual is willing to pay to acquire a good/service. According to Ref. [13], “Marginal cost is the increment in cost that occurs when the output produced is increased by one unit.” Therefore, marginal cost is the difference in total cost that is experienced when the quantity of production is increased or the cost of producing one additional product is.

3. Results

3.1. Carbon Emission for Pulp-Making and Converting Operations

LCA modeling was conducted on OpenLCA software version 1.11.0 for pulp-making and converting operations. The databases specified under Table 8 were combined and used to model the pulp-making and converting operations.

Thus, baseline data is used from these databases. OpenLCA is used to calculate the carbon emission for pulp-making and converting operations (excluding transportation). Table 9 below shows the results from OpenLCA software for the two phases.

3.2. Carbon Emissions from Transportation

Carbon emission from the transportation of goods is calculated by using the following formula:

Carbon emission (kgCO₂-eq) = (Weight of the product in kg) × (Distance traveled per vehicle/mode of transport in km) × (Emission factor for respective vehicle/mode of transport in kgCO₂-eq/kg.km)

The product’s weight and travel distance are specified in the Life cycle inventory section. The emission factors are from the United States Environment Protection Agency‘s GHG emission factors Hub, as shown in Table 8 (April 2022) [24]. Below are the results in Table 10 and Table 11 for the transportation based on phases of the lifecycle.

3.3. Carbon Emission for Use Phase

It is difficult to identify/calculate the distance traveled by an average CCB and its mode of transport. In general, corrugated cardboard boxes are mainly used for packaging and transporting products. Usually, this phase is ignored, and the carbon emission from the use phase of CCB is allocated to the product that CCB holds for the sake of its transportation. To approximately calculate carbon emissions from this phase, the mean distance traveled by the average corrugated box with respect to the mode of transport is given in Table 12 which is obtained from the United States Census Bureau’s CFS Preliminary Report (CF1700P2): Shipment characteristics by total modal activity (2017) [8]. Here, the mass of the product is considered to be 1 kg as the functional unit in this research is 1 kg of CCB.

3.4. Carbon Emission for the End-of-Lifecycle (EoL) Phase

To calculate carbon emission at the EoL phase of 1 kg of CCB, it is important to understand the waste management methods used and emissions from respective methods. The reference data from 2018 is specified under the lifecycle inventory step in Table 4. Out of the total waste collected, 81% is recycled, 4% is combusted, and 15% is landfilled. To calculate the carbon emission from each of the above management pathways, the authors use emission factors from the United States Environment Protection Agency‘s GHG emission factors Hub, as shown in Table 9 (April 2022) [24]. The emission factors from this reference data include the actual emission from the management pathway as well as the transport of the waste. Table 13 shows the data for emission factors of CCB for different waste management methods.

Carbon emission from EoL in kgCO₂-eq = Weight of CCB (kg) × percentage of management pathway × emission factor for respective management pathway (kgCO₂-eq/kg).

Carbon emission from EoL in kgCO₂-eq = (1 × 0.81 × 0.12125) + (1 × 0.04 × 0.05511) + (1 × 0.15 × 0.9920).

Carbon emission from EoL = 0.2492 kgCO₂-eq.

3.5. Carbon for the Newly Proposed “Reuse” Phase

The “Reuse” phase proposes collecting used corrugated boxes similar to trash/recycling waste and then checking for usability and reselling the box to be reused. The proposed phase is imagined as a truck driving toward the individual’s location to collect old CCB as well as to collect trash. To calculate the carbon emission in the transportation of CCB from a general person’s location to a local collection point to reuse the CCB, it is important to identify the average distance the collection truck would travel. The United States Environment Protection Agency‘s Waste Transfer Stations, a manual for decision-making reports, was used [25]. The report refers to the break-even point between the hauling cost and round-trip distance. The break-even point is 35 miles round trip from the waste source to the disposal. Thus, the transportation for this “reuse” phase is assumed to be 35 miles round trip. For emission factors, the United States Environment Protection Agency‘s GHG emission factors Hub (April 2022) was used and is shown in Table 8 [24].

Carbon emission from “Reuse” phase in kgCO₂-eq = Weight of waste (kg) × Distance of travel (mile) × Emission factor (kgCO₂-eq/kg-mile)

Carbon emission from the “Reuse” phase in kgCO₂-eq = 1 × 35 × 0.00023

Carbon emission from the “Reuse” phase = 0.00805 kgCO₂-eq

Thus, the carbon emission for each phase of the lifecycle is given in Table 14.

Thus, below are the overall results:

• The carbon emission of a CCB over its lifecycle (excluding the Reuse phase) is 4.45677 kgCO₂-eq for single use;

• The carbon emission of a CCB reused once (including the Reuse phase once and Use phase twice) is 5.84332 kgCO₂-eq, i.e., 2.92166 kgCO₂-eq per use;

• The carbon emission saved by the “reuse” cycle for every use would be 4.45677 − 2.92166 = 1.53511 kgCO₂-eq per use.

In order to show relative comparisons among multiple studies, Table 15 compares these results with the previous literature conducted on carbon emissions from CCBs.

3.6. Economic Modeling: Benefit-Cost Analysis

The functional unit considered in this paper is 1 kg of CCB. Thus, a CCB of 18 3/8 × 18 3/8 × 18 5/8″ (±1/8″) dimension is considered. The mass of this particular CCB is 1.01 kg. This particular CCB is currently (December 2022) sold at $2.83 [29]. It is assumed that the cost of a new CCB ($2.83) includes the cost of manufacturing, transportation, and profits (i.e., there is no net external subsidization). The cost of motivation for reuse with a “Positive Reinforced Ethos” incentive is $1.80, as mentioned in Ref. [1]. Also, it is important to assume and evaluate the cost of reselling CCB. The selling price of a used box to resell is assumed to be $2. Another assumption made for this calculation is that the benefit-cost analysis is carried out for a total of 100,000 boxes. This means we assume there is a need to use 100,000 boxes. Now in this scenario, it can be the use of 100,000 new CCBs or 50,000 boxes which are reused once in their lifecycle as proposed. To perform a benefit-cost analysis, it is important to identify benefits and costs for the newly proposed “reuse” phase.

Benefits:

• Social cost: It is also important to evaluate the social cost of carbon emissions to use in economic modeling. According to Ref. [30], the social cost of carbon could be $900/tCO2, i.e., $0.9/kgCO₂;

• Cost saving for second use: This is the cost that is saved by using a used box instead of a new box. Basically, it is the cost of production, transportation, and profit of the new box that is saved. In other words, the number of reused boxes is multiplied by the cost of the new box ($1.83). This is beneficial as the “reuse” cycle saves the cost of manufacturing and operating costs.

Cost:

• Cost of motivation: This is the cost that is needed to motivate the general population to assign their CCBs to the “reuse” cycle. This cost is $1.80 per box;

• Cost of reselling the CCBs: This is the cost that individuals pay to buy the reused boxes. This cost includes the operation cost plus the profit for the entity that would coordinate the whole “reuse” cycle.

Thus, the benefits-cost analysis is shown in Table 16.

Sensitivity Analysis

• 1.. Case I: Lowest cost of a new box ($1.17) for the “reuse” cycle to be profitable as shown in Table 17.

• 2.. Case II: The highest cost of a used box ($3.66) for the “reuse” cycle to be profitable as shown in Table 18.

• 3.. Case III: Highest cost for motivation ($3.46) for the “reuse” cycle to be profitable as shown in Table 19.

3.7. Economic Modeling: Marginal Cost–Willingness-to-Pay Curves

Willingness-to-pay (WTP) for a new CCB is evaluated by considering eight CCBs with different dimensions and thicknesses as shown in Table 20. The reference data is used from “Uline” company’s catalog. It is made sure that the mean weight of all eight CCBs is equal to 1 kg.

Although WTP for old CCBs is not available, the authors assumed that the WTP curve for old CCBs would be proportionate to that of the WTP curve of new CCBs. Thus, the slope of the WTP curve for the new CCBs was calculated. In order to draw the WTP curve for old CCBs, the mean of all the prices from Table 20 (i.e., $3.686) is taken and is assumed to be proportionate to $2, which is the assumed cost for old CCBs. Thus, that is how values of cost for different numbers of old CCBs are evaluated, as shown in Table 21:

The marginal cost curves are evaluated from the database collected for the previous survey [1]. In this survey, the authors asked 13 quantitative questions related to incentives with the help of specific persuasion techniques. Thus, a mean of 13 quantitative questions was taken for each of the 92 participants and categorized them with respect to persuasion techniques. Therefore, there are four marginal cost curves for aesthetics, ethos, logos, and pathos. To plot the WTP and marginal curves, the number of boxes (x-axis) is normalized from 0 to 1. The marginal cost curves show the relation of money to acquire more boxes via the “reuse” cycle. The willingness to pass curve shows the relation of money to consumers buying the number of boxes. Thus, Figure 3 below shows WTP and marginal cost curves for CCB.

4. Discussion

OpenLCA software is a tool that uses different databases to get the baseline values and properties of the materials and processes. Thus, multiple databases listed under Table 8 were combined to get more precise and specific data to model the CCB lifecycle. Once the model is complete, emission analysis is carried out with a custom impact method, as explained in the methodology section. There are two types of carbon emissions: fossil and biogenic carbon emissions. The only difference between both is their source of carbon emissions. For fossil carbon emission, the source is fossil fuels, and it exposes carbon to the atmosphere, which was trapped in geological reserves for many years. On the other hand, biogenic carbon emission is from woody biomass. The carbon emission from biomass is not trapped for a long time, as the carbon is absorbed from the atmosphere by the biomass. For this paper, authors have considered overall carbon emissions (excluding biogenic CO₂ emission). Thus, the results from OpenLCA software consist of the production of CCB ignoring the transportation of the material. As explained in the introduction, pulp-making operations use more energy and have more steps in order to convert the raw material into a paper sheet which explains the high carbon emission in pulp-making operations compared to converting operations. In terms of the transportation of materials and products in pulp-making operations and converting operations, the carbon emission in the converting phase is more than that of the pulp-making operation. One of the main reasons for this is the transportation of containerboard and corrugated sheet to the converting operations, as these are mainly done with the help of trucks. In addition, the transportation of corrugated products to use phase uses trucks as a primary mode of transportation which further adds to carbon emissions. The carbon emission in the use phase is the second highest contributor to the carbon emission of CCB over its lifecycle. One of the main reasons for the high carbon emission in the use phase is the transportation of packages by air. The transportation of CCB by air alone contributes to 93.7% of total carbon emissions in the use phase. From the EoL phase, it is important to notice that the emission factor for recycling waste is more than from the combustion of waste. Thus, 59.7% of the carbon emission in the EoL phase is due to landfilling of CCBs, and 39.4% is due to the recycling of CCBs. The carbon emission of the reuse phase is just 0.18% of all the other phases combined (the current CCB lifecycle). Thus, the current CCB lifecycle carbon emission is 4.46 kgCO₂-eq (single-use CCB). Although the carbon emission from CCB is higher compared to the other literature, as shown in Table 15, it is important to note that the carbon emission values heavily depend upon the scope and assumptions of the LCA process. Another reason for higher carbon emissions could be because the authors have tried to be more compressive/exhaustive about all the possible carbon sources compared to other papers. The carbon emission for a reused box (used once and reused once) is 2.92 kgCO₂-eq per use. Thus overall, the reused CCB would save 1.54 kgCO₂-eq for the second time it is used as well, as it will save on the efforts of producing a new CCB.

The overall result from the benefit-cost analysis shows that for the assumed 100,000 uses of a CCB, the 50,000 reused CCBs would give a net profit of $83,103 with a benefit-cost ratio of 1.44. Although the benefit-cost analysis depends on the assumption made with respect to the operating cost of reuse and resell value of the reused box, sensitivity analysis is carried out to test the boundaries of this business model. The business can break even without making a profit if the cost of the new box is lowered to $1.17, if the reused box is sold at its maximum price of $3.66, or if the cost for motivation is increased to its highest limit of $3.46. Going above the limit specified will adversely affect the profitability of the reuse cycle. The marginal cost and WTP curves give a brief idea of the supply and demand of the CCBs. It can be observed from the graph that the marginal cost of ethos is significantly less than that of the marginal costs of aesthetics, logos, and pathos. Thus, motivating the general population with ethos will have more individuals participating in the reuse cycle at a lower cost. The WTP of the new CCB is included for reference, but the main output of the graph is the intersection point between the WTP of the old CCB and the marginal curves. The point of intersection between the marginal cost curve and the WTP curve is the economic efficiency point. The point of intersection “X” is where the cost of motivation for the used CCB is just exactly equal to the marginal value of the CCB. Thus, the quantity “Qx (0.6022)” at value ‘Px ($1.825)’ is efficient because it produces a balance between the marginal worth of CCB and what it costs to motivate the general population as measured in the marginal cost curve.

5. Conclusions

The purpose of this study was to introduce a new sustainable, feasible way of handling the disposal of CCBs. This paper calculates the carbon emission of CCBs for their current lifecycle, which is 4.46 kgCO₂-eq. The paper also explains the proposed “reuse” phase, which allows individuals to use a single CCB multiple times. If the CCB is reused once, then it consists of two use phases which means the overall carbon emission for each use drops from 4.46 kgCO₂-eq to 2.92 kgCO₂-eq. This significantly decreases carbon emissions of CO₂ by approximately 34.44%. Thus, by conducting a life cycle analysis, it can be concluded that “reuse” is more sustainable compared to recycling in terms of environmental gains.

It was observed that in terms of economic analysis, the benefit-cost analysis gave a benefit-cost ratio of 1.44 for base assumptions. The sensitivity analysis gave a brief idea of the boundary conditions for this model to keep the benefit-cost ratio above or equal to one. Marginal cost versus willingness-to-pay curves indicated that out of the four available persuasion techniques, the use of ethos for incentivization gave more boxes to be reused at the lowest cost. This further supports the recommendation of a previous paper [1] to use ethos to motivate the general population. Thus, it can be concluded from the benefit-cost analysis and cost curves that “reuse” is more sustainable compared to recycling in terms of economic feasibility. The approach that authors took in this research paper—simultaneously including analytics, WTP and marginal cost curves, and LCA—suggests a model repurposable for use in other products and processes where one can incentivize the general population to take pressure off of the extraction industry as a part of the business. This will allow businesses to take out or lower the extraction needs from similar industries, which would promote sustainable efforts.

The future scope and prospects of this research include how to assess other sustainable efforts for their feasibility across the whole lifecycle and how to evaluate the monetary aspect of the sustainable effort with the help of economics. Although it is well-known that CCBs can be used multiple times in an industrial setting [38,39], it is also important to explore the feasibility and practicality of the implementation of the proposed reuse process. There is a strong possibility of the use of this framework to evaluate other sustainable efforts, such as promoting the use of sustainable cars.

Author Contributions

Conceptualization, H.K. and S.S.; methodology, H.K. and S.S.; formal analysis, H.K. and S.S.; writing—original draft preparation, H.K.; writing—review and editing, S.S.; visualization, H.K.; supervision, S.S.; funding acquisition, S.S. All authors have read and agreed to the published version of the manuscript.

Institutional Review Board Statement

Not applicable.

Informed Consent Statement

Not applicable.

Data Availability Statement

The data on the list of impact categories and their GWP values is available upon request.

Acknowledgments

We wish to show our appreciation to Angie Chromiak for guiding us through the IRB application. We would also like to thank the following people for helping us with the distribution of surveys and administrative tasks: Ingrid Bridge, Chrissy Charny, Debra Dandaneau, and Mary Gomez.

Conflicts of Interest

The authors declare no conflict of interest.

Footnotes

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Figures and Tables

Figure 1. Inputs and outputs of pulp and paper-making operation.

Figure 2. Inputs and outputs of converting operation.

Figure 3. Cost curves: WTP curve vs. Marginal cost curve.

Table 1

Input/Output material and energy for production on containerboard [7].

Input/Output	Quantity	Unit
INPUTS
Resources
Water intake	30.9	kg
Fiber raw material
Hardwood logs	0.14	kg
Softwood logs	0.58	kg
Purchased hardwood chips	0.10	kg
Purchased softwood chips	0.32	kg
Recovered fiber	0.57	kg
Chemicals
Sodium hydroxide (Caustic)	7.6 × 10−3	kg
Sulfuric Acid	1.2 × 10−2	kg
Aluminum Sulfate	2.7 × 10−3	kg
Starch	5.4 × 10−3	kg
Lime	9.0 × 10−3	kg
Soda	3.6 × 10−3	kg
Pitch dispersant	6.0 × 10−5	kg
Strength agents	7.0 × 10−3	kg
Other fillers	5.5 × 10−3	kg
Energy
Electricity	8.55	MJ
Purchased power	1.66	MJ
Purchased steam	0.77	MJ
OUTPUTS
Products and co-products
Containerboard	1.10	kg
Turpentine and tall oil	0.017	kg
Sold power	0.07	kWh
Emission to air
Nitrogen oxides (NOx)	1.56 × 10−3	kg
Sulfur oxides (Sox)	1.15 × 10−3	kg
Total reduced sulfur (TRS), as H2S	7.71 × 10−5	kg
Particulates	6.11 × 10−4	kg
Carbon monoxide (CO)	2.57 × 10−4	kg
Carbon dioxide (CO2), biogenic	1.23	kg
Carbon dioxide (CO2), fossil	0.331	kg
Methane (CH4), biogenic	1.22 × 10−3	kg
Methane (CH4), fossil	1.3 × 10−5	kg
Nitrous oxide (N2O)	5.01 × 10−5	kg
Evaporated water	3.67	kg
Emissions to water
Process effluent	26.8	kg
Cooling water discharges	1.82	kg
Adsorbable Organic Halides (AOX)	4.21 × 10−6	kg
Biochemical oxygen demand (BOD5)	9.73 × 10−4	kg
Total suspended solids (TSS)	1.34 × 10−3	kg
Total nitrogen	2.04 × 10−4	kg
Total phosphorus	3.45 × 10−5	kg
Residuals
Wastewater treatment plant residuals	0.036	kg
Wood ashes	0.023	kg
Coal ashes	0.006	kg
Other solid wastes	0.049	kg

Table 2

Input/Output material and energy for production on corrugated boxes.

Input/Output	Quantity	Unit
INPUTS
Resources
Water intake	0.457	kg
Fiber raw material
Containerboard	1.10	kg
Chemicals
Starch	2.00 × 10−2	kg
Wax	3.76 × 10−3	kg
Ink	1.30 × 10−3	kg
Adhesive	1.61 × 10−3	kg
Coating	5.13 × 10−4	kg
Borax	3.03 × 10−4	kg
Resin	3.38 × 10−4	kg
Sodium hydroxide (Caustic)	5.51 × 10−4	kg
Energy
Electricity	1.40	MJ
Purchased power	0.142	MJ
Purchased steam	2.41 × 10−3	MJ
OUTPUTS
Products and co-products
Corrugated cardboard box	1.0	kg
Emission to air
Nitrogen oxides (NOx)	5.09 × 10−5	kg
Sulfur oxides (Sox)	1.03 × 10−6	kg
Particulates	4.37 × 10−5	kg
Carbon monoxide (CO)	5.44 × 10−5	kg
Carbon dioxide (CO2), fossil	8.51 × 10−2	kg
Methane (CH4), fossil	1.46 × 10−6	kg
Nitrous oxide (N2O)	2.37 × 10−7	kg
Non-methane VOCs	1.39 × 10−4	kg
Evaporated water	0.215	kg
Emissions to water
Effluent, direct	0.0133	kg
Effluent, indirect and other	0.252	kg
BOD, direct	4.53 × 10−6	kg
TSS, direct	2.52 × 10−6	kg
Residuals
Converting losses to recycling	0.125	kg
Other solid wastes	0.049	kg

Table 3

Data from 2017 CFS preliminary report: Shipment characteristics by total modal activity.

Mode of Transport	Year	Ton-Miles (Millions)	Ton-Miles (Percent of Total)	Average Miles per Shipment
Truck	2017	1,347,240	43	186
Rail	2017	1,460,158	46.6	969
Water	2017	216,794	6.9	439
Air	2017	6560	0.2	1006
Other	2017	27,189	0.8	886

Table 4

Total paper and paperboard containers and packaging in MSW by weight (in thousands of U.S. tons).

Management Pathway	2000	2005	2010	2015	2017	2018
Generation	39,940	39,640	37,680	39,920	41,060	41,900
Recycled	21,040	23,610	26,850	31,200	30,080	33,890
Composted	-	-	-	-	-	-
Combustion with Energy Recovery	3670	2920	1920	1710	2160	1570
Landfilled	15,230	13,110	8910	7010	8820	6440

Table 5

U.S. utility-scale electricity generation by source, amount, and share of the total in 2021.

Energy Source	Billion kWh	Share of Total
Total—all sources	4108
Fossil fuels (total)	2508	61.0%
Natural gas	1579	38.4%
Coal	898	21.9%
Petroleum (total)	19	0.5%
Petroleum liquids	12	0.3%
Petroleum coke	8	0.2%
Other gases	11	0.3%
Nuclear	778	18.9%
Renewables (total)	815	19.8%
Wind	378	9.2%
Hydropower	252	6.1%
Solar (total)	115	2.8%
Photovoltaic	112	2.7%
Solar thermal	3	0.1%
Biomass (total)	54	1.3%
Wood	36	0.9%
Landfill gas	9	0.2%
Municipal solid waste (biogenic)	6	0.1%
Other biomass waste	2	0.1%
Geothermal	16	0.4%
Other sources	12	0.3%

Table 6

Electricity modeling in OpenLCA by source, share, and values.

Energy Source	Share of Total	Pulp-Making Operations (10.98 MJ)	Converting (1.544 MJ)
Coal	21.90%	2.24	0.42
Petroleum	0.50%	0.05	0.01
Natural gas	38.40%	3.92	0.73
Nuclear	18.90%	1.93	0.36
Wind	9.20%	0.94	0.18
Hydropower	6.10%	0.62	0.12
Biomass	1.30%	0.13	0.02
Average Electricity mix	3.80%	0.39	0.07

Table 7

Transportation data for distance, mode of transportation, and its share.

Material	Truck		Train		Boat, Barge		Boat, Ocean
	%	km	%	km	%	km	%	km
Wood logs to Pulp & Paper mills	98.4	159	1.6	1577
Wood chips to Pulp & Paper mills	94.5	299	5.5	1674
Recovered fiber to pulp and paper mills	85.4	241	12.6	505	2.0	822
Pulp to pulp and paper mills	80.1	262	19.8	1511
Chemicals	58.1	217	28.0	1333	12.8	674	1.0	2992
Containerboard to converting	80.1	262	19.8	1511
Corrugated sheets	80.1	262	19.8	1511
Corrugated product to use	95.7	283	4.3	2446

Table 8

List of databases that were combined in OpenLCA.

Database Name	Source
Agribalyse v3.0.1	French Agency for Ecological Transition [14]
BioEnergieDat	German BioEnergieDat Project [15]
Ecoinvent v3.7	Ecoinvent [16]
Environmental Footprint v2.0	European Commission’s Single Market for Green Products initiative [17]
ELCD v3.2	European reference of Life Cycle Database of the Joint Research Center [18]
Exiobase v3.4	Multi-regional Environmentally Extended Supply and Use/Input-Output database (MR EE SUT/IO) [19]
NEEDS	New Energy Externalities Developments for Sustainability [20]
OpenLCA v2.1.3	OpenLCA [21]
OzLCI 2019	The Evah Institute [22]
Worldsteel_2020 (EF 3.0)	The World Steel Association [23]

Table 9

OpenLCA results for pulp-making and converting operations.

Emission Type	Pulp-Making (kgCO2-eq)	Converting (kgCO2-eq)
Fossil	2.03313	0.36044
Biogenic (GWP 20 years)	1.33393	-
Biogenic (GWP 100 years)	1.26464	-

Table 10

Carbon emission from transportation in pulp-making operation.

Material	Mode of Transport	Percentage Used	Distance (km)	Kg × Km	Emission Factor (kgCO2-eq/kg × km)	CO2 Emission (kgCO2-eq)
Wood log to P&P mill (0.72 kg)	Truck	98%	159	112.6483	0.00037	0.04217
	Train	2%	1577	18.1670	0.00004	0.00071
Wood chips to P&P mill (0.42 kg)	Truck	95%	299	118.6731	0.00037	0.04442
	Train	6%	1674	38.6694	0.00004	0.00151
Recovered fiber (0.57 kg)	Truck	85%	241	117.3140	0.00037	0.04391
	Train	13%	505	36.2691	0.00004	0.00142
	Boat, Barge	2%	822	9.3708	0.00007	0.00068
Pulp to paper mill (0.005 kg)	Truck	80%	262	1.0493	0.00037	0.00039
	Train	20%	1511	1.4959	0.00004	0.00006
Chemicals (0.04656 kg)	Truck	58%	217	5.8701	0.00037	0.00220
	Train	28%	1333	17.3781	0.00004	0.00068
	Boat, Barge	13%	674	4.0168	0.00007	0.00029
	Boat, Ocean	1%	2992	1.3931	0.00007	0.00010
Total Carbon emission in kgCO2-eq						0.1385

Table 11

Carbon emission from transportation in converting operation.

Material	Mode of Transport	Percentage Used	Distance (km)	Kg × Km	Emission factor (kgCO2-eq/kg × km)	CO2 Emission (kgCO2-eq)
Chemicals (0.0283 kg)	Truck	58%	217.0000	3.5774	0.00037	0.00134
	Train	28%	1333.0000	10.5907	0.00004	0.00041
	Boat, Barge	13%	674.0000	2.4480	0.00007	0.00018
	Boat, Ocean	1%	2992.0000	0.8490	0.00007	0.00006
Containerboard (1.1 kg)	Truck	80%	262.0000	230.8482	0.00037	0.08641
	Train	20%	1511.0000	329.0958	0.00004	0.01284
Corrugated sheets (1 kg)	Truck	80%	262.0000	209.8620	0.00037	0.07855
	Train	20%	1511.0000	299.1780	0.00004	0.01168
Corrugated product to use (1 kg)	Truck	96%	283.0000	270.8310	0.00037	0.10138
	Train	4%	2446.0000	105.1780	0.00004	0.00410
Total Carbon emission in kgCO2-eq						0.2970

Table 12

Carbon emission in the use phase for CCB.

Mode of Transportation	Average Distance Traveled (mile)	Emission Factor in kgCO2-eq/kg-Mile	Emission (kgCO2-eq)
Truck	186	0.00023	0.0433
Rail	969	0.00002	0.0235
Air	1006	0.00128	1.2919
Water	439	0.00005	0.0198
Total Carbon emission in kgCO2-eq			1.3785

Table 13

Emission factors for CCB w.r.t waste management method.

	Emission Factor in Metric Tons CO2-eq/Short Ton Material
Material	Recycled	Landfilled	Combusted
Corrugated Container	0.11	0.90	0.05

Table 14

Overall carbon emission of CCB over its lifecycle with all the phases.

Emission Type	Pulp-Making Operation	Converting Operation	Use Phase	Reuse Phase	EoL Phase
Fossil kgCO2-eq	2.17163	0.65744	1.3785	0.00805	0.2492
Biogenic KgCO2-eq (GWP 20 years)	1.33393	-	-	-	-
Biogenic KgCO2-eq (GWP 100 years)	1.26464	-	-	-	-

Table 15

Comparison of carbon emission with the other literature.

Source	Carbon Emission (kgCO2-eq)	Functional Unit (kg)	Carbon Emission per kg of CCB (kgCO2-eq/kg)
[26]	9.9	4	2.475
[27]	3.046	1	3.046
[28]	0.876	0.546	1.60
This paper	4.4567	1	4.4567

Table 16

Benefit-cost analysis for CCB.

Base costs	New box	$2.83
	Used box	$2.00
	Cost for motivation	$1.80
Benefit	Social cost (1.5351 × 0.9 × 100,000 × 1.01)	$131,603.27
	The cost saved by reusing (2.83 × 50,000)	$141,500.00
	Total benefit	$273,103.27
Cost	Motivation cost (1.80 × 50,000)	$90,000.00
	Resell used boxes (operating costs plus profits) (2 × 50,000)	$100,000.00
	Total cost	$190,000.00
	Net Benefit (Total benefit − Total cost)	$83,103.27
	Benefit-Cost ratio (Total benefit/Total cost)	$1.44

Table 17

Benefit-cost analysis with the lowest cost of a new box.

Base costs	New box	$1.17
	Used box	$2.00
	Cost for motivation	$1.80
Benefit	Social cost (1.5351 × 0.9 × 100,000 × 1.01)	$131,603.27
	The cost saved by reusing (1.17 × 50,000)	$58,500.00
	Total benefit	$190,103.27
Cost	Motivation cost (1.80 × 50,000)	$90,000.00
	Resell used boxes (operating costs plus profits) (2 × 50,000)	$100,000.00
	Total cost	$190,000.00
	Net Benefit (Total benefit − Total cost)	$103.27
	Benefit-Cost ratio (Total benefit/Total cost)	1.00

Table 18

Benefit-cost analysis with the highest cost of a used box.

Base costs	New box	$2.83
	Used box	$3.66
	Cost for motivation	$1.80
Benefit	Social cost (1.5351 × 0.9 × 100,000 × 1.01)	$131,603.27
	The cost saved by reusing (2.83 × 50,000)	$141,500.00
	Total benefit	$273,103.27
Cost	Motivation cost (1.80 × 50,000)	$90,000.00
	Resell used boxes (operating costs plus profits) (3.66 × 50,000)	$183,000.00
	Total cost	$273,000.00
	Net Benefit (Total benefit − Total cost)	$103.27
	Benefit-Cost ratio (Total benefit/Total cost)	1.00

Table 19

Benefit-cost analysis with the highest cost for motivation.

Base costs	New box	$2.83
	Used box	$2.00
	Cost for motivation	$3.46
Benefit	Social cost (1.5351 × 0.9 × 100,000 × 1.01)	$131,603.27
	The cost saved by reusing (2.83 × 50,000)	$141,500.00
	Total benefit	$273,103.27
Cost	Motivation cost (3.46 × 50,000)	$173,000.00
	Resell used boxes (operating costs plus profits) (2 × 50,000)	$100,000.00
	Total cost	$273,000.00
	Net Benefit (Total benefit − Total cost)	$103.27
	Benefit-Cost ratio (Total benefit/Total cost)	1.00

Table 20

Willingness-to-pay for a new CCB.

		Price per Box ($)
Dimension of CCB	Weight (kg)	25	100	250	500	1000
20 × 18 × 16″ [31]	0.98	4.26	3.97	3.73	3.52	3.27
20 × 16 × 20″ [32]	1.01	4.25	4.04	3.8	3.71	3.43
20 × 12 × 12″ [33]	0.98	4.83	4.39	3.97	3.64	3.38
19 × 19 × 19″ [34]	0.95	4.36	3.97	3.86	3.52	3.29
18 × 18 × 8″ [35]	1.09	5.52	5.16	4.79	4.49	4.3
18 × 18 × 12″ [36]	0.94	2.45	2.45	2.45	2.45	2.45
18 × 18 × 18″ [29]	1.01	2.83	2.83	2.83	2.83	2.83
20 × 18 × 18″ [37]	1.07	4.42	4.15	3.91	3.72	3.39
Average	1.00	4.115	3.87	3.6675	3.485	3.2925

Table 21

Willingness-to-pay for old CCB.

		Price per Box ($)
	Weight (kg)	25	100	250	500	1000
Old CCBs	1.00	2.23	2.10	1.99	1.89	1.79

References

1. Ketkale, H.; Simske, S. Encouraging Reuse in the Corrugated Packaging Industry Using Persuasion and Operant Conditioning. Sustainability; 2022; 14, 6454. [DOI: https://dx.doi.org/10.3390/su14116454]

2. ABB Group. All of Those Boxes. Available online: https://new.abb.com/docs/librariesprovider15/default-document-library/no5_boxes_oct14.pdf?sfvrsn=2 (accessed on 22 December 2022).

3. Recycling.com. Why Cardboard Recycling Is Crucial to Protect the Earth. Available online: https://www.ocrecycling.com/cardboard-recycling-crucial (accessed on 22 December 2022).

4. Corrugated Packaging Alliance. Corrugated Packaging—A Recycling Success Story; Corrugated Packaging Alliance: Elk Grove Village, IL, USA, 2016.

5. Fibre Box Association. Corrugated Packaging—An Extraordinary Recycling Success Story. Available online: http://www.corrugated.org/wp-content/uploads/2019/12/Recycling_White_Paper_2019_vfinal.pdf (accessed on 22 December 2022).

6. Curran, M. LIFE-CYCLE ASSESSMENT; Encyclopedia of Ecology; Subject Area: Human, Ecology Jorgensen, S.E.; Fath, B. Elsevier BV: Amsterdam, The Netherlands, 2008; Chapter 13 pp. 2168-2174. ISBN 978008045405

7. National Council for Air and Stream Improvement, Inc. (NCASI). 2014 Life Cycle Assessment of U.S. Average Corrugated Product—Final Report; Report prepared for the Corrugated Product Alliance (CPA) National Council for Air and Stream Improvement, Inc.: Cary, NC, USA, 2017.

8. United States Census Bureau: CF1700P2|CFS Preliminary Report: Shipment Characteristics by Total Modal Activity: 2017. Available online: https://data.census.gov/table?q=cf1700p2&hidePreview=true&tid=CFSPRELIM2017.CF1700P2 (accessed on 22 December 2022).

9. United States Environmental Protection Agency: Paper and Paperboard Containers and Packaging. Available online: https://www.epa.gov/facts-and-figures-about-materials-waste-and-recycling/containers-and-packaging-product-specific#PaperandPaperboardC&P (accessed on 22 December 2022).

10. U.S. Energy Information Administration: U.S. utility-scale electricity generation by source, amount, and share of total in 2021. Available online: https://www.eia.gov/tools/faqs/faq.php?id=427&t=3#:~:text=In%202021%2C%20about%204%2C108%20billion,facilities%20in%20the%20United%20States.&text=About%2061%25%20of%20this%20electricity,%2C%20petroleum%2C%20and%20other%20gases (accessed on 22 December 2022).

11. Stocker, T.F.; Qin, D.; Plattner, G.K.; Tignor, M.; Allen, S.K.; Boschung, J.; Nauels, A.; Xia, Y.; Bex, V.; Midgley, P.M. Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change; Cambridge University Press: Cambridge, UK, New York, NY, USA, 2013; 1535.

12. Field, B.; Field, M. Environmental Economics an Introduction; 8th ed. McGraw-Hill: New York, NY, USA, 2021.

13. Carey, K. Cost Function Estimates. Encyclopedia of Health Economics; Culyer, A. Elsevier: Amsterdam, The Netherlands, 2014; pp. 121-125.

14. OpenLca Nexus: AGRIBALYSE. Available online: https://nexus.openlca.org/database/Agribalyse (accessed on 22 December 2022).

15. OpenLca Nexus: BIOENERGIEDAT. Available online: https://nexus.openlca.org/database/bioenergiedat (accessed on 22 December 2022).

16. OpenLca Nexus: Ecoinvent. Available online: https://nexus.openlca.org/database/ecoinvent (accessed on 22 December 2022).

17. OpenLca Nexus: PEF Database. Available online: https://nexus.openlca.org/database/Environmental%20Footprints (accessed on 22 December 2022).

18. OpenLca Nexus: JRC European Commission. Available online: https://nexus.openlca.org/database/ELCD (accessed on 22 December 2022).

19. OpenLca Nexus: Exiobase. Available online: https://nexus.openlca.org/database/exiobase (accessed on 22 December 2022).

20. OpenLca Nexus: NEEDS. Available online: https://nexus.openlca.org/database/NEEDS (accessed on 22 December 2022).

21. OpenLca Nexus: OpenLca. Available online: https://nexus.openlca.org/database/openLCA%20LCIA%20methods (accessed on 22 December 2022).

22. OpenLca Nexus: The Evah Institute. Available online: https://nexus.openlca.org/database/OzLCI2019 (accessed on 22 December 2022).

23. OpenLca Nexus: Worldsteel Association. Available online: https://nexus.openlca.org/database/worldsteel (accessed on 22 December 2022).

24. United States Environmental Protection Agency: GHG Emission Factors Hub. Available online: https://www.epa.gov/climateleadership/ghg-emission-factors-hub (accessed on 22 December 2022).

25. United States Environmental Protection Agency: Waste Transfer Stations: A Manual for Decision-Making. Available online: https://www.epa.gov/sites/default/files/2016-03/documents/r02002.pdf (accessed on 22 December 2022).

26. Dominic, C.A.; Östlund, S.; Buffington, J.; Masoud, M.M. Towards a conceptual sustainable packaging development model: A corrugated box case study. Packag. Technol. Sci.; 2015; 28, pp. 397-413. [DOI: https://dx.doi.org/10.1002/pts.2113]

27. Su, Y.; Duan, H.; Wang, Z.; Song, G.; Kang, P.; Chen, D. Characterizing the environmental impact of packaging materials for express delivery via life cycle assessment. J. Clean. Prod.; 2020; 274, 122961. [DOI: https://dx.doi.org/10.1016/j.jclepro.2020.122961]

28. Koskela, S.; Dahlbo, H.; Judl, J.; Korhonen, M.R.; Niininen, M. Reusable plastic crate or recyclable cardboard box? A comparison of two delivery systems. J. Clean. Prod.; 2014; 69, pp. 83-90. [DOI: https://dx.doi.org/10.1016/j.jclepro.2014.01.045]

29. ULINE: 18 × 18 × 18” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-4185/Corrugated-Boxes-200-Test/18-x-18-x-18-Corrugated-Boxes (accessed on 24 December 2022).

30. Ackerman, F.; Stanton, E.A. Climate risks and carbon prices: Revising the social cost of carbon. Economics; 2012; 6, pp. 1-25. [DOI: https://dx.doi.org/10.5018/economics-ejournal.ja.2012-10]

31. ULINE: 20 x 18 x 16” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-4795/Corrugated-Boxes-200-Test/20-x-18-x-16-Corrugated-Boxes (accessed on 24 December 2022).

32. ULINE: 20 x 16 x 20” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-23993/Corrugated-Boxes-200-Test/20-x-16-x-20-Corrugated-Boxes (accessed on 24 December 2022).

33. ULINE: 20 x 12 x 12” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-12603/Heavy-Duty-Boxes/20-x-12-x-12-275-lb-Double-Wall-Corrugated-Boxes (accessed on 24 December 2022).

34. ULINE: 19 x 19 x 19” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-4860/Corrugated-Boxes-200-Test/19-x-19-x-19-Corrugated-Boxes (accessed on 24 December 2022).

35. ULINE: 18 x 18 x 8” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-14232/Heavy-Duty-Boxes/18-x-18-x-8-275-lb-Double-Wall-Corrugated-Boxes (accessed on 24 December 2022).

36. ULINE: 18 x 18 x 12” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-4399/Corrugated-Boxes-200-Test/18-x-18-x-12-Corrugated-Boxes (accessed on 24 December 2022).

37. ULINE: 20 x 18 x 18” Corrugated Boxes. Available online: https://www.uline.com/Product/Detail/S-14286/Corrugated-Boxes-200-Test/20-x-18-x-18-Corrugated-Boxes (accessed on 24 December 2022).

38. Box LatchTM. Products Featured in London Trade Show-Box Latch Products. Available online: https://www.boxlatch.com/box-latch-products-featured-london-trade-show/ (accessed on 24 December 2022).

39. Box Latch 10+ Box Re-Use|Closed-Loop Production Process | Wisconsin Plastics, Inc. Available online: https://www.youtube.com/watch?v=FkjqiLX39yg (accessed on 24 December 2022).