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Carbon footprint of shopping (grocery) bags in China, Hong Kong and India

Subramanian Senthilkannan Muthu, Y. Li *, J.Y. Hu, P.Y. Mok

Institute of Textiles and Clothing, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China

article info

Article history:

Received 8 July 2010

Received in revised form

28 August 2010

Accepted 23 September 2010

Keywords:

Plastic bags

Paper bags

Non-woven bags

Woven bags

Life cycle impact assessment

SIMAPRO

IPCC 2007

Carbon footprint

Recycle

Reuse

Disposal to landfill

1. Introduction

abstract

Human beings exert tremendous pressure on our earth, from

which there has been a severe damage caused to the natural

environmental system, and global environmental change due to

excessive carbon emissions is one of the most important changes.

The impact of global environmental change has been a topic of

interest for many researchers in different fields. Among the various

effects, the impact of climate change on human health is of greatest

concern and has attracted close attention (McMichael et al., 2006;

* Corresponding author. Tel.: þ852 2766 6479; fax: þ852 2773 1432.

E-mail address: tcliyi@inet.polyu.edu.hk (Y. Li).

1352-2310/$ e see front matter Ó 2010 Elsevier Ltd. All rights reserved.

doi:10.1016/j.atmosenv.2010.09.054

Atmospheric Environment 45 (2011) 469e475

Contents lists available at ScienceDirect

Atmospheric Environment

journal homepage: www.elsevier.com/locate/atmosenv

Carbon footprint has become a term often used by the media in recent days. The human carbon footprint

is professed to be a very serious global threat and every nation is looking at the possible options to

reduce it since its consequences are alarming. A carbon footprint is a measure of the impact of human

activities on earth and in particular on the environment; more specifically it relates to climate change

and to the total amount of greenhouse gases produced, measured in units of carbon dioxide emitted.

Effort of individuals in minimizing the carbon footprint is vital to save our planet. This article reports

a study of the carbon footprint of various types of shopping bags (plastic, paper, non-woven and woven)

using life cycle impact assessment (LCIA) technique in two stages. The first stage (baseline study),

comprised the study of the impact of different types of shopping bags in the manufacturing phase,

without considering their usage and disposal phases (cradle to gate stage). The LCIA was accomplished by

the IPCC 2007 method, developed by the Inter Panel on Climate Change in SIMAPRO 7.2. The GWP (Global

Warming Potential) values calculated by the IPCC 2007 method for 100 years were considered as

a directive to compare the carbon footprint made by the different types of shopping bags under

consideration. The next stage was the study of the carbon footprint of these bags including their usage

and disposal phases (cradle to grave stage) and the results derived were compared with the results

derived from the baseline study, which is the major focus of this research work. The values for usage and

end-of-life phases were obtained from the survey questionnaire performed amongst different user

groups of shopping bags in China, Hong Kong and India. The results show that the impact of different

types of shopping bags in terms of their carbon footprint potential is very high if no usage and disposal

options were provided. When the carbon footprint values from different disposal options were

compared, the carbon footprint values were lower in the case where a higher percentage of reuse is

preferred to recycling and disposing to landfill. The results indicate that a higher percentage of reuse

could significantly scale down the carbon footprint. Once the shopping bags reached the point where

they can no longer be reused, they must be forwarded to recycling options, rather than being disposed to

landfill. At this juncture, consumer’s perceptions and behaviours in connection with the respective

government’s policies in promoting & facilitating recycling systems could be critical in reducing the

carbon footprint of various shopping bags.

Ó 2010 Elsevier Ltd. All rights reserved.

Haines et al., 2006). The major risks posed by climatic change to

human health may have both direct and indirect causes and the

major possible health risks could be: 1. Effects of heat waves and

other extreme events (cyclones, floods, storms, wildfires);

2. Changes in patterns of infectious disease; 3. Effects on food

yields; 4. Effects on freshwater supplies; 5. Impaired functioning of

ecosystems (for example, wetlands as water filters); 6. Displacement

of vulnerable populations (for example, low lying island and

coastal populations); 7. Loss of livelihoods (McMichael et al., 2008).

A carbon footprint is a measure of the impact of human activities

on the environment (in particular climate change) in terms of the

amount of greenhouse gases produced through burning of fossil

fuels for electricity, heating and transportation, etc. and has units of

tonnes (or kg) of carbon dioxide equivalent (Carbon footprint;


470

Hertwich and Peters, 2009). There are two types of carbon footprints

- primary and secondary. Primary footprints, which are

under our direct control, are the result of direct emissions of CO2

from the burning of fossil fuels including domestic energy

consumption and transportation (Ex: Usage of electricity and

transportation, etc.). The secondary footprints are related to the

indirect CO2 emissions from the whole life cycle of the products

human beings use - those associated with their manufacture and

eventual breakdown (Ex: Usage of clothes and other products,

recreation and leisure, etc) (Hertwich and Peters, 2009). Human

beings are the major source of carbon emissions and they will be

the most affected by the emissions, particularly those deemed

serious.

Production, usage and consumption of any product pose a threat

to carbon footprint. Shopping bags, a symbol of the throw-away

society, exacerbate the seriousness of the human carbon footprint.

It is worthwhile studying the entire life cycle phase of different

types of shopping bags from the manufacturing stage to the

disposal stage. Once the product is decided to be disposed of, there

may be three possibilities: reuse of the product for the same or for

different purposes; recycle the product; dispose it off to landfill.

Human dimensions in consumer behaviour rule the decision of

a product’s disposal phase and consequently the environmental

impact. Apart from human dimensions, governmental policies also

assume greater significance in the environmental impact. There are

many dimensions of environmental impact caused by shopping

bags; of which global environmental change is one of the prime

concerns and this is discussed in detail in this article. Out of all the

phases of a product’s life cycle, the disposal phase is very critically

related to the environmental issues and is solely decided by the

consumer’s attitude and the governmental policies to facilitate

recycling of the product.

There are different types of shopping bags available to cater for

the shopping needs of people. A variety of raw materials and

technologies are employed to manufacture them, the most popular

of those are plastic, paper, non-woven and woven bags.

Plastic bags are made from non-renewable resources, where the

key ingredients are petroleum and natural gas. Polyethylene-high

density (HDPE), low density (LDPE), linear low-density polyethylene

(LLDPE) are the raw materials widely used for the

manufacture of plastic bags (Lajeunesse, 2004). The shopping bags

used by super markets are ideally produced out of LLDPE to get the

desired thickness and glossy look. And if one needs very thin and

gauzy bags then LDPE would be an ideal choice (Dilli, 2007). A very

detailed explanation of plastic bags manufacturing process can be

referred from (Muthu et al., 2009).

Paper bags are made out of pulpwood from trees, which is

a renewable source. However, we get paper bags from felling trees,

which destroys both plants and animals and the production process

engrosses energy created by coal or natural gas. The created pulp

will be converted into a paper bag by different processes and

machines after consuming a tremendous amount of energy from

fossil fuels, electricity, various chemicals, etc. (Decker and Graff).

Further details about the paper bag manufacturing process can be

referred from (Muthu et al., 2009).

Although non-woven bags made from many different types of

raw materials are available today in the market, the ones made of

polypropylene (PP) are most commonly seen for shopping

purposes (Muthu et al., 2010b). The production process of a woven

bag made out of cotton is cumbersome compared to that of

a non-woven bag and further details of this process can be referred

from (Muthu et al., 2010b).

All products have an impact on the planet. Quantifying

the impact is crucial to reduce it. Among many techniques to study

the eco-impact of a product, life cycle assessment (LCA) is one

S.S. Muthu et al. / Atmospheric Environment 45 (2011) 469e475

of the most widely used and popular ones. LCA examines the

product from its initial (cradle stage) to final stage (grave stage),

covers its entire life cycle, and also evaluates the product in terms of

the environmental impact during its life time.

A life cycle assessment (LCA) is an analytical tool which can help

to understand the environmental impacts from the acquisition of

raw materials to final disposal (SETAC, 1993).

In accordance with the definition given by The Society of Environmental

Toxicology and Chemistry (SETAC), LCA is an iterative

process for evaluating the environmental burdens associated with

a product, process or activity by identifying and quantifying energy

and materials used and wastes released to the environment. LCA

can also be used to assess the impact of those energy and materials

used and released to the environment and can help to identify and

evaluate opportunities to effect environmental improvements. The

assessment includes the entire life cycle of the product, process or

activity, encompassing extracting and processing raw materials;

manufacturing, transportation and distribution, use, reuse, maintenance,

recycling and final disposal (Fava et al., 1991). According to

ISO 14040, an LCA study essentially consists of four interconnected

steps/phases (ISO 14040, 2006):

Goal and scope definition

Inventory analysis

Impact Assessment

Interpretation

Further details about life cycle assessment (LCA) can be found in

(Muthu et al., 2009; SETAC, 1993; Fava et al., 1991; ISO 14040, 2006;

ISO 14044, 2006).

Shopping bags, as an example of unnecessary waste, require LCA

to assess the environmental impact in terms of their carbon footprint.

A large number of studies have been conducted to investigate

the LCA of various shopping bags (Muthu et al., 2009, 2010b;

Brower et al., 1999; Chaffee and Yaros, 2007; Ecobilan, 2008;

Nolan ITU et al., 2002; ExcelPlas Australia et al., 2004; James

and Grant, 2005; FRIDGE; Los Angeles County Department of

Public Works, 2007; Paper vs. Plastic Bags, 1990; Ellis et al., 2005;

www.sustainability-ed.org). Most of the studies focused on plastic

and paper bags. However, very little work has been done on nonwoven

and woven bags compared to plastic and paper bags. And

also there have been no published articles till date focusing

primarily on the carbon footprint created by shopping bags.

Research into the influence of the consumer’s attitude and

governmental policies on this is entirely lacking. This article bridges

the gaps identified above and also describes the impact of different

types of shopping bags on the human carbon footprint and also

how consumer and policy dimensions influence it.

Consumer behaviour and governmental policies play an

important role in the disposal stage of shopping bags. Notwithstanding

the capability of certain types of bags to be recycled and

reused, it is in the hands of customers to reuse a bag until it can be

discarded or recycled, i.e. to reuse the shopping bags many times

till they can be disposed of and to keep them in recycling bins

provided by the government, rather than dispose to landfill, which

is detrimental to the environment as far as eco-impact is concerned.

It is the responsibility of government to provide more

recycling options and viable policies to set things in place in terms

of recycling. Frequent promotion of recycling options by government

and the behaviour of the consumer to reuse the shopping

bags till they can be discarded is crucial in reducing the carbon

footprint.

To determine the attitude of users of shopping bags and to

understand the disposal scenarios, a questionnaire survey was

conducted in China, Hong Kong and India among different user


groups of shopping bags and the findings are reported in (Muthu

et al., 2010a). These three territories were particularly chosen,

since the authors are from these territories and they intend to

create awareness and consequently educate people of the country

to which they belong to. The aims of the survey lie in comprehending

how different user groups use and dispose plastic, paper,

non-woven and woven bags. Usage and disposal behaviors are

defined as how many times people reuse different shopping bags,

what percentage of shopping bags can be recycled/sent to landfill

with the existing possibilities of recycling in their own country and

what percentage of shopping bags people perceive can be reused/

recycled/sent to landfill. Also this survey intends to comprehend

the existing recycling options provided by the government and the

willingness of people to support the government’s policies further

to improve the possibilities of recycling.

2. Research methodology

2.1. Study of impact of various shopping bags on carbon footprint

This paper revolves around the study of global climate change

due to the production, usage and disposal phases of various types of

shopping bags in China, Hong Kong and India. The initial step of this

study is the collection of secondary data for Life cycle inventory

(LCI) for various types of shopping bags for the three countries

under consideration in this present study. For different types of

shopping bags such as plastic (HDPE), paper (Kraft), non-woven

(PP) bags and woven cotton bags, the data were obtained from the

final report prepared for Environment Australia in 2002 (Nolan ITU

et al., 2002). An LCI of different types of shopping bags under

consideration in this study also appears in an updated version of

this study published in 2004 (ExcelPlas Australia et al., 2004). The

basic data referred from these sources were converted to the

functional unit assumed for China, Hong Kong and India.

The data arising from this study included the total energy

consumed by a bag to get it manufactured, where total energy

represents process and feedstock energy and the quantity of

pollutants emitted to the atmosphere during the manufacturing

process.

The goal of the study under discussion is to analyse the carbon

footprint of these four types of bags in China, Hong Kong and India

with the available data from a secondary source (cradle to gate) in

the first step and in the second step, to study the effect of

consumer’s attitude and policy dimensions in the carbon footprint

of these four types of shopping bags (cradle to grave). The scope of

this study includes the comparative investigation of carbon footprint

of plastic, paper, non-woven and woven shopping bags in

both cradle to gate and grave states from the data sources

mentioned above in China, Hong Kong and India. The cradle to gate

assessment phase of this study considers impacts at each life cycle

stage of four types of shopping bags under consideration which

includes extraction/processing or growing/harvesting of resources;

the process of manufacturing; transport from the manufacturer to

the wholesaler/retailer as indicated in the secondary data sources

from which the cradle to gate data were referred. For cradle to grave

stage, public opinion from China, Hong Kong and India on

percentage of reuse, recycle and disposal to landfill were considered

to build the end-of-life scenarios in addition to the above

mentioned areas in cradle to gate stage.

To derive the functional unit which suits better for the three

territories considered, the consumption statistics of shopping bags

was referred from the literature pertaining to China, Hong Kong

and India. Among the four bags under consideration in this present

study, statistics were readily available on the consumption of

plastic bags. As per our currently available literature survey on

S.S. Muthu et al. / Atmospheric Environment 45 (2011) 469e475 471

statistics on shopping bags consumption, an average Chinese and

a Hong Kong resident, on an average uses 3 plastic bags per day

(EPD, HK, 2009; Environmental News Network, 2008). Although

there is no readily available statistics for the usage of plastic bags in

India compared to Hong Kong and China (Businessgreen.com, 2010;

The Times of India, 2009), as per one of the references pertaining to

the consumption of plastic bags in India, India’s per capita

consumption is 150 plastic bags a year (Online Edition of The Hindu,

2010).

The functional unit of this present study is the, “number of

shopping bags used for grocery shopping per year by an average

Chinese/Indian/HK resident”. For the territories considered for this

study, we assume that plastic and paper bags are comparable and

they are equivalent to each other in their functional front. When it

comes to non-woven and woven bags, we assume that 1 nonwoven

and 2 woven cotton bags will replace 100 single use plastic

and paper bags. Further, our above said assumptions can be validated

from the relevant literature also (Nolan ITU et al., 2002;

ExcelPlas Australia et al., 2004; James and Grant, 2005; Reusable

shopping bags; Envirosax; Alburyenvirobags). Hence 1095 plastic

and paper bags, 10.95 non-woven and 21.9 woven bags are required

to fulfill the functional unit assumed for this study for an average

Chinese and HK residents. For Indians, 150 plastic and paper bags,

1.5 non-woven and 3 woven bags are needed to fulfill this study’s

functional unit.

The end-of-life values were derived from a survey conducted in

China, Hong Kong and India as reported in the references in detail

(Muthu et al., 2010a). Results from the survey were used in Life

cycle impact calculations in the usage and disposal states were

compared with the life cycle stage without usage and disposal

criteria.

2.2. Life cycle inventory (LCI) of shopping bags

The energy and pollutants data for the functional unit considered

for different shopping bags under consideration in this present

study was taken from the previous studies (Nolan ITU et al., 2002;

ExcelPlas Australia et al., 2004) and is tabulated in Table 1 for China

and Hong Kong and Table 2 for India.

2.3. Survey results of usage and disposal behaviour

of shopping bags

The major focus of this study is to investigate the influence of

human behaviour and governmental policies on the carbon footprint

of various types of shopping bags. A survey was conducted

among students, home makers and employed professionals in

various professions of different age groups, who are the users of

shopping bags and who have the knowledge on the usage and

disposal behaviour of the same in China, Hong Kong and India. This

survey was mainly aimed at understanding the consumer’s

perception of reuse, recycle and disposal to landfill, recycling

Table 1

Life cycle inventory data of plastic, paper, non-woven and woven bags in China and

Hong Kong.

Alternative Weight/bag Bags/year Material Green house Primary

consumption gas emissions

(CO2 eq.)

energy

Plastic bag 6 g 1095 6.57 kg 12.8 kg 442.2 MJ

Paper bag 42.6 g 1095 46.65 kg 24.8 kg 1518.3 MJ

PP fibre nonwoven

bag

65.6 g 10.95 718.32 g 5.17 kg 122.2 MJ

Woven

cotton bag

125.4 g 21.9 2.75 kg 6.06 kg 385 MJ


472

Table 2

Life cycle inventory data of plastic, paper, non-woven and woven bags in India.

Alternative Weight/bag Bags/year Material

consumption

possibilities with the existing government provisions/policies for

recycling, willingness to support recycling systems/policies to

reduce the percentage of landfill and so on (Muthu et al., 2010a).

The major results extracted from this survey are presented in

Table 3.

From the survey results, usage and end-of-life scenario values

are deduced to the following categories, which can be seen from

Table 3.

3. Results and discussions

Green house

gas emissions

(CO2-eq.)

3.1. Life cycle assessment analysis and results without

usage and disposal options

Primary

energy

Plastic bag 6 g 150 900 g 1.74 kg 60 MJ

Paper bag 42.6 g 150 6.39 kg 3.41 kg 210 MJ

PP fibre nonwoven

bag

65.6 g 1.5 98.4 g 708 g 16.73 MJ

Woven cotton

bag

125.4 g 3 376.2 g 831 g 52.74 MJ

In this section, energy and pollutants data were processed by

using one of the commercial LCA softwareseSIMAPRO 7.2. The IPCC

2007 method (IPCC method) for LCIA was employed to assess the

carbon footprint, which is expressed in terms of Global Warming

Potential of 20 years, 100 and 500 years. LCIA modelling was done

in three phases: Global Warming Potential of 20 years, 100 and 500

years by using the same method for China and Hong Kong separately

and for India separately as per the functional unit assumption.

Results of these analyses can be seen from Fig. 1 for China and

Hong Kong and Fig. 2 for India. For the functional unit assumed,

non-woven bags made out of polypropylene score out all other

bags, followed by woven cotton bags in the three territories

considered for this study. Plastic bags and paper bags have very

high global warming potential for 20, 100 and 500 years compared

to non-woven and woven bags. Life cycle inventory data presented

in Tables 1 and 2 clearly enumerate these results and indicate that

non-woven bags occupy better position in this comparative analysis.

For the functional unit assumed, non-woven bags consume

lesser energy and fewer amounts of materials and also they emit

lesser green house gas emissions in the production phase of

shopping bags in comparison with its counterparts in China, Hong

Kong and India.

According to the first part of this study, paper bags seem to be

very much detrimental to the environment in terms of more

amounts of carbon emissions compared to its counterparts as per

the secondary data source references. However this can be further

studied with the inclusion of the positive effect of the photo

synthesis effect created by trees, from where the paper is primarily

being made. This part certainly needs to be included in the carbon

footprint modelling part.

Table 3

Values for usage and disposal options from survey results (Muthu et al., 2010a).

S.S. Muthu et al. / Atmospheric Environment 45 (2011) 469e475

3.2. Life cycle assessment analysis and results with usage

and disposal options

The results of the survey findings tabulated in Table 3 were

employed to investigate the impact of plastic, paper bags, nonwoven

and woven bags on carbon footprint in terms of global

warming potential and they were compared with the results

obtained from without usage and disposal options (baseline study).

The GWP results of the same for China, Hong Kong and India are

described in Figs. 3 and 4 respectively. For better clarity and ease of

comparison, only the results from 100 years are considered for this

discussion.

The data tabulated in Figs. 3 and 4 permit a comparative

investigation between, without and with usage and disposal

options according to the existing consumer behaviour and

government policies in China, Hong Kong and India. In all the cases,

the carbon footprint values are less than those of the without usage

and disposal options. When the comparison is made between the

options from three countries under discussion here, one can see

that for plastic bags, the carbon footprint values from India is less

compared to other countries. This is due to the fact that reuse

option is most selected by Indians for plastic bags. For other categories

of shopping bags, the carbon footprint values from China are

less, due to the same fact mentioned above. The influence of reuse

option on reducing carbon footprint values is very much pertinent

in all the cases under discussion here. While looking at the results

in Table 3 for woven bags in China and Hong Kong, we can notice

that a 5% difference in percentage of reuse results in 22 Kg CO2

equivalents of global warming potential (around 20% of GWP) in

Fig. 3, which showcases the importance of reuse option. It is a wellknown

fact that the more reuse of shopping bags, lesser will be the

environmental impact. However the magnitude of importance

needs to be revealed, which will portray the real scenario to the

consumers of shopping bags. Even 1% of more reuse of shopping

bags will make a world of difference in terms of environmental

impact, which has to be unveiled to public, if one wants them to be

educated in terms of environmental improvement. If we expect the

Percentage Plastic bags Paper bags Non-woven bags Woven bags

China HK India China HK India China HK India China HK India

Recycle 21% 22% 18% 31% 25% 25% 22% 25% 21% 20% 23% 27%

Reuse 46% 42% 55% 42% 38% 28% 78% 69% 55% 80% 75% 73%

Sent to landfill 33% 36% 27% 27% 37% 47% 0% 6% 24% 0% 2% 0%

2500

2000

1500

1000

500

0

Plastic Bags Paper Bags Non-woven bags Woven Bags

GWP (KgCo2-eq.) in 20 Years

GWP (KgCo2-eq.) in 100 Years

GWP (KgCo2-eq.) in 500 Years

Fig. 1. Carbon footprint results without usage and disposal options in China and Hong

Kong (Results rounded-off).


350

300

250

200

150

100

50

0

Plastic Bags Paper Bags Non-woven bags Woven Bags

GWP (KgCo2-eq.) in 20 Years

GWP (KgCo2-eq.) in 100 Years

GWP (KgCo2-eq.) in 500 Years

Fig. 2. Carbon footprint results without usage and disposal options in India (Results

rounded-off).

Woven bags

Non-woven bags

Paper bags

Plastic bags

0 500 1000 1500 2000

GWP(KgCo2-eq.) in 100 Years

Baseline study China HK

Fig. 3. Carbon footprint results with usage and disposal options in China and Hong

Kong (Results rounded-off).

Woven bags

Non-woven

bags

Paper bags

Plastic bags

0 50 100 150 200 250

GWP(KgCo2-eq.) in 100 Years

Baseline study India

Fig. 4. Carbon footprint results with usage and disposal options in India (Results

rounded-off).

public to appreciate the environmental education in terms of their

contribution to reduce environmental impact, they should be

aware of the real values of environmental impact. Based on the

above results and discussions, one important point to be noted here

is, if any product is not reused till the end of its life, the concerns

about environmental impact are huge. On the other hand if any

product is not recycled and sent to landfill more, the eco-impact

S.S. Muthu et al. / Atmospheric Environment 45 (2011) 469e475 473

Fig. 5. Recycling System in China (Shenzhen City).

Fig. 6. Recycling System in Hong Kong (Hung Hom Area).

concerns are more acute than the manufacturing and usage state,

which can be understood from the results of this research work. So,

usage and disposal of shopping bags assumes greater significance

in minimizing the carbon footprint.

If policies of these governments have been reconsidered and

recycling systems are encouraged and if they are in their appropriate

places, percentage of recycling options will be increased and

it is beyond anybody’s doubt that the impact of global climatic

change will come down enormously. Though governmental policies

to promote recycling can be seen all around the globe, still

they need to be up to the mark; thereby every individual goes for

it. As far as China and Hong Kong is concerned, recycling systems

can be seen in major areas, some photos taken in China

Fig. 7. Recycling Bins from an apartment in HK.


474

(Shenzhen) and Hong Kong (Hung Hom) are presented in Figs.5

and 6. Also in order to support government’s activities, individuals

also need to take some initiative to promote recycling activity.

One typical example is the initiative taken by residents of an

apartment in Hong Kong to promote recycling options, which can

be seen from Figs.7 and 8. Such activities should be initiated and

continued by all individuals.

The emphasis on interpretation phase of this analysis is not on

concluding which one is much better. Actually the conclusion needs

to be drawn on how to reduce the impacts caused by carbon

footprint by all variety of shopping bags. One of the possible ways to

decipher this is by means of finding ways to reduce, reuse and

recycle. In fact, many retail stores have started utilizing this

philosophy of reducing, recycling and reusing the grocery bags.

Building up public awareness and motivation to reduce, reuse and

recycle all these bags will definitely help to resolve the environmental

problems to a greater magnitude.

4. Conclusions

This research article encompasses the study of carbon footprint

of different types of shopping bags in both cradle to gate and cradle

to grave stages in China, Hong Kong and India. Among different

phases of a product’s life cycle, disposal phase assumes greater

significance as far as the environmental impact on carbon footprint

is concerned. The peculiar part of this phase is that end-of-life

scenarios are mostly decided by consumer behaviour and governmental

policies. In this research paper, an exploratory study was

performed to analyse the impact of various shopping bags on

carbon footprint by using secondary data for LCI to manufacturing

phase. In this stage, reusable bags such as non-woven bags made

out of polypropylene followed by woven cotton bags seem to be

environmental friendly compared to the conventional plastic and

paper bags for the functional unit assumed for this comparative

study. As far as the end-of-life phase is concerned, it lies mostly in

the hands of the public. Also it is vitally important to use real values

rather than assumptions, which can be obtained only from the

actual users. Hence the inputs from public opinion were employed

to deduce the values for end-of-life scenarios. In the first stage of

LCA modelling without disposal options, according to the LCI data

S.S. Muthu et al. / Atmospheric Environment 45 (2011) 469e475

Fig. 8. Recycling Bins for used clothes recycling from an apartment in Hong Kong.

and the software used for this study, which also has certain

hypothesis and assumptions, non-woven bags made out of polypropylene

are found to be better in terms of carbon footprint

compared to its counterparts. However this stage of conclusion

depends solely upon the secondary data and the LCA software

employed for the study. Public opinion was used to model the usage

and disposal values of LCA, where the GWP values of all bags were

less in all cases.

It was found in all of the cases under study that the more the

option of reuse is chosen, the lower the environmental impact. In

one of the cases in this study, it was found that even a 5% increase in

reuse option selected, around 20% of carbon footprint will be saved.

Hence, the key here is that consumers must reuse the bags till they

can be discarded. Once they decide to discard, the other best option

would to be sending the bag to recycling rather than disposing it off

to landfill.

The production process of the various shopping bags considered

in this study is a long chain and the amount of carbon footprint of

the same could be different in today’s scenario when compared to

the results presented in this study, derived from second-hand data

sources. It should also be noted that the number of times each type

of bag can be reused and potential of each type of bag to be recycled

with their consequent environmental implications also would be

different from each other.

The consumers’ behaviour and governmental policies are pivotal

in terms of encouraging people to go for reusable bags and promote

more recycling systems to scale down the environmental impacts

made by any type of shopping bag. We have only one planet to live it

is imperative for every one of us to take care of the same. We must

unite as one human family in new understanding and care for this

wonderful nest in the stars: Planet Earth, our home.

Acknowledgements

The authors are grateful to The Hong Kong Polytechnic University

for providing funding support to this research through project

RP7Q and to all the respondents to the survey conducted in China,

India and Hong Kong. The authors are also thankful to Dr. Xuemei

Ding, Laili Wang and Weibang Chen, of Donghua University,

Shanghai, China for their help in conducting the survey in China.


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