The Comparing Study between Plastic bags and Shopping bags by The Life
Cycle Assessment
Abstract
Due to too high proportion plastics in the waste, EPA (Environmental Protection
Administration) promotes “ limited usage policy of plastic shopping bags” since July
1,2002 to reach to the goal of plastic bags reduction. However, while this policy is promoted, whether it can really reduce environmental impact? Or it will cause more danger to whole or local natural environment? Therefore, with scientific, objective and effective method─life cycle assessment(LCA),this study attempted to carry out evaluation, which aimed at shopping bags of different specification and material provided by convenient shops and hyper-marts before and after this policy was promoted. And comprehensive evaluations and suggestions are conducted and presented from the opinions of businessmen, consumers, energy consumption and whole environment.
In this study, the plastic bags and shopping bags provided and sold by 7-11,
Family convenient shops and RT-MART, Carrefour hyper-marts serve as study objectives. The first reason was that both convenient shops and hyper-marts were the targets of limited usage policy; the second reason was that all plastic bags and shopping bags provided to consumers for shopping conforms to tote bags suggested after limited usage policy of EPA. In this study, analysis and comparison matched with disassembly, inventory and interview will be carried out by regarding consumption amount of resources, purchasing cost, proportion of recycling use and price policy; and analyze the impact of two kinds of shops to environment with life cycle assessment software SimaPro. The results of the study were shown as follower:
Compare the normalized environmental impact caused by per of shopping bags use with life cycle assessment software SimaPro. For the environmental impact value caused after shopping bag, which is provided by convenient shop, is used each time under equal capacity, the middle plastic bag from 7-11 convenient shop that has 2.02 mPt environmental impact value is the most harmless to environment, the next is the
2.27mPt of large plastic bag from 7-11 convenient shop, and the No. 20 plastic bag from Family convenient shop that has 2.70 mPt,of which environmental impact value is the most harmful to environment.For the shopping bag provided by hyper-marts, the shopping bag of no-woven fabric material that has 1.44 mPt environmental impact value is the most harmless to environment, the next is the 2.06mPt of PE material shopping bag, and the worst is the shopping bag of nylon material that has 6.54 environmental impact value.
For the three stages of manufacturing, distribution and sell and discard of product, the manufacturing stage, which occupies about 95%~99% environmental

impact proportion, is the highest. For three environmental impact aspects of whole life cycle, all the impact values from plastic bag sold by convenient shop and shopping bag sold by hyper-marts concentrate on resources consumption aspect, which occupies about 70%; the next is human health aspect, which occupies about 25%. For the characterized impact value of 11 items, impact values from plastic bag sold by convenient shop and shopping bag sold by hyper-marts mostly concentrate on fossil fuels, inorganics that affect respiration, climate change. For the energy consumption aspect, the energy consumption of plastic bags provided by convenient shop occupies about 70% of total environmental impact; then the consumption of large plastic bags from 7-11 convenient shop is 1.60mPt; the consumption of middle plastic bag from
7-11 convenient shop is 1.42mPt; and the consumption of No. 20 plastic bag from
Family convenient shop is 1.91mPt. For the energy consumption of shopping bag provided by hyper-marts, thick plastic bag is 2.71mPt, PE shopping bag is 1.56mPt and nylon shopping bag is 5.15mPt, they all occupy 70% of total impact value. The energy consumption of no-woven fabric shopping bag is only 0.69mPt, which occupies 48% of total impact value.
For the plastic bag sold by convenient shop, it is the most economic when consumers choose to buy large plastic bag of 7-11 convenient shop, the reason is that it has the same price but the maximum capacity compared with other plastic bag and average usage amount is only 0.30NT$; For amount in one time use of shopping bag sold by hyper-marts, thick plastic bag is the most economic that just is 0.22 NT$, the next is no-woven shopping bag that is 0.53NT$, and nylon shopping bag is the most expensive that is 1.73NT$. But the most economic selection is not the same selection of environmental protection.
Keyword ： life cycle assessment, environmental impact, limited usage policy of plastic bag, recycling use, energy resources