Paper bags vs. non-woven bags vs. plastic bags: A comparison of life cycle costs and environmental impacts
Release time：2025-08-26 Classification：Knowledge
The number of reuses is the key to environmental protection
Have you ever faced this choice at the supermarket checkout: paper bag, non-woven bag, or plastic bag? In today's world of growing environmental awareness, this seemingly simple choice hides a complex environmental truth. When we delve deeper into the lifecycle costs and environmental impacts of these three common shopping bags, some counterintuitive facts gradually emerge.
1. Ecological Footprint of Raw Materials and Production Processes
Paper bag production begins in the forest. Logs are harvested, transported to pulp mills, and then undergo chemical or mechanical pulping to become paper. This process not only consumes vast quantities of wood—approximately four tons are needed to produce one ton of pulp —but also requires vast quantities of water, exceeding 50 tons per ton . Pulp mill wastewater contains high concentrations of organic matter and suspended solids, with COD (chemical oxygen demand) and BOD (biochemical oxygen demand) levels significantly higher than other industrial wastewater, placing significant strain on the aquatic environment.
Traditional plastic bags are made from petroleum. Through extraction, refining, and cracking, they are ultimately polymerized into polyethylene (PE) or polypropylene (PP). While this production process is energy-efficient, it relies entirely on non-renewable fossil resources. A typical plastic shopping bag weighs only 6-8 grams , making its extremely low weight a significant advantage.
Non-woven bags are still primarily made of plastic—polypropylene (PP) fibers account for over 90%. Despite being labeled "eco-friendly bags," they are still essentially plastic products. The production process uses a spunbond process, which involves melting, spinning, laying, and hot-pressing polypropylene into a web. This consumes far more energy than traditional plastic bag production.
Degradable plastic bags , an emerging solution, fall into two main categories: biodegradable materials like polylactic acid (PLA), derived from plant starches like corn and cassava; and petroleum-based biodegradable plastics like PBAT, which can break down under specific conditions. PLA bags can reduce overall carbon emissions by up to 70% compared to traditional PE bags.
2. Performance and Reusability Comparison
Paper bags face significant limitations in everyday use. They have poor water resistance, their strength drops dramatically when wet, and their load-bearing capacity is limited (typically no more than 10kg). Poor foldability makes them difficult to carry, and they have a short lifespan, breaking after an average of only two to three reuses.
Plastic bags offer exceptional practicality: they are waterproof and moisture-proof, highly flexible, and highly foldable, with a load-bearing ratio far exceeding their own weight. High-density polyethylene (HDPE) plastic bags can withstand loads up to 1,000 times their own weight . These properties make them particularly reusable, especially thicker supermarket shopping bags.
The durability of non-woven bags is their greatest advantage. Made from polypropylene spunbond fabric, these bags can withstand an average weight of 5-10kg and last over 50 times. Their softness and compact size also make them easy to carry.
Research data shows that a non-woven bag needs to be reused at least four times to offset the emissions of producing a disposable plastic bag . To achieve real environmental benefits, the number of uses must reach 50 or more.
3. The truth about waste disposal and end-of-life environmental impact
Paper bags offer inherent advantages after disposal. Under suitable conditions, they naturally degrade within one to two months , breaking down into carbon dioxide, water, and biomass, leaving no harmful residue. Even when incinerated, they produce far fewer pollutants, such as dioxins, than plastic.
Disposal of traditional plastic bags is an environmental nightmare. In the natural environment, PE plastic bags take hundreds of years to fully degrade , breaking down into microplastic particles. These microplastics have invaded ecosystems worldwide—the average Malaysian ingests 502.3 mg of microplastics daily, equivalent to approximately 494,000 particles, with over 50% coming from fish consumption.
Non-woven bags also face the problem of plastic pollution after disposal. When discarded as single-use items, their environmental impact is magnified: a single-use bag consumes 17.8 times more energy than a disposable plastic bag and emits 16.7 times more greenhouse gases. Even more worryingly, a survey shows that nearly 30% of consumers use non-woven bags directly as garbage bags, and 42.6% do not reuse them outdoors, significantly reducing their environmental value.
The final disposal of degradable plastic bags requires specific conditions. In industrial composting facilities (maintaining temperatures of 55-60°C), PLA bags can decompose within 12 weeks . However, in the natural environment, their degradation rate may be significantly slower. Currently, some "degradable plastics" on the market are simply fragmented plastics, which still release microplastics.
IV. Comparative Analysis of Environmental Impacts Throughout the Life Cycle
The following table summarizes the environmental impact comparison of the three shopping bags at each stage of their life cycle:
| Evaluation indicators | paper bag | non-woven bags | plastic bag |
|---|---|---|---|
| Raw material acquisition | High pressure on forest resources | Fossil resource consumption | Fossil resource consumption |
| Production Process | High water consumption and water pollution | Medium to high energy consumption | Low energy consumption and low emissions |
| Performance | Easy to break, not waterproof | Durable and can be used multiple times | Lightweight, waterproof and durable |
| Disposal | Degradable and recyclable | Refractory (microplastics) | Refractory (microplastics) |
| Global Warming Potential | Maximum (one-time) | Medium (low with multiple uses) | Low (one-time) |
| Ideal number of uses | 3 times | More than 50 times | Repeated use |
A research team from Nanyang Technological University in Singapore found through modeling analysis that the global warming potential of disposable kraft paper bags is more than 80 times that of reusable non-woven bags . Even reusable cotton bags (used 50 times) have a global warming potential more than 10 times that of non-woven bags (used 50 times).
Polyethylene shopping bags primarily contribute to air pollution, while kraft paper shopping bags primarily cause water and solid waste pollution. The production of paper bags produces large volumes of wastewater containing high concentrations of suspended solids, COD, and BOD, making it difficult to treat and posing a serious threat to aquatic ecosystems.
V. Innovative Solutions and Development Trends
Faced with environmental challenges posed by traditional packaging materials, global innovation forces are seeking breakthroughs:
A global packaging leader has made significant progress in high-performance, plastic-reducing paper bag technology. This innovative product replaces traditional plastic liners with a 20-micron high-performance barrier film, reducing plastic usage by 60% while maintaining excellent moisture-proof performance. This product is certified recyclable and can be directly integrated into existing production lines.
Truly plastic-free compostable bags have arrived. Developed by the innovative environmental brand Earthya, these bags contain no polyethylene (PE) or polypropylene (PP) components. They are made from calcium carbonate and certified compostable polyester. They completely decompose into plant fertilizer in the natural environment, leaving no microplastic residue. They also have a shelf life of up to two years , addressing the short shelf life of traditional biodegradable bags (six months).
The cost of biodegradable materials is rapidly declining. The production cost of polylactic acid (PLA) has dropped from 28,000 yuan per ton in 2020 to 16,000 yuan per ton in 2025, and is projected to fall further to 8,000 yuan per ton by 2030. This narrowing price gap is accelerating market adoption—the Chinese biodegradable plastic bag market is projected to exceed 50 billion yuan in 2025 and reach 150 billion yuan by 2030.
VI. Recommendations for Consumers and Policymakers
A practical selection guide for consumers:
- Prioritize reuse : Regardless of the material, increasing the number of uses is fundamental to reducing environmental impact. Non-woven bags must be used at least 50 times to achieve their environmental benefits.
- Think rationally about paper bags : Don't be blinded by their environmental appeal. In terms of resource consumption and carbon emissions, their environmental costs may be higher than those of properly used plastic bags.
- Identify truly biodegradable products : Choose bags with international compost certification (such as OK Compost) and avoid pseudo-degradable products such as "oxidative degradation".
- Bring your own shopping bags : Develop the habit of carrying foldable shopping bags with you to reduce packaging consumption caused by temporary shopping needs.
Recommendations for policymakers:
- Formulate policies based on local conditions : In large cities with well-developed waste incineration systems, a closed-loop plastic recycling system should be established; in areas with weak waste management, compostable bags can be promoted.
- Strengthen the supervision of non-woven bags : standardize the minimum weight of non-woven bags (for example, Hainan prohibits the use of non-woven bags weighing less than 100 grams per square meter), improve durability, and avoid disposable use.
- Support technological innovation : Increase support for the research and development of truly environmentally friendly materials, such as fluorine-free pulp molded tableware (currently over 90% of products have excessive fluorine content).
- Improve the recycling system : Establish a convenient plastic recycling network and increase the recycling rate. For example, China has reduced the number of traditional plastic bags by about 20 billion each year through policies .
There is no perfect packaging, only more responsible choices
When we expand our perspective to encompass the entire life cycle, there's no clear winner in the environmental competition between paper bags, non-woven bags, and plastic bags. The environmental advantages of paper bags at the end of life are offset by the high resource consumption during their production process; the potential for reuse of non-woven bags is often undermined by single-use habits; and the low carbon footprint of plastic bags during production and transportation is negated by the long-term pollution they create after they're discarded.
A truly sustainable solution lies not in simply replacing materials but in building a circular system—developing truly environmentally friendly materials through technological innovation, establishing an effective recycling system through policy guidance, and cultivating the habit of reuse through consumer education. Only by working together can we break free from the "environmental dilemma" and achieve harmonious coexistence between packaging and the environment.
