Non-woven bags are much stronger than single-use plastic bags, and we have to recycle them many times to compensate for their environmental impact, yet most of the time, people don't make the most of them.
At the same time, another seemingly innocuous paper packaging is on the rise, even if this paper bag is not completely degradable, because at present, most of them need to be covered with a traditional plastic film in order to obtain water and oil repellent. Effect.
Therefore, we need a "life cycle assessment" study to help us figure out the impact of common types of reusable bags. The above-mentioned "global plastic ban" also involves the entire life cycle of plastics, including its production, design, recycling and processing.
1. Life cycle assessment
Life cycle assessments take into account a wide range of factors, including raw materials, manufacturing, transportation and final disposal. By looking at all these factors, the researchers calculated greenhouse gas emissions, waste disposal, water and energy consumption, and various other impacts.
To complicate matters, if you choose a plastic bag, is it made from virgin or recycled plastic? Even if the bag is recycled, shipping is an issue, where is it made? Printing on bags also adds to the burden on the environment. Finally, what happens to the bags when they can no longer be used? Is it recycled, reused as a garbage bag, or thrown away immediately?
2. How many times must a bag be reused?
Once all this information has been distilled, scientists can often provide a fairly straightforward guideline: how many times a replacement bag should be reused compared to standard supermarket plastic bags.
A 2018 Danish study, looking at the number of times a plastic bag should be reused before being used as a garbage bag and then thrown away, found:
The non-woven bag should be used 37 times.
The paper bag should be used 43 times.
Cotton bags should be used 7100 times.
Another UK study found that, considering only climate change impacts, it has a lower global warming potential than single-use plastic bags:
The paper bag should be used 3 times.
LDPE bags (thicker plastic bags commonly used in supermarkets) should be used 4 times.
The non-woven polypropylene bag should be used 11 times.
Cotton bags should be used 131 times.
If the non-woven bag is only used once, the energy consumption of a single non-woven bag is 17.8 times that of a single-use plastic bag, and the carbon emission is 16.7 times that of a single-use plastic bag. Assuming that the non-woven bag can be used for more than one year (calculated according to once/week), the energy consumption of the non-woven bag is only 34% of that of disposable plastic bags, and the emission is 32% of that of disposable plastic bags. Therefore, the non-woven bag needs to be reused for a long time to achieve the purpose of environmental protection, otherwise it will cause greater environmental pollution.
A 2014 study in the US found that reusable LDPE and polypropylene non-woven bags do have a lower environmental impact than the plastic bags commonly found in supermarkets, but only if they are reused enough times.
The last consideration is how many bags you need. The Danish researchers equalised the volume of the bags so that they could be assessed on the same volume of space (meaning that for some assessments it was necessary to consider the effect of both bags).
As with all environmental issues, we must have the right knowledge to make informed decisions. After looking at all this data, here are the things I want you to remember:
Whatever type of bag you use, use as many as you can.
Choose bags made from recyclable materials.
Avoid bags with printing or decoration, which alone can greatly increase the environmental burden of bags.
Never let bags become garbage, recycle, reuse and repurpose your bags.
