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Almost everyone has heard that to help the environment at the grocery store you need to choose paper bags over plastic. But why is this? And with new manufacturing technology, does that adage still hold true?
In a study done in 1990, paper and plastic bags were assessed based on both the energy used to produce the bags and the pollutants produced from the bags. The study had interesting results. Researchers found that products of two plastic bags used only 87% of the energy used to produce one paper bag. To produce a paper bag, high amounts of coal, wood, and petroleum are used, resulting in a total energy usage of 1,680 kilojules (kj). Plastic bags, on the other hand, use petroleum and natural gas, and use only 1,470 kj to produce two.
In looking at the pollutants generated by both plastic bags and paper, plastic bags again came out the winner. Researchers divided the pollutants into three different waste categories: solid, atmospheric, and waterborne. In every category, two plastic bags produced less pollution than did one paper bag. There are flip sides to the argument, however.
While plastic takes less energy to produce than paper, and produces less pollutants, paper can be composted, while plastic cannot. Also, a common energy source to produce plastic bags is nuclear fission, which results in radioactive waste – a potentially harmful pollutant in its own right. So what is the right answer? Unfortunately, there is no clear cut winner. If you really want to be as contentious as possible when bagging your groceries, bring your own string or cloth bags that can be reused.
|Jennifer Mathes, Ph.D.|