It's a question that echoes through the aisles of supermarkets across the country, but is there a right answer?
The city of San Francisco thinks so: paper.
In comparing each alternative, the city found that though producing paper bags creates more air and water pollution, they are easier overall on the environment than plastic.
This is because plastic bags are made of polyethylene, a compound coming from crude oil and natural gas, which is non-biodegradable. Also, though plastic bags can be recycled, the EPA estimates that only around 5% actually are. This means a significant number of bags are going into landfills or being littered, causing problems for the environment.
As a result of these findings, the city has mandated that stores discontinue all non-biodegradable plastic bags, and use only paper or biodegradable plastic.
Bringing your own reusable bag, however, remains the best solution.