Paper Or Plastic?
It's a loaded question, and you won't believe how complicated the answer really is
By Renée Despres
You choose your groceries carefully and consciously. Most of your choices are clear: Organic coffee and vegetables are better for both you and the environment. To minimize wasteful packaging, you buy dry goods from bulk containers, and you refill your own glass honey jar every few weeks. But if you're perplexed about whether to carry those groceries away in paper or plastic, you're not alone.
About 40 billion grocery bags are used each year in the United States: 30 billion are plastic, 10 billion paper. There's lively debate on both sides of this question. An expert in the plastics industry will argue persuasively that plastics are by far the preferable environmental choice; but a paper industry leader will make paper seem the better solution. Whether it really matters is another question. The authors of The Consumer's Guide to Effective Environmental Choices, released by The Union of Concerned Scientists (Three Rivers Press, 1999), argue that the use of either paper or plastic grocery bags has insignificant environmental impact compared to bigger consumer choices that we routinely make, such as houses, cars, food and appliances.
No matter what we answer in the checkout line, Americans love their grocery bags, to the tune of 40 billion bags a year. According to the Food Marketing Institute (FMI), the average American makes 2.3 trips to the grocery store each week. Walk away with five to 10 bags each time (not hard to do if you're feeding a family of four) and that's between 600 and 1,200 bags per shopper each year.
"There are different things to consider" for which choice is best, says Miranda Bliss, testing-lab supervisor at the Institute of Paper Science and Technology in Atlanta, Ga. Bliss suggests that consumers ask themselves four questions: What resources are required to make the bags you use? Which type of bag will be easier for you to reduce the amount of trash you generate? Can they be reused? And are they likely to be recycled?
Both paper and plastic bag production use natural resources and produce numerous pollutants. "It's hard to make a qualitative comparison between the two," says Preston Horne-Brine, senior associate at the recycling company Marathon Recovery in Kent, Wash. "Both are fairly heavy-duty industrial processes, large in scale, and both are heavily involved in extraction of raw materials."
But there are differences. Bluntly, paper bags are made out of trees. According to the American Forest and Paper Association (AFPA), about 700 bags can be made from one 15- to 20-year-old tree. In 1999, more than 14 million trees were felled to produce the 10 billion paper grocery bags used by Americans that year, though paper advocates point out that trees are a renewable resource.
More than 14 million trees were felled in 1999 to produce the 10 billion paper grocery bags used by Americans. Wood pulp is the major component of "Kraft" paper, the familiar, rough, brown paper used to make bags. Kraft paper is particularly noted for its strength and elasticity, both of which come from virgin pulp. Most paper bags are made from a mixture of virgin pulp and 25 percent to 60 percent recycled paper, according to the AFPA. The percentage of recycled content is usually printed on the bottom of the bag.
The overall environmental impact of using secondary fiber, instead of virgin resources, is significant, and the manufacturing process is cleaner. "You don't have to go through the cleaning process, which uses chemicals," says Horne-Brine. "Instead, you create a hydropulp, which is like mixing the pulp with water in a blender."
In contrast, the "plastic" used in bags is high-density polyethylene, which is made from petroleum, a nonrenewable resource. "Most plastic grocery bags are made of primarily virgin material for strength," says Horne-Brine. "For the most part, they don't use recycled materials in making plastic grocery bags."
The process of producing plastic bags is "very, very efficient," says Horne-Brine. "The yield from the raw material is more than 90 percent. When you make paper products, the total yield of the finished product compared to the raw materials is closer to 75 percent. So production of plastic is more efficient in terms of yield from raw materials."
According to the American Plastics Council, it requires 20 percent to 40 percent less energy to manufacture two plastic bags than to create one paper bag. But in the checkout line, the numbers may compute differently. A well-packed standard-size paper bag can hold up to 14 items, whereas an average plastic bag often holds only three to five items. So although each plastic bag may weigh less than its paper counterpart, three to four plastic bags may be used for every one paper bag. Bag for bag, that means that paper bags actually consume less energy during the manufacturing process.
Overall, about 45 percent of all paper products are recycled, while only 5 percent of plastics get recycled. Plastic bag manufacturing, however, releases 92 percent fewer emissions into the air than paper bag production. During paper production a variety of byproducts are produced. "Most are basic chemicals that come out in the sludge and the wastewater, and most [byproducts] are recovered," says Horne-Brine.
Carrying your groceries is just the first step in a bag's life; consumers also need to consider what happens to the bags after they get them home. "Although both can be recycled, many bags of both types end up in landfills," says Bliss. "A plastic bag is going to compress down and take up a lot less volume." Plastic bags are clearly less bulky than paper, and the smaller volume of plastic bags can help conserve landfill space. Two thousand plastic bags weigh only 30 pounds, while 2,000 paper bags weigh 280 pounds and take up considerably more room. A stack of 2,000 paper bags stands about seven feet high; a stack of 2,000 plastic bags measures 7 1/4 inches.
"If you look at the bag size, it's minuscule," says Rob Krebs, director of communications for the American Plastics Council. "One truck of plastic bags will hold about 1 million plastic bags. The same amount of paper bags would take up six trucks. Fewer trucks on the road means less gas used and fewer greenhouse gases emitted in transporting the bags."
According to Krebs, plastic grocery bags generate 80 percent less solid waste, based on weight, than paper bags. However, the Paper Bag Council of the AFPA counters that this statistic presumes that all paper and plastic bags end up in landfills. Since a higher percentage of paper bags are recycled, the presence of paper bags in landfills is not nearly as high as that 80 percent figure would suggest. And plastic bags that don't make it into the recycling loop or into landfills often end up in lakes, rivers, oceans, and forests, where they pose hazards to wildlife as well as to those environments.
Once in the landfill, both plastic and paper bags are biodegradable—but not necessarily during your lifetime. Modern landfills are designed to prevent materials from degrading and contaminating groundwater, so nothing—not even grass clippings—breaks down fast enough to affect landfill space. "A lot depends on how much water and air get into the landfill," says Horne-Brine. "Plastic bags do degrade, but over a very, very long period of time—hundreds, if not more, years. Although it depends on the conditions in the landfill, paper has the potential to degrade much faster."
Whether paper or plastic, grocery bags can be reused in an endless number of ways. Many supermarket chains encourage reuse of bags by offering a 5-cent-per-bag discount to customers who provide their own. If every bag were used just twice, the number of bags used per year would be cut in half.
Both paper and plastic bags are also strong and flexible enough to hold dry trash and to store other objects, from toys to tools. Consumers can reuse plastic bags to store paintbrushes overnight, protect water and gas valves in the wintertime, line a bicycle pack or backpack, or pick up dog waste.
Paper doesn't fare as well if it gets wet, but kids and adults can use paper bags for creative projects. They make great templates for drawing or writing and can be used to make baskets, book covers or other craft items. Paper bags are also biodegradable, which means that they can be composted. Gardeners can throw garden clippings into a paper bag, then put the whole package into a composting bin, which hastens the breakdown of the bags.
All paper and most plastic bags are recyclable, but that doesn't mean they will get recycled. Here, paper bags have a decided advantage over plastic. Almost all curbside pickup and recycling centers allow customers to mix paper bags with their newspapers for recycling; some even request that other paper items be placed in paper bags.
A standard "T-shirt" style plastic bag costs store owners about 1.2 cents. A traditional paper bag costs store owners 3 to 4 cents. Fewer places accept used plastic bags for recycling. Many grocery stores recycle plastic bags, but they need to be clean and dry when they're placed in the bin. Some stores, such as Spartan, a large supermarket chain with stores throughout the Midwest, discontinued plastic bag recycling programs because about 20 percent of the returned bags were contaminated with food, water, or even dirty diapers and hypodermic needles.
Until recently, the market for recycled plastic bags has been small. Relatively few plastic bags will ever be recycled into their original form because the process is too costly, and the resulting bags would lose too much strength. But rapid changes in the recycling industry may mean it will be easier to recycle plastic bags (called "film" by recyclers) in the not-so-distant future. "I wouldn't even venture a guess as to what the recovery rate for film is now, but it's growing at an extraordinary rate," says Horne-Brine. "We've been recycling paper grocery sacks very actively for 25 years. The recovery rate for [these] sacks is more than 70 percent, and recycling options are available just about everywhere. The recycling of plastic film is new, but collection systems are being developed rapidly."
The recycling market for plastic bags has grown significantly in recent years with the appearance of companies like Marathon Recovery (www.rsarecycle.com) and Trex Inc. in Winchester, Va. (www.trex.com), two of about 200 small-to-midsize companies that are making a wood-polymer lumber that consists of half wood and half recycled plastic film. The impact on recycling has been huge. Trex alone buys about 30 million pounds of recycled plastic grocery bags—at 3 cents a pound—each year from grocery stores in the United States.
This composite lumber saws, planes and nails just like wood. And it has some advantages. It's not susceptible to mold and termites or other bugs, so it doesn't need to be treated with toxic preservatives, stains, insect deterrents or mold-and-mildew killers. Nothing can leach out or soak into the lumber, making it an ideal material to use for building raised beds in gardens, decks and indoor-outdoor furniture.
"The big advantage is that these wood-polymer lumbers do not degrade readily in moist or marine situations," says Horne-Brine. "They represent a real alternative to pressure- or creosote-treated timbers."
The Best Choice
"Reusable cloth bags are simply the way to go," says Liz Delaney, waste management expert at the Eastern Research Group in Arlington, Va. But Americans seem to be stuck on the convenience of paper or plastic, even if the question causes angst. According to the Grocery Industry Committee on Solid Waste, less than 1 percent of shoppers consistently use cloth bags. Many shoppers find these bags too bulky to carry, forget to bring them or simply can't be bothered.
About 1 percent of Americans bring their own cloth or net bags to the grocery store. So the next time you're asked "paper or plastic?" choose whichever type of bag fits your needs. Reuse it as many times as you can. Recycle it when you're done with it. And next year, with your help, maybe we'll start to make a dent in those 40 billion grocery bags.
Renée Despres, an author and ultrarunner based in Gila Hot Springs, N.M., is the proud owner of four brand-new cloth grocery bags.