The Green Lantern

Today's Lesson: Which Is Better for the Planet, Chalk or Dry-Erase Markers?

By Nina Shen Rastogi
Thursday, September 10, 2009

Over the summer, the high school where I teach had a complete makeover, which included replacing all our old chalkboards with whiteboards. I'm happy not to be breathing in any more chalk dust, but with all those plastic pens I'll be throwing away, is the new system really any better for the environment?

Veteran teachers will debate endlessly the merits of chalk vs. dry-erase markers. Some insist that their preferred system has pedagogical benefits (one science teacher said she wrote more slowly with chalk, giving students more time to absorb difficult concepts), while others appreciate its feel or smell. With apologies to both camps, let's assume that blackboards and whiteboards are interchangeable with respect to teaching so we can figure out which is better for the planet.

The Lantern was surprised to discover that the boards themselves are more or less the same. Until the 1960s, chalkboards were made from slate, which is extracted from the earth through quarrying. These days, though, a blackboard consists of a steel core with a porcelain overlay, just like most wall-mounted whiteboards. So the primary comparison here comes down to chalk sticks vs. markers.

Chalk is a relatively simple product: Start with either calcium sulfate or calcium carbonate -- the main sources of which are gypsum and limestone, respectively -- mix with water and pigments, extrude into stick form, and then bake. All these steps require energy, and quarrying gypsum and limestone has the potential to cause air pollution.

Dry-erase pens, on the other hand, have a number of components -- plastic barrels, caps, filaments and ink -- so they have a much more complicated life cycle. As with mechanical pencils, the main issue is the plastic: Plastic manufacturing requires petroleum, a nonrenewable resource. And at the end of their lives, whiteboard markers are virtually guaranteed to end up in the trash bin. Even if you felt motivated to disassemble your pens so you could dispose of them more responsibly, it wouldn't do much good. Most markers don't indicate what kind of plastic they're made of, and those that do are often polypropylene, which generally isn't recyclable.

Chalk, however, can be a very low-waste product, especially if you use a chalk holder that allows you to use the sticks until the bitter end. Chalk also tends to be packaged much more simply, which means less trash headed for the landfill. There is the issue of chalk dust, which can trigger allergies and aggravate asthma. Some teachers also report that chalk dust can muck up electronic equipment. That means more cleaning supplies, plus the potential need for more-frequent replacements. Dry-erase pens can produce dust, too, though, and the residue left on the board often requires special cleansers.

Many chalk adherents claim that chalk is cheaper than its competitor, which would certainly boost its green cred. Money saved on writing implements, after all, can be put toward environmentally friendly classroom upgrades, such as swapping out T-12 fluorescent bulbs for the T-8 variety, which the Department of Energy estimates can save up to 30 percent of a school's lighting energy. It's not obvious, though, that the math works out in favor of chalk. You can get a box of 12 colored chalk sticks for just 99 cents on Office Depot's Web site, while a four-pack of colored markers costs $5.39. But some teachers say it is possible for a single pen to outlast 16 sticks of chalk, making it a better value.

To compare a stick of chalk with a disposable dry-erase marker, we'd need better data on how the manufacturing impacts stack up. The pen maker Bic says 90 percent of the environmental impacts of its Cristal-brand plastic ballpoints stem from the production phase. Because your school has already made the switch to whiteboards, reusable pens, such as AusPens and Artline's Eco marker, are your best bet, provided the ink refills and replacement nibs for these products aren't overly packaged.

As one teacher, you might not have much say in your school's procurement policies. Having been a high-school teacher, the Lantern knows how whiteboard pens have a tendency to migrate from classroom to classroom. If you have the time and the resources to buy your own pens -- and then ensure that they're used properly and not chucked as soon as they run out of ink -- the Lantern heartily applauds your efforts. If that's unrealistic, there are plenty of free, easy things you can do to reduce your classroom's footprint.

For example, shut off all the lights if the room will be empty for more than a few minutes. According to Pacific Gas and Electric, between 8 and 20 percent of a school's lighting energy can be saved this way. Keep computers, printers, televisions and other electronics powered down when not in use. Better yet, involve your students in your monitoring efforts. If you can help them understand how small choices made in individual classrooms can add up on an institutional level, you'll be doing a lot more for the planet than you would by personally choosing one type of writing utensil over another.


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