The Loh Down On Science

Is dustless chalk really all it claims to be?

Larramendi and others, Ann. of Allergy, Asthma, & Immunology, May 2013.

This is a gel electrophoresis blot. Gel electrophoresis is a technique to separate proteins by size through application of an electric current. The markers are molecules of known sizes to help size the the substances of interest--in this case, the milk protein casein, in chalk. Notice how the chalk extract has dark bands at about 30 and 37, which correspond to bands in the casein sample (far right).

Some kids really are allergic to school, or at least, to their classrooms!

This is Sandra Tsing Loh with the Loh Down on Science

And on the hidden dangers of chalkboards.  Remember writing on the blackboard and getting chalk all over yourself?  That’s why they came up with dustless chalk.  But, according to researchers from Alicante, Spain, dustless chalk isn’t really dustless … and it can cause real problems.  

Carlos Larramendi and colleagues found that chalk labeled as “dustless” still releases small particles into the air. When those particles are breathed in by children with milk allergies?  They can cause congestion, sneezing, shortness of breath, runny noses, even asthma attacks. Milk?  Chalk?  What’s the connection?

Turns out the milk protein casein is among the particles released.  And despite modern technology, chalk is still found in most classrooms around the globe.  Oh boy.

Wait—there's more:  Just switching to white boards may not help entirely.  That's because chalk isn’t the only classroom product to contain milk proteins.  They can also be in glue, ink, and paper.

Of course, this is not a problem for all children.  Just in case my kids are taking notes.

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The Loh Down on Science is produced by LDOS Media Lab, with 89.3 KPCC. And made possible by the generous support of the Gordon and Betty Moore Foundation.

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