Description:

Issued on April 1, 2011. Paper folder (15 x 11 cm.) containing a foam-padded compartment with a plastic window, through which is visible an enlarged colored map of Charleroi, Belgium, and a clear plastic tube. Printed on the item are instructions for use, a colored map of Belgium including Charleroi showing nanoparticles on April 1, and a graph depicting atmospheric concentration of nanoparticles on the first day of each month.