From Modern Mechanix

Civilian Designs Simple Gas Mask
With the threat of gas raids hanging” over more and more cities in Europe, the demand for gas masks in many communities far exceeds the supply. To provide some sort of gas protection in case of an emergency, an ingenious Scandinavian inventor has designed the improvised mask shown at the left. It consists simply of a hollow wooden tube and a cloth bag filled with chemicals. Air purified by the chemicals is sucked into the mouth through the tube, while the nose is held shut with the thumb and forefinger of the hand holding the mask.