This is supposed to be water proof... that's exactly what caused me to break my head over how an indirect contact with few molecules of water had damaged it.. (androidcentral.com)
Changes in ozone layer concern mainly the stratosphere and I used to think there are very few molecules (even atoms, in fact) upward. (realclimate.org)
The important effect of this decrease in pressure is this: in a given volume of air, there are fewer molecules present. (altitude.org)