harmful substances and making it feel less irritating [2–4]. It is estimat-
ed that hookah is used daily by more than 100 million people world-
wide, and its use has been steadily increasing in Europe and the USA,
where an estimated 30% to 48% of college-aged students have reported
using the apparatus [5,6]. A conventional hookah is shown in Fig. 1a and
poses complex and misunderstood potential health problems. Other im-
ages of hookahs can be searched online [7].