During each 30 min smoking session, the air flow in the four devices
was off for 20 s and on for 3 s, simulating a smoker not inhaling and then
inhaling from the hose. Every ten to twelve minutes the charcoal would
be removed from the head and lightly tapped to remove any ash (re-
ferred to as “ashing” in the hookah smoking jargon). There were 80
on/off cycles and a total of 28.0 L of aerosol smoke passed through the
filters. The total material passed through the filters was derived fromthe EPA's inhalation rates for short-term exposure. A male between the
ages of 18 to b30 with an average weight of 76 kg has an inhalation rate
between 7.2 and 8.7 L/min (when resting [lying] and sedentary [sitting
or standing], respectively). A female between the ages of 18 to b30 with
an average weight of 62 kg has an inhalation rate between 5.5 and 6.7 L/
min (when resting [lying] and sedentary [sitting or standing], respec-
tively). Our flow meter was set to 7.0 L/min, mimicking the average of
the male and female inhalation rates [42]. Blank analyses were per-
formed at the beginning of each day with a clean apparatus, two filters
in parallel, 20.0 g of 3.0 mm acid washed glass beads in the head, no
charcoal, and the vacuum turned on and off for 80 cycles. Finally, one
simulated smoking session involved filling a Pyrex head with either
Mya stones (30.0 g) or Shiazo stones (20.0 g) with Coco Nara or Fantasia
charcoals used as the heat sources (25.0 g) and using the vacuum. Alter-
natively, to compare the toxic metal contributions from the two char-
coals, an e-charcoal ignition source (electrical resistance heater) was
used.