Schematic representation of the glass closed condenser. 1. Inclined glass condenser with a moveable plunger. 2. Swan-neck tubing (saliva trap) and two-way non-rebreathing valve, connected to a face mask with separated nose and mouth cavity. 3. Entrance of inspired room air. 4. Cooling unit. 5. Sample vial to collect EBC. 6. Ventilator system for recirculation of non-condensed exhaled breath. 7. Heated (at 37°C) inert Tedlar™ gas sample bag to collect the residual non-condensed exhaled breath.