System for collecting exhaled particles

A system for collecting exhaled particles, said system comprising:

• a) a reservoir having a first opening and a second opening;
• b) a two-way mouthpiece and a one-way valve configured to open to permit the user to inhale through said mouthpiece via said one-way valve and to close thereafter, thereby preventing outside air from entering the system when the user exhales through said mouthpiece;
• c) an inertial impactor having an inlet and an outlet, said impactor being arranged to pass a gas stream comprising particles between said inlet and said outlet, said inlet of said inertial impactor being connected to said first opening of said reservoir, and said outlet of said inertial impactor being connected to said second opening of said reservoir;
• d) a pump having an inlet and an outlet, said pump being arranged to maintain a constant gas stream flow through said impactor;
• e) a first valve disposed between said mouthpiece and said inertial impactor;
• and
• f) a further valve disposed between said first valve and said inertial impactor and configured to allow exhaled air to enter said impactor and/or said reservoir, or to be let out of the system, wherein
• said first opening of said reservoir is connected to said mouthpiece via said first valve and said further valve,
• said pump is located downstream of said impactor,
• said second opening of said reservoir is connected to said outlet of said pump, and
• the system is configured to collect exhaled particles in the exhaled air without permitting outside air to be added to the reservoir.