Summary of particle fluxes indoors. The possible inlets and outlets of particles. Q
is a main inlet, such as an open window, Q
the leakage, Q
the filtered inlet, Q
an internal filtered recirculation, E the internal emission, R the re-suspension, D
the deposition to walls, floor, and ceiling, Cn0 and C
the outdoor and indoor concentrations of every particle size fraction, and V the room volume. Both Q
are subject to certain efficiency.