$C_S$	Cunningham correction, -
$D$	Diffusion Coefficient, m2 s
$K$	Kuwabara factor, -
$Kn$	Knudsen Number, -
$Pe$	Peclet Number, -
$R$	Interception parameter, -
$R{e}_f$	Reynolds number, -
$Stk$	Stokes number, -
$T$	Temperature, K
$U$	Face velocity, m s−1
$D_f$	Fiber diameter, m
$d_p$	Particle diameter, m
$k_B$	Boltzmann constant, m2 kg s−2 K−1
$\alpha$	Solidity, -
${\eta }_{fe}$	Filtration efficiency, -
${\eta }_d$	Filtration efficiency due to diffusion
${\eta }_I$	Filtration efficiency due to interception
${\eta }_{Imp}$	Filtration efficiency due to impaction
${\rho }_p$	Particle density, kg m−3
$\rho$	Air density, kg m−3
$\mu$	Viscosity, kg m−1 s−1
$\lambda$	Mean free path, m