Gas properties

Temperature K
Pressure atm
Gas

Viscosity
-
Pa·s
Mean free path
-
nm

Mass-mobility relationship

This section sets the mass-mobility parameters and shape factor used throughout the rest of the web app. Note that ρeff,100 is the effective density of a particle having a mobility diameter of 100 nm. Default is for soot [a].
ρeff,100 kg/m3
Exponent (Dm)
Matl. density

Pre-factor (k, m0)
-
fg
m @ 100 nm (m100)
-
fg
ρeff,100
-
kg/m3
χ @ 100 nm
-
(
-
)

Equivalent sizes

Mass and effective density at the chosen mobility diameter are computed via the mass-mobility relation. Cunningham slip corrections are calculated via the expressions of Kim et al. For dynamic shape factor and aerodynamic diameter, the value in the brackets is the equivalent quantity when not accounting for the slip correction, giving an indication of the significance of this effect.

Mobility diameter nm
Knudsen number (Kn)
-
Mass
-
fg
ρeff @ dm
-
kg/m3
Volume eq. diameter
-
nm
χ @ dm
-
(
-
)
Cunningham slip @ dm
-
Cunningham slip @ da
-
Aerodynamic diameter
-
(
-
) nm
Mechanical mobility (B)
-
m/(N·ns)
Electrical mobility (Zp)
-
cm2/(V·s)
Diffusion coefficient (D)
-
cm2/s
dp,100 nm
DTEM
dp @ dm
-
nm
Number of primaries (Np)
-
kf nm
Df
Radius of gyration
-
nm

Distribution moments

This section computed equivalent distribution moments using a combination of Hatch-Choate and the above size conversions. In the plot, the blue line corresponds to the number distribution and the red line to the mass distribution.

CMD nm
GSD
MMD
-
nm
CMAD
-
nm
MMAD
-
nm
GSD (for da)
-
CMM
-
fg
MMM
-
fg
GSD (for mp)
-

Acronyms
CMD - Count median (mobility) diameter
MMD - Mass median (mobility) diameter
CMAD - Count median aerodynamic diameter
MMAD - Mass median aerodynamic diameter
CMM - Count median single particle mass
MMM - Mass median single particle mass

Average charge algorithms

This section uses average charge methods to compute the average particle mass and integer charge that would be transmitted (trans.) through a mass-to-charge classifier (e.g., CPMA and APM). Based on a draft manuscript that is yet to be published.

Mass-to-charge s.p., m* fg
Pre-factor, q0
Exponent, v
Interp. factor, n
c0
-
β
-
Ave. trans. mass
-
Ave. trans. charge
-
Footnotes
a Soot [1]: ρeff,100 = 510 kg/m3, ρm = 1860 kg/m3, Dm = 2.48
b NaCl [2]: ρeff,100 = 1940 kg/m3, ρm = 2160 kg/m3, Dm = 2.97
c Water/PSL: ρeff,100 = 1000 kg/m3, ρm = 1000 kg/m3, Dm = 3
* This web app is currently under construction and has not been fully validated.
* Roughly equivalent MATLAB code is available here.

References
[1] Olfert and Rogak, "Universal relations between soot effective density and primary particle size for common combustion sources", Aerosol Sci. Technol. (2019).
[2] For density of NaCl see Sipkens et al., "Comparison of measurement systems for assessing number- and mass-based particle filtration efficiency". (2022).