  Understanding the interfacial properties of aerosol particles is important
for science and medicine, crucial for air quality, human health, and
environmental chemistry. Qian et al. presented vibrational sum frequency
scattering (SFS) measurements of organic molecules on aerosol particles.$^{1}$
Relating an aerosol sample with a 40 nm average size and 10 - 300 nm particle
size distribution at a density of 10$^{6}$ particle/mL to vibrational sum
frequency scattering spectra recorded in a different apparatus, it was
concluded that the vibrational spectra reported on the surface structure of the
particles in the aerosol. Here, we show that the SF scattering power of such
small particles with a density of 10$^{6}$ particle/mL is $\sim$ 10$^{7}$
smaller than the detection limit of the presented SFS experiment. We determine
the detectable number density of particles, both theoretically and
experimentally, to demonstrate the limits of the SFS method. We also propose
possible reasons for the 10$^{7}$ order of magnitude discrepancy.
