Regarding to the uncertainty introduced by Sa measurement, I agree with the reviewer that it is nearly impossible to be only between 37-40% if you include the contributions of all the factors. For instance, the ambient aerosol surface area density was calculated from the dry particle size distributions. For typical electrical mobility based aerosol size distribution measurement, the charging fractions in atmospheric conditions can be different from instrument-default conditions and then leads to significant uncertainty. There has been quite some discussions on this topic. In addition, the unknown morphology of aerosol particles can introduce significant uncertainty when deriving aerosol surface area from particle number based measurements.

In addition to just state that “the uncertainty introduced by Sa measurement would be propagated to an uncertainty of 30%......to evaluate the uncertainty from different parameters (Wang et al., 2018)”, therefore, I suggest that you clearly and concisely specify which factors were included in your uncertainty evaluation. This will help the readers to understand the reported uncertainty range.