|Dicarboxylic acids, oxoacids, benzoic acid, a-dicarbonyls, WSOC, OC, and ions in spring aerosols from Okinawa Island in the western North Pacific Rim: Size distribution and formation processes|
By Deshmukh et al.
The revised manuscript was evaluated. The discussion for the inorganic ions has been improved considerably. However, it was still hard to follow the discussion for the organic components. As proven by the 27 “may”s in the text, the revised manuscript still had too many speculations to explain the observations during this case study. Particularly, it was hard to follow the discussion on the oxidative production of organic components in aqueous droplets. There were also some points that the authors did not seem to address in the revision (e.g., line 354-357). I still saw many writing issues too, such as tense (i.e., mixing present and past tense as referring the observed results), conciseness (e.g., line 434-438), etc. After reading it, I am impressed unfortunately that the revised manuscript is still not an acceptable form by ACP. The followings are specific points I would like to make.
Figure 2 is still confusing. The authors should provide the time information (in UTC or local time) for the trajectories as well.
In the text the discussion the authors are making with Figure 3 is about the overall chemical composition in the “fine” and “coarse” modes of particles. Such information is available from Table 1. I still do not see a point that the authors need to show Figure 3. This point has not been improved.
Line 186: The reference by Takiguchi et al. does not seem to show the analytical results of organic aerosols, but nitrate aerosols. This group has published a better publication showing the analysis of oxygenated organic aerosols in Okinawa (Irei et al.,EST, 2014). This reference seems more appropriate in this case.
Line 215-223: A writing issue. The authors should be able to organize the possible sources of C2 more concisely.
Line 300-302: State explicitly that the particle size grew during the long-range transport.
Line 341-347 and line 464-475: To explain the observed results of oxidation products found in the fine mode, the authors hypothesized that photooxidation occurred first in cloud droplets, which must be in large size, and then the droplets dried and shrank to smaller size. Did the authors find any supporting result for this particle shrink from the model calculation of LWC? If the latter assumption really happened, I expect that the oxidation products and the LWC were anti-correlated because the particles were dried. Contradictorily, the authors state later that the high correlation was observed between the ratio of WSOC, a group of oxidation products, to OC (or SO42-, for example) and LWC. The logic does not make sense…It will be worthwhile to show time series plot of temperature, RH, and the calculated LWC during the sampling periods (from March 18 to April 13) so that the hypothesis of particle shrink is partially supported by own data.
Line 428-431: I cannot follow the logic why the high loading of WSOC suggests significant contribution from fossil fuel combustion and biomass burning.
Line 646-654: I cannot follow the logic. The authors ruled out a possibility that the observed wC9 originated from sea-surface microlayer. Does the microlayer never contain wC9? The authors should show scientific evidence using references or observations.
Scatter plot of oxalic acid concentration vs. other organic compound concentration: N=5 does not sound an acceptable reason for excluding this plot from the paper because the authors are submitting this manuscript based on the 5 sample analysis anyway. Correlation coefficients for some linear regressions seem to be very high, indicating something. Error analysis should be used to judge that the slopes themselves and the differences between the slopes are significant. The authors should scientifically analyze the plots a little more deeply.