Measurements of Particulate Matter from Electronic and Conventional Cigarettes: A Comparative Analysis of Methods
, Chiara Veronese 1, Andrea Tittarelli 4, Roberto Boffi 1, Martina Bertoldi 3, Esteve Fernández 5,6,7,8, Cinzia De Marco 9 and TackSHS Project Investigators †
Round 1
Reviewer 1 Report
The paper is well described and the results are promising. However, there are some comments need to be addressed as follows. I suggest accepting this manuscript for publication after all comments listed below are well addressed by the authors. Besides, I strongly recommend that the English of the manuscript need to be polished before publication.
Comments:
1. Line 28: SHA should be the abbreviation of second hand aerosol.
2. Line 104: Add “it” before “introduces significant and non-linear changes”.
3. Line 109: Change “14C” to “14C”.
4. Line 148: How did you determine the distance between the instruments and the smoker (2 m)? The distance could be important since it might influence the particle number and size of high volatility aerosol from ECs.
5. Line 169: The term “between >0.5 and >2.5 μm” is ambiguous.
6. Line 195: The section title is too long.
7. Line 205: More details are needed for the “Semple equation”, such as what Semple et al. have done in their study and why you can use their equation in your study.
8. Line 206: What does “ax2” mean?
9. Table 2: The median, max, and min value are the same for column 5, 7, and 9. The data of the BAM 1020 remained unchangeable during e-cig?
10. Why you use different model and sampling time in 3.2.1 and other sections? The results in 3.2.1 is not comparable with those in other sections.
11. Line 308: Too informal.
12. Line 309: What is eq. 4?
13. Figure 5: Need to label the y-axis. Same with Figure 7 and Figure 8.
14. Line 318: Same with line 296. Please delete it.
15. Line 356: “the reference instrument BAM-1020 indicated only small increments” is not accurate, since the BAM-1020 showed significant increase in SHS from CC (Figure 1).
16. Line 385: Add some references about the health effect correlated with particle size.
17. Line 390: You mentioned several times in the manuscript that if the RH never exceeds 45/50%, the interference could be ignored. I suggest you add some experiment data or references in the supplementary materials to support this conclusion.
18. Several studies have measured the particle size of aerosol from ECs with FMPS or DMS, and indicated the size distribution within hundreds of nanometers, which could not be detected by OPC. Could you please summarize the amount of studies and advantage of using OPC to measure SHA from ECs to emphasize the importance of your study?
19. In line 177 you mentioned the filter correction method (a) and chose method (b). However, as shown in your study, method (b) is not applicable when measuring aerosol from ECs. Do you think it is applicable to use filter correction method instead with ECs measurement (as done in Sousan et al., 2022)? If not, what is the disadvantage of this method?
Author Response
See attached file
Author Response File: 
Author Response.docx
Reviewer 2 Report
Line 58-71- The authors need to put a few references for this section
Line 72-77- The authors need to put a few references for this section. The authors also need to mention the particle size range of this method.
Line 130, Equation 1. You indicated that the RH range for this equation is 0-1, if RH is 1, the second part of the equation will go to infinity. So, the upper range can’t be 1.
Line 141-142, how significant that error pertaining to the study as volatile and semi-volatile particles are key.
Figure 1b, X-axis and y-axis needs to be titled. The graph title is not a substitute
Table 2. the number between parentheses is confusing. You need to organize the table better
Line 288-290: Although large particles may have dropped, but small particles can linger for longer in this environment. So this could be a real phenomenon associated with ultrafine particles below 100 nm in diameter.
Figure 4 is not very clear visually
Figure 5 needs to be clearly labeled. Why the background for 0.4 µm is higher?
353-371- The measurement you performed with CC to show correlation is different than the measurement you performed with EC to show lack of correlation between BAM and OPC. The concentration during CC reached 800 µg/m³ while the concentration during EC reached only 30 µg/m³. It sounds to me that the discrepancy is more or less related to sensitivity for this type of aerosol produced. In order to shown whether the BAM will have an equivalent behavior for CC and EC, you will need to compare your results at the same concentration level.
The conclusion sounded like a discussion. The conclusion should be related to the work performed and not to a solution. Incorporate some points discussed in the discussion section or recommendations. Also, measure particle number is important but it is not a substitute for particle mass. We need to be able to measure both metrics to understand the significance of this problem
Author Response
see attached file
Author Response File: Author Response.docx
Reviewer 3 Report
Comments for author File: 
Comments.pdf
Author Response
see attached file
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments for author File: Comments.pdf
Author Response
see the attached file of the review
Author Response File: Author Response.docx
