Answer for 'Review of manuscript'

Abstract

Response to Review 2 Thank you very much for your constructive comments. The point-by-point responses to your comments are given below. Your comments were all considered, and the manuscript was revised accordingly. In the revised manuscript, all changes are marked in blue. Line87 : "The introduction of spectroscopy technique [sic] has facilitated measurement through instrumentation such as Chemical Ionization Mass Spectrometry (CIMS).. . C1 ACPD Interactive comment Printer-friendly version Discussion paper CIMS is not an optical spectroscopy technique like the others listed. In addition, it is not discussed later in the paragraph when the positives and negatives are described. Yes, CIMS was discussed after spectroscopic techniques. Section 2.2.2 : Section 2.2.2 is difficult to understand. Parameters are weakly defined and technical terminology that is not typical for the atmospheric sciences makes the section challenging to understand for a likely ACP audience (including this reviewer). It is recommended that the authors include a description of how the choices made by the authors impact the outcomes of the ANN approach. We should have been more cautious when introducing new method and terminology. In the revised manuscript, the method section regarding the ANN was shortened and instead, a full explanation is given in supplementary information including the structure of ANN and the detailed procedure of calculation. Lines 263-267 : The average concentrations cited are not necessarily useful numbers because the diel variations in mixing ratios are so large. The nocturnal HONO and daytime O3 mixing ratios are the most important, respectively. Do the 'average' values for the high-O3 and non-episode days reflect the day-long averages? If so, the authors should consider changing the presentation of data to be more applicable to the chemistry at hand Yes, the daily averaged concentration is not useful for O3 in urban areas because of a big difference between the daytime and nighttime. In comparison, the daily average of HONO concentrations reflect the nighttime level well and thus, can be compared from region to region and from time to time. The daily averaged concentrations are to compare the HONO level of Seoul with those of other cities from previous studies. In this study, HONO was discussed in relation with O3 and for this reason, the O3 average concentration was given in pairs with HONO. The various types of concentrations are discussed and compared in the text. For clarity, they are summarized in Table 2 in the revised manuscript. Lines 280-282 : The reason for the anti-correlation of O3 and HONO is due to the source and sink processes for these two gases. While the paper is suggesting that a relationship between these two important reactive trace gases exists, the sources of variation in the diel profile of HONO and O3 are actually *distantly* related. I do not understand why it is appropriate to discuss the data in such a simplistic C2