Contribution of Road Transport to Pakistan’s Air Pollution in the Urban Environment
Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
I read this manuscript with interest. It is written in very good language and contains a lot of useful information. This article could be used as comprehensive material about the state of pollution in the atmosphere of the large metropolises in Pakistan.
However, since the article is actually a review of the available literature on this topic, I would recommend that the authors should significantly shorten the text, especially chapters 1-3, which mainly contain widely known and repeatedly published information, and present the manuscript in the form of brief information.
It is advisable for the authors to provide a list of all potential organic pollutants resulting from vehicle transport. As a recommendation, I would advise adding more information on the most important toxic organic pollutants, such as polyaromatic hydrocarbons, their nitrogen-containing derivatives, and other nitrogen- and sulfur compounds, which are necessary for calculating the air quality in large cities.
Therefore, I could recommend the publication of this manuscript in one of the journals as a short communication.
Comments on the Quality of English Language
English is very good. The authors did a great job.
Author Response
Please see the attachment.
Author Response File: 
Author Response.pdf
Reviewer 2 Report
Comments and Suggestions for Authors
Page 1, Title, Road Transport’s Contribution to Pakistan’s Urban Air Pollution: My suggestion is to change the title to “Road Transport’s Contribution to Pakistan’s Air Pollution in the Urban Environment”. I believe that the suggested title better indicates that both “Road Transport” and “Air Pollution” refer to urban areas.
Page 2, lines 46-47, The discussion includes the major urban centres of Pakistan — Karachi, Lahore, Rawalpindi/Islamabad, Faisalabad, Peshawar, Gujranwala, and Quetta.: Perhaps the inclusion of a map with the above-mentioned urban centres will help the reader to better follow your research.
My suggestion is to include the structure (Sections) of the paper at the end of Section 1 (1. Introduction and Background).
Page 5, line 202, Euro 6 and Euro 7 thus have strict PM and particle number: It would be useful to include some estimates concerning the forthcoming Euro 7 limits, if possible.
Section 6. Conclusions and Recommendations: Are there any limitations/constraints in your methodological approach which could be included in Section 6?
Page 17, Reference 20: Please include the names of all the authors (instead of “et.al.”).
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Reviewer 3 Report
Comments and Suggestions for Authors
Dear Authors,
To improve the quality of the paper I propose to take into account the following issues:
1) Lines 80-84: It would be beneficial to clarify the information on AQI used by Punjab's Environmental Protection Department.
2) Table 1: The requirements for gasoline, i.e., 150ppm for EURO 3, should also be completed. It would also be beneficial to add a column in the table with sulfur limits by standards in Pakistan.
3) Line 202: The authors indicate the EURO 7 standard, which has not yet been introduced and is not in force? I suggest removing this reference.
4) Section 4.1.1 Ground Sampling and Chemical Analysis (Receptor Based): The Authors present PM2.5 levels with values expressed in g/m3. They should rather use mg/m3. How were these shares of PM emissions from the transportation sector determined?
5) Line 317: The abbreviation PFM should be expanded (and completed in the list of abbreviations).
6) Line 501: PM2.5 concentrations are, after all, determined in mg/m3.
7) Figure 4: Does the chart include (except in the case of PM2.5) all analyzed pollutants as transport air pollution share? As is known for each pollutant, the transport share is different. How was the total air pollution and the transport sector share determined?
8) Line 543: The Authors in the content indicate the share of 2/3 wheelers with a value of 36%-64%. In contrast, Figure 5 shows this share in the range of 38%-64%?
9) Figure 5: How should we understand the relative emissions factors (HDV 1.2-1.5, LCV 1-1.3, 2/3 wheelers 1.75-3? How were these values determined?
10) Line 551: ... "attributed around 80% of the total transport emissions in Lahore"... How is total transport emissions to be understood? Is it the sum of the masses of all the pollutants analyzed? Rather, the analysis should distinguish individual pollutants, as the volume of PM, NOx or VOC emissions are different. This also applies to emission factors. I ask the authors to clarify this concept for the reader.
Best regards,
Comments on the Quality of English Language
The article needs to be corrected before publication and contains several language errors, such as:
Line 278: “lion's share”; Tables 2 and 3: SO2 - 2 should be in subscript; Figure 3: “fidelity” I suggest replacing accuracy;
Author Response
Please see the attachment.
Author Response File: Author Response.pdf
Round 2
Reviewer 3 Report
Comments and Suggestions for Authors
Dear Authors,
In my opinion, the manuscript in its current version can be accepted for publication in the journal Air.
Best regards
