We sincerely thank the reviewer for this helpful comment. In response, we have substantially expanded the literature review in order to provide a more structured overview of the state of research. More specifically, we added dedicated subsections on the evolution of fixed air quality monitoring systems, the emergence of low-cost and mobile monitoring technologies, calibration and machine learning-based correction approaches, and applications in developing and resource-constrained urban contexts. We also introduced a clear subsection on identified research gaps and reformulated the transition toward the objectives of the study. This change can be found in Section 2 (Literature Review), especially Sections 2.1 to 2.5.

We appreciate the reviewer's valuable feedback on this point. To address their concerns, we have significantly enhanced our literature review to offer a better organized examination of current research developments. We incorporated new dedicated sections covering several key areas: how traditional fixed air quality monitoring systems have developed over time, the rise of affordable and portable monitoring technologies, methods for calibration and machine learning-based adjustments, and uses within developing countries and cities with limited resources. Additionally, we created a specific section highlighting gaps in existing research and revised how we connect these gaps to our study's goals. These improvements are located in Section 2 (Literature Review), particularly in Sections 2.1 through 2.5.