This study proposes a 1D photonic crystal gas sensor based on TiO₂/ZrO₂ and CsAgBr₃ for detecting environmental pollutants like NH₃, CH₄, CS₂, and CHCl₃. While the computational results show promising sensitivity and performance metrics, major revisions are needed. Key concerns include the lack of experimental validation, limited discussion on cross-sensitivity, and insufficient details on material stability and practical implementation. More comprehensive testing in real-world conditions and improvements in sensor accuracy and quality factors are essential to enhance the study’s relevance and impact.
• The study presents a novel design for a 1D photonic crystal gas sensor using plasmonic and perovskite nanosurfaces, but more experimental validation is required to support the computational findings.
• The choice of pollutants (NH₃, CH₄, CS₂, CHCl₃) is relevant for environmental monitoring, yet the sensor’s selectivity towards these gases in a mixed-gas environment should be investigated further to assess practical applicability.
• While the computational results are promising, the lack of real-world testing limits the credibility of the claims. Experiments involving real gas samples are essential to validate the sensor's performance.
• The use of the transfer matrix method (TMM) is appropriate for simulating the optical properties of the sensor, but the manuscript lacks sufficient explanation of how the model parameters (e.g., angle of incidence, thickness) influence gas detection sensitivity and specificity.
• The authors claim a high sensitivity of 2170 nm/RIU and a figure of merit of 500/RIU; however, no comparison is made with existing gas sensors to contextualize these results in terms of competitive advantage.
• Some references could be helpful to improve the introduction and overall section of the manuscript, such as recent studies on; Cauliflower-shaped ZnO nanostructure for enhanced NO2 gas sensor application; Enhanced NO2 gas sensor device based on supramolecularly assembled polyaniline/silver oxide/graphene oxide composites; α-MnO2 Nanowires as Potential Scaffolds for a High-Performance Formaldehyde Gas Sensor Device; Star-Fruit-Shaped CuO Structures for High Performance Ethanol Gas Sensor Device; Gas sensor device for high-performance ethanol sensing using α-MnO2 nanoparticles; An insight into improvement of room temperature formaldehyde sensitivity for graphene-based gas sensors; Label-free electrochemical aptasensor for the detection of SARS-CoV-2 spike protein based on carbon cloth sputtered gold nanoparticles; A highly sensitive poly (chrysoidine G)–gold nanoparticle composite based nitrite sensor for food safety applications; Polyaniline-functionalized TiO2 nanoparticles as a suitable matrix for hydroquinone sensor.

• The sensor's detection accuracy of 0.815 and quality factor of 0.24 are relatively low, raising concerns about the sensor's efficiency in identifying gases at low concentrations. Improving these parameters should be a key focus of future optimization efforts.
• The material selection for the dielectric layers (TiO₂/ZrO₂) and the perovskite (CsAgBr₃) is interesting, but the manuscript does not discuss the stability and long-term durability of these materials, especially in harsh environmental conditions.
• The optimization process of the defect layer thickness is mentioned, but further details on how the defect layer impacts the sensor’s performance are needed. A sensitivity analysis of this layer could offer better insights.
• The manuscript lacks discussion of potential cross-sensitivity issues, particularly in real-world scenarios where multiple pollutants may be present simultaneously. Investigating interference between gases would strengthen the study’s practical implications.
• The angle of incidence is reported to be a critical factor in the sensor’s performance, but the practical limitations of controlling this parameter in real sensor applications are not addressed.
• No details are provided regarding the fabrication methods or scalability of producing the proposed 1D-PC structure. Without clear guidelines for manufacturing, the practical implementation of this sensor remains uncertain.
• The authors should conduct more detailed simulations or experiments across a wider range of gas concentrations to confirm the linearity and dynamic range of the sensor.
• The environmental stability and potential degradation of the perovskite material, especially in humid conditions, should be considered. These factors could significantly impact the sensor's long-term functionality.
• The manuscript would benefit from a deeper discussion on the economic feasibility of integrating the proposed sensor in large-scale environmental monitoring systems, especially when compared to conventional gas detection methods.

Accept