This manuscript provides an interesting exploration of the varying sensitivities of different VOC sensors in an array. The plots are very clear and useful for considering how a multi-sensing-technology (PID, MOx, EC) array can be used to gather species (or species-group) specific information. However, this is not the first time sensor arrays have been used to measure VOCs, yet the manuscript does not seem to fully acknowledge much of the other work on VOC sensing and sensor arrays, making it difficult to fully assess the impact of this work. A number of suggestions are given below to better contextualize this work within the related body of VOC sensing efforts.

Line 78: More recent examples of e-noses should be given here, as there have been many developments in this space since 1994.

Line 83: You mention that sensor sensitivities to non-VOC gases are a challenge for VOC sensors. Why was this not explored in the present study, alongside the exploration of RH and VOC mixture impacts? If it cannot be added into the study, the reasoning for excluding it, as well as suggested avenues for testing these impacts, should at least be mentioned.

Paragraph starting on line 85: Examples of prior MOx sensor arrays are given. Examples of successful uses of PID sensors should also be mentioned (even if they are not arrays) to give context to the prior use of these sensors.

Line 97-98: There actually are examples using a range of sensing technologies that should be acknowledged here. Two examples: Xu, Linjie, et al. "Hybrid gas sensor array to identify and quantify low-concentration VOCs mixtures commonly found in chemical industrial parks." IEEE Sensors Journal 22.13 (2022): 13434-13441. And Fumian, Francesca, et al. "Development and performance testing of a miniaturized multi-sensor system combining MOX and PID for potential UAV application in TIC, VOC and CWA dispersion scenarios." The European Physical Journal Plus 136.9 (2021): 913.

There are also many examples of using sensor arrays with temperature cycling that are worth mentioning in the introduction, as they have provided another route to gain species-specific information using VOC sensors. One such example: Baur, Tobias, et al. "Field study of metal oxide semiconductor gas sensors in temperature cycled operation for selective VOC monitoring in indoor air." Atmosphere 12.5 (2021): 647.

Lines 125-126: This is not true. Temperature control has been used many times in VOC sensing. Mostly in indoor applications, but since this work is in a controlled laboratory setting, it cannot exclude indoor applications in its analysis: See above with work by Baur et. al., as well as He, Junjie, et al. "Low-cost MOX sensor for indoor ppb-level VOC detection using pulsed temperature-voltage dual modulation." Sensors and Actuators B: Chemical (2025): 138289. And Leidinger, M., et al. "Selective detection of hazardous VOCs for indoor air quality applications using a virtual gas sensor array." Journal of Sensors and Sensor systems 3.2 (2014): 253-263. And On the performance evaluation of hybrid and mono-class sensor arrays in selective detection of VOCs: A comparative study

Lines 138-140: This is also not true. VOC EC sensors have been used for methane detection (Silberstein, Jonathan, Matthew Wellbrook, and Michael Hannigan. "Utilization of a Low-Cost Sensor Array for Mobile Methane Monitoring." Sensors 24.2 (2024): 519.) and for VOCs: Mayer, Thomas, et al. "Toward an Event-Based and Quality-Assured Air Sampling: A Portable System for Sensing and Sampling Volatile Organic Compounds." Analytical Chemistry 97.43 (2025): 23765-23772.

Line 138-140: Although VOC EC sensors have indeed been used before (see above), they certainly are less common. Is there any explanation for why this is that can be added?

Lines 232-233: Why were these compounds chosen? Also, what are the typical ambient concentrations of these compounds? Is 5 ppb a reasonably low detection limit for all of these? It seems like some would often be much lower.

Figure 4 (and related discussion): This figure is really interesting, as it shows the different chemical “fingerprints” produced using the sensor array. However, these fingerprints are only clear when there is only one compound present. What happens in ambient air when there is a complex mixture of compounds? Prior work has used pattern recognition / machine learning to disentangle these effects. Some discussion of how the information provided by the array could actually be used in an environmental application is needed. The following reference provides some ideas for interpretation: Rath, Ronil J., et al. "Chemiresistive sensor arrays for gas/volatile organic compounds monitoring: a review." Advanced Engineering Materials 25.3 (2023): 2200830.

Line 302: Why were these two compounds chosen for the RH testing? Wouldn’t it have been more useful to choose two more chemically different species (i.e. an alkene and an aromatic) to understand how the effects vary more broadly? This choice should be justified.

Line 350: Again, why were two chemically-similar alkenes chosen for the binary mixture? Would the additive nature of the sensors also apply in a mixture that contains an alkene and an aromatic? It seems as if the response would be very different, which limits the applicability of these findings.

Lines 422-427: Sensor colocation with reference instruments and “novel application of data analysis techniques that directly interpret air sensor measurements” has already been done extensively with VOC sensors, which should be acknowledged. A few examples include: Hong, Gung-Hwa, et al. "Long-term field calibration of low-cost metal oxide VOC sensor: Meteorological and interference gas effects." Atmospheric Environment 310 (2023): 119955. , Frischmon, Caroline, et al. "Improving the quantification of peak concentrations for air quality sensors via data weighting." Atmospheric Measurement Techniques 18.13 (2025): 3147-3159. And Okorn, Kristen, and Michael Hannigan. "Applications and limitations of quantifying speciated and source-apportioned vocs with metal oxide sensors." Atmosphere 12.11 (2021): 1383.

Line 449: Discussion of how the “chemically specific information about VOCs” would actually work in practice is lacking. The fingerprints shown in Figure 4 are certainly interesting, but how would they be applied or used in contexts where there is a complex mixture of compounds (thereby making it difficult to distinguish the individual fingerprints).

This paper provides a valuable demonstration of how the characteristics of different OEM VOC sensors can be leveraged to build an array capable of identifying individual compounds. A measurement system such as this would be extremely useful in ambient and indoor air quality studies, thus this work demonstrating these fundamental characteristics in a controlled laboratory setting is particularly helpful.  Furthermore, the in-depth look at the impact of RH (especially the complicated effects for MOx sensors) was appreciated. 

Comment 1: Was the variability of the sensor array’s response to each compound examined? (i.e., how consistent are the “fingerprints” in Figure 4?) I’m not clear on whether the array was exposed to each compound through one or more calibration sequences. If yes, it would be good to share these results. If not, consider including this in the discussion of the limitations. 

Comment 2: Why were 1-hexene and 1-octene selected as the only multi-compound mixture to expose the array to? A mixture of compounds producing very different "fingerprints" of response from the array would be interesting as well (e.g., 1-hexene or 1-octene vs acetone or isoprene). If additional mixtures were examined, this would be very useful data to add as well, or recommend discussing how this multi-compound mixture was selected. 

Minor Comments

• Lines 11 - 14: this sentence is a little long, recommend breaking up key points for readability
• Line 19: “measuring environmental VOCs” - maybe specify ‘speciated VOCs’, or ‘individual VOCs’, or ‘differentiating individual VOC compounds’, etc.
• Lines 42 - 43: I don’t think this sentence needs to be in parentheses, recommend removing the parentheses
• Line 98: might be more appropriate to say “has not been fully explored”
• Lines 85 - 98: some additional papers it may be helpful to review/consider including (to give a fuller picture of related work): 
• Leidinger et al., 2014 on the identification on individual VOCs (for indoor air quality) using a sensor array
• Leidinger et. al., 2016 on the incorporation of a pre-concentrator to reach sub ppm levels of quantification for VOCs 
• Sauerwald et al., 2018 on the detection of benzene in the presence of interferents
• Collier-Oxandale et. al., 2020 on the incorporation of non-VOC sensors to inform sources of VOCs