From the journal Environmental Science: Atmospheres Peer review history

26-Aug-2022

Dear Dr Vance:

Manuscript ID: EA-ART-08-2022-000099
TITLE: Aerosol emissions and their volatility from heating different cooking oils at multiple temperatures

Thank you for your submission to Environmental Science: Atmospheres, published by the Royal Society of Chemistry. I sent your manuscript to reviewers and I have now received their reports which are copied below.

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Associate Editor, Environmental Sciences: Atmospheres

************

Reviewer 1

This work investigated the emissions of aerosols from the use of different cooking oils over a range of cooking temperatures. The authors also quantified the amount of aerosol deposited in the different regions of the respiratory system upon exposure based on their experimental results. Overall, the results show that volatility of the compounds in these cooking aerosols can play role in indoor transport. I have comments and suggestions listed below.

Comments.

Line 154, "The APS was kept on an elevated platform (30 cm above the fume hood floor surface) next to the heat plate inside the fume hood whereas the SMPS sampled emissions through a copper inlet (0.64 cm ID) installed at the top of the fume hood." Does the location/position of the sampling inlet of the APS and SMPS affect the aerosol mass and size measurements?

Line 194, "Samples were extracted with acetonitrile and concentrated under a gentle flow of ultra-pure nitrogen." My major question: Why acetonitrile is chosen for extraction? What the polarity of targeted compounds in the samples? Both polar and non-polar compounds were being detected? Did the FT-ICR-MS run in both positive and negative mode?

Line 217, "The model uses empirical equations to estimate deposition in three main regions of the human respiratory system- head airways (HA), tracheobronchial (TB) and alveolar (AL) using aerosol number size distribution data." Did the time resolved aerosol number size distribution data or the single value (e.g. time averaged or steady state) use for model simulations?

For the aerosol size distribution, how the aerosol size and mass change with time in the experiments?

Line 276, "Overall, these findings present strong evidence for ensuring cooking temperatures below the smoke point and, if possible, employing the use of a strict temperature control, especially in commercial settings such as restaurants and in situations in which a high efficiency extracting range hood is not available." Can the authors determine or estimate the aerosol emission factors under different conditions from their measurements?

Line 317, "Overall, these results suggest that peanut oil and lard generated higher volatility aerosols compared to the remaining oils, which has potential implications for fate and transport indoors and outdoors." While the non-volatile or lower volatile compounds can be charactered by the FT-ICR-MS study, could the author comment what are the volatile components of these oils?

For 3.3 FT-ICR-MS, do the author run the MS in both positive and negative mode? What are the polarity of the compounds being analysed by the MS? Any potential sampling artefact during the aerosol sampling and sample preparation?

Line 379, "Since these results were calculated using a fixed-point sampling method, the deposition values are meant for a qualitative comparison between different oils." What are the sensitivities of the modeled results to the aerosol size and mass distribution data? Can the authors comment if the composition of the cooking aerosols affect the aerosol deposition in different regions of the respiratory system?

Reviewer 2

Overall: This is a well written and interesting manuscript describing the aerosol emissions from different cooking oils at various temperatures related to their smoke point. The methods used are appropriate, the figures are generally well done and the results and conclusions are well justified. However, it seems worth putting the highest temperatures measured into some context related to cooking practices. Is frying at 247C very common? Other specific comments are mentioned below.

Specific Comments:

Abstract: The first sentence in awkward; I think it should be “emits”. On line 44 please specify what is meant by “highest average deposition” – the deposited fraction? Deposited mass? Finally, as the authors note, deep fat frying typically requires fairly high temperatures, perhaps the abstract could be more specific about oil recommendations that can reduce exposure for this common cooking technique?

Line 126: Please specify the type of pan and whether it had any non-stick coating applied.

Figure 2: It would be useful to indicate the direction of flow.

Line 221: Please provide some justification of the selection of breathing rate for sitting. Cooking might be considered light exercise, particularly in busy commercial/restaurant kitchens.

Figure S3: It would be helpful to also label the points by oil name.

Line 286: Did the authors use a statistical test for linearity of the GMD with temperature?

Table S1: This is a useful table. Perhaps the authors could move this to the main text. I find this more useful than Figure 6, for example.

Figure S5: It is difficult to see the distribution lines for the elevated temperatures, have the authors considered using a log scale on the y axis? Or perhaps the distributions for the elevated temperatures could be multiplied by a constant? For the paragraph beginning on line 302, it is not possible to observe the trends reported in this figure.

Line 312: Why was a linear interpolation used when the data is clearly not linear?

Lines 318-324: This is an interesting discussion; however, it also seems there should be consideration of the dramatically lower mass concentration observed for the peanut oil.

Figure 6: Please add the temperature to the caption.

Figure 8 and associated text: The total mass deposited in each region of the respiratory tract is a strong function of the total mass concentration for each oil type. It would be useful to also know if there are variable deposition fractions of particles deposited in the regions of the respiratory tract based on the variable size distributions measured. Suggest changing the y-axis scale for panel b. It is probably also worth mentioning that this analysis assumes the cook is standing directly over the oil for 30 minutes without the benefit of dilution of the aerosol into the room – is this correct? The beginning of section 3.4 has information that should be included in the methods, instead of the results.

This text has been copied from the PDF response to reviewers and does not include any figures, images or special characters.

We thank the reviewers for reading our manuscript and for their reviews, comments, and suggestions. We believe that these comments led to an overall improvement of our manuscript. Below, the original reviewer comments are shown in italic blue font, while our replies are in the ordinary typeface. The newly added text is indented and in red.

Reviewer #1
Comment: This work investigated the emissions of aerosols from the use of different cooking oils over a range of cooking temperatures. The authors also quantified the amount of aerosol deposited in the different regions of the respiratory system upon exposure based on their experimental results. Overall, the results show that volatility of the compounds in these cooking aerosols can play role in indoor transport. I have comments and suggestions listed below.
Line 154, "The APS was kept on an elevated platform (30 cm above the fume hood floor surface) next to the heat plate inside the fume hood whereas the SMPS sampled emissions through a copper inlet (0.64 cm ID) installed at the top of the fume hood." Does the location/position of the sampling inlet of the APS and SMPS affect the aerosol mass and size measurements?

Response: The conditions inside the fume hood could allow the mixing of aerosol flow to a certain extent but the possibility of the existence of spatial concentration gradients inside the fume hoods still exists. However, since the aim of the study was to perform a comparative analysis of the emissions between different oils we did not quantify these spatial gradients. The APS was kept inside the fume hood towards the back panel to ensure that the majority of the submicron aerosols emitted from cooking oils could be sampled through the instrument inlet. In the case of SMPS, the inlet sampled cooking oil emissions directly from the top of the frying pan. To further address this issue we have edited the paragraph below accordingly.

'An aerodynamic particle sizer (APS 3330, TSI, Shoreview MN) and a scanning mobility particle sizer (SMPS 3936, TSI), composed of a long differential mobility analyzer (DMA 3080L, TSI) and a water-based condensation particle counter (CPC 3788, TSI), were used for sampling aerosol size distributions. The sampling locations for both the instruments were chosen based on the inherent flow conditions inside the fume hood while at the same time ensuring maximum capture efficiency while sampling aerosols in ultrafine and fine size ranges. The APS was kept on an elevated platform (30 cm above the fume hood floor surface) next to the hot plate inside the fume hood whereas the SMPS sampled emissions through a copper inlet (0.64 cm ID) installed at the top of the fume hood. The last remaining section of the inlet was connected to conductive silicone tubing for connection with the SMPS inlet. We assumed a particle density of 1 g cm-3 throughout our analysis based on recommendations from previous studies.9,43'

Comment: Line 194, "Samples were extracted with acetonitrile and concentrated under a gentle flow of ultra-pure nitrogen." My major question: Why acetonitrile is chosen for extraction? What the polarity of targeted compounds in the samples? Both polar and non-polar compounds were being detected? Did the FT-ICR-MS run in both positive and negative mode?

Response: Previous work in the field has demonstrated methylation of secondary organic aerosol extracts when methanol is used as the solvent and then dried. We used acetonitrile to have an organic solvent that evaporates rapidly but is less likely to drive chemical changes in the system. The targeted compounds should have a range of solubility and no one solvent will give the complete
picture. From an experimental standpoint, we have found success in the lab using acetonitrile as the extraction solvent and then methanol as the spray solvent for electrospray ionization (ESI). The ionization method used is overall not quantitative, so all choices were made based on optimization of the overall signal from previous work. The FT-ICR data were collected in positive and negative ion mode but a factor of 2-3 times more peaks were observed in positive ion mode. Negative ion mode can be useful for some samples, but it is limited in what can be ionized, without the addition of adducts, to only chemicals that can be deprotonated. We focused on positive ion mode here because it provided more ionized chemicals and it is a good comparison to previous work on indoor surface films which were also analyzed with positive ion mode ESI. Since most of these decisions were made to replicate prior work on indoor surface films, which contained a large fraction of deposited oils, we have added the following text to the manuscript.

'For chemical characterization of oil-generated smoke, a comparable heating set-up was used in a hood at William & Mary to minimize the time between collection of particles and extraction for further analysis. For these studies, the oils were heated to around the smoke point or up to ~ 20 °C above it. Smoke particles were collected through a small denuder at ~4-5 lpm onto a Teflon filter for ~1 hour. A similar protocol to what has been previously used to characterize indoor surface films was used.39 Samples were extracted with acetonitrile and concentrated under a gentle flow of ultra-pure nitrogen. For analysis, these samples were shipped over-night on ice to Old Dominion University for analysis in a Fourier Transform-Ion Cyclotron Resonance (FT-ICR) Mass Spectrometer.'

Comment: Line 217, "The model uses empirical equations to estimate deposition in three main regions of the human respiratory system- head airways (HA), tracheobronchial (TB) and alveolar (AL) using aerosol number size distribution data." Did the time resolved aerosol number size distribution data or the single value (e.g. time averaged or steady state) use for model simulations?
For the aerosol size distribution, how the aerosol size and mass change with time in the experiments?

Response: Time-resolved aerosol number size distribution data corresponding to 180 oC cooking temperature was used to calculate the averaged deposition results presented in section 3.4. Temporal changes in the aerosol size and mass distributions for each cooking oil being heated at 180 oC have already been quantified in the data presented in Figure 3 via shaded regions. These variations can be attributed to the 4-6% difference between the actual and set temperatures in addition to different aerosol physical and chemical transformations taking place over the course of the experiment. For further clarification, we have added the following line in section 2.5.

'The model input parameters were set to a particle density of 1 g cm-3 and a volumetric inhalation rate of 7.8 l min-1, which corresponds to the breathing rate for adults engaged in sitting activity.47 Time-resolved number distribution data corresponding to the 180 oC cooking temperature was used to compare aerosol mass deposited in the different regions of the respiratory system for a given cooking oil exposure. Since these results were calculated using a fixed-point sampling method, the deposition values are meant for a
qualitative comparison between different oils.'

Comment: Line 276, "Overall, these findings present strong evidence for ensuring cooking temperatures below the smoke point and, if possible, employing the use of a strict temperature control, especially in commercial settings such as restaurants and in situations in which a high efficiency extracting range hood is not available." Can the authors determine or estimate the aerosol emission factors under different conditions from their measurements?

Response: The continuously mixed flow reactor model used in previous studies for calculating emissions factors during cooking activities couldn't be applied to our study due to the inherent flow conditions inside the fume hood. The development of an updated model pertinent to these flow conditions would have been out of the scope of this study so we did not pursue it further.

Comment: Line 317, "Overall, these results suggest that peanut oil and lard generated higher volatility aerosols compared to the remaining oils, which has potential implications for fate and transport indoors and outdoors." While the non-volatile or lower volatile compounds can be charactered by the FT-ICR-MS study, could the author comment what are the volatile components of these
oils?

Response: We thank the reviewer for this comment. As per the reviewer’s suggestion, we have edited this section to include information about the volatile components from these oil emissions.

'Using large quantities of these oils in a poorly ventilated indoor space could accelerate various gas-particle phase transformation processes indoors, and these compounds can also act as a precursor to ambient SOA formation. Previous studies on the characterization of VOC emissions from heated cooking oils have reported that these aerosols usually contain aldehydes, alkanes, alkenes, and aromatics including benzenes and furans which could also pose a carcinogenic risk upon human exposure.24,31,32 For further chemical characterization of these aerosols, we will now focus on the high molecular mass compounds that might remain in particle phase via organic films as described in the next section.'

Comment: For 3.3 FT-ICR-MS, do the author run the MS in both positive and negative mode? What are the polarity of the compounds being analysed by the MS? Any potential sampling artefact during the aerosol sampling and sample preparation?

Response: We ran both positive and negative ionization mode, but 2-3 times more ions were observed with positive ion mode. It is also the mode used for an analysis of indoor surface films in a kitchen using the same technique. The polarity of all the chemicals in the mixture is not known, but targeting the solvent effects of extractions for these types of samples would be a good target for future work. For that, we would recommend using a quantitative technique instead of the qualitative one used here. There are plenty of potential artifacts in the analysis of complex organic mixtures, to highlight this, we have added the following text to the experimental (section
2.3) and 3.3

'Where C, H, and N represent the number of carbon, hydrogen, and nitrogen atoms in the molecular formula. The data were converted to neutral mass (subtracting the mass of Na+ or H+ as needed). For this detailed characterization, a subset of the four cooking oils were selected based on the availability of the same products in Williamsburg (lard, peanut, soybean, and canola oil). Since these are complex mixtures and direct injection ESI is not a quantitative technique, this method provides a perspective on the range of molecular
formulas observed in the smoke across the oils.
Overall, this analysis provides insights into the chemical properties of the lower volatility chemicals that are collected in aerosol particles formed from oils at or just above their smoke point. These results also provide a good qualitative comparative analysis into the lower volatility portion of the mixture which is the fraction that would be expected to remain in the particles during dilution, or remain on surfaces after particles deposit. However, we also acknowledge that cooking emissions usually contain low molecular mass decomposition compounds. Some of these will be lost due to volatilization during collection, some to volatilization during the sample preparation (concentrating). Others may have lower intensity due to lower ionization efficiencies and the tuning in the FT-ICR.30,53 These mass spectra show one perspective on the composition. In the future, a wider range of solvents, ionization methods, and chromatography can be used to expand our understanding of the full range of chemicals found in these types of samples.'

Comment: Line 379, "Since these results were calculated using a fixed-point sampling method, the deposition values are meant for a qualitative comparison between different oils." What are the sensitivities of the modeled results to the aerosol size and mass distribution data? Can the authors comment if the composition of the cooking aerosols affect the aerosol deposition in different regions of the respiratory system?

Response: We thank the reviewer for suggesting this comment to add a comment about the chemical composition of these aerosols affecting the deposition characteristics. We have edited the discussion in section 3.4 to include this information. The ICRP model was developed in order to readily interlink the age, and activity status parameters of a test subject with exposure-related information (size distribution and time of activity) using empirical equations. In order to include the sensitivities of the modeled results, we have incorporated the time-resolved number distribution data to calculate the average deposition values along with the standard errors as
shown in Figure 8 and Figure 9.

'It is also important to mention here is that between the deposition values corresponding to AL and TB regions in all the oils, the values for AL were an order of magnitude higher. In a real life-setting the dilution in the room could reduce the actual deposition values associated with cooking oil exposure but one has to understand that emissions from these oils at 180 °C still have the potential to reach the deepest parts of the respiratory system. Moreover, the chemical composition of these aerosols may also influence a biological effect due to the volatile content getting dissolved in the lung fluid which reiterates the need for effective control measures, especially when using large quantities of such oils.54'

Reviewer #2
Comment: Overall: This is a well written and interesting manuscript describing the aerosol emissions from different cooking oils at various temperatures related to their smoke point. The methods used are appropriate, the figures are generally well done and the results and conclusions are well justified. However, it seems worth putting the highest temperatures measured into some context related to cooking practices. Is frying at 247C very common? Other specific comments are mentioned below.

Response: We thank the reviewer for their time, comments, and appreciation of this work. The reviewer has made valuable points that we address in the responses below. We feel that these revisions and additions have strengthened our paper. As to the question about whether temperatures above the smoke point are common, we believe that they are unlikely to be as commonplace as lower temperatures. However, there are several high-temperature cooking processes–other than deep frying–that are likely to reach above the smoke point of oils involved, such as stir-frying, baking, grilling, etc. To provide additional context and a more complete dataset, we included datasets at 20 °C above each oil’s smoke point. To further address this comment we have added this line in the methods section to include this information.

'The pan was washed with dish soap before each experiment and preheated for ~15 min on the electric hot plate to remove any oil residue from the previous experiment and from any deposition taking place during storage. Afterwards, a given oil sample was poured
onto the heated pan, and the resulting emissions were sampled. The temperature of the PID-controlled hot plate was set to 100 °C, 150 °C, 180 °C (the most commonly used deep-frying temperature), each oil’s smoke point, and 20 °C above the smoke point (to account for several high-temperature cooking processes–other than deep frying–that are likely to reach above the smoke point of oils involved, such as stir-frying, baking, grilling, etc.).'

Comment: Abstract: The first sentence in awkward; I think it should be “emits”. On line 44 please specify what is meant by “highest average deposition” – the deposited fraction? Deposited mass? Finally, as the authors note, deep fat frying typically requires fairly high temperatures, perhaps the abstract could be more specific about oil recommendations that can reduce exposure for this
common cooking technique?

Response: Thanks for pointing out the grammatical inaccuracies in the abstract. We have edited the paragraph accordingly. The overall aim of this study was to characterize the oil emissions in terms of their physical and chemical properties that could affect various indoor and outdoor chemistry-related processes. We would like to refrain from making any direct recommendations for choosing any particular type of oil because as seen in the case of peanut oil, even though the PM exposure associated with 30 minutes of exposure was the lowest, the higher volatile content in these emissions could lead to the higher secondary organic aerosol formation on longer time
scales. Therefore, we would like the readers to come up with their own recommendations based on their own interpretations of the results and discussion presented in this study.

'Heating cooking oils at high temperatures emits aerosols in the fine and ultrafine size ranges as well as a variety of volatile organic compounds. Exposure to these emissions has been associated with various respiratory and cardiovascular ailments. In this study, we characterized aerosol emissions from various popular frying oils using an electric heat source at multiple temperatures (below and above their individual smoke points). At 180°C, a common deep-frying temperature, oils with lower smoke points (olive oil and lard) generated the highest aerosol mass concentrations among all oils tested. The volatility characteristics of these oil-generated aerosols were also studied by analyzing their volume distributions after thermal conditioning through a thermodenuder. For most of the oils, thermal conditioning beyond temperatures of 75 °C resulted in the near complete removal of volatiles leaving behind non-volatile cores in the 60-100 nm range. Fourier Transform-Ion Cyclotron Mass Spectrometry analyses of sample extracts obtained from smoking different oils exhibited large chemical similarity with average molecular mass in the range of 620-640 atomic mass units and low oxygen-to-carbon ratios (~0.16). Lastly, we estimated the respiratory deposition values of different oils for a 30-minute exposure period, and the results show that lard had the highest average particle mass deposition in all three regions of the respiratory system (1-10 µg), whereas peanut oil had the lowest average values (~1 µg).

Comment: Line 126: Please specify the type of pan and whether it had any non-stick coating applied.

Response: We have edited this line to include information regarding the material of the frying pan as per the reviewer’s suggestion:

'Briefly, 200 ml of oil was heated in a shallow stainless steel frying pan placed on an electric hot plate inside a fume hood.'

Comment: Figure 2: It would be useful to indicate the direction of flow.

Response: We have mentioned the flow direction in the figure caption.

'Figure 2. Cross-sectional view of the thermodenuder used in the study, highlighting its different components. The temperature of the heating section was monitored via a K-type thermocouple placed at the mid-section surface of the sampling tube, providing feedback
to an external temperature controller unit. The aerosol flow direction is from the left towards the denuder section to the right.'

Comment: Line 221: Please provide some justification of the selection of breathing rate for sitting. Cooking might be considered light exercise, particularly in busy commercial/restaurant kitchens.

Response: 'We concur with the reviewer that cooking activities in busy commercial/restaurants could be considered light exercise, however, the breathing rate input to the ICRP model acts as a scaling factor for the respiratory deposition results. The objective of this study was to compare the values among different types of oils to relate the aerosol size distribution results with the health effects associated with a given cooking oil exposure.

Comment: Figure S3: It would be helpful to also label the points by oil name.

Response: We thank the reviewer for this edit. We have edited the figure caption for better clarity.

'Figure S3. Aerosol mass and number concentrations as a function of oil smoke point. The smoke points of different oils in increasing order are as follows: Lard (190 oC), Coconut (204 oC), Olive (208 oC), Peanut (227 oC), Soybean (234 oC), and Canola (238 oC).

Comment: Line 286: Did the authors use a statistical test for linearity of the GMD with temperature?

Response: The linearity of the GMD decrease demonstrates that the size of the aerosols is shrinking upon evaporation. Further analysis for the linearity of this trend would have been useful for modeling studies specific to a certain volatile organic compound (VOC) or semivolatile organic compound (SVOC) being analyzed in controlled chamber studies which wasn't the case in our study so we didn't perform any statistical test for linearity.

Comment: Table S1: This is a useful table. Perhaps the authors could move this to the main text. I find this more useful than Figure 6, for example.

Response: As per the reviewer's suggestion, we have moved the table from SI to the main file.

'A summary of the number of similar compounds in the smoke sample extracts from different oils is also presented in Table 2. All the plant-based oils (Peanut. Soybean, and Canola) exhibited greater similarity among them in terms of chemical compounds containing C, H, and O ions when compared to Lard possibly due to similar saturated fat content and smoke point temperatures.
Table 2. Number of similar chemical compounds containing C, H, and O ions between the smoke samples of different oils used in this study.'

Comment: Figure S5: It is difficult to see the distribution lines for the elevated temperatures, have the authors considered using a log scale on the y axis? Or perhaps the distributions for the elevated temperatures could be multiplied by a constant? For the paragraph beginning on line 302, it is not possible to observe the trends reported in this figure.

Response: We tried using the log y-axis and with that, all the lines merge together to a point where it becomes hard to observe a distinct mode even for TD off condition. On the other hand, multiplying distributions by a constant will distort the message about the quantity of volatile content getting evaporated with a mere 50 oC heated section temperature.

Comment: Line 312: Why was a linear interpolation used when the data is clearly not linear?

Response: We used a simplified approach to come up with a metric with which we could compare different oils in terms of their volatility dependence on temperature. Similar methods have been used in previous studies on modeling volatility parameters for a specific SVOC under chamber conditions that are already cited in the manuscript.1,2
1) Saha, P. K., & Grieshop, A. P. (2016). Exploring divergent volatility properties from yield and thermodenuder measurements of secondary organic aerosol from α-pinene ozonolysis. Environmental Science & Technology, 50(11), 5740-5749.
2) An, W. J., Pathak, R. K., Lee, B. H., & Pandis, S. N. (2007). Aerosol volatility measurement using an improved thermodenuder: Application to secondary organic aerosol. Journal of Aerosol Science, 38(3), 305-314.

Comment: Lines 318-324: This is an interesting discussion; however, it also seems there should be consideration of the dramatically lower mass concentration observed for the peanut oil.

Response: The discussion here refers to the use of lard and peanut oil in large quantities in a commercial setting. We agree with the reviewer that peanut oil had a dramatically lower mass concentration than lard; however, the volatility content of the aerosols could lead to higher SOA formation that would ultimately lead to greater exposure. Therefore we would like to refrain from adding this point to the discussion.

Comment: Figure 6: Please add the temperature to the caption.

Response: As per the reviewer’s recommendation, we have added the figure caption to include information about the heating temperatures.

'Figure 6. Soft ionization mass spectra for the C, H, and O containing ions in the extract obtained during the smoking of different oils. The oils were heated to temperatures ~20oC above their smoke points. Panels a-d represent canola, lard, peanut, and soybean oil
respectively.'

Comment: Figure 8 and associated text: The total mass deposited in each region of the respiratory tract is a strong function of the total mass concentration for each oil type. It would be useful to also know if there are variable deposition fractions of particles deposited in the regions of the respiratory tract based on the variable size distributions measured. Suggest changing the y-axis scale for panel b. It is probably also worth mentioning that this analysis assumes the cook is standing directly over the oil for 30 minutes without the benefit of dilution of the aerosol into the room – is this correct? The beginning of section 3.4 has information that should be included in the
methods, instead of the results.

Response: In the ICRP model, the deposition fraction is a function of particle diameter and the aerosol mass deposited is a function of the deposition fraction and the number distribution data; the latter will have some variability which leads to the standard error values for the averaged values presented in Figure 8 and Figure 9. We have changed the y-axis scale in panel b as per the reviewer's suggestion. We have also moved the pertinent information to the methods section. We have also included the discussion about the dilution as per the reviewer’s suggestion.

'It is also important to mention here that between the deposition values corresponding to AL and TB regions in all the oils, the values for AL were an order of magnitude higher. In a real-life setting, the dilution in the room could reduce the actual deposition values associated with cooking oil exposure but one has to understand that the emissions from these oils at 180 °C still have the potential to reach the deepest parts of the respiratory system. Moreover, the chemical composition of these aerosols may also influence a biological effect due to the volatile content getting dissolved in the lung fluid which reiterates the need for effective control measures, especially when using large quantities of such oils.54'

21-Sep-2022

Dear Dr Vance:

Manuscript ID: EA-ART-08-2022-000099.R1
TITLE: Aerosol emissions and their volatility from heating different cooking oils at multiple temperatures

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Reviewer 1

The authors have properly addressed the reviewers' comments. I support the publication of this revision.