Occupational Exposure to Ultrafine Particles (UFPs) in Pizzerias: Personal Monitoring and Comparison of Oven Technologies
, Alessandro Murru 1, Joanna Izabela Lachowicz 1,2, Simone Milia 1, Tatiana Pedrazzi 3, Giuseppe De Palma 3, Marcello Campagna 1,* and Luigi Isaia Lecca 1
Round 1
Reviewer 1 Report
Comments and Suggestions for AuthorsReview of environments 4422716 Occupational Exposure to Ultrafine Particles (UFPs) in Pizzerias
Line 27. What exactly is a “high risk industrial environment”? Is this cooking or something else?
The abstract might briefly explain how ventilation differences and outdoor air levels were controlled for (if they were)
Line 70. The word “study” is missing
Line 145. If the instrument excludes large particles, then the authors might want to explain if the so-called total particle dose is really “total”.
Line 170. Correct the grammar in this sentence
Line 323. Although the discussion section says that electric ovens produced higher exposures than wood burning ovens, the conclusion section seems to suggest that this might be due to better exhaust in the latter. The authors might consider adding language to the discussion or results section describing the differences in exhaust ventilation for the different stove types. As written, the article seems to suggest that substituting wood for electric might be a way to control exposures, but in fact this may be due more to differences in capture efficiency, flow rate and other exhaust ventilation design parameters.
Thanks for the opportunity to review this study, it is well done.
Author Response
Line 27. What exactly is a “high risk industrial environment”? Is this cooking or something else?
We thank the Reviewer for pointing out this ambiguity. The Reviewer is entirely correct: a commercial pizzeria belongs to the food service sector and is not an industrial environment. Our intended meaning was to draw a parallel strictly regarding the magnitude of particle concentrations—which, as detailed in the Discussion section, can reach values comparable to those measured during specific industrial processes (e.g., welding or automotive manufacturing)—rather than classifying the kitchen itself as an industrial facility.
To correct this terminology and avoid misunderstanding, we have thoroughly revised the text in both the Results (Line 27) and Conclusions (Line 31) sections of the Abstract.
The abstract might briefly explain how ventilation differences and outdoor air levels were controlled for (if they were)
Response: The Reviewer raises an important point regarding potential confounding factors. Because this was designed as a cross-sectional observational study under real-world working conditions, ventilation systems and outdoor air exchanges could not be actively controlled or standardized. Instead, ventilation efficiency and hood typologies were thoroughly documented as independent operational variables during the auditing phase, allowing us to identify ventilation differences as a primary driver of the variation in UFP levels (as noted in the Conclusions). Outdoor air influence was minimized by scheduling samplings during high-production indoor hours when cooking sources heavily dominated the indoor microenvironment. We have added a brief clarification in the Methods section of the Abstract:
Ventilation characteristics were documented at each site to evaluate their influence under real-world operating conditions
Line 70. The word “study” is missing
We thank the Reviewer for catching this oversight. The missing word has been inserted into the sentence at Line 70.
Line 145. If the instrument excludes large particles, then the authors might want to explain if the so-called total particle dose is really “total”.
We entirely agree with the Reviewer’s observation. Since the DISCmini monitoring range is restricted to 10 – 700 nm, it naturally excludes coarse particles and the upper fraction of PM2.5. Therefore, calling the calculated metric a “total particle dose” without qualification is terminologically inaccurate. Our intention was to refer to the total dose within the measured submicron/ultrafine range. It is worth noting that while larger particles (>700nm) dominate airborne particulate mass, ultrafine and submicron particles dominate the airborne particle number concentration (PNC) and lung-deposited surface area (LDSA) by orders of magnitude. To address the Reviewer's concern and ensure scientific accuracy, we have replaced the term "total particle dose" with "total particle dose within the 10–700 nm range" throughout the manuscript, including Line 145.
Line 170. Correct the grammar in this sentence
We apologize for the grammatical issues in the original sentence. Following the helpful suggestions of the Reviewers, this section regarding the ELPI+ sampling methodology has been completely rewritten to ensure proper academic English grammar, syntax, and terminological clarity.
Line 323. Although the discussion section says that electric ovens produced higher exposures than wood burning ovens, the conclusion section seems to suggest that this might be due to better exhaust in the latter. The authors might consider adding language to the discussion or results section describing the differences in exhaust ventilation for the different stove types. As written, the article seems to suggest that substituting wood for electric might be a way to control exposures, but in fact this may be due more to differences in capture efficiency, flow rate and other exhaust ventilation design parameters.
We thank the reviewer for this productive comment. The variance in UFP metrics between electric (EO) and wood-fired oven (WFO) environments may be driven by specific ventilation design parameters rather than the heating technology itself. The Discussion section has been expanded to address these potential physical mechanisms, ensuring that exposure mitigation is discussed with appropriate caution regarding ventilation dynamics rather than simple fuel substitution.
Thanks for the opportunity to review this study, it is well done.
We sincerely thank the Reviewer for their thorough evaluation, constructive feedback, and positive remarks. Their insights have significantly helped improve the clarity, accuracy, and overall quality of our manuscript.
Reviewer 2 Report
Comments and Suggestions for AuthorsThis paper presents very original results on indoor fine particles pollution in pizzerias. After reading this paper, one may conclude that pizzerias are not necessarily safe place in which to eat ! This study is of importance because it focuses on a real public health issue that may affect workers in such establishments. The paper could be published provided that the following comment are addressed.
To compare their results with those reported for other cooking activities, do the authors consider the maximum concentrations measured in pizzerias or the mean concentrations values?
The same question applies to the comparison with the values recommended by WHO.
Put the numbers in superscript where necessary.
Line 166: The authors should explain why they chose a value of 1g/cm3, as I may be too low for compact carbon particles (having typically a density of 2 g/cm3) and too high for fluffy particles.
Figure 1: Please add axis labels to clarify the meaning of the values shown on the x-axis and y-axis.
Figure 2: Please add axis labels to clarify the meaning of the values shown on the y-axis.
Figure 4: Please add the legend to understand the meaning of the number on the x-axis and y-axis.
Author Response
This paper presents very original results on indoor fine particles pollution in pizzerias. After reading this paper, one may conclude that pizzerias are not necessarily safe place in which to eat ! This study is of importance because it focuses on a real public health issue that may affect workers in such establishments. The paper could be published provided that the following comment are addressed.
R: We thank the Reviewer for the positive evaluation and for recognizing the public health and occupational relevance of our study. The reported particle concentrations indeed underscore a significant indoor air quality issue. While our investigation specifically targeted the cooking zone to characterize the personal exposure of operators during their work shifts, we agree that particle dynamics in these environments deserve careful consideration regarding overall indoor air quality.
To compare their results with those reported for other cooking activities, do the authors consider the maximum concentrations measured in pizzerias or the mean concentrations values?
R: We appreciate the Reviewer’s guidance on this point. We have thoroughly revised this paragraph to ensure a mathematically rigorous comparison. We now explicitly differentiate between average/median baselines and maximum peak values when comparing our data to the existing literature. Additionally, we have cleaned up the references in this section to ensure that each comparison is accurately aligned with its corresponding study.
The same question applies to the comparison with the values recommended by WHO.
We thank the Reviewer for the question. The comparison with the WHO hourly guideline was performed using the median concentration values measured during the shifts. The text has been updated to specify this metric clearly.
Put the numbers in superscript where necessary.
We thank the Reviewer for this formatting note. We have systematically revised the entire manuscript to ensure that all exponents in scientific notation and measurement units are properly formatted in superscript.
Line 166: The authors should explain why they chose a value of 1g/cm3, as I may be too low for compact carbon particles (having typically a density of 2 g/cm3) and too high for fluffy particles.
We thank the Reviewer for this insightful comment. The Reviewer is entirely correct: compact carbonaceous cores can reach densities near 2 g/cm3, while fresh, fluffy soot aggregates often exhibit effective densities well below 1 g/cm3 due to internal void spaces. In this study, the SEM-EDS analysis revealed a highly heterogeneous aerosol matrix, composed of irregular organic aggregates, soot, and heavier inorganic/metallic fragments (such as Fe and Al). Given this complex mixing state, assuming a standard unit density of 1 g/cm3 represents a widely accepted convention in occupational hygiene and indoor air quality monitoring. This assumption provides a standardized baseline and prevents systematic over- or underestimation of the mass/volume equivalent when real-time, morphology-dependent density functions are unavailable. We have added a brief clarification in the revised manuscript to justify this choice.
Charvet, A., Bau, S., Bémer, D., & Thomas, D. (2015). On the Importance of Density in ELPI Data Post-Treatment. Aerosol Science and Technology, 49(12), 1263–1270. https://doi.org/10.1080/02786826.2015.1117568
Katz, E. F., Guo, H., Campuzano-Jost, P., Day, D. A., Brown, W. L., Boedicker, E., … DeCarlo, P. F. (2021). Quantification of cooking organic aerosol in the indoor environment using aerodyne aerosol mass spectrometers. Aerosol Science and Technology, 55(10), 1099–1114. https://doi.org/10.1080/02786826.2021.1931013
Lizonova, D., Nagarkar, A., Demokritou, P. et al. Effective density of inhaled environmental and engineered nanoparticles and its impact on the lung deposition and dosimetry. Part Fibre Toxicol 21, 7 (2024). https://doi.org/10.1186/s12989-024-00567-9
Figure 1: Please add axis labels to clarify the meaning of the values shown on the x-axis and y-axis.
We thank the Reviewer for this note. Axis labels specifying both the metrics and the corresponding measurement units have been added to the x-axis and y-axis of all panels in Figure 1 to ensure immediate clarity.
Figure 2: Please add axis labels to clarify the meaning of the values shown on the y-axis.
We thank the Reviewer for this comment. The appropriate axis label, including the metric and the measurement unit, has been added to the y-axis of Figure 2 to ensure complete clarity.
Figure 4: Please add the legend to understand the meaning of the number on the x-axis and y-axis.
We thank the Reviewer for pointing this out. A clear legend and detailed axis labels have been added to Figure 4 to fully explain the meaning of the numbers and metrics shown on both the x-axis and y-axis.
