Indoor Air Quality: A Review of Cleaning Technologies

Round 1

Reviewer 1 Report

Dear Authors,

I am glad having an opportunity to review the manuscript. It is a interesting paper.  I particularly appreciate the main idea of this  article intends to review the actual panorama in respect to the existent alternatives in “cleaning” indoor air. A lot of authors already deal with similar topics for example I found articles Szczotko, M.; Orych, I.;M  ̨aka, Ł.; Solecka, J. A Review of Selected Types of Indoor Air Purifiers in Terms of Microbial Air Contamination Reduction. Atmosphere 2022, 13, 800. https:// doi.org/10.3390/atmos13050800; Juliana P. Sá, Maria Conceição M. Alvim-Ferraz, Fernando G. Martins, Sofia I.V. Sousa, Application of the low-cost sensing technology for indoor air quality monitoring: A review,
Environmental Technology & Innovation, Volume 28, 2022,
102551, ISSN 2352-1864, https://doi.org/10.101 /j.eti.2022.102551; Walaa S.E. Ismaeel, Ahmed Gouda Mohamed,
Indoor air quality for sustainable building renovation: A decision-support assessment system using structural equation modelling,
Building and Environment, Volume 214, 2022, 108933,
ISSN 0360-1323,https://doi.org/10.1016/j.buildenv.2022.108933; Luengas, A., Barona, A., Hort, C. et al. A review of indoor air treatment technologies. Rev Environ Sci Biotechnol 14, 499–522 (2015). https://doi.org/10.1007/s11157-015-9363-9 etc.
 While reading the submitted manuscript, inaccuracies were  noticed, which I recommend to fix.
1.    The purpose of the study should be clearly stated at the end of the introduction,
2. Check in manuscript  the typos and spaces, and the size of the space between lines (especially in references).

Thus, the topic is interested, however, some redaction aspects must be revised before the acceptation for this Journal.

Author Response

Dear Reviewer

Thank you very much for your suggestions. They helped us to improve the text.

Concerning the references proposed, some of them we have added but others not, and we explain why.

Szczotko, M.; Orych, I.;M  ̨aka, Ł.; Solecka, J. A Review of Selected Types of Indoor Air Purifiers in Terms of Microbial Air Contamination Reduction. Atmosphere 2022, 13, 800. https:// doi.org/10.3390/atmos13050800; - This is an interesting article – we have added it to the references list and we have cited it in our introduction as follows:

“The review organized by Szczotko [30], focused on microbial air contamination reduction by selected types of indoor air purifiers, showing that according to a wide range of articles on the topic, the actual effectiveness of the selected air purifiers is significantly lower, when applied to real conditions, than the values declared by manufacturers in their marketing materials and technical specifications. This is without doubt a major handicap of the air purifiers offered to consumers.”

Luengas, A., Barona, A., Hort, C. et al. A review of indoor air treatment technologies. Rev Environ Sci Biotechnol 14, 499–522 (2015). https://doi.org/10.1007/s11157-015-9363-9 - it is already cited in our article.

Juliana P. Sá, Maria Conceição M. Alvim-Ferraz, Fernando G. Martins, Sofia I.V. Sousa, Application of the low-cost sensing technology for indoor air quality monitoring: A review, Environmental Technology & Innovation, Volume 28, 2022,
102551, ISSN 2352-1864, https://doi.org/10.101 /j.eti.2022.102551; -  although this is an interesting article, it is focused on sensors for monitoring indoor air quality and not for air cleaning. So, it is out of our manuscript scope and thus, it was not added to our review.

Walaa S.E. Ismaeel, Ahmed Gouda Mohamed, Indoor air quality for sustainable building renovation: A decision-support assessment system using structural equation modelling, Building and Environment, Volume 214, 2022, 108933, ISSN 0360-1323,https://doi.org/10.1016/j.buildenv.2022.108933; - although this is an interesting article, it is focused on models to help in building renovation maintaining a good indoor air quality. Air cleaning technologies are not the focus. So, it is out of our manuscript scope and thus, it was not added to our review.

While reading the submitted manuscript, inaccuracies were noticed, which I recommend to fix.
1.    The purpose of the study should be clearly stated at the end of the introduction.

The following sentence was included in the end of the introduction:

 “The indoor air cleaning technologies can play an important role in improving in-door air quality. However, its effective application requires an adequate technical and environmental analysis of the real conditions for its use, as well as a characterization of the main pollutants existing in a given indoor environment. It may be necessary to adopt different technologies to be used simultaneously for a more effective air cleaning and maintenance of a good indoor quality. Hence, this work reviews the key indoor air treatment technologies, their main advantages and disadvantages, and target pollutants.”

2. 
   Check in manuscript the typos and spaces, and the size of the space between lines (especially in references).

The manuscript was checked for typos and spaces, in particular the size of the space between the lines of the references.

Reviewer 2 Report

Review

Indoor air quality: cleaning technologies, a review

Authors:  Teresa M. Mata1, António A. Martins, Cristina S. C. Calheiros, Florentina Villanueva, Nuria P. Alonso- Cuevilla, Marta Fonseca Gabriel, and Gabriela Ventura Silva

Abstract: Lines 20-32

Please structure it as:

Introduction-Aims

Method

Results and interpretation

Introduction lines 35-144

The subchapter should be developed

Literature review should be done, updated to 2022 and internationalized.

Please analyses critically the findings of the articles and the limitations.

Please indicate also at least tree similar article to your research published recently (last 5 years).

Aim of the study is not clear expressed. Please revise

Method

The subchapter is missing. Please revise.

Please insert a flowchart of your research methodology steps for better visibility and understanding by the journal readers as well as as large public

References: update the references to 2022

We consider useful, to improve this paper, also the following papers. Please cite also:

A.    Oneț, D. C. Ilieș, A. Ilieș, G. V. Herman, L. Burtă, F. Marcu, R. Buhaș, T. Caciora, Ș. Baias, C. Oneț, M. Ilieș, A. Lincu, 2020, Indoor air quality assessment and its perception. Case study - historic wooden church, Romania, in  Romanian Biotechnological Letters 3:1547-1551 (https://www.e-repository.org/rbl/vol.25/iss.3/5.pdf).

Is it relevant and
interesting?

The paper is relevant and synthetizes the actual available literature data. The paper is interesting for devices marketing, too, because the tests results contribute to reflect the real dimensions and conditions in different environments.

How original is the topic?

Is an actual topic even it is not very original; but the subject is important especially in the post pandemic period to save the sick buildings syndrome and help to improve the public health.

What does it add to the subject
area compared with other published material?

The paper should be better documented (more than relevant150 scientific published articles in references list), these must be updated to 2022.

Is the paper well written?

The paper is well written. The quality of English translation is good.

Is the text clear and easy to read?

The text is well structured, clear and easy to read from the specialists in the field but as well as from the persons from public.

Are the conclusions consistent with the evidence and arguments presented?

The conclusions are well represented in the paper for the large public, too. The authors must underline the potential application of different technologies for Classifying Indoor Air Quality for tracing the source of indoor pollution, influencing factors, etc effects on the human community.

August  2022

Author Response

Dear Reviewer

Thank you very much for your suggestions. They helped us to improve the manuscript text.

Abstract: Lines 20-32

Please structure it as:

Introduction-Aims

Method

Results and interpretation

We acknowledge the reviewer comment and structured the Abstract according to the suggestion, as follows:

“Abstract: Aims: Indoor air quality (IAQ) has gained a new focus with the emergence of COVID-19. Ventilation is perhaps the area with the most proposed changes to answer to the emergency caused by this virus. However, other strategies are possible, as source control and extraction of pollutants. This last one incorporates the clean technologies, one of the emergent areas on IAQ. Method: Various air treatment technologies can be used for control of contaminants, which are reviewed and discussed in this work, including the physicochemical technologies (e.g., filtration, adsorption, UV-photocatalytic oxidation, ultraviolet disinfection and ionization) and the biological technologies (e.g., plant purification methods and microalgae-based methods). Results and interpretation: This work reviews the actual panorama in respect to the available solutions or technologies for “cleaning” the indoor air, looking for the inconveniences and advantages of them. One of the most common problems in this area is the emission of other pollutants, different and sometimes more dangerous to human health than those that the technologies developed aim to remove. Another aspect is the limitation of each technology in relation to the type of pollutants that need to be removed. Each technology works well for a family of pollutants with similar characteristics, but it is not applicable to all pollutant types. Thus, the solution can be the use of a combination of technologies, to extend the scope of application, and also the development of new materials, for example using nanotechnology.”

Introduction lines 35-144

The subchapter should be developed. Aim of the study is not clear expressed. Please revise

Two subchapters were included in the Introduction: one to describe the “Scope and Objectives” and the other for the “Method”.

An additional Figure (1) was included in the introduction to better explain the Scope and Objectives

Literature review should be done, updated to 2022 and internationalized. Please analyses critically the findings of the articles and the limitations.

The following new references, recently published (2022), were added to the manuscript and critically analysed: Szczotko et al. [30], Shayegan et al. [83]

Please indicate also at least tree similar article to your research published recently (last 5 years).

We have found two articles (already cited in our review) that do some review on the several methodologies, both from 2021.The articles are not similar but it was the more related we have found:

10. González-Martín, J.; Kraakman, N.J.R.; Pérez, C.; Lebrero, R.; Muñoz, R. A state–of–the-art review on indoor air pollution and strategies for indoor air pollution control. Chemosphere 2021, 262, doi:10.1016/j.chemosphere.2020.128376.
11. Megahed, N.A.; Ghoneim, E.M. Indoor Air Quality: Rethinking rules of building design strategies in post-pandemic architecture. Environ. Res. 2021, 193, doi:10.1016/j.envres.2020.110471.

On the other hand, we have found reviews focused in one technology that are already cited in our review, as filtration, PCO or green systems as it is the case of:

73. Wang, H.; Li, X.; Zhao, X.; Li, C.; Song, X.; Zhang, P.; Huo, P. A review on heterogeneous photocatalysis for environmental remediation: From semiconductors to modification strategies. Chinese J. Catal. 2022, 43, 178–214, doi:10.1016/S1872-2067(21)63910-4.
74. Liu, G.; Xiao, M.; Zhang, X.; Gal, C.; Chen, X.; Liu, L.; Pan, S.; Wu, J.; Tang, L.; Clements-Croome, D. A review of air filtration technologies for sustainable and healthy building ventilation. Sustain. Cities Soc. 2017, 32, 375–396, doi:10.1016/j.scs.2017.04.011
75. Moya, T.A.; van den Dobbelsteen, A.; Ottelé, M.; Bluyssen, P.M. A review of green systems within the indoor environment. Indoor Built Environ. 2019, 28, 298–309.

We have also found reviews focused in one pollutant (already cited in our review):

117. Nguyen, T.T.; Johnson, G.R.; Bell, S.C.; Knibbs, L.D. A Systematic Literature Review of Indoor Air Disinfection Techniques for Airborne Bacterial Respiratory Pathogens. Int. J. Environ. Res. Public Health 2022, 19, doi:10.3390/ijerph19031197.

For this reason, we were unable to fulfil the request of to add three new references.

Method

The subchapter is missing. Please revise.

One subchapter was included in the Introduction to describe the “Method”

Please insert a flowchart of your research methodology steps for better visibility and understanding by the journal readers as well as as large public.

One graphical abstract was included to better describe the research scope and methods.

References: update the references to 2022

The following new references, recently published (2022), were added to the manuscript and critically analysed: Szczotko et al. [30], Shayegan et al. [83]

We consider useful, to improve this paper, also the following papers. Please cite also:

5. Oneț, D. C. Ilieș, A. Ilieș, G. V. Herman, L. Burtă, F. Marcu, R. Buhaș, T. Caciora, Ș. Baias, C. Oneț, M. Ilieș, A. Lincu, 2020, Indoor air quality assessment and its perception. Case study - historic wooden church, Romania, in Romanian Biotechnological Letters 3:1547-1551 (https://www.e-repository.org/rbl/vol.25/iss.3/5.pdf). – It is an interesting case study, and presents an existent problem of microbiological contamination in a real space. However, it is not focused on clean air technologies, that is our subject. We thank you the suggestion, but it was not added to our review.

      What does it add to the subject area compared with other published material?

The paper should be better documented (more than relevant 150 scientific published articles in references list), these must be updated to 2022.

The following new references, recently published (2022), were added to the manuscript and critically analysed: Szczotko et al. [30], Shayegan et al. [83]

Are the conclusions consistent with the evidence and arguments presented?

The conclusions are well represented in the paper for the large public, too. The authors must underline the potential application of different technologies for Classifying Indoor Air Quality for tracing the source of indoor pollution, influencing factors, etc effects on the human community.

Following your suggestion, we added a sentence in conclusions:

“Furthermore, the current reality has shown the importance of good indoor air quality. Thus, these new technologies can contribute to its improvement, despite all their limitations. It is essential that people give importance to clean air as they give to pure water. It will be necessary to define minimum parameters for the classification of a good IAQ. And it would be important to see a generalization of IAQ audits, which would enhance source control and ventilation, the main vectors to ensure a good IAQ.”