Research article

Achieving a healthy indoor environment by using an emissions barrier to stop the spread of chemicals from a building into the indoor air

Authors
  • Lennart Larsson (Lund University, Lund, Sweden)
  • Johan Mattsson orcid logo (cTrap AB, Råbylunds Gård, Prästavägen 12, 224 80 Lund, Sweden)

Abstract

An emissions barrier was used in a premises due to complaints about the indoor air quality (IAQ) as a result of emissions from the building in question. The emissions comprised chlorophenols/chloroanisoles and polycyclic aromatic hydrocarbons (PAH) from treated wood and volatile organic compounds (VOCs), mainly 2-ethylhexanol, from polyvinyl chloride (PVC) flooring and the glue used to paste the flooring onto a concrete slab. Attaching the barrier at the surfaces from where the emissions were spread (floor, walls, ceilings) resulted in a fresh and odour-free indoor air. We conclude that using an emissions barrier in buildings made unhealthy by moisture is an efficient way of restoring pleasant and healthy indoor air.

Keywords: emissions barrier, adsorbent, healthy buildings, restoration

How to Cite: Larsson, L., & Mattsson, J. (2022). Achieving a healthy indoor environment by using an emissions barrier to stop the spread of chemicals from a building into the indoor air. UCL Open Environment, 4. https://doi.org/10.14324/111.444/ucloe.000033

Rights: © 2022 The Authors.

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Published on
16 Mar 2022
Peer Reviewed

Introduction

Building moisture typically results in the spread of chemical and biological emissions into the indoor air leading to illnesses and symptoms such as asthma, skin and eye irritation, fatigue, etc. [1,2]. Drying is a necessary first step in remediation of a building as it will stop further moisture-driven reactions with the building materials as well as (continued) mould growth. However, drying is not enough to secure clean indoor air, as the numerous chemicals that have been formed from water – or moisture – acting on the materials will still remain in the building, and over time will inevitably be emitted into the indoor air. The emissions may be, for example, volatile organic compounds (VOCs) from paints, glue, insulation materials, chipboard, microorganisms, impregnation and plasticiser chemicals, or toxins from microorganisms such as mould (see, e.g., [3]).

Airborne particles released during building construction may be removed by using portable air cleaners with mechanical air filtration, for example, with high efficiency particulate arresting (HEPA) filters or by electronic cleaning whereby the particles are charged and thereafter accumulated on a collector or precipitated following a reaction with ions generated with an ion generator [4]. VOCs (including odours) may be removed by pumping the air through a filter containing an adsorbent. Some air cleaners are designed to destroy the contaminants; for example, microbes may be killed by ultraviolet (UV) light. Photocatalytic oxidation (PCO) cleaners and ozone generators use UV together with a catalyst to convert harmful pollutants to less harmful products. Such measures, as well as increasing the ventilation, may decrease the concentrations of the airborne contaminants, but will not prevent them from being spread into the indoor air. Furthermore, PCO cleaners [5] as well as ozone generators [6,7] may in fact increase the concentrations of some other VOCs including potential lung irritants such as formaldehyde. Replacing damaged materials with new ones may, in some instances, be useful but also very time-consuming, costly and – when the damaged materials are vital for the stability and function of the building – often impossible to do.

Attaching a sealant on indoor surfaces (floors, ceilings or walls) from where the emissions are spread constitutes an alternative approach. Examples of sealants are various polymers, aluminium/plastic laminates, etc. Such sealants can be extremely efficient in stopping the emissions and thus improving the indoor air quality (IAQ); however, it is necessary to first know the source of the emissions. In the present study we applied a new type of emissions barrier [8,9] developed at Lund University, Sweden to stop emissions in some buildings with different complaints regarding the IAQ.

Methods

Three buildings with IAQ complaints due to emissions resulting from the construction of the building were studied. In short, the surfaces from where the emissions were spread (floors, ceilings, walls) were covered with an emissions barrier to prevent them from reaching the indoor air. In the specific barrier used, the cTrap, an adsorption layer functions together with a hydrophilic polymer sheet making the adsorption virtually irreversible [8,9]. The flexible cTrap cloth was attached to the surfaces using an adhesive tape and/or a staple gun. The indoor air concentrations of the emissions were measured both before and after the cTrap installations by pumping air through an adsorbent material followed by thermal or chemical desorption and analysis using gas chromatography-mass spectrometry by Eurofins Pegasuslab Ltd, Uppsala, Sweden.

Results

1. We studied the living room and a bedroom of a wooden summer house built in 1964 with a disturbing ‘summer cottage smell’ indoors which was attributed to chloroanisoles. The building had previously been treated with chlorophenol-containing preservatives which were widely used in the 1960s and 1970s; in moist conditions chlorophenols may be biomethylated to form chloroanisoles having an intense, characteristic mould-like odour. The ceiling, walls and floor in the bedroom (as well as the doorway between the bedroom and the living room), but not in the living room, were covered with the cTrap cloth. Subsequently, air sampling for chlorophenols/chloroanisoles was carried out simultaneously in both rooms. Tetrachlorophenol, trichloroanisole and pentachloroanisole were detected in the air of the living room, but only tetrachlorophenol was found in the bedroom, and in an air concentration 93% lower than in the living room (Table 1). In addition, the cTrap installation team reported the disappearance of the mouldy odour in the bedroom.

Table 1.

Results of cTrap installations (μg/m3 air)

Emissions Without cTrap With cTrap
Tetrachlorophenol 0.14 0.01
Chloroanisoles 0.013 n.d.
PAH 1.726 0.139
2-ethylhexanol 63 1.5
  • n.d., not detected (<0.0018 μg/m3 2,4,6-trichloroanisole; <0.00091 μg/m3 pentachloroanisole).

2. A building where a creosote-based tar layer had been attached to the concrete slab as a moisture barrier was studied. The air concentrations of polycyclic aromatic hydrocarbons (PAH) were 1726 ng/m3 air. There was a disturbing smell similar to that of car tires or asphalt inside the building which persisted even after the tar had been removed. The cTrap cloth was installed on about 75% of the wall surface. The smell disappeared and the PAH air concentrations decreased to 139 ng/m3, thus corresponding to a reduction of 92% (Table 1).

3. A townhouse was studied where the tenants suffered from itching all over their bodies while at home, symptoms which disappeared when they were outside the building. A polyvinyl chloride (PVC) flooring had been glued onto a concrete slab which had become moist through the diffusion of water from the ground. The air concentration of 2-ethylhexanol, a compound which is ubiquitous in small concentrations in indoor air but which was found in increased concentrations, for example, following hydrolysis of the glue and/or phthalates of PVC floorings, was found to be 63 μg/m3 (directional measurement). The cTrap was attached to the existing flooring, and the itchiness disappeared. Three months after the cTrap was installed the air concentration was 1.5 μg/m3 (Table 1), a value which persisted in a follow-up study six years after its installation; the residents have reported no further symptoms.

Results are summarised in Table 1.

Discussion

Staying in a moist building can cause health problems [1,2], for example, skin and mucous irritation and respiratory disorders. Such conditions are frequently referred to as building-related illnesses (BRI) and are caused by the spread of chemical emissions from the building itself into the indoor air. Research has shown that mixtures of VOCs emitted from building materials may act in synergy in worsening the perceived air quality [10,11] even when present in concentrations below the odour thresholds. The studies presented here demonstrate that such emissions can be effectively stopped by using an emissions barrier. Through scientifically validated questionnaires it has also been found that health symptoms and/or unpleasant odours can be decreased or totally eliminated (data not shown). Still, the awareness that use of emissions barriers is an efficient weapon against BRI is not widespread – not even among indoor air professionals.

The specific device used in the studies presented here, the cTrap (surface emissions trap) cloth, contains two active layers; one adsorption layer and one hydrophilic polymer layer. The device is airtight while at the same time allowing moisture to pass through with almost no resistance at all, and will thus not affect the moisture balance of the building. It has been shown to be efficient against a wide range of chemicals including, for example, alcohols, aldehydes, sulfur compounds, PAH, chloroanisoles, chlorophenols, mould products and odours [8,9], and the effect has been found to be long term (several years). After the barrier has been applied to a floor, a surface layer, for example, a laminate, parquet or plastic flooring, etc., is installed on top of the cTrap cloth. When attached on walls or to a ceiling the cloth is usually covered with a gypsum board which is then painted or decorated with a wallpaper. When the building is eventually demolished the cTrap cloth, with the adsorbent layer containing the emitted chemicals, will be disposed of by combustion thus avoiding leakage of the chemicals into the environment from deposited building materials.

In summary, we conclude that use of an emissions barrier represents an effective, economic, and eco-friendly way of restoring healthy indoor air in buildings affected by moisture.

Conclusions

An emissions barrier can be used to restore fresh and healthy indoor air in buildings made unhealthy due to moisture damage.

Financial support from Lund University is gratefully acknowledged. We are grateful to Johnny Lorentzen for his active participation in the chlorophenol/chloroanisole study.

Declarations and conflicts of interest

Research ethics statement

Not applicable.

Consent for publication statement

The author declares that research participants’ informed consent to publication of findings – including photos, videos and any personal or identifiable information – was secured prior to publication.

Conflicts of interest statement

Johan Mattsson is employed by cTrap AB, Sweden. All other authors declare no conflicts of interest in connection to this article.

Open data and materials availability

No further data was used in addition to referenced works.

Authorship contribution

Johan Mattsson was instrumental in initiating and realising the described projects while Lennart Larsson compiled the data and did most of the writing.

References

[1]  Mendell, M; Mirer, A; Cheung, K; Tong, M; Douwes, J. (2011).  Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence.  Environ Health Perspect [online]. 119 (6) : 748–56, DOI: http://dx.doi.org/10.1289/ehp.1002410

[2]  Bornehag, CG; Sundell, J; Sigsgaard, T. (2004).  Dampness in buildings and health (DBH): report from an ongoing epidemiological investigation on the association between indoor environmental factors and health effects among children in Sweden.  Indoor Air, [online]. Suppl 7 : 59–66, DOI: http://dx.doi.org/10.1111/j.1600-0668.2004.00274.x

[3]  Ligotski, R; Sager, U; Schneiderwind, U; Asbach, C; Schmidt, F. (2019).  Prediction of VOC adsorption performance for estimation of service life of activated carbon based filter media for indoor air purification.  Build Environ [online]. 149 : 146–56, Available from:. DOI: http://dx.doi.org/10.1016/j.buildenv.2018.12.001

[4]  Zhang, YP; Mo, JH; Li, YG; Sundell, J; Wargocki, P; Zhang, JS. (2011).  Can commonly-used fan-driven air cleaning technologies improve indoor air quality? A literature review.  Atmos Environ [online]. 45 : 4329–43, DOI: http://dx.doi.org/10.1016/j.atmosenv.2011.05.041

[5]  Kolarik, J; Wargocki, P. (2010).  Can a photocatalytic air purifier be used to improve the perceived air quality indoors?.  Indoor Air [online]. 20 : 255–62, DOI: http://dx.doi.org/10.1111/j.1600-0668.2010.00650.x

[6]  Weschler, CJ. (2006).  Ozone’s impact on public health: contributions from indoor exposures to ozone and products of ozone-initiated chemistry.  Environ Health Perspect [online]. 114 : 1489–96, DOI: http://dx.doi.org/10.1289/ehp.9256

[7]  Wolkoff, P; Clausen, PA; Wilkins, CK; Nielsen, GD. (2000).  Formation of strong airway irritants in terpene/ozone mixtures.  Indoor Air [online]. 10 : 82–91, DOI: http://dx.doi.org/10.1034/j.1600-0668.2000.010002082.x

[8]  Markowicz, P; Larsson, L. (2012).  The surface emissions trap: A new approach in indoor air purification.  J Microbiol Methods [online]. 91 : 290–4, DOI: http://dx.doi.org/10.1016/j.mimet.2012.08.019

[9]  Markowicz, P; Larsson, L. (2015).  Improving the indoor air quality by using a surface emissions trap.  Atmos Environ [online]. 106 : 376–81, Available from:. DOI: http://dx.doi.org/10.1016/j.atmosenv.2014.04.056

[10]  Knudsen, HN; Kjaer, UD; Nielsen, PA; Wolkoff, P. (1999).  Sensory and chemical characterization of VOC emissions from building products: impact of concentration and air velocity.  Atmos Environ [online]. 33 : 1217–30, Available from:. DOI: http://dx.doi.org/10.1016/S1352-2310(98)00278-7

[11]  Patterson, MQ; Stevens, JC; Cain, WS; Cometto-Muñiz, JE. (1993).  Detection thresholds for an olfactory mixture and its three constituent compounds.  Chem Senses [online]. 18 : 723–34, DOI: http://dx.doi.org/10.1093/CHEMSE/18.6.723

 Open peer review from Pawel Markowicz

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.APQW7K.v1.RQTNJY
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Materials technology , Historic preservation , Civil engineering , Public health
Keywords: Healthy buildings , Pollution and health , Adsorbent , Sustainability in architecture and the built environment , People and their environment , Emissions barrier , Sustainability , Restoration

Review text

no further comments



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.

 Open peer review from Aleksandra Monika Sebastian

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.AWPTMF.v1.ROTLFS
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Materials technology , Historic preservation , Civil engineering , Public health
Keywords: Healthy buildings , Pollution and health , Adsorbent , Sustainability in architecture and the built environment , People and their environment , Emissions barrier , Sustainability , Restoration

Review text

The manuscript proposes unique methodology for isolation/encapsulation of indoor pollution sources if it is impossible or too expensive to remove them. Especially useful when experiencing adverse health effects from moisture damage buildings and when reparation needs to be done quickly. What makes this research very interesting are documented practical interventions in existing troublesome indoor environments, leading to significant improvements in the air quality and symptoms of the tenants.

Introduction, Second paragraph

I really like comprehensive information about indoor air cleaning techniques and harmfulness of devices using UV light and ozone for destroying microorganisms and converting airborne VOCs.

Methods

Some more information/citations about analytical methodology would be appreciated.

Results 1

Authors mention odour assessment in a few places in the manuscript. It would be interesting to know if they used a special smell validation protocol and how many persons took part in the test.

“The ceiling, walls and floor in the bedroom (as well as the doorway between the bedroom and the living room), but not in the living-room.  were covered with the cTrap cloth.  Subsequently, air sampling for chlorophenols/chloroanisoles was carried out simultaneously in both rooms.”

How long did it take between covering the surfaces with the cTrap and subsequent sampling? Was it an adequate time to reach the equilibrium?

Results 2

“The air concentrations of PAH were 1726 ng/m3 air. There was a disturbing smell inside the building which persisted even after the tar had been removed. Then, the cTrap cloth was installed on about 75 percent of the wall surface. The smell disappeared and the PAH air concentrations decreased to 139 ng/m3, thus corresponding to a reduction of 92% (Table 1).”

Even tough, the reduction of PAHs concentration is huge, is it enough to justify the installation of the clothe? Please provide exposure limits for occupational conditions or, if possible, indoor environments.

Likewise, for other substances mentioned in the Table 1.

Results 3

“3 months after cTrap had been installed the air concentration was 1.5 μg /m3 (Table 1), a value which persisted in a follow-up study 6 years after the installation -and the residents still reported no symptoms.”

Long term studies are very much appreciated!

Discussion

Please provide also some more resent references in the first paragraph.



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.

 Open peer review from Pawel Markowicz

Review

Review information

DOI:: 10.14293/S2199-1006.1.SOR-ARCH.AV5ARZ.v1.RKLEGY
License:
This work has been published open access under Creative Commons Attribution License CC BY 4.0 , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Conditions, terms of use and publishing policy can be found at www.scienceopen.com .

ScienceOpen disciplines: Materials technology , Historic preservation , Civil engineering , Public health
Keywords: Healthy buildings , Pollution and health , Adsorbent , Sustainability in architecture and the built environment , People and their environment , Emissions barrier , Sustainability , Restoration

Review text

Introduction:

Airborne particles released from the building construction may be removed by using portable air cleaners with mechanical air filtration (HEPA etc) - Please provide HEPA abbreviation for the clarification.

Results 1st installation:

Also, the mouldy odour disappeared in the bedroom following the cTrap installation. Is that a personal statement of the authors? If yes, please indicate that in the paragraph.

General comment: Please keep air concentration unites consistant with the table 1 (µg/m 3 not µg/m3). All air concentration unites should ideally be presented or as per ng or µg /m 3 for consistency.

Results: 2nd  installation:

There was a disturbing smell inside the building which persisted even after the tar had been removed. If possible, please provide more information about a smell.

Table 1:

a) n.d. for chloroanisoles. Please provide the abbreviation of n.d. If not detected, please provide a limit of detection (LOD) for this compound.

b) The unit of µg/m 3 is not applicable for the 'emmisions'  table row but for 'without cTrap' and ' with cTrap' rows. Please modify it for the clarification.

References

Kolarik, J., and Wargocki P. (2010). Can a photocatalytic air purifier be used to improve the perceived air quality indoors? Indoor Air 20, 255-262. Markowicz, P. and Larsson, L. (2012). The surface emissions trap: A new approach in indoor air purification. J. Microbiol. Methods 91, 290-294.\

Please separate both references



Note:
This review refers to round of peer review and may pertain to an earlier version of the document.