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

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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.

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