Review of 'Achieving a healthy indoor environment by using an emissions barrier for stopping spread of chemicals from building into the indoor air'

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. We have added that the analyses were made by a commercial laboratory viz Eurofins Pegasuslab Ltd, Uppsala, Sweden.

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. Information has been added.

“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? It took a few hours. We agree that long term results cannot be evaluated from this experiment; a comment has been added under Discussion.

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. Exposure limits differ very much for the different PAH. In general, if the odour complaints disappear then it is assumed that the PAH problem has been solved.

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. Has been done.