Issue link: https://hi.iaq.net/i/664324
findings it is questionable if we should aim to remove all microbes and microbe-associated compounds from the indoor air. So, in conclusion, while most scientists agree that exposure to man-made chemicals indoors should be avoided we are less certain if this is true also for all microorganisms. Air cleaning Portable air cleaners may be used to remove air-borne particles by mechanical air filtration (HEPA etc) or electronic air cleaning where the particles are charged and thereafter either accumulated on a collector of opposite charge or precipitated following reaction with ions generated with an ion generator. VOCs (including odors) may be removed by pumping the air through a filter containing an adsorbent such as for example activated carbon. Some air cleaners are designed to destroy the contaminants; for example, microbes may be killed by UV light. PCO (photocatalytic oxidation) cleaners and ozone generators use UV together with a catalyst aiming to convert harmful pollutants to less harmful products. Attaching a sealant at surfaces indoors (floor, ceiling, or walls) from where the emissions are spread constitutes an alternative approach. The symptoms associated with building dampness are due to the large number of products formed when water comes into contact with building materials and then are emitted into the indoor air, and by using a sealant such emissions can be stopped selectively. Examples of sealants are various polymers, aluminum/plastic laminates, etc. Such products are typically tight both for VOCs and moisture; the fact that they force moisture and emissions to stay in the construction is a disadvantage. A new product, the surface emissions trap, was developed at Lund University, Sweden, initially as a PhD project. The aim was to construct a sealant that was easy to install, environmentally friendly (containing no chemicals), with a very low water vapor resistance and at the same time being able to trap particles and VOCs efficiently through adsorption. The surface emissions trap is a flexible laminate with two protective sheets of nonwoven polyester fabric surrounding an adsorbent layer and a hydrophilic polymer sheet (Markowicz and Larsson 2012, 2015). Below is described a case study from using this device in a building with unsatisfactory IAQ due to dampness. The surface emissions trap – a case study A school built in the 1970:s, with a long history of complaints on air quality among the pupils and the school staff, was studied. Air sampling had revealed elevated concentrations of 2- ethylhexanol that strongly indicating floor emissions of hydrolysis products from components of the glue used to attach the PVC flooring on the concrete. Increased ventilation and use of air purifiers in the rooms had not resulted in any clear improvements in the perceived IAQ. A surface emissions trap prototype was attached on the existing PVC flooring, by using a double sided adhesive tape, in an office room (30 m 2 ). The trap, a laminate with one adsorption and one polymer layer, adsorbs only from the adsorption layer side; hence the device was applied with the adsorption layer facing the floor. Over the device was laid a laminate flooring. The ventilation in both rooms was 2-2.5 air exchanges per hour. Air samples as well as samples of the trap cloth from the floor (immediately replaced with new pieces of the device) were taken at different time periods for measuring the amounts of 2- ethylhexanol in the air and adsorbed on the cloth, respectively. Tenax TA tubes were used for passive air samplings, and the analyses were performed by thermal desorption and GC-MS. IAQA 19th Annual Meeting The views and opinions herein are those of the volunteer authors and may not reflect the views and opinions of IAQA. The information is offered in good faith and believed to be reliable but it is provided without warranty, expressed or implied, as to the merchantability, fitness for a particular purpose or any other matter.