Methods for measurement, reduction and evaluation of VOC emissions from engineered softwood panels

Abstract

Abstract nur in Englisch

In the past twenty years, the scientific interest towards characterization of volatile organic compounds (VOC) emitted indoors arose rapidly. The main reason for this is the construction of energy‐efficient buildings with reduced indoor air exchange rates resulting in an increased exposure of the occupants to VOC. Engineered softwood panels are often a pronounced VOC source and as such an assessment of their VOC emissions potential (and in respect with the demands of the current indoor air quality labeling schemes) should be done and if necessary a reduction of certain emissions should be aimed at. In the present doctoral thesis a biotechnological approach was taken to address the problem of aldehyde emissions by using microorganisms ‐ fungi and bacteria ‐ capable of metabolizing aldehyde precursors (unsaturated fatty acids). Reduction of more than 60% of aldehydes emissions from laboratory panels was achieved. The concentrations of unsaturated fatty acids in the treated panels were also reduced in this range. In terms of analytical methodology, headspace‐SPME‐GC/MS analytics established itself as a convenient tool for screening for microorganisms capable of reducing aldehyde emissions. The utilization of so‐called Micro‐Chambers for the purpose of characterizing VOC emissions from engineered wood panels showed high potential especially after the implementation of a humidity control unit. The analytical methods employed in the experiments were refined and further developed resulting in the adaptation and the usage of the micro‐chamber humidifier as novel method for characterization of VOC present in dry‐kiln condensates. In the field of indoor air quality (IAQ) evaluation schemes assessment it was shown that these schemes should also be evaluated in order for the industry to rapidly trace problematic substances and to adapt its production processes to changes in IAQ assessment schemes. In this work, the author proposes a mechanism for applying such evaluation in order to estimate the restrictiveness of evaluation schemes towards industrial production. Furthermore, the safety margins of IAQ evaluation schemes towards softwood‐based products were estimated. It was established that the evaluation of softwood VOC emissions according ISO 16000‐9 under certain conditions can lead to overestimation of the emissions with factors from 2 to 20 when compared with close‐to‐reality measurements. Unpublished data from experiments of the author aiming at VOC reduction as well as considerations regarding the critical points of VOC measurement techniques by means of small‐scale analytics can be found in the appendix of this work.