Assessment of Indoor Air Quality and Hygrothermal Conditions of Boarders During Autumn, Winter and Spring in Two of Estonian Straw-Bale Houses

Abstract

Indoor air quality affects human health. These effects can be either positive of negative. Straw bale building has been claimed as a sustainable way of building. The aim of this study was to evaluate indoor air quality in two of Estonian straw bale houses and provide solution of monitoring for indoor air quality and hygrothermal conditions of boarders as complex. Samples were collected between October 2014 til March 2015. Sampling media and procedure was designed according to ISO standard 16000-18: Detection and enumeration of moulds—Sampling by impaction. Data loggers for collecting the data about CO2, temperature and humidity were also used. Two of them (recorded temperature and humidity) were installed inside the wall (depth ~20 cm), the third logger was used as a desktop logger. We also collected some straw samples inside the wall to see which kind of microorganisms are living on them. Samples were plated, total colony forming units were counted and identified from the isolated colonies. The results from air samples (CFU) were in one house higher than in the other one. Temperature, humidity and CO2 levels were also higher in one house. This is probably affected by the different building characteristics (one of the houses is modular wall straw bale house, the other one is timber frame straw bale house). Species, which we found, were similar in both houses. The most fungal genes isolated from samples were Aspergillus, Penicillium, Alternaria and Cladosporium.