New Zealand house indoor microclimate and allergens

Abstract

The most common indoor allergens and triggers for people with asthma and allergic rhinitis are dust-mites, moulds, pets and pollen. Allergens from dust mites and moulds are strongly associated with indoor microclimate. Indoor microclimate conditions are closely related to house thermal performance and R-value of its envelope. Based on the field studies of indoor microclimatic conditions, tests of allergen levels of dust mites and mould growth of a number of sample houses, this study provides physical evidence to identifies thresholds or ranges of indoor microclimatic conditions related to different levels of dust-mite allergen and mould growth, a correlation between dust-mite allergen levels and mould growth levels, the most common type of indoor mould and the minimum requirement of indoor microclimatic conditions to control indoor dust-mite allergens at an acceptable level and prevent indoor mould problem. The study evaluates indoor microclimatic conditions related to indoor allergens of the sample houses with different R-values in their envelopes in accordant to the requirement of the current building code for New Zealand Climate Zone 1 and 2 (New Zealand Standard 4218: 2009) and the previous building code (New Zealand Standard 4218:1996).