Indoor mold concentrations, prevalence, and relation to building characteristics in homes in very cold climates

People in the U.S. spend more than 90% of their time indoors. In very cold climates including Alaska (ASHRAE Climate Zone 8), homes provide essential shelter, yet these homes are often smaller, overcrowded, and not designed for the harsh cold climate that requires year-round heating. Extreme cold weather also creates potential condensation risk and thus the potential for mold growth. Previous research has found that many Alaska residents have concerns about mold growth in their homes and also has shown the prevalence of mold-induced respiratory infections and conditions particularly for children in these locations. However, it is rare for studies to quantify the concentration of mold or quantify its causes. This study utilized surface and airborne mold tests alongside in-person home assessments in 72 households in two rural coastal Alaskan communities. Results detected the potential for mold in the air of 39% of homes tested, and mold was found on at least one surface in 67% of homes tested. Nonparametric statistical tests including the Spearman Rank test, Mann-Whitney U-Test, and Kruskal Wallis test were performed to analyze correlations between indoor mold concentrations and housing characteristics. Higher concentrations of surface mold were found in homes that were older, more densely occupied, were more humid, did not have Heat Recovery Ventilators (HRVs), and for samples taken from windows. Airborne and surface mold concentrations were noted to be higher in one of the communities. This study highlights the household characteristics that are more likely to suggest the presence of air and surface mold growth in homes in very cold climates. • Relationships found between various household factors and indoor moldiness were found • Elevated concentrations of surface mold were found in windows in homes in cold climates, indicating a potential synergistic effect with condensation formation common in these environments. • Testing room was not found to affect mold concentrations • Correlation was found between airborne and surface mold concentrations in homes