Characteristics of annual mold variations and association with childhood allergic symptoms/diseases via combining surveys and home visit measurements

Abstract

The presence of dampness and visible molds leads to concerns of poor indoor air quality which has been consistently linked with increased exacerbation and development of allergy and respiratory diseases. Due to the limitations of epidemiological surveys, the actual fungal exposure characteristics in residences has not been sufficiently understood. This study aimed to characterize household fungal diversity and its annual temporal and spatial variations. We developed combined cross-sectional survey, repeated air sampling around a year, and DNA sequencing methods. The questionnaire survey was conducted in 2019, and 4943 valid cases were received from parents; a follow-up case-control study (11 cases and 12 controls) was designed, and onsite measurements of indoor environments were repeated in typical summer, transient season, and winter; dust from floor and beddings in children's room were collected and ITS based DNA sequencing of totally 68 samples was conducted. Results from 3361 children without changes to their residences since birth verified the significant associations of indoor dampness/mold indicators and prevalence of children-reported diseases, with increased adjusted odd ratios (aORs) >1 for studied asthma, wheeze, allergic rhinitis, and eczema. The airborne fungal concentrations from air sampling were higher than 1000 CFU/m 3 in summer, regardless of indoors and outdoors, indicating an intermediate pollution level. The DNA sequencing for dust showed the Aspergillus was the predominant at genus level and the Aspergillus_penicillioides was the most common at species level; while the fungal community and composition varied significantly in different homes and seasons, according to α and β diversity analyses. The comprehensive research methods contribute to a holistic understanding of indoor fungal exposure, including the concentrations, seasonal variations, community, and diversity, and verifies the relations with children's adverse health outcomes. The study further elucidates the role of microbiome in human health, which helps setting health-protective thresholds and managing mold treatments in buildings, to promote indoor air quality and human well-beings.

A Predictive Model for the Growth Diameter of Mold under Different Temperatures and Relative Humidities in Indoor Environments

“…According to our previous home investigations and fungal measurements in air and dust in typical residences in Chongqing, China [39,40], as well as in other studies [41,42],…”

“…According to our previous home investigations and fungal measurements in air and dust in typical residences in Chongqing, China [39,40], as well as in other studies [41,42], Aspergillus niger is a common fungal species that is widely detected in residential environments, causing some allergic or respiratory diseases due to the emitted allergens [16,43]. Therefore, Aspergillus niger (ATCC 16404, same as AS3.3928, American Type Culture Collection (ATCC)) was chosen as inoculation strain, as shown in Figure 1a.…”

Why should we target the burden of disease for indoor air pollutants?

“…In particular, several studies in this special issue have evaluated the exposure levels of formaldehyde, 12 typical volatile organic compounds (VOCs), 13 and phthalates 14 in residences, offices, and schools, through systematic review and statistical modeling. Other studies in this issue focus on the associations between indoor air pollutants and different health outcomes, including meta-analyses of VOCs, 15 radon, 16 and phthalates, 14 and original studies of desert dust and mold, 17,18 and the mediation of indoor air pollution effect on health. 19 Additionally, some studies directly provide the attributable burden of diseases, such as for phthalates 14 and radon.…”

A Cross Sectional Study on the 24 – Hour Variation of Fungal Pollution in the Atmosphere of Erbil City, Iraq

“…Studies indicate that outdoor airborne fungi OAF fungi are the main source of indoor airborne fungi IAF [2]. These two groups include etiologic diseases, and the variation of fungal communities according to indoor environments and their relationship with temporal and spatial changes were demonstrated [3]. Studies also focused on ventilation systems as an additional factor related to indoor aeromycoflora [4,5].…”

“…The relationship between asthma patients and IAF was validated [6,7]. Fungal populations vary as a result of the interaction between atmospheric and interior environmental factors [3].…”