Microbial growth and volatile organic compound (VOC) emissions from carpet and drywall under elevated relative humidity conditions

Haines, Sarah R.; Hall, Emma; Marciniak, Katarzyna; Misztal, Pawel K.; Goldstein, A. H.; Adams, Rachel; Dannemiller, Karen C.

doi:10.1186/s40168-021-01158-y

Cited by 14 publications

(4 citation statements)

References 80 publications

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“…corroborated the associative link between microbial exposure and allergic reactions. Additional exacerbating factors like high ambient humidity and inadequate ventilation further compound these risks, as corroborated by studies from Haines et al [9] and Onmek et al [10].…”

Section: Introductionmentioning

confidence: 79%

Pilot Study on the Physical, Chemical, and Biological Determinants of Indoor Air Quality in University Classrooms

Edelmers,

Kauce,

Konopecka

et al. 2023

Environmental and Climate Technologies

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In the context of an escalating energy crisis, the burgeoning prevalence of remote work, and challenging climatic conditions, ensuring optimal indoor air quality (IAQ) has emerged as a pressing concern. This pilot study rigorously investigates the complex interplay between biological, chemical, and physical parameters that characterize IAQ, focusing specifically on university classrooms during active teaching sessions. Employing a comprehensive array of instrumentation – such as SAS SUPER ISO 100 for microbiological sampling, Aranet4 for monitoring relative humidity, temperature, and CO2 concentration, and PCE-PCO 1 and PCE-RSCM 16 for particulate matter (PM2.5 and PM10) quantification—the study spanned a duration of three days in November 2022 and covered classrooms of varying dimensions, both reliant on natural ventilation. An extensive collection of 52 microbiological samples were obtained and cultured on specialized growth media to differentiate between various classes of airborne microorganisms. Concurrently, the pilot study meticulously recorded students’ activity patterns, along with the temporal dynamics of window openings and closures. The colony-forming units per cubic meter (CFU/m3) fluctuated between 174 and 934 CFU/m3, with fungi constituting the majority. Furthermore, the CFU/m3 for fungi cultivated on Sabouraud Dextrose Agar ranged from 24 to 610 CFU/m3, whereas bacteria cultured on Trypticase Soy Agar and Mannitol Salt Agar exhibited ranges of 42–476 CFU/m3 and 42–254 CFU/m3, respectively. Contrasting these findings with extant guidelines that recommend microbiological contamination not exceeding 500 CFU/m3 highlights significant IAQ concerns. Thermal assessments revealed that the smaller classroom surpassed the acceptable indoor temperature threshold of 25 °C within an average duration of 50 minutes, while the larger classroom remained compliant. Notably, the highest CO2 concentrations recorded over the three-day period were alarmingly high: 2689 ppm, 1970 ppm, and 2131 ppm on the first, second, and third days, respectively. A 25-minute ventilation intervention was sufficient to reduce CO2 levels to 499 ppm, although existing literature stipulates that CO2 concentrations should not surpass 1000 ppm. Importantly, the pilot study highlighted the rapid increasing of PM2.5 and PM10 concentrations in crowded instructional settings, averaging 400 μg/m3 and 35 μg/m3, respectively. This underscores the necessity for a continuous air ventilation and purification mechanism during classroom activities. Despite these pivotal findings, the study identifies a glaring absence of standardized regulations or guidelines pertaining to maximum acceptable concentrations of particulate matter and microbial CFU in public indoor environments, indicating a critical area requiring immediate policy intervention.

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Section: Introductionmentioning

confidence: 79%

Pilot Study on the Physical, Chemical, and Biological Determinants of Indoor Air Quality in University Classrooms

Edelmers,

Kauce,

Konopecka

et al. 2023

Environmental and Climate Technologies

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“…Other traditional methods and techniques 4 , 6 , 17 , 43 – 47 , such as biological air and dust samplings, culture-based analysis, morphology techniques, and microbial volatile organic compound (VOC) measurements 48 – 51 , were used to evaluate the levels of molds and bacteria measured in indoor and outdoor environments, including residential dwellings (households), daycare centers, kindergartens, schools, and elderly care centers. However, many previous studies reported several limitations.…”

Section: Discussionmentioning

confidence: 99%

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

Lee,

Ryu,

Sul

et al. 2024

Sci Rep

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This study aims to characterize levels of molds, bacteria, and environmental pollutants, identify the associations between indoor mold and dampness exposures and childhood allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, using three different exposure assessment tools. A total of 50 children with their parents who registered in Seoul and Gyeonggi-do in Korea participated in this study. We collated the information on demographic and housing characteristics, environmental conditions, and lifestyle factors using the Korean version of the International Study of Asthma and Allergies in Childhood questionnaire. We also collected environmental monitoring samples of airborne molds and bacteria, total volatile organic compounds, formaldehyde, and particulate matter less than 10 µm. We evaluated and determined water damage, hidden dampness, and mold growth in dwellings using an infrared (IR) thermal camera and field inspection. Univariate and multivariate regression analyses were performed to evaluate the associations between prevalent allergic diseases and exposure to indoor mold and dampness. Indoor mold and bacterial levels were related to the presence of water damage in dwellings, and the mean levels of indoor molds (93.4 ± 73.5 CFU/m3) and bacteria (221.5 ± 124.2 CFU/m3) in water-damaged homes were significantly higher than those for molds (82.0 ± 58.7 CFU/m3) and for bacteria (152.7 ± 82.1 CFU/m3) in non-damaged dwellings (p < 0.05). The crude odds ratios (ORs) of atopic dermatitis were associated with < 6th floor (OR = 3.80), and higher indoor mold (OR = 6.42) and bacterial levels (OR = 6.00). The crude ORs of allergic diseases, defined as a group of cases who ever suffered from two out of three allergic diseases, e.g., asthma and allergic rhinitis, and allergic rhinitis were also increased by 3.8 and 9.3 times as large, respectively, with water damage (+) determined by IR camera (p < 0.05). The adjusted OR of allergic rhinitis was significantly elevated by 10.4 times in the water-damaged dwellings after adjusting age, sex, and secondhand smoke. Therefore, a longitudinal study is needed to characterize dominant mold species using DNA/RNA-based sequencing techniques and identify a causal relationship between mold exposure and allergic diseases in the future.

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“…Next generation DNA sequencing-based tools using sequence analysis of microbes [19] have not yet been able to identify speci c species as a consistent microbial signature of dampness [20][21][22]. Solely analyzing species composition changes in response to moisture is not su cient to quantify microbial growth due to the in uence of sampling site [20,23,24].…”

Section: Introductionmentioning

confidence: 99%

Moving beyond species: Fungal function in house dust provides novel targets for potential indicators of mold growth in homes

Balasubrahmaniam,

King,

Hegarty

et al. 2024

Preprint

Self Cite

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Background: Increased risk of asthma and other respiratory disease is associated with exposures to microbial communities growing in damp and moldy indoor environments. The exact causal mechanisms remain unknown, and occupant health effects have not been consistently associated with any species-based mold measurement methods. We need new quantitative methods to identify homes with potentially harmful fungal growth that are not dependent upon species. The goal of this study was to identify genes consistently associated with fungal growth and associated function under damp conditions for use as potential indicators of mold in homes regardless of fungal species present. A de novo metatranscriptomic analysis was performed using house dust from across the US, incubated at 50%, 85%, or 100% equilibrium relative humidity (ERH) for one week. Results: Gene expression was a function of moisture (adonis2 p<0.001), with fungal metabolic activity increasing with increase in moisture condition (Kruskal-Wallis p=0.003). Genes associated with fungal growth such as sporulation (n=264), hyphal growth (n=62) and secondary metabolism (n=124) were significantly upregulated at elevated ERH conditions when compared to the low 50% ERH (FDR-adjusted p≤0.001, log2FC≥2), indicating that fungal function is influenced by damp conditions. A total of 67 genes were identified as consistently associated with the elevated 85% or 100% ERH conditions and included fungal developmental regulators and secondary metabolite genes such as brlA (log2FC=7.39, upregulated at 100% compared to 85%) and stcC (log2FC=8.78, upregulated at 85% compared to 50%). Conclusions: Our results demonstrate that moisture conditions more strongly influence gene expression of indoor fungal communities compared to species presence. Identifying genes indicative of microbial growth under damp conditions will help develop robust monitoring techniques for indoor microbial exposures and improve understanding of how dampness and mold is linked to disease.

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Microbial growth and volatile organic compound (VOC) emissions from carpet and drywall under elevated relative humidity conditions

Cited by 14 publications

References 80 publications

Pilot Study on the Physical, Chemical, and Biological Determinants of Indoor Air Quality in University Classrooms

Pilot Study on the Physical, Chemical, and Biological Determinants of Indoor Air Quality in University Classrooms

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

Moving beyond species: Fungal function in house dust provides novel targets for potential indicators of mold growth in homes

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