Abstract View
Measuring Microbial Growth and MVOC Emissions in Carpet and Drywall Under Elevated Relative Humidity
SARAH R. HAINES, Emma C. Hall, Pawel K. Misztal, Allen Goldstein, Rachel I. Adams, Karen C. Dannemiller, Ohio State University
Abstract Number: 442
Working Group: Indoor Aerosols
Abstract
Microorganisms grow in carpet dust and on drywall at elevated relative humidity (RH) conditions (>80% and >90% RH, respectively). Growth may release microbial volatile organic compounds (MVOCs). However, it is unknown how microbial growth and MVOC emissions vary in various building materials under different RH conditions. The goal of this study is to characterize the microbial contribution to indoor chemistry under elevated relative humidity conditions and in different building materials. Dust was collected from San Francisco, CA, Columbus, OH and Gainesville, FL, embedded into unused nylon carpet. Samples of painted drywall were inoculated in homes in San Francisco, CA and Columbus, OH. Samples were incubated at either 50%, 65%, 70%, 75%, 80%, 85% or 95% equilibrium RH for 2 – 4 weeks depending on the experiment. A proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS) was used to measure VOCs at 1s time resolution. Results indicated that location origin of the sample (CA, OH, FL) was most indicative of determining species composition (R2=0.21, p=0.001). Fungal communities in samples of CA dust embedded in carpet incubated at elevated RH for 4 weeks were found to cluster into three distinct groups based on equilibrium relative humidity, Low (50%-70% RH), Medium (75%-85% RH) and High (95% RH). Aspergillus sydowii (p=0.03, p=0.0002), Penicillium chrysogenum (p=0.02, p=0.002), and Penicillium gladioli (p=0.009, p=0.0003) were more associated with the High RH conditions than Low or Medium conditions, respectively. Wallemia canadensis (p=0.006), Wallemia muriae (p=0.02), Wallemia sebi (p=0.02) and Wallemia tropicalis (p=0.002) were more associated with the Medium RH condition when compared to the Low RH condition. Further work will examine relationships between MVOCs and the different groupings of relative humidity.