Non-microbial sources of microbial volatile organic compounds

Area of Science:

• Environmental Health
• Indoor Air Quality
• Chemical Exposure

Background:

• The origins of microbial volatile organic compounds (MVOCs) in indoor environments are not fully understood.
• Identifying the sources of these compounds is crucial for assessing indoor air quality and potential health risks.

Purpose of the Study:

• To determine the microbial and non-microbial sources of 28 compounds commonly identified as MVOCs.
• To investigate the relationship between specific indoor pollutants and the overall concentration of these 28 VOCs.

Main Methods:

• A cross-sectional study involving 390 homes, assessing water/mold damage, environmental conditions (humidity, temperature, ventilation), and collecting air and dust samples.
• Air samples were analyzed for volatile organic compounds (VOCs). Dust samples were analyzed for fungal concentration and phthalates.
• Four benchmark source variables were defined: total concentration of 17 propylene glycol ethers (Σ17 PGEs), 2,2,4-trimethyl-1,3-pentanediol monoisobutyrate (TMPD-MIB), mold index, and total fungal load.

Main Results:

• Higher concentrations of Σ17 PGEs and TMPD-MIB in air samples were significantly associated with increased levels of Σ 28 VOCs in damp homes.
• Elevated total fungal load and absolute humidity were also linked to significantly increased median Σ 28 VOCs.
• The combined concentration of Σ17 PGEs and TMPD-MIB was a significant predictor of high Σ 28 VOCs, even after adjusting for other factors. Absolute humidity and mold index showed a positive interaction effect.

Conclusions:

• Indoor concentrations of Σ 28 VOCs are significantly associated with markers of synthetic chemicals (Σ17 PGEs, TMPD-MIB) and, to a lesser extent, microbial sources (mold index).
• These findings suggest that synthetic chemicals commonly used in building materials and consumer products may be significant contributors to compounds previously attributed solely to microbial activity.