Volatile organic compound emissions during HOMEChem

Area of Science:

• Environmental Chemistry
• Indoor Air Quality
• Atmospheric Science

Background:

• Accurate quantification of speciated volatile organic compounds (VOCs) and their emissions is crucial for understanding indoor air dynamics, atmospheric chemistry, and human exposure.
• Indoor environments are complex systems influenced by emissions from building materials, furnishings, human activities, cooking, and cleaning products.

Purpose of the Study:

• To quantify speciated VOC source strengths from various indoor activities and baseline conditions within a residential setting.
• To determine the relative contributions of different emission sources (building materials, cooking, cleaning, occupancy) to overall indoor VOC concentrations.
• To simulate 24-hour VOC emissions to assess the long-term impact of various sources.

Main Methods:

• Utilized a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) for precise VOC measurements.
• Combined VOC measurements with tracer-based air-change rate determinations.
• Employed mass-balance calculations to derive speciated, time-resolved VOC source strengths from scripted experiments and unperturbed baseline measurements.

Main Results:

• The building materials and contents were identified as the dominant source of indoor VOCs, notably acetic acid, methanol, and formic acid.
• Cooking emissions (primarily ethanol) exceeded those from cleaning activities.
• Bleach cleaning released chlorinated compounds, while natural product cleaning emitted terpenoids. Occupancy led to significant morning siloxane emissions from personal care products.

Conclusions:

• Emissions from the house itself and its contents constitute nearly half of the total indoor VOC emissions over a 24-hour period.
• Understanding source-specific VOC emissions is essential for developing effective strategies to manage and improve indoor air quality.