High-Resolution Exposure Assessment for Volatile Organic Compounds in Two California Residences

Abstract

Time spent in residences substantially contributes to human exposure to volatile organic compounds (VOCs). Such exposures have been difficult to study deeply, in part because VOC concentrations and indoor occupancy vary rapidly. Using a fast-response online mass spectrometer, we report time-resolved exposures from multi-season sampling of more than 200 VOCs in two California residences. Chemical-specific source apportionment revealed that time-averaged exposures for most VOCs were mainly attributable to continuous indoor emissions from buildings and their static contents. Also contributing to exposures were occupant-related activities, such as cooking, and outdoor-to-indoor transport. Health risk assessments are possible for a subset of observed VOCs. Acrolein, acetaldehyde, and acrylic acid concentrations were above chronic advisory health guidelines, whereas exposures for other assessable species were typically well below the guideline levels. Studied residences were built in the mid-20th century, indicating that VOC emissions even from older buildings and their contents can substantially contribute to occupant exposures.

Determination of acrolein in ambient air and in the atmosphere of environmental test chambers

“…Recently, indoor exposure to a large range of volatile organic compounds (VOCs) was investigated with high time resolution both during summer and winter in two Californian residences. 50 Due to continuous indoor sources (e.g. lumber), the main daily occupant exposure was ~4.6 ppb-h d -1 (mean value).…”

“…The results confirmed the fact that heated cooking oil is a major acrolein source indoors. 50 In Canadian homes, measured acrolein concentrations were between 0.1 µg m -³ and 4.9 µg m -³. 52 During the "House Observations of Microbial and Environmental Chemistry (HOMEChem)" study, 53 the emissions of scripted everyday activities were measured in a test house in Texas.…”

“…The classic DNPH method according to ISO 16000-3 55 and ASTM D5197 56 is applied in different testing protocols, but has been criticized to be unsuitable. [57][58][59] Alternative techniques have therefore been developed including derivatization with dansylhydrazine (DNSH), [60][61][62] sampling on solid sorbents, 63 thermal desorption gas chromatography, 64 online monitoring using proton-transferreaction-mass-spectrometry (PTR-MS), 50,65,66 solid phase microextraction 67 and derivatization with o-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA). 68…”

“…65 For acrolein, the nominal target M+1 ion is m/z 57, the proton affinity of acrolein is 797.0 kJ mol -1 80 and the calculated proton transfer reaction rate constant between H 3 O + and acrolein is 3.35•10 -9 cm³ s -1 . 65,66,81 Lunderberg et al 50 used a proton-transfer-reaction time-of-flight mass spectrometer (PTR-TOF-MS) to investigate occupant exposure patterns indoors in two California residences.…”

“…They reported a reaction constant of k = 4.2•10 -9 cm³ s -1 , which is applicable for their particular instrument. However, a PTR-TOF-MS, as used by Lunderberg et al 50 is much better suited to correct for interferences and, thus, for detecting acrolein in real indoor environments.…”