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Indoor VOC (volatile organic compound) exposure has been shown to be correlated with airway symptoms and allergic manifestations in children. An investigation was conducted within an ongoing birth cohort study (LISA: Lifestyle-Immune System-Allergy) of the association between maternal exposure to VOCs and immune status at birth, in particular the cytokine secretion profile of cord-blood T cells. In a randomly selected group of 85 neonates, cytokine-producing cord-blood T cells were analyzed using intracellular cytokine detection. VOC exposure was measured in children's dwellings by passive sampling, while parents were asked to complete questionnaires about possible sources of VOC exposure. Adjusted odds ratios (ORs) were calculated by logistic regression based on categorized quartiles. A positive association was found between elevated percentages of interleukin-4-producing (IL-4) type 2 T cells and exposure to naphthalene (OR = 2.9) and methylcyclopentane (OR = 3.3). Exposure to tetrachloroethylene was associated with reduced percentages of interferon-gamma-producing (IFN-gamma) type 1 T cells (OR = 2.9). In addition, smoking during pregnancy was correlated with a higher indoor air concentration of naphthalene (OR = 3.8), new carpets in infants' bedrooms with elevated methylcyclopentane concentrations (OR = 4.1), and home renovation with a higher trichloroethylene burden (OR = 4.9). Our data suggest that maternal exposure to VOC may have an influence on the immune status of the newborn child.

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To assess the adverse health effects of volatile organic compounds (VOCs), epidemiological studies combine the health outcome of individuals with their concomitant VOC exposure. While the latter is representative of the studied period, health effects might also be the result of long-term exposure or emerge in consequence of a peak pollution throughout the year. To address these problems, additional information about the spatiotemporal distribution of VOCs is necessary. The present paper aims at elucidating the spatial and temporal variation of VOC concentrations in Leipzig, Germany. The analysis is based on 1499 indoor and 222 outdoor measurements taken in the period between 1994 and 2001. All data were collected in the frame of epidemiological studies (Diez et al., 1999; Fritz et al., 1998; Schulz et al., 1999). The analysis comprised concentrations of 30 VOCs belonging to the groups of alkanes, cycloalkanes, aromatics, volatile halogenated hydrocarbons, and terpenes. We found that the VOC load in indoor air is, on average, 10 times higher than outdoors. For the studied period there was a clear downward tendency for all VOCs in apartments in Leipzig, except for terpenes which show an upward trend in the period 1996-99. In indoor air we observe an annual cycle for the total VOC concentration as well as the sum concentrations of the above called groups. Highest concentrations occur during the winter months, approximately three times higher than the summer burden. We summarize this finding in a seasonal model, which is fitted to our measurements. Based on the model we develop a procedure for seasonal adjustment, which enables to roughly estimate the annual peak concentration utilizing one monthly observation.