Exposure to formaldehyde, nitrogen dioxide, ozone, and terpenes among office workers and associations with reported symptoms.

PURPOSE: To compare exposure to formaldehyde, nitrogen dioxide, ozone and terpenes among office workers with and without sick building syndrome and the odds ratio for exposure. Are there significant differences? METHODS: In this cross-sectional study of office workers, we investigated the associations between exposure to formaldehyde, nitrogen dioxide, ozone, α-pinene, and D-limonene using a case-control analysis. Data on perceived general, mucosal, and skin symptoms were obtained by questionnaires. Personal exposure measurements of the compounds were performed among cases and controls, and the odds ratios for exposures to the substances, both singly and in combination, were investigated. RESULTS: Exposures varied for formaldehyde between 0.23 and 45 µg/m(3), nitrogen dioxide between 0.26 and 110 µg/m(3), ozone between <16 and 165 µg/m(3), α-pinene between 0.2 and 170 µg/m(3), and D-limonene between 0.8 and 1,400 µg/m(3). No consistent differences in exposure odds ratios were found between cases and controls or for individual symptoms.

A novel approach to evaluation of adsorbents for sampling indoor volatile organic compounds associated with symptom reports.

This article addresses problems that complicate attempts to compare methods when several factors may be associated with an effect, but it is not known which factors are relevant. Chemicals that may contribute to 'sick building syndrome' (SBS), and thus should be sampled in investigations of SBS, are not currently known. A study was undertaken to compare the utility of three adsorbents (Carbopack B, Chromosorb 106 and Tenax TA) for detecting differences in personal chemical exposure to volatile organic compounds in indoor air, between persons with and without SBS symptoms (cases and controls). On the basis of office workers' responses to a questionnaire, 15 cases and 15 controls were chosen. They simultaneously carried diffusive samplers with adsorbents during a week at work, and the acquired samples were analysed by gas chromatography/mass spectrometry (GC/MS). The adsorbents were then compared in terms of their ability to separate cases and controls in partial least square discriminant analysis (PLS-DA) models. This method of comparison takes into account detected differences in chemical exposure between cases and controls measured with the different adsorbents. Tenax TA gave the best PLS-DA models for separating cases and controls, but a combination of measurements with Tenax TA and Carbopack B gave better PLS-DA models than models based on measurements from either adsorbent alone. Adding measurements from Chromosorb 106 did not improve the results.

Can NO(2) be used to indicate ambient and personal levels of benzene and 1,3-butadiene in air?

The aim of this study was to investigate the relation between two toxic volatile organic compounds, 1,3-butadiene and benzene, and a commonly used indicator of vehicle exhaust fumes, NO(2). This was to see if NO(2) can be used to indicate personal exposure to carcinogenic substances or at least estimate ambient levels measured at a stationary point. During the winter of 2001, 40 randomly selected persons living in the City of Umea (in the north of Sweden) were recruited to the study. Personal measurements of 1,3-butadiene, benzene and NO(2) were performed for one week, and were repeated for 20 of the 40 participants. Additional information was gathered using a diary kept by each participant. During the same time period weekly stationary measurements were performed at one urban background station and one street station in the city centre. The results from the personal measurements showed a negligible association of NO(2) with 1,3-butadiene (r= 0.06) as well as with benzene (r= 0.10), while the correlation coefficient between 1,3-butadiene and benzene was high and significant (r= 0.67). In contrast to the personal measurements, the stationary measurements showed strong relations between 1,3-butadiene, benzene and NO(2) both within and in-between the street and urban background station. This study supports NO(2) as a potential indicator for 1,3-butadiene and benzene levels in streets or urban background air, while the weak relations found for the personal measurements do not support the use of NO(2) as an indicator for personal 1,3-butadiene and benzene exposure.

Variability of personal chemical exposure in eight office buildings in Sweden.

This study focuses on the variability in chemical exposures for individuals working in office buildings. The study involved eight office buildings with 79 participants, and exposures were measured using personal samplers for volatile organic compounds, aldehydes, amines, nitrogen dioxide, ozone, and particles. Ventilation was assessed in each individual office. "Variability among buildings" and "variability among individuals" were evaluated for any component (of the 123) measured in samples from at least 20 persons, using variance component analysis and principal component analysis. Interpersonal differences explained the major part of the variance for 78% of the compounds versus between-buildings differences for 14% of the compounds. For 8% of compounds, the variation was explained in equal amounts by the differences among individuals and among buildings. This study illustrates the necessity for individualised measurements (versus stationary measurements in building) to estimate personal exposures. These results also support the conclusion that in case-referent studies of "sick building syndrome" (SBS), referents to SBS cases can be randomised for building location.

Development of a LC-MS/MS method for the analysis of volatile primary and secondary amines as NIT (naphthylisothiocyanate) derivatives.

High-performance liquid chromatography with mass spectrometric detection was used for the structure elucidation of eighteen primary and secondary amines and ammonia derivatised with naphthylisothiocyanate (NIT). A fragmentation scheme was established using reference compounds and the scheme was applied to real air samples from a tyre repair shop and from the air above a bacterial culture. The sampling was performed using a solid sorbent, XAD-2, impregnated with NIT, and the derivatives were extracted with acetonitrile and analysed with LC-MS/MS. A three-step process was developed for screening and identifying of volatile amines. The first step, selected reaction monitoring; SRM was applied in order to screen the samples for NIT derivatives. In the second step, a precursor ion scan gave the [M+H](+) ion, and in the third step a product ion scan gave the fragments needed for identification. The detection limits varied between 0.12 and 0.25 ng microL(-1) when screening for unknown derivatised amines. It was possible to separate and identify all the amines with the structural information obtained and the method proved to be general, sensitive and well suited for sampling and analysis of complex environmental samples.

A gas-phase biosensor for environmental monitoring of formic acid: laboratory and field validation.

In order to encourage more exposure measurements to be performed, a formic acid gas-phase biosensor has been developed for this purpose. In the present paper, an enzyme based biosensor has been validated with respect to analyte selectivity and on-site use. To ensure that the sampler developed measures the compound of interest the biosensor was exposed to three near structural homologues to formic acid, i.e. acetic acid, methanol and formaldehyde. These vapours were generated with and without formic acid and the only compound that was found to have an effect on the performance of the biosensor, albeit a small one, was acetic acid. The field test was performed in a factory using formic acid-containing glue for glulam products. In parallel to the measurements with the biosensor a well defined reference method was used for sampling and analysing formic acid. It was found that the biosensor worked satisfactorily in this environment when used in a stationary position. It was also shown that the biosensor could determine formic acid vapour concentrations down to 0.03 mg m(-3).

Volatile metabolites from microorganisms grown on humid building materials and synthetic media.

Growth of different microorganisms is often related to dampness in buildings. Both fungi and bacteria produce complicated mixtures of volatile organic compounds that include hydrocarbons, alcohols, ketones, sulfur- and nitrogen-containing compounds etc. Microbially produced substances are one possible explanation of odour problems and negative health effects in buildings affected by microbial growth. A mixture of five fungi, Aspergillus versicolor, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis and Wallemia sebi were grown on three different humid building materials (pinewood, particle board and gypsum board) and on one synthetic medium. Six different sampling methods were used, to be able to collect both non-reactive volatile organic compounds and reactive compounds such as volatile amines, aldehydes and carboxylic acids. Analysis was performed using gas chromatography, high-performance liquid chromatography and ion chromatography, mass spectrometry was used for identification of compounds. The main microbially produced metabolites found on pinewood were ketones (e.g. 2-heptanone) and alcohols (e.g. 2-methyl-1-propanol). Some of these compounds were also found on particle board, gypsum board and the synthetic medium, but there were more differences than similarities between the materials. For example, dimethoxymethane and 1,3,5-trioxepane and some nitrogen containing compounds were found only on particle board. The metabolite production on gypsum board was very low, although some terpenes (e.g. 3-carene) could be identified as fungal metabolites. On all materials, except gypsum board, the emission of aldehydes decreased during microbial growth. No low molecular weight carboxylic acids were identified.

Passive sampling in combination with thermal desorption and gas chromatography as a tool for self-assessment of chemical exposure.

Diffusive samplers for monitoring of air quality are user-friendly devices that can normally be operated by the user himself. Hence these samplers are suitable for self-assessment. Practical and work organisational aspects of self-assessment of chemical exposure were studied in different occupational settings. It was found that the diffusive sampler used in these studies, the Perkin-Elmer tube in combination with thermal desorption, worked well for the purpose and could be correctly handled by the individuals using it. The results from self-assessments agreed well with expert measurements carried out by an occupational hygienist. However, in order to obtain a sustainable system of self-assessment strong organizational support is needed.