Anna-Sara Claeson

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.

Overlap in prevalence between various types of environmental intolerance.

Environmental intolerance (EI) is characterized by attribution of several, multisystem symptoms to specific environmental exposures, such as exposure to odorous/pungent chemicals, certain buildings, electromagnetic fields (EMFs) and everyday sounds. The symptoms are medically unexplained, non-specific and the symptoms overlap between different types of EI. To approach the issue of underlying mechanisms the matter of overlap in prevalence between intolerances can provide valuable information. The aim of the study was to examine if the overlap between intolerance to odorous/pungent chemicals, certain buildings, EMFs and sounds is larger than the expected overlap if no association would exist between them. The study was using cross-sectional data from the Västerbotten Environmental Health Study in Sweden; a large questionnaire-based survey. 8520 adults (18-79 years) were randomly selected after stratification for age and sex, of whom 3406 (40%) participated. Individuals with the four types of intolerance were identified either through self-report, or by having been physician-diagnosed with a specific EI. The overlaps between the four EIs were greater than predictions based on coincidence for both self-reported and diagnosed cases (except for the overlap between diagnosed intolerance to sounds and EMFs). The results raise the question whether different types of EI share similar underlying mechanisms, or at least that the sufferers of EI share some predisposition to acquire the conditions.

Effects on perceived air quality and symptoms of exposure to microbially produced metabolites and compounds emitted from damp building materials

UNLABELLED This work investigated perceived air quality and health effects from exposure to low to high levels of volatile organic compounds (VOCs) emitted from damp building materials and a mixture of molds growing on the materials. A mixture of Wallemia sebi, Fusarium culmorum, Penicillium chrysogenum, Ulocladium botrytis, and Aspergillus versicolor was inoculated on pine wood and particle board. In Study 1, each of 27 participants took part in two exposure conditions, one with air from molds growing on building materials (low levels of emissions from the building materials and the mold mixture) and one with blank air, both conditions during 60 min. In Study 2, each of 24 participants was exposed (10 min) four times in a 2 x 2 design randomly to air from moldy building materials (high levels) and blank, with and without nose-clip. The participants rated air quality and symptoms before, during, and after each exposure. Self-reported tear-film break-up time and attention and processing speed (Study 1) was also measured. Exposure to high VOC levels increased the reports of perceived poor air quality, and in the condition without nose-clip enhanced skin symptoms were also noted. No such outcome was observed when exposing the participants to low VOC levels. PRACTICAL IMPLICATIONS Emissions from building materials caused by dampness and microbial growth may be involved in indoor air health problems. This study showed that exposure to high levels of VOC emitted from damp building materials and a mixture of mold may cause perceived poor air quality. It also indicated that stimulation of chemical warning systems (the nasal chemosensory part of the trigeminal system and the olfactory system) may enhance skin symptoms.

Volatile organic compounds (VOCs) emitted from materials collected from buildings affected by microorganisms.

In this study mould damaged materials, including carpet, concrete, gypsum board, insulation, plastic, sand and wood, from 20 different buildings with moisture problems were collected. To study emissions from these materials both conventional methods for sampling, such as collection on Tenax TA, were used as well as complementary methods for sampling a wider spectrum of compounds, such as more volatile VOCs, amines and aldehydes. Analysis was carried out using gas chromatography and high-performance liquid chromatography. Mass spectrometry was used for identification of compounds. Alcohols and ketones were almost exclusively emitted from the materials after they had been wet for a week. Acids were also emitted in large quantities from wet gypsum board and plastic. No primary or secondary amines could be identified, but two tertiary amines, trimethylamine and triethylamine, were emitted from sand contaminated by Bacillus. The most common moulds found were Penicillium and Aspergillus. A multivariate method (partial least squares, PLS) was used to investigate the emission patterns from the materials. Materials with bacterial growth had a different VOC profile to those with only mould growth.

The influence of health-risk perception and distress on reactions to low-level chemical exposure

The general aim of the current study was to investigate how perceived health risk of a chemical exposure and self-reported distress are related to perceived odor intensity and odor valence, symptoms, cognitive performance over time as well as reactions to blank exposure. Based on ratings of general distress, 20 participants constituted a relatively low distress group, and 20 other participants a relatively high distress group. Health risk perception was manipulated by providing positively and negatively biased information regarding n-butanol. Participants made repeated ratings of intensity, valence and symptoms and performed cognitive tasks while exposed to 4.7 ppm n-butanol for 60 min (first 10 min were blank exposure) inside an exposure chamber. Ratings by the positive and negative bias groups suggest that the manipulation influenced perceived health risk of the exposure. The high distress group did not habituate to the exposure in terms of intensity when receiving negative information, but did so when receiving positive information. The high distress group, compared with the low distress group, rated the exposure as significantly more unpleasant, reported greater symptoms and performed worse on a cognitively demanding task over time. The positive bias group and high distress group rated blank exposure as more intense. The main findings suggest that relatively distressed individuals are negatively affected by exposures to a greater degree than non-distressed.

Stress and odor sensitivity in persons with noise sensitivity

Previous research has indicated that sensory sensitivity/intolerance to a specific modality may be part of a more general environmental hypersensitivity, and possibly mediated by stress. This study investigated the relationship between noise sensitivity, perceived stress, and odor sensitivity in a group of men. A quasi-experimental design was used. One-hundred and thirty-four male undergraduate students completed Weinsteins noise sensitivity scale from which a low-sensitivity group (n = 16) and a high-sensitivity (n = 16) group were formed. These two groups were screened for loss in auditory and olfactory detection sensitivity, and completed the perceived stress questionnaire (PSQ) and the chemical sensitivity scale (CSS). One-way analysis of variance and Spearman correlational analyses were performed. Significantly higher scores on the PSQ (P < 0.05) and the CSS (P < 0.05) were found in the high noise-sensitivity group compared to the low noise-sensitivity group. These findings raise the question of whether the relation between noise and odor sensitivity reflects a general environmental sensitivity.

Brain responses to olfactory and trigeminal exposure in idiopathic environmental illness (IEI) attributed to smells — An fMRI study

OBJECTIVE Idiopathic environmental intolerance (IEI) to smells is a prevalent medically unexplained illness. Sufferers attribute severe symptoms to low doses of non-toxic chemicals. Despite the label, IEI is not characterized by acute chemical senses. Theoretical models suggest that sensitized responses in the limbic system of the brain constitute an important mechanism behind the symptoms. The aim was to investigate whether and how brain reactions to low-levels of olfactory and trigeminal stimuli differ in individuals with and without IEI. METHODS Brain responses to intranasally delivered isoamyl acetate and carbon dioxide were assessed in 25 women with IEI and 26 non-ill controls using functional magnetic resonance imaging. RESULTS The IEI group had higher blood-oxygenated-level-dependent (BOLD) signal than controls in the thalamus and a number of, mainly, parietal areas, and lower BOLD signal in the superior frontal gyrus. The IEI group did not rate the exposures as more intense than the control group did, and there were no BOLD signal differences between groups in the piriform cortex or olfactory regions of the orbitofrontal cortex. CONCLUSIONS The IEI reactions were not characterized by hyper-responsiveness in sensory areas. The results can be interpreted as a limbic hyperreactivity and speculatively as an inability to inhibit salient external stimuli.

Inflammatory Mediator Profiling of n-butanol Exposed Upper Airways in Individuals with Multiple Chemical Sensitivity

Background Multiple Chemical Sensitivity (MCS) is a chronic condition characterized by reports of recurrent symptoms in response to low level exposure to various chemical substances. Recent findings suggests that dysregulation of the immune system may play a role in MCS pathophysiology. Objectives The aim of this study was to examine baseline and low dose n-butanol-induced upper airway inflammatory response profiles in MCS subjects versus healthy controls. Method Eighteen participants with MCS and 18 age- and sex-matched healthy controls were enrolled in the study. Epithelial lining fluid was collected from the nasal cavity at three time points: baseline, within 15 minutes after being exposed to 3.7 ppm n-butanol in an exposure chamber and four hours after exposure termination. A total of 19 cytokines and chemokines were quantified. Furthermore, at baseline and during the exposure session, participants rated the perceived intensity, valence and levels of symptoms and autonomic recordings were obtained. Results The physiological and psychophysical measurements during the n-butanol exposure session verified a specific response in MCS individuals only. However, MCS subjects and healthy controls displayed similar upper airway inflammatory mediator profiles (P>0.05) at baseline. Likewise, direct comparison of mediator levels in the MCS group and controls after n-butanol exposure revealed no significant group differences. Conclusion We demonstrate no abnormal upper airway inflammatory mediator levels in MCS subjects before or after a symptom-eliciting exposure to low dose n-butanol, implying that upper airways of MCS subjects are functionally intact at the level of cytokine and chemokine production and secretory capacity. This suggests that previous findings of increased cytokine plasma levels in MCS are unlikely to be caused by systemic priming via excessive upper airway inflammatory processes.

Metric properties and normative data for brief noise and electromagnetic field sensitivity scales

Aims: Lack of brief questionnaire instruments for quantifying affective reactions to and behavioral disruptions attributed to sounds and electromagnetic fields (EMFs) motivated the present development and metric evaluation of such instruments, called the 11-item Noise Sensitivity Scale (NSS-11) and the 11-item Electromagnetic Field Sensitivity Scale (EMFSS-11). Another objective was to establish normative data for these instruments. Method: Data from 3406 individuals who took part in the Västerbotten Environmental Health Study was used. The participants constitute a random sample of inhabitants in the county of Västerbotten in Sweden, aged 18 to 79 years, stratified for age and gender. The participants responded to the NSS-11 and EMFSS-11 and to additional questions for evaluation of concurrent validity. Results: The results show satisfying reliability (Cronbach α = 0.71–0.85, varying with age group and gender), concurrent validity, and unidimensionality of the NSS-11 and EMFSS-11, and that the scales generate scores with approximately normal distributions, irrespective of age group and gender. Mean scores, standard deviations, and confidence intervals constitute normative data. Conclusions: The favorable metric properties of the NSS-11 and EMFSS-11 in combination with their fast usage suggest that they are particularly useful for assessment in epidemiological studies, and have the advantage of available normative data.

Symptom-trigger factors other than allergens in asthma and allergy

Abstract Several environmental exposures of particular relevance for indoor air quality, such as exposure to odorants, may be associated with asthma and allergy. The aim of this study was to investigate attribution of symptoms and behavioral disruptions to various chemical and physical environmental sources in persons with self-reported asthma and allergy. Data from a population-based study, the Västerbotten Environmental Health Study, were used to compare persons with asthma, allergic rhinitis, allergic dermatitis, multiple diagnoses of asthma/allergy and no asthma or allergy. Persons with asthma and multiple diagnoses reported odorous/pungent and building-related environmental factors to trigger symptoms to a larger extent than did the reference group, mainly due to perfume and odors from flowers. They also reported behavioral disruptions and affective reactions to odorous/pungent environments. These findings increase the understanding of the role of odorants in symptom development and thereby the prevention of health problems in asthma and allergy in indoor air.