Indoor air quality : aromatic and aliphatic hydrocarbons and their health effects at low level exposure

Concentrations of volatile organic compounds (VOCs) were measured in eleven office buildings, previously characterised as sick buildings, in the city of Hobart, Tasmania. The principal aim of the study was to ascertain the types and concentrations of hydrocarbons found in non-industrial work environments, as well as determining the health effects caused by exposure to these low level compounds. Two hundred and sixty five offices workers (136 males and 129 females) in selected public and private sector buildings were surveyed. The systematic building investigation consisted of measuring aromatic and aliphatic hydrocarbons, temperature, relative humidity and other building variables. In addition a self administered questionnaire assessed symptoms experienced while in the work environment, psychosocial factors and past disease history. Hydrocarbon samples were collected on activated charcoal diffusion tubes and analysed using gas chromatography /mass spectrometry. Statistical methods, both parametric and non-parametric, highlighted correlations between variables and their levels of significance. These included the Chi-square test, correlation coefficients, and analysis of variance test. Results indicated that individual hydrocarbon levels typically found in sampled buildings ranged from 0-1.758 mg/m\\(^3\\) (1 week average). Weekly TVOC levels fluctuated and ranged from 0.012-1.934 mg/m\\(^3\\). Types of VOCs identified included several alkanes, aromatics, halogenated hydrocarbons, alcohols and ketones. Levels of VOCs varied seasonally. Higher concentrations were detectable in the winter months compared to summer. These values were affected by temperature, but not by humidity. Qualitative findings showed that symptoms typical of sick building syndrome were reported in 88.5% of respondents. Characteristic, and most frequently experienced symptoms included irritation of the eyes, nose and throat, cognitive effects, general manifestations, and cardiovascular effects. Psychosocial factors and other variables such as temperature and humidity had no significant effects on symptoms, but asthma and allergies did appear to influence symptom levels. Individual species of VOCs influenced the types of symptoms reported, and VOC mixtures (TVOCs), were correlated with elevated retrospectively reported symptom levels (r=.1789, <.05). Sixty three percent of buildings were in the TVOC
o effects\" range while 36.4% were above 0.20 mg/m\\(^3\\). Both SBS symptoms and sensory irritation were observed at levels below 0.20 mg/m\\(^3\\). Buildings were categorised as sick or healthy buildings on the basis of the VOCs in the air. It appears that specific organic compounds especially those of the aromatic/ aliphatic class and the quantity detected are critical in determining a building's potential to cause adverse health effects. The TVOC concept was examined as a generic indicator to sensory irritation and sick building syndrome as well as a review of current standards and guidelines in relation to low dose exposures to VOCs."