A method of quantifying dilute volatile organic compounds in air

Air quality is a major concern for the residents of Gladstone and the cumulative impact of air pollution from industry on the health and well-being of the community has been the subject of a number of studies. It is known that air quality and unpleasant industrially-related odours can affect the perceptions of industries by the local population and lead to alienation between the two groups. There is also growing evidence that low chemical levels that are not normally measured by conventional monitoring methods are harmful to human health (McDermott et al, 2007). The technology currently used for the detection and quantification of odorous chemicals from alumina refineries has not been sufficient to provide reliable quantitative data at low levels. The odorous compounds are mostly VOCs (volatile organic compounds) produced during the processing of bauxite and some of these have been associated with cancer and asthma. However, most of the VOCs in air are present at very dilute concentrations. The focus of this study has been on the development of a method to pre-concentrate VOCs prior to injection into a gas chromatograph/mass spectrometer (GCMS). This project uses a system based on thermal desorption tubes to pre-concentrate the gases and improve detection levels to parts per billion by volume. The efficiency of recovery of the VOCs was studied and was found to be reasonably high at these levels.