Development of Novel Methods of Analysis for Indoor Air Pollutants

The current variability and speciation of indoor VOCs are studied by analysing indoor air in UK homes and offices. These measurements were carried out via passive sampling into silica-treated canisters followed by thermal desorption-gas chromatography and high mass accuracy time-of-flight mass spectrometry (TD-GC-Q-TOF/MS). It was found that majority of the homes had d-limonene and α-pinene as the most abundant VOCs, with average concentrations ranging from 18 μg m-3 to over 1400 μg m-3 and 2 μg m-3 to 230 μg m-3 respectively. In these analyses, cyclic volatile methyl siloxanes (cVMS) were frequently detected in high abundances. cVMS are chemicals in high volume production as they are used as solvents in formulations of consumer products. They were found in persistently high background concentrations in our analyses. Hence, a passive sampling method involving sorbents was developed to allow the analysis and quantification of these compounds, with LODs calculated to be 7.2 to 16.8 ng m-3. This method was validated with real indoor air sampling with average D5 and D6 concentrations of about 2480 ng m-3 and 664 ng m-3 respectively. Advancements have also been made in the development of a multispecies sensor for the detection of VOCs. A temperature control method was developed using a Peltier device and a control software programme written in LABVIEW. Attempts were made to manufacture a lab-on-a-chip GC column, but was deemed unsuitable due to leakage and mechanical problems. Instead, a short length of column was wound and placed in a copper enclosure. Tests were conducted using photoionsation detector (PID) as the detection method in this sensor development. The final set-up involved the assembly of the temperature control method, the GC column enclosure and the PID for the detection. Tests were conducted by introducing headspace standards into the set-up, with promising results.