a) Volatile Organic Compounds (VOC)
Individual and total volatile organic compounds are adsorbed on activated charcoal, solvent desorbed and analysed by means of a GC coupled to a mass-spectrometer (GC/MS).
The samples in the micro-environments will be taken with high uptake rate diffusive samplers. The laboratory has experience with this type of sampler (e.g. FLEHS) and all parameters are well known. The typical sampling period can vary from eight hours up to 30 days. The sampler has been validated for 1 week use (e.g. MACBETH) and for 4 weeks weeks. After sampling, the dosimeters are collected in the laboratory for analysis. The samplers are extracted in the laboratory with carbon disulfide (CS2). Analysis is performed on a HP6890 GC hyphenated with a HP5973 MS (or equivalent). TVOC is measured in full scan-modus, while the other compounds are measured in selected ion monitoring (SIM) mode. External standards are used for calibration.
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b) Aldehydes
Aldehydes are sampled with diffusive dosimeters. These samplers (UMEx 100) have been used and validated in laboratory and field experiments. It is principally a chemisorption method where aldehydes react with dinitrophenolhydrazine (DNPH). The aldehydes are extracted with ethylacetate and analysed by GC-FID/MS or extracted with acetonitrile and analysed by LC-UV. Interference from other pollutants such as ozone and nitrogen dioxide is well known (ISO 2001). These effects and possible solutions have been thoroughly investigated in the CEC-FP4-SMT Aldehydes project.
c) Nitrogen Dioxide
Nitrogen dioxide is sampled with diffusive monitors developed by IVL. After the extraction with ultra pure water, the samples are analysed with an ion-chromatograph. A validation survey has been conducted at VITO by order of the Flemish Environment Agency (VMM).
d) Particulate Matter
Particulate matter will be measured with portable dust monitors manufactured by GRIMM or an equivalent monitor. It is a continuous measurement technique based on spectrometry. It is able to run during the same period as the other dosimeters. PM10, PM2.5 and PM1 can be measured simultaneously by means of the GRIMM monitor.