Polycyclic aromatic hydrocarbons (PAHs) are recognized as very toxic group of organic compounds, with documented carcinogenic, mutagenic and teratogenic properties. PAHs are formed as a result of the incomplete combustion of organic materials. They are produced naturally like by wood fire, volcanoes and by human activities like coal and gasoline combustion. They are particularly prevalent in urban and industrial environments. This different sources, combined with their toxicity, has resulted in the implementation of regulation with very low limit levels for urban and workplace air.
PAHs cover a relatively wide volatility range, from naphthalene (b.p. 218°C) to benzo[ghi] perylene (b.p. 500°C). This means that they are present in gaseous phase and particulate phase in ambient air. Light compounds tends to be in gas phase which represent more than 96% of the total PAH amount. This light PAHs in gas phase are very sensitive to the amount OH radicals in the air which is mainly from ozone photolysis. This impact the lifetime of these gaseous PAHs which is short and can be down to some minutes for Acenaphthylene.
To control their emissions and effects on people’s health there is a need to monitor continuously the PAHs concentrations with a one hour period of time between measurements. Based on more than 30 years of experience in online gas chromatography, Chromatotec® has developed over the last 5 years turnkey solutions to monitor online and continuously PAHs and linear alkanes in ambient air using a Trap Thermal Desorption Gas Chromatograph equipped with Flame Ionization Detector and Mass Spectrometer (TD GC FID MS). This unique solution allows the automatic measurement of all gaseous phase PAHs up to Anthracene with a cycle time of 1 hour for a complete analysis using vistaMS software for GCMS data.
The system has a very high sensitivity down to 0.7 ppt for Naphthalene. It is robust and could be installed in analyzer shelter on site as well as in mobile van.