PAHs and levoglucosan in particulate matter sources apportionment through GC-C-IRMS and GC-MS

Air pollution is a leading cause of human health problems. Among various dangerous substances that may be found in atmosphere, Particulate Matter (PM) is one of the main concerns , since small size particles (<10 μm Ø) can easily enter the lungs and convey pollutants like heavy metals, dioxins, nitrogen oxides, etc.

EU directive 2008/50/CE of May 21^st  2008 defines objectives for environmental air quality designed to avoid, prevent or reduce harmful effects on human health and the environment as a whole. The directive fines EU countries in which PM atmospheric concentration (in particular PM 10 and PM 2.5) and pollutants concentrations transported by the PM overcome certain limits, but those fines are applied only if the PM has anthropogenic origins ; therefore, it is essential to be able to perform PM sources apportionment.

 

For this purpose, in collaboration with the region Campania environmental agency (ARPAC), we are developing analytical methods for:

• Extraction and purification of some Polycyclic Aromatic Hydrocarbons ( PAHs ) from quartz filters (which are the physical supports where PM is collected during sampling). These molecules derive from incomplete combustion of organic matter (included fuels) and are present in PM emission of both anthropogenic and non anthropogenic sources.
• Extraction, purification, and derivatization of levoglucosan from quartz filters. Levoglucosan is a molecule deriving from the combustion of biomasses containing cellulose and hemicellulose and it is present in PM emission of both anthropogenic and non anthropogenic sources , like chimneys emissions and forest fires.
• The determination of isotopic ratio of carbon stable isotopes (δ ¹³C ) using isotopic ratio mass spectrometry coupled with gas chromatography GC-C-IRMS of PAHs and levoglucosan, which carbon isotopic fingerprint is dependent on the origin of these molecules.
• Target molecules identification by GC-MS.
• Quantitative analysis of PAHs on PM using GC MS method (US EPA 8270 E).
• Quantitative analysis of levoglucosan using Ionic Chromatography coupled with a Pulsed Amperometric Detector (IC-PAD).

ARPAC is collecting samples of PM 10 and PM 2.5 in different sites, both urban and rural, usinig both low volume (2.3 m³/h for 24h on 47mm Ø quartz filters) and high volume (100 L/min for 24h on 102mm Ø quartz filters) sampling methods. ARPAC will also provide PM samples collected at the main PM sources to get more accurate data about PAHs and levoglucosan isotopic fingerprint in their atmospheric emissions.

The attribution of these substances to anthropogenic sources and their quantification can provide essential information about the origins of the collected PM and, in case of PM limits exceeding, when it is possible, regional authorities of Campania could use the information collected to take steps to lower PM level.