Mass closure on the chemical species in size-segregated atmospheric aerosol collected in an urban area of the Po Valley, Italy

[摘要] A complete size segregated chemical characterisation was carried out for aerosol samplescollected in the urban area of Bologna over a period of one year, using five-stage low pressureBerner impactors. An original dual-substrate technique was adopted to obtain samplessuitable for a complete chemical characterisation. Total mass, inorganic, and organiccomponents were analysed as a function of size, and a detailed characterisation of the watersoluble organic compounds was also performed by means of a previously developedmethodology, based on HPLC separation of organic compounds according to their acidcharacter and functional group analysis by Proton Nuclear Magnetic Resonance. Chemicalmass closure of the collected samples was reached to within a few percent on average in thesubmicron aerosol range, while a higher unknown fraction in the coarse aerosol range wasattributed to soil-derived species not analysed in this experiment. Comparison of thefunctional group analysis results with model results simulating water soluble organiccompound production by gas-to-particle conversion of anthropogenic VOCs showed that thispathway provides a minor contribution to the organic composition of the aerosol samples inthe urban area of Bologna.

[学科分类] 大气科学