Prospects of real-time single-particle biological aerosol analysis:A comparison between laser-induced breakdown spectroscopy and aerosol time-of-flight mass spectrometry

摘要

In this paper we discuss the prospects of real-time,in situ laser-induced breakdown spectroscopy applied for the identification and classification of bio-aerosols (including species of potential bio-hazard) within common urban aerosol mixtures.In particular,we address the issues associated with the picking out of bio-aerosols against common background aerosol particles,comparing laser-induced breakdown spectroscopy measurements with data from a mobile single-particle aerosol mass spectrometer (ATOFMS).The data from the latter provide statistical data over an extended period of time,highlighting the variation of the background composition.While single-particle bio-aerosols are detectable in principle,potential problems with small (approx1mum size) bio-aerosols have been identified;constituents of the air mass other than background aerosols,e.g.gaseous CO_2 in conjunction with common background aerosols,may prevent unique recognition of the bio-particles.We discuss whether it is likely that laser-induced breakdown spectroscopy on its own can provide reliable,real-time identification of bio-aerosol in an urban environment,and it is suggested that more than one technique should be or would have to be used.A case for using a combination of laser-induced breakdown spectroscopy and Raman (and/or) laser-induced fluorescence spectroscopy is made.