An Aerosol Chemical Speciation Monitor (ACSM) for Routine Monitoring of the Composition and Mass Concentrations of Ambient Aerosol

Author： Ng N. L.

Publisher： Taylor & Francis Ltd

ISSN： 1521-7388

Source： Aerosol Science and Technology, Vol.45, Iss.7, 2011-07, pp. : 780-794

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Abstract

We present a new instrument, the Aerosol Chemical Speciation Monitor (ACSM), which routinely characterizes and monitors the mass and chemical composition of non-refractory submicron particulate matter in real time. Under ambient conditions, mass concentrations of particulate organics, sulfate, nitrate, ammonium, and chloride are obtained with a detection limit <0.2 g/m3="" for="" 30 min="" of="" signal="" averaging.="" the="" acsm="" is="" built="" upon="" the="" same="" technology="" as="" the="" widely="" used="" aerodyne="" aerosol="" mass="" spectrometer="" (ams),="" in="" which="" an="" aerodynamic="" particle="" focusing="" lens="" is="" combined="" with="" high="" vacuum="" thermal="" particle="" vaporization,="" electron="" impact="" ionization,="" and="" mass="" spectrometry.="" modifications="" in="" the="" acsm="" design,="" however,="" allow="" it="" to="" be="" smaller,="" lower="" cost,="" and="" simpler="" to="" operate="" than="" the="" ams.="" the="" acsm="" is="" also="" capable="" of="" routine="" stable="" operation="" for="" long="" periods="" of="" time="" (months).="" results="" from="" a="" field="" measurement="" campaign="" in="" queens,="" ny="" where="" the="" acsm="" operated="" unattended="" and="" continuously="" for="" 8="" weeks,="" are="" presented.="" acsm="" data="" is="" analyzed="" with="" the="" same="" well-developed="" techniques="" that="" are="" used="" for="" the="" ams.="" trends="" in="" the="" acsm="" mass="" concentrations="" observed="" during="" the="" queens,="" ny="" study="" compare="" well="" with="" those="" from="" co-located="" instruments.="" positive="" matrix="" factorization="" (pmf)="" of="" the="" acsm="" organic="" aerosol="" spectra="" extracts="" two="" components:="" hydrocarbon-like="" organic="" aerosol="" (hoa)="" and="" oxygenated="" organic="" aerosol="" (ooa).="" the="" mass="" spectra="" and="" time="" trends="" of="" both="" components="" correlate="" well="" with="" pmf="" results="" obtained="" from="" a="" co-located="" high="" resolution="" time-of-flight="" ams="" instrument.="">