Elemental analysis of oxygenated organic coating on black carbon particles using a soot-particle aerosol mass spectrometer

摘要: Abstract. Chemical characterization of organic coatings is important to advance our understanding the physio-chemical properties and environmental fate of black carbon (BC) particles. The soot-particle aerosol mass spectrometer (SP-AMS) has been utilized for this purpose in recent field studies. The laser vaporization (LV) scheme SP-AMS can heat BC cores gradually until they are completely vaporized, during which be vaporized at temperatures lower than that thermal vaporizer (TV) used in a standard high-resolution time-of-flight spectrometer (HR-ToF-AMS) employs flash vaporization. This work investigates the effects schemes on fragmentation elemental analysis of known oxygenated species using three instruments. We show that LV reduce molecules. Substantial enhancement C 2 H 3 O + / CO and C 4 signals was observed most tested species when used, suggesting observational frameworks based use HR-ToF-AMS data may not be directly applicable for evaluating chemical evolution (OOA) components coated ambient uncertainties H:C O:C determined improved-ambient (I-A) method both TV approaches were similar, scaling factors 1.10 0.89 for determined facilitate more direct comparisons between observations from two schemes. Furthermore, I-A method was updated multilinear regression model scheme measurements. parameters relative errors from −26.3  % 5.8 %, whereas remain roughly the same. Applying the I-A data, we found even though time series OOA components TV strongly correlated at the same location, OOA likely less compared to those externally mixed with BC.