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SUMMARY:Characterisation of aerosol by PMF analysis of single particle mas
 s spectra - Chiara Giorio (University of Cambridge)
DTSTART:20131202T141500Z
DTEND:20131202T153000Z
UID:TALK47017@talks.cam.ac.uk
CONTACT:Dr Amanda Maycock
DESCRIPTION:The Aerosol Time-of-Flight Mass Spectrometer (ATOFMS) is one o
 f few instruments able to measure the size and mass spectra of individual 
 airborne particles with high temporal resolution. Data analysis is challen
 ging and for the first time\, Positive Matrix Factorization (PMF) was dire
 ctly applied to single particle mass spectra to a regional ATOFMS dataset 
 collected at Harwell\, UK. The analysis allowed the extraction of 10 facto
 rs\, their time-series and size distributions. Different inorganic\, EC an
 d OC components were separated: fresh EC (factor EC-) from aged EC (factor
  EC+)\, different organic families\, such as oxidised organic aerosol\, ar
 omatic aerosol\, fresh N-containing organic aerosol and oxidised N-contain
 ing organic aerosol (factors NH4-OOA\, OC-Arom\, OC-CHNO and CNO-COOH resp
 ectively)\, and inorganic factors such as nitrate (factor NIT)\, potassium
  (factor K)\, sulphate (factor SUL) and sodium chloride (factor NaCl). A c
 omparison was conducted between PMF and two methods commonly used in ATOFM
 S data treatment\, K-means cluster analysis and the ART-2a artificial neur
 al network. Relationships were also examined between the estimated volumes
  of ATOFMS PMF factors and species concentrations measured independently b
 y GRAEGOR and AMS instruments\, showing generally moderate to strong corre
 lations.\nThe optimized approach was then applied to a dataset collected i
 n a six-lane road within an urban canyon in central London\, UK in which t
 he PMF analysis was able to separate the contribution of marine\, backgrou
 nd\, local and vehicular traffic-related factors.
LOCATION:Unilever Lecture Theatre\, Department of Chemistry
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