Rapid Sampling of Individual Organic Aerosol Species in Ambient Air with the Photoionization Aerosol Mass Spectrometer
Titel:
Rapid Sampling of Individual Organic Aerosol Species in Ambient Air with the Photoionization Aerosol Mass Spectrometer
Auteur:
Dreyfus, Matthew A. Johnston, Murray V.
Verschenen in:
Aerosol science and technology
Paginering:
Jaargang 42 (2008) nr. 1 pagina's 18-27
Jaar:
2008-01
Inhoud:
Analytical methods developed to sample and characterize ambient organic aerosols often face the trade-off between long sampling times and the loss of detailed information regarding specific chemical species present. In the work presented here, high-time resolution ambient measurements (3.5 minutes) are achieved by using the Photoionization Aerosol Mass Spectrometer (PIAMS) in conjunction with the mini-Versatile Aerosol Concentration Enrichment System (m-VACES). Aerosol sampling took place for one week at State of Delaware Air Quality Monitoring Site in Wilmington, Delaware in June 2006. The soft, universal ionization scheme of PIAMS allows for identification of various chemical compounds by a signature ion, often the molecular ion. Meteorological data was used to link some species, such as palmitic and oleic acid, to potential sources; whereas other compounds, like PAHs, have no significant wind dependence. Some classes, including n-alkanes and n-alkanoic acids, are shown to be in abundance during late night/early morning hours, potentially due to the combined effects of temperature inversion, and fresh emissions in a cooler environment. The high-time resolution data shows that rapid concentration changes of a common individual species can be lost with traditional bulk sampling, and a time resolution of 30 minutes is suggested to accurately represent these changes.
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