10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
Abstract View
Identification and Atmospheric Abundance of Primary Biological Aerosol Particles
Maria Zawadowicz, Karl D. Froyd, Daniel Murphy, Dominick Spracklen, Colette Heald, Peter Buseck, DANIEL CZICZO, MIT
Abstract Number: 891 Working Group: Bioaerosols
Abstract Measurements of bioaerosol (primary biological aerosol particles and particles containing fragments as part of an internal mixture), especially in the free troposphere, are scarce. Single particle mass spectrometry (SPMS) has been used to probe aerosol chemical composition from ground and aircraft for over 20 years. We present a method for identifying bioaerosols using SPMS. We show that identification of bioaerosol using SPMS is complicated because phosphorus-bearing mineral dust and phosphorus-rich combustion by-products such as fly ash produce mass spectra with peaks similar to those typically used as markers for bioaerosol. We have developed a methodology to differentiate and identify bioaerosol using machine learning statistical techniques applied to mass spectra of known particle types. This improved method provides far fewer false positives compared to approaches reported in the literature. The new method was then applied to ambient data sets, showing an abundance 10 or more times lower than for mineral dust. The methodology extends measurement of bioaerosol using historic data, allows for comparison to modern techniques, and is in general agreement with a global aerosol model.