AAAR 31st Annual Conference
October 8-12, 2012
Hyatt Regency Minneapolis
Minneapolis, Minnesota, USA
Abstract View
Particle Formation, Growth and Composition from Exposed Ocean Vegetation
ANDREW HORAN, Daniel MacDonald, George Luther, Murray Johnston, University of Delaware
Abstract Number: 760 Working Group: Aerosol Chemistry
Abstract The research question to be addressed in this work is: Do gaseous emissions from marine biota cause new particle formation in ambient air? Answering this question is important because new particle formation contributes substantially to the ambient particle number concentration, which can influence visibility, human and ecosystem health, and global climate. In these experiments air is drawn over a sample of macro- or micro- algae. Gaseous emissions from biota in the sample are mixed with OH radicals generated in a photolysis chamber to nucleate and grow particles. Particle size and composition are monitored with a scanning mobility particle sizer (SMPS) and the nano aerosol mass spectrometer (NAMS). Initial experiments were performed with emiliania huxleyi, thalassiosira pseudonana, laminaria, ulva and fucus samples. Gaseous emissions from all of these species were found to produce particles when exposed to OH. Macroalgae gave higher yields of particulate matter than microalgae. Particle sizes were generally in the 10 to 80 nm size range. Elemental analysis with NAMS showed that they were composed mostly of carbon, plus some nitrogen, oxygen and sulfur. Ongoing work is directed toward identifying key gas and particle phase molecular species, with the goal of characterizing particle formation and growth mechanisms.