Chemical Composition of Newly Formed Nanoparticles in Diverse Environments by the Nano Aerosol Mass Spectrometer
Abstract
The Nano Aerosol Mass Spectrometer (NAMS) permits quantitative measurement of the atomic composition of individual nanoparticles between 7 and 30 nm diameter. NAMS was deployed to urban, rural/coastal, and remote environments in order to determine the composition of 15-21 nm mobility diameter nanoparticles during new particle formation (NPF) events. In general, only small changes in nanoparticle atomic composition were observed during NPF relative to nanoparticle composition before and after the events. Typically, these changes indicated a shift towards increased inorganic nanoparticle content during NPF. Nonetheless, nanoparticles in this size range still contained a significant organic component, characterized by a high carbon content. Additionally, atomic composition measurements indicate that during NPF nanoparticles are fully neutralized. In the rural/coastal environment, nitrogen content increased most significantly (by 15%) during NPF, whereas carbon content decreased most significantly (by 25%). During NPF in the remote environment, sulfur content increased whereas carbon content decreased. Chemical composition measurements also show that nanoparticle composition changes before the mode particle diameter reaches the NAMS size range, implicating condensable gases as the source of material for particle growth. Taken together, these observations suggest important roles for both inorganic and organic species during the formation and growth of new particles. However, inorganic species (sulfate and/or nitrate) appear to be critical to either the formation or growth of particles during NPF.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2011
- Bibcode:
- 2011AGUFM.A31G..01B
- Keywords:
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- 0305 ATMOSPHERIC COMPOSITION AND STRUCTURE / Aerosols and particles;
- 0365 ATMOSPHERIC COMPOSITION AND STRUCTURE / Troposphere: composition and chemistry;
- 0394 ATMOSPHERIC COMPOSITION AND STRUCTURE / Instruments and techniques