نتایج جستجو برای: ozonolysis

تعداد نتایج: 657  

2017
Theodora Nah Renee C. McVay Jeffrey R. Pierce John H. Seinfeld Nga L. Ng

The effect of vapor-wall deposition on secondary organic aerosol (SOA) formation has gained significant attention; however, uncertainties in experimentally derived SOA mass yields due to uncertainties in particle-wall deposition remain. Different approaches have been used to correct for particle-wall deposition in SOA formation studies, each having its own set of assumptions in determining the ...

Journal: :The Analyst 2012
Shane R Ellis Jessica R Hughes Todd W Mitchell Marc in het Panhuis Stephen J Blanksby

Unsaturated lipids deposited onto a range of materials are observed to react with the low concentrations of ozone present in normal laboratory air. Parent lipids and ozonolysis cleavage products are both detected directly from surfaces by desorption electrospray ionisation mass spectrometry (DESI-MS) with the resulting mass spectra providing clear evidence of the double bond position within the...

Journal: :Environmental science & technology 2006
Nga L Ng Jesse H Kroll Melita D Keywood Roya Bahreini Varuntida Varutbangkul Richard C Flagan John H Seinfeld Anita Lee Allen H Goldstein

Biogenic hydrocarbons emitted by vegetation are important contributors to secondary organic aerosol (SOA), but the aerosol formation mechanisms are incompletely understood. In this study, the formation of aerosols and gas-phase products from the ozonolysis and photooxidation of a series of biogenic hydrocarbons (isoprene, 8 monoterpenes, 4 sesquiterpenes, and 3 oxygenated terpenes) are examined...

Journal: :Proceedings of the National Academy of Sciences of the United States of America 2012
Véronique Perraud Emily A Bruns Michael J Ezell Stanley N Johnson Yong Yu M Lizabeth Alexander Alla Zelenyuk Dan Imre Wayne L Chang Donald Dabdub James F Pankow Barbara J Finlayson-Pitts

Airborne particles play critical roles in air quality, health effects, visibility, and climate. Secondary organic aerosols (SOA) formed from oxidation of organic gases such as α-pinene account for a significant portion of total airborne particle mass. Current atmospheric models typically incorporate the assumption that SOA mass is a liquid into which semivolatile organic compounds undergo insta...

1998

The sonolytic degradation of ozone (O3) was investigated in both closed and open continuous-flow systems to examine effects of mass transfer on chemical reactivity in the presence of ultrasound. Degradation of O3 followed apparent first-order kinetics at frequencies of both 20 and 500 kHz in all the systems. Degassing of O3 was observed at 20 kHz due to the effects of rectified diffusion and la...

2010
P. S. Chhabra R. C. Flagan J. H. Seinfeld

The elemental composition of laboratory chamber secondary organic aerosol (SOA) from glyoxal uptake, α-pinene ozonolysis, isoprene photooxidation, single-ring aromatic photooxidation, and naphthalene photooxidation is evaluated using Aerodyne high-resolution time-of-flight mass spectrometer data. SOA O/C ratios range from 1.13 for glyoxal uptake experiments to 0.30–0.43 for α-pinene ozonolysis....

Journal: :Journal of Geophysical Research: Atmospheres 2001

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