Download or read book Chemistry of Atmospheric Aerosol Particles and Their Resulting Warm Cloud-nucleation Properties written by Meagan Julia Kerry Moore and published by . This book was released on 2011 with total page 281 pages. Available in PDF, EPUB and Kindle. Book excerpt: Atmospheric aerosol particles are a major component of the troposphere and affect regional and global atmospheric chemistry and climate. The size and chemistry of these particles influences the warm and cold cloud nucleation ability and optical properties of the aerosol particles. This dissertation investigates the atmospheric chemistry of aerosol particles and their role in warm cloud nucleation through a combination of laboratory experiments and field measurements. The effect of organics on the cloud condensation nuclei (CCN) activity of sea spray aerosols is described in Chapter 2. Sea spray aerosol produced by bubbling solutions composed of simplistic mixtures of NaCl and oleic acid or SDS had a significant effect on CCN activity, even in very small amounts; while artificial seawater solutions containing microorganisms, the common cyanobacteria (Synechococcus) and DMS-producing green algae (Ostreococcus), produced particles containing ~34 times more carbon than the particles produced from pure ASW, with no significant change observed in the overall CCN activity. During the fall of 2007 and 2008, over 300,000 acres burned in San Diego County wildfires. The resulting particle chemistry and estimated hygroscopicity during these wildfire events are explored in Chapter 3. The contribution of wildfire emissions were much larger and played a more significant role in affecting cloud condensation nuclei and total particle concentrations in 2007 than in 2008. The overall particle hygroscopicity during the biomass burning dominated periods was very similar; however in 2008, the particle hygroscopicity was dominated by local sources rather than biomass burning, due to the much smaller particle size mode. Owens Lake is one of the largest sources of PM2.5 in the Western Hemisphere, producing highly soluble dust plumes, and therefore there is great potential for those particles to impact cloud formation and possibly precipitation in the region. Chapter 4 explores particle chemistry and estimated hygroscopicity at Owens Lake. No significant change in particle hygroscopicity or CCN activity occurred concurrently with the change in mixing of particle classes during two different dust events at Owens Lake; indicating that the large dust particles were most likely completely CCN active and the smaller particles are likely dictating the hygroscopicity, as most of the dust particles are large enough and would activate to become CCN regardless of their hygroscopicity. The Cloud Indirect Forcing Experiment (CIFEX) took place to study the influence of aerosols on cloud properties at Trinidad Head, a coastal site in northern California representing clean marine air with periodic long-range transport. Chapters 5 & 6 explore particle chemistry, mixing state, optical properties and estimated hygroscopicity during CIFEX. Our measurements demonstrate how changes in hygroscopicity and optical properties evolve over time in the atmosphere as a function of particle chemistry and the mixing state of the aerosol. Two distinct oxalate events with enrichment of oxalate on different particle types and sizes suggest two separate sources of oxalate.