Understanding Climatic Effects of Aerosols Modeling Radiative Effects of Aerosols

Tarek Ayash, Sunling Gong, and Charles Q. Jia Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, Ontario M5S 3E5, Canada Climate on the Earth is a highly dynamic and complex system in which aerosols have been increasingly recognized as a key component. While the production, transport and fate of aerosols are fundamentally determined by the elements of climate, such as wind and and precipitation, aerosols may affect the Earth's climate through complex...

The Role of Morphology on Aerosol Particle Reactivity

Rosen1, and Tomas Baer1'* Department of Chemistry, University of North Carolina, Chapel Hill, NC 27599 Reaction rates of aerosol particles with gas-phase species can vary by several orders of magnitude depending on the morphology of the particle. The ozonlolysis of oleic acid in mixed particles represents a system in which morphology plays a significant role in reactivity. Particularly important is the particles' surface structure, including phase and molecular...

Atmospheric Aerosols and Their Importance

Kommalapati1 and Kalliat T. Valsaraj2 'Department of Civil and Environmental Engineering, P.O. Box 519, Mail Stop 2510, Prairie View A& M University, Prairie View, TX 77446 2Cain Department of Chemical Engineering, Louisiana State University, Baton Rouge, LA 70803 Apart from trace gases, the atmosphere contains a variety of liquids and solids that exist as dispersed phases in the air. They are collectively called aerosols. An aerosol is considered a two phase system consisting of...

Surface Activity of Perfluorinated Compounds at the Air Water Interface

Department of Chemistry and Biochemistry and CIRES, Campus Box 215, University of Colorado, Boulder, CO 80309 The surface activity of two perfluorinated compounds, perfluorododecanoic acid and 8-2 fluorotelomer alchol, was investigated using a Langmuir trough. Surface pressure-area isotherms of the perfluorinated acid and alcohol in single and multi component films containing hydrocarbon organic acids were collected and characterized. Evaporation from the subphase and film stability and...

Chemical Reactions on Urban Films

At this time, there have been no laboratory studies reported investigating reactions on real urban films, i.e. films allowed to develop outdoors in an urban setting. Most studies have involved oxidation of single-component (e.g self-assembled monolayers, oleic acid or solid PAH - see Rudich (2) for a recent review) organic films by ozone, though some very recent work on OH and N03 has been reported. (10-13) In all cases studied to date, the reaction rate is significantly faster than the...

Introduction

The direct effect of aerosols involves the scattering and absorption of solar radiation by the aerosol particles. It is critically determined by some of their intrinsic properties, and is also influenced by certain atmospheric conditions. Aerosols' interference with solar radiation is dictated by their radiative properties, which in turn is fundamentally determined by the particle's size, shape and chemical composition. The interaction of aerosols with solar radiation is greatest when the...

Photochemical Aging of Organic Aerosol

Aerosol can remain suspended in the atmosphere for several days, especially under dry conditions (9, 45, 46). During this time, particles can significantly change their chemical composition because of exposure to gas-phase oxidants (47) and solar radiation (48, 49). Additionally, reactions between different species inside the particles can modify the composition long after the initial particle growth (36, 37, 50). These aging processes may play an important role in determining hygroscopic and...

The Characteristics and the Cytotoxic Effects of Particulate Matter in the Ambient Air of the Chiang Mai Lamphun Basin

Narongpan Chunram1, Usanaee Vinitketkumnuen2, Richard L. Deining3, and Richard M. Kamens4 'Department of Applied Science, Faculty of Science and Technology, Chiang Mai Rajabhat University, Chiang Mai 50300, Thailand department of Biochemistry, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand department of Chemistry and Biochemistry, California State University at Fullerton, Fullerton, CA 92834 department of Environmental Science and Engineering, University of North...

References

Westberg, H. A National Inventory of Biogenic Hydrocarbon Emissions. Atm. Environ. 1987,21, 1695-1705. 2. Guenther, A. Hewitt, C. N. Erickson, D. Fall, R. Geron, C. Graedel, T. Harley, P. Klinger, L. Lerdau, M. A Global Model of Natural Volatile Organic Compound Emissions. J. Geophys. Res. D 1995,100, 8873-8892. 3. Pio, C. Valente, A. A. Atmospheric Fluxes and Concentrations of Monoterpenes in Resin-Tapped Pine Forests. Aim. Environ. 1998, 32, 683691. 4. Geron, C....

Results and Discussions

Arachidic Acid Isotherm

The fluorinated compounds used for the study were perfluorododecanoic acid (CF3(CF2)ioCOOH, denoted PFDDA), which is the perfluorinated analog of dodecanoic acid, and a partially fluorinated telomer alcohol containing 8 carbons that are fully fluorinated and 2 carbons that are hydrogenated with the formula CF3(CF2)7CH2CH2OH (denoted 8-2 FTOH). These compounds were chosen because they are used industrially and also, because they have been observed in the atmosphere. Experiments were conducted...

Experimental

Chromosorb P (60-80 mesh size, acid washed) and porous polymer adsorbent (Orbo 43) were obtained from Supelco (Bellefonte, PA). Phenanthrene .(> 96 ), furfuryl alcohol (99 ), 9, 10-phenanthrenequinone (> 99 ), 9- fluorenone (98 ), and deuterium oxide (99.9 atom D) were obtained from Aldrich. Suwannee River fulvic acid (SRFA) was obtained from the International Humic Substances Society (Cat. No. 1 SI OIF). Sodium dodecyl sulfate (SDS) (> 99.5 ) was obtained from Gibco BRL (Grand Island,...

SOA from Atmospheric Oxidation of Monoterpenes

Biogenic volatile organic compound (BVOC) emissions are an order of magnitude greater than anthropogenic VOC emissions on a global scale (1,2). Monoterpenes (C10H16) comprise a significant portion of BVOC emissions (2, 3), and it is important to understand the atmospheric fates of monoterpenes and their oxidation products. The most commonly occurring monoterpenes (4) are shown in Figure 1. The emission patterns of the various monoterpenes strongly depend on the type of vegetation and on the...

Absorption Spectra of Monoterpene SOA

In principle, one could envision modeling the absorption spectra of SOA as an appropriately weighed linear combination of the spectra of all individual SOA constituents. This approach is impractical because of the very large number of compounds found in SOA. Alternatively, the absorption spectra of monoterpene SOA can be deduced from spectroscopy of actual particle samples. Measurements of absorption spectra of aerosol are non-trivial because one has to separate the scattering and absorption...