Chemical Speciation and Characterization

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Carbonaceous and inorganic aerosols: sources and ambient; VOC, SVOC, SOA, organic and black carbon; biomass and biogenic aerosol

Inflorescence Composition of V...

Title: 
Inflorescence Composition of Volatile Emissions of Amorphophallus titanum (Araceae)
Abstract: 

The composition of the inflorescence (a spike of many small flowers) odors of Amorphophallus titanum (Becc. for Odoardo Beccari) Becc. ex Arcang. (Syn. Titan Arum), the world's largest unbranched inflorescence, a plant growing only in the equatorial tropical rainforests of Sumatra, has been investigated, we believe, for the first time. The scent of various Amorphophallus species has been analyzed in the past but the rarity of A. titanum's flowering makes this a unique study. The collection of the inflorescence odors was carried out during a 60 minute period about 6 hours after the opening of the spathe. Gaseous samples were collected on a Fluorisil cartridge and in a Tedlar bag at The Rose Hills Foundation Conservatory for Botanical Science, at The Huntington Botanical Garden, San Marino, California, on June 17, 2009. The samples were analyzed by GCxGC-TOFMS. The foul odors of this species, with carrion smells that inspired the apt nickname "Corpse Flower",  have a relatively simple chemical composition, consisting mainly of dimethyl disulphide, dimethyl trisulphide, n-alkanes and branched alkanes from C-6 up to C13 among other minor emanating volatiles. The production of odors containing dimethyl oligosulphides appears to be a common feature of sapromyophilous flowers that attract carrion insects.

Major species identified by GCxGC-TOFMS, in decreasing order of relative concentration, included:Heptane, 5-ethyl-2,2,3-trimethyl (11.07%); Hexane, 2,2,3-triethyl- (8.29%); Hexane, 3,3-dimethyl (7.53%), Heptane, 5-ethyl-2,2,3-trimethyl (5.66%); Undecane, 2,8-dimethyl- (3.59%); Benzaldehyde (3.30%); Dodecane (2.94%); Heptane, 5-ethyl-2,2,3-trimethyl (2.88%); Ethane- 1,1,2,2-tetrachloro- (2.00%); 2-Pentene, 1-bromo-3,4-dimethyl- (1.13%); 2,6,10,14,18,22-Tetracosahexaene, 2,6,10,15,19,23-hexamethyl-, (all-E)-  (1.09%); Pentane, 2,2,4,4-tetramethyl (1.09%); 1-Hexanol, 2-ethyl- (0.98%); Dodecanamide (0.96%); Octane, 4-methyl- (0.88%); Pyrrolidine (0.85%); Hexane, 2-bromo- (0.62%); Hexane, 2,4-dimethyl (0.62%); 2-Dodecanol, 2-methyl- (0.59%); Octadecane (0.45%); Benzene, 1,2-dimethyl- (0.40%); 1,8-Nonanediol, 8-methyl- (0.39%); 1,3-cyclopentadiene, 5-(1-methylethylidene)- (0.29%); Benzene, 1,4-dichloro- (0.19%); Ethanone, 1-phenyl- (0.19%); Benzoic acid, methyl ester (0.11%); Sulfurous acid, dodecyl pentyl ester (0.07%); and 7-Nonenamide (0.03%).

Worthy of note was a "nose-detection" in the change of the smelly odor, from rotten eggs at the beginning, to boiled aspargus several hours after the start of the plant's bloom. Another interesting observation during the early hours after the opening of the spathe, was the occurrence of a gas-to-particle processes which produced fine light scattering particles.

Presentation Type: 
Platform Presentation
Co-Authors
Author 1: 
JiYi Lee
Author 2: 
Douglas A. Lane
Author 3: 
John Trager
Author 4: 
Antonio H. Miguel
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Antonio H. Miguel
Presenting Author: 
Antonio H. Miguel

PM trend study for the 1998 - ...

Title: 
PM trend study for the 1998 - 2010 period: A consequence of an air quality decontamination and prevention plan.
Abstract: 

Since 1998 and until 2010, Santiago (Chile) exhibited PM2.5 yearly concentration averages several times the EPA annual standard.
PM2.5-10 and PM2,5 samples were collected in an urban site between 1998 and 2010. Elemental chemical analysis was made for approximately 60% of samples using XRF technique at DRI Lab (USA). Mixed regression analysis was used in order to know the PM and elemental trends, following the procedure described by Koutrakis et al, 2005.
A break in the PM2.5 trend curve was observed involving elements such as S, K, Mn, and Cr between 2006-2007 period. This can be explained as a consequence of restriction in natural gas supply that comes from Argentina. In the recent years, Br and Pb cannot longer be used as traffic tracers due the fact that additives remove politics were implemented by the Chilean environmental authorities during the late of 90’s. The changes of Al and Si are similar and have been associated to resuspended dust. The lowest concentrations of these elements were found in 2002-2003 and 2003-2004 periods and are produce by the rainfall increment during these years. Ca increases observed from 2003 was associated with the intensification building construction activities.
Cr, Mn, Cu and Zn in PM2.5 exhibited strong decrease during weekend indicating anthropogenic influence, associated to a decrease in traffic and industrial activities.
P contend in PM2.5-10 indicated a clear increase in wintertime as consequence of fertilizers use in agriculture mainly outside of the city.
The changes that Santiago experimented due new environment protect politician regulations and depression/boom economic period can be observed in the elemental composition of PM. It can see too that despite the growth of the city in recent years, the PM concentrations did not have changed significantly.

Presentation Type: 
Poster
Co-Authors
Author 2: 
Felipe André Reyes
Author 3: 
Andrés Henriquez
Author 4: 
Pedro Pablo Oyola
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Marcela Andrea Castillo
Presenting Author: 
Marcela Andrea Castillo

Aplication of the ratios betwe...

Title: 
Aplication of the ratios between polycyclic aromatic hydrocarbons in the assessment of emission sources of the particulate matter (PM10) in São Paulo state.
Abstract: 

Most recent studies on atmospheric chemistry are focused in urban areas where emissions of organic compounds have caused major impact on air quality. The atmospheric chemistry of non-urban areas represents an important area of study due to poor knowledge about the influence of mixed environments. Samples of particulate matter (PM10) were collected in three cities of São Paulo state (Brazil): (i) University City - SPA, urban site with heavy traffic of light and heavy vehicles , (ii) ESALQ – PRB, region impacted by agriculture and biomass burning (sugar cane), (iii) Core Forest Santa Virginia - MAT, primary forest with low human impact. Many studies have used the diagnostic ratios of the PAHs concentrations as a tool to infer possible sources of airborne particulate matter. Although there are problems related to the use of diagnostic ratios, they are still an important source of information on the origin and/or characteristic of the particulate matter and should be used jointly, reducing the probability of assigning a false diagnosis. Aiming to synthesize the information obtained, the group used the relative contribution of emissions to assess their magnitude in these sites and periods of study. The SPA site was influenced by sources of vehicular emissions, industrial activities, wood burning and the presence of retene (biomass burning). The PRB site had emissions associated with anthropogenic factors, such as: vehicle emissions, industrial activity, biomass burning (retene) and mainly the coal burning that was present only in PRB samples. The MAT site presented influence of the transport of air mass (ratio BaP/BeP and air mass back trajectories), vehicular emissions and biomass burning occurred in the north - northeast of São Paulo state.

Presentation Type: 
Poster
Co-Authors
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Fernando Cavalcante dos Santos
Presenting Author: 
Fernando Cavalcante dos Santos

Caracterization of particulate...

Title: 
Caracterization of particulate matter from urban air pollution in Salvador, BA, Brazil
Abstract: 

The increased atmospheric pollution has been related to the levels of urban and industrial development of a region, what makes necessary local studies that evaluate the chemical composition of particles. OBJECTIVE: To quantify heavy metals in the particulate matter from the urban atmospheric pollution in Salvador, through the use of the atmospheric biomonitor, Tillandsia usneoides, and to analyze the morphology and distribution of respirable particles in the samples of the particulate matter. METHODS: The samples of plants had been transplanted from a non-contaminated area for seven places of intense motor vehicle traffic in the city of Salvador. They had been exposed for 45 days in two seasons of the year (summer and  winter). After this period samples were prepared for analysis by atomic absorption spectroscopy and scanning electron microscopy with X-ray microanalysis. The morphologic study associated to elementary analysis of metals made it possible to characterize the distribution of particles aerodynamic diameters. RESULTS: Seven metals were detected in the exposed samples. The concentrations of these elements in the particulate matter to varied temporal and spatial, depending on the suburb and season analyzed. The urban atmosphere particle of Salvador displayed a distribution in which aerodynamic sizes between PM2.5 and PM10 comprised over 60% in the analyzed samples. CONCLUSIONS: The urban particulate matter of Salvador presented, in its composition, a significant contamination by metals, as compared with samples from control non-urbanized areas. The fine particulate predominated in the analyzed samples of the Salvador urban atmosphere. These results strengthen the demand of use of the biomonitoring as an alternative tool in the survey of environmental indicators, as they will allow the achievement of local epidemiological studies to evaluate the level of human exposition to the air pollution, as well as, to support the implementation of public policies.
  

Presentation Type: 
Poster
Co-Authors
Author 1: 
Nelzair Araujo Vianna
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Nelzair Araujo Vianna
Presenting Author: 
Nelzair Araujo Vianna

Preliminary results of aerosol...

Title: 
Preliminary results of aerosol monitoring in the megacity of Buenos Aires: Regional/local perspective
Abstract: 

A study was undertaken to assess levels of key components (metals, metalloids, ions and black carbon) of PM2.5 collected in the metropolitan area of Buenos Aires along a three-point transect representative of well-mixed urban and suburban conditions for this extended air basin.
We selected three monitoring sites: Costa Salguero (CS) on the shore of the Río de la Plata; Parque Centenario (PC) in the geographical center of the City of Buenos Aires (CBA); and INTA Castelar (IC) in the surroundings of the CBA. The sites cover an area of ~ 500 km2.
We collected 24-hour samples of PM2.5 during 18 months, from August 2008 to December 2009, on Teflon filters of 0.45 µm, using an Airmetrics sampler (5 L/min), totaling 400 samples. Particles were also collected on polycarbonate filters for morphology analysis and major chemical components by Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM) and by Energy Dispersive Spectrometer (EDS).
Our results evidenced increasing levels of PM2.5 from the shore to the innermost sites. PM2.5 varied within a range of: (CS) 2.92 – 35.0 µgm-3; (PC) 5.69 – 58.7 µgm-3; (IC) 4.01 – 71.2 µgm-3. The fraction of black carbon (BC) in PM2.5 was highest at the urban site (PC), which is indicative of the impact of traffic emissions on black carbon content. The medians of the BC/PM2.5 ratio were in the order: PC (0.20) > IC (0.16) > CS (0.10). Soot levels at the periurban site were significant.
Analysis of particles using different and complementary microscopic techniques showed that: IC and CS had a higher content of biological origin particles and minerals, and a lower proportion of material from vehicular traffic. CS also presented sodium chloride particles. PC had the highest proportion of vehicular source material.
Determination of ions, metals and metalloids is in progress.

Presentation Type: 
Poster
Co-Authors
Author 1: 
Victoria Pereyra
Author 2: 
Raquel Jasan
Author 3: 
Griselda Polla
Author 4: 
Laura Dawidowski
Author 5: 
Darío Gómez
Author 6: 
Patricia Smichowski
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Patricia Smichowski
Presenting Author: 
Victoria Pereyra

The Production and Evolution o...

Title: 
The Production and Evolution of Secondary Organic Aerosol During Smog Chamber Photochemical Reaction Studies of PAH with the OH Radical and the Subsequent Detection of These Products in Smog Samples from Seoul, South Korea and Los Angeles, California
Abstract: 

It has long been known that Polycyclic Aromatic Hydrocarbons (PAH) react with atmospheric oxidants such as ozone and the OH radical.  Our experiments have uniquely centered on the reactions of PAH with the OH radical in a 10m3 smog chamber.  PAH such as naphthalene, acenaphthene and phenanthrene have been studied, primarily because they can easily be put into the vapor phase for gas-phase reactions.  The OH radical is generated through the photochemical reaction of isopropylnitrite in the presence of NO and light to generate the OH radical while, at the same time eliminating ozone from the reaction.  Thus, the products are formed from the unique reaction of the PAH with the OH radical.  Ultra-violet fluorescent lamps surrounding the chamber are turned on for a measured amount of time then turned off.  While the lights are on, OH is produced.  When the lights are turned off, the OH radical production ceases immediately, thus freezing the reaction so that air samples may be withdrawn from the chamber for product analysis.  The lights are then turned back on and the process is repeated numerous times until the isopropyl nitrite and/or NO are depleted and ozone begins to appear.  The products are withdrawn from the chamber either through an annular diffusion denuder and filterpack for gas/particle partitioned analysis of the products or through a thermal desorption tube containing XAD resin for total product analysis by thermal desorption-multidimensional gas chromatography-time of flight mass spectrometry (TDS-GCxGC-TOFMS).  The denuder samples are solvent extracted and run as solutions by GCxGC-TOFMS.

This paper will describe our experimental system and will demonstrate how the gas to particle partitioning of products evolves during the course of the reactions and the production of  secondary organic aerosols (SOA).   Numerous products detected in the smog chamber, will be shown to be present in smog samples from Seoul, South Korea.  Additionally, we will show the monthly variation of the concentrations of products such as 2-formylcinnamaldehyde and dibenzopyranone over the course of a year.

Presentation Type: 
Invited Presentation
Co-Authors
Author 1: 
Douglas A. Lane
Author 2: 
JiYi Lee
Author 3: 
Antonio H. Miguel
Additional Authors: 
no more authors
Author Roles
Corresponding Author: 
Douglas A. Lane
Presenting Author: 
Antonio H. Miguel