Origem e implicações dos ácidos carboxílicos na atmosfera

Souza, Sílvia Ribeiro de; Carvalho, Lilian Rothschild Franco de

doi:10.1590/s0100-40422001000100012

Cited by 7 publications

(5 citation statements)

References 52 publications

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“…31 Each filter was extracted from the membranes containing particulate matter using 1 mL of deionized water under mechanical agitation at 100 rpm (Tecnal E140) for 90 min at room temperature. 44 Oxalate, malonate, succinate, formate and acetate were determined by ion chromatography using a SYCAM S1100 with Dionex AG11/HPIC-AS11 separation columns and Dionex AMMS micro-membrane suppressor. Elution was carried out with a 30 mmol L −1 NaOH solution at a flow rate of 1.5 mL min −1 and 12.5 mmol L −1 H 2 SO 4 solution as a suppressor at 2 mL min −1 .…”

Section: Analysis Methodsmentioning

confidence: 99%

Size-segregated particulate matter and carboxylic acids over urban and rural sites in Londrina City, Brazil

Freitas¹,

Martins

Solci³

2012

J. Braz. Chem. Soc.

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Amostragens simultâneas de material particulado (PM) de 0,25 a 10 mm foram realizadas entre os meses de março e abril de 2007 em área urbana e rural de Londrina (Paraná). Os resultados indicaram que o material particulado fino (PM 2,5 ) representa uma significativa porção da massa de material particulado PM 10 (70 e 67% na área urbana e rural, respectivamente). Ácidos dicarboxílicos foram encontrados em maior concentração respondendo por 78% e 69% da massa de PM 2,5 na área urbana e rural, respectivamente, sendo que o oxalato e succinato foram os mais abundantes. A distribuição de massa do oxalato em área urbana apresentou picos dominantes em 0,25-0,5 µm. A razão de massa de acetato e formato indicou as emissões veiculares primarias como fonte dominante de ácidos carboxílicos em Londrina. Além disso, análises das trajetórias indicaram a ocorrência de transporte de poluentes do estado de São Paulo para a região de estudo.Samplings of atmospheric particulate matter (PM) from 0.25 to 10 µm were performed between the months of March and April 2007, simultaneously in urban and rural areas of Londrina City (Paraná State, Brazil). Results indicated that the fine fraction (PM 2.5 ) represents a significant portion of the PM 10 mass (70 and 67% in urban and rural areas, respectively). Dicarboxylic acids were found in larger concentration, contributing to the PM 2.5 fraction with 78% in urban and 69% in rural areas, being oxalate and succinate the most abundant species. Mass size distribution of oxalate in urban site was presented as the dominant mode, with peaks at 0.25-0.5 µm. Acetate-to-formate mass ratio indicated the primary vehicular emissions as dominant source of carboxylic acids in Londrina. Moreover, backward trajectories indicated the transport of pollutants from São Paulo State to Londrina region.Keywords: size-segregated particulate matter, carboxylic acids, PM 2.5 , urban and rural aerosols IntroductionThe occurrence and abundance of carboxylic acids in atmospheric particulate matter (PM) depend on meteorological conditions and characteristics of the ambient. The carboxylic acids represent a major fraction of the organic acids present in the atmospheric particulate matter. Among them, the oxalic acid has been the main species, followed by succinic and malonic acids. [1][2][3][4][5][6] Mono-and di-carboxylic acids are important groups of organic compounds identified in the atmospheric particles. 7,8 Formic and acetic acids, the dominant species of organic acids in tropospheric aqueous and gaseous phases, are also ubiquitous in aerosol particles. Oxalic acid has been detected as the major fraction of water-soluble organic compounds in urban, rural and even in remote areas. [3][4][5][6] Since carboxylic acids are highly water-soluble, they have the potential to modify the hygroscopic properties of atmospheric particles, including their ambient size and cloud condensation nuclei activity. 9,10 Weak organic acids could contribute ca. 40 and 60% to the free acidity in precipitation in urban and remote areas, respe...

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Section: Analysis Methodsmentioning

confidence: 99%

Size-segregated particulate matter and carboxylic acids over urban and rural sites in Londrina City, Brazil

Freitas¹,

Martins

Solci³

2012

J. Braz. Chem. Soc.

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“…In the aqueous phase, the acetic and formic acids are found in significant amounts in rainwater, ice, snow and aerosol particles as they have low molecular weight and relatively high polarity. In the particulate phase, the high molecular weight and low volatility acids are generally found, as the dicarboxylic and carboxylic acids [13].…”

Section: Introductionmentioning

confidence: 99%

Thermodynamic study of fatty acids adsorption on different adsorbents

Freitas

Mendes

Coelho

2007

The Journal of Chemical Thermodynamics

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“…They interact easily with the aqueous phase and, due to their solubility, they are removed from the atmosphere by rainfall . Souza and Carvalho, 2001). Acetate was quantified in 37 of the samples (53% of the rainfall) with VWM highest concentration of 1.9 mg L -1 .…”

Section: Concentration Levels Of Inorganic and Organic Ions In Rainwatermentioning

confidence: 97%

Changes on wet deposition of major organic and inorganic ions in subtropical region of Brazil

Batista

Martins

Beal

et al. 2022

Rev. Bras. Geog. Fis.

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Wet precipitation composition could be an indicator of air quality since it carries components such as strong and weak inorganic and organic acids. These originate from oxidation of compounds containing sulphur, nitrogen, and hydrocarbons, coming from biomass burning, fuel combustion and industrial processes, as well as agricultural and biogenic activities. Wet precipitation samples were obtained from May 2014 to May 2015 in the city of Londrina -Paraná, Brazil, with an automatic rain collector. Volume, pH, conductivity, acetate, format, chloride, nitrate, sulphate, and ammonium concentrations were determined. The pH results revealed slightly acidic rainfall in 41% of the samples. The Volume Weighted Mean (VWM) showed an average annual concentration of inorganic ions of 0.71, 0.55, 0.24 and 0.20 mg L -1 for nitrate, sulphate, chloride, and ammonium, respectively and for organic ions of 1.00 and 0.29 mg L -1 for acetate and format, respectively. In the spring, the highest concentrations of nitrate and chloride were observed, which were possibly influenced by long-distance transport from fires in the north and west regions. The VWM of inorganic ions decreased compared with previous work (1998)(1999)(2000)(2001)(2002) carried out for the same place, with reductions of approximately 35% for nitrate and sulphate. Finally, the extensive use of fuel ethanol in Brazil contributes to the higher concentrations of acetate and format compared to other places in the world. Keywords: rainfall, air pollution, majority ions, the trajectories of air masses Mudanças na deposição úmida em relação aos principais íons orgânicos e inorgânicos em região subtropical do Brasil R E S U M OA composição da precipitação úmida pode ser um indicador da qualidade do ar, uma vez que transporta componentes como ácidos inorgânicos e orgânicos fortes e fracos. Estes se originam da oxidação de compostos contendo enxofre, nitrogênio e hidrocarbonetos, provenientes da queima de biomassa, combustão de combustível e processos industriais, assim como atividades agrícolas e biogênicas. As amostras de precipitação úmida foram obtidas no período de maio de 2014 a maio de 2015 na cidade de Londrina-Paraná, Brasil, com um coletor de chuva automático. Foram determinados volume, pH, condutividade e as concentrações dos íons acetato, formato, cloreto, nitrato, sulfato e amônio. Os resultados de pH revelaram chuvas ligeiramente ácidas em 41% das amostras. A média ponderada pelo volume (MPV) mostrou a concentração média anual de íons inorgânicos de 0,71, 0,55, 0,24 e 0,20 mg L -1 para nitrato,sulfato, cloreto e amônio, respectivamente e para os íons orgânicos de 1,00 e 0,29 mg L -1 para acetato e fomato, respectivamente. Na primavera, foram observadas as maiores concentrações de nitrato e cloreto, que foram possivelmente influenciadas pelo transporte de longa distância dos incêndios nas regiões norte e oeste do país. O MPV de íons inorgânicos diminuiu em comparação com trabalhos anteriores (1998)(1999)(2000)(2001)(2002) realizados no mesmo local, com reduções de a...

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Origem e implicações dos ácidos carboxílicos na atmosfera

Cited by 7 publications

References 52 publications

Size-segregated particulate matter and carboxylic acids over urban and rural sites in Londrina City, Brazil

Size-segregated particulate matter and carboxylic acids over urban and rural sites in Londrina City, Brazil

Thermodynamic study of fatty acids adsorption on different adsorbents

Changes on wet deposition of major organic and inorganic ions in subtropical region of Brazil

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