Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 2—contribution of formic and acetic acids

Fornaro, Adalgiza; Gutz, Ivano Gebhardt Rolf

doi:10.1016/s1352-2310(02)00885-3

Cited by 96 publications

(79 citation statements)

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“…40 and 60% to the free acidity in precipitation in urban and remote areas, respectively. [11][12][13] Carboxylic acids have several different sources, including primary emissions from fossil fuel combustion and biomass burning, homogeneous photochemical oxidation of organic precursors from both anthropic and biogenic origin, 3,14,15 as well as in-cloud and heterogeneous formations. 16,17 Carboxylic acids in atmospheric aerosols have been investigated in several studies.…”

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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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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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“…A 300 mg L -1 sulfate solution was obtained by rigorous dilution of the previous one. This was used to prepare the working standard solutions with concentrations of 0.10, 0.25, 0.50, 0.75, 1.00, 1.50 and 2.00 mg L -1 SO 4 2-and was done by appropriate dilution with water. Before use, the resin was converted to nitrate form has been described elsewhere.…”

Section: Reagents and Samplesmentioning

confidence: 99%

“…In the second step, V 1 , V 2 , V 3 and V 4 were switched ON at the same time to direct the sample stream through the resin column (Rc) towards the waste (W), thereby allowing the sulfate ions to be retained by the resin. After a pre-set loading time, these valves were switched OFF, and V 6 was switched ON/OFF to perform the eluting step.…”

Section: Flow System and Proceduresmentioning

confidence: 99%

“…Acid rain has as its main constituent sulfate ion and its principal contributor to pollution is sulfur dioxide, which is oxidized in the atmosphere to sulfate and converted into an environmentally harmful strong acid (H 2 SO 4 ). [3][4][5][6] Traditionally, the most commonly used procedures for sulfate determination have been based on measurements of barium sulfate turbidity, 7 methylthymol blue colorimetry, 8,9 or ion chromatography. 10,11 Sulfate has been also determined by inductive coupled plasma optical emission spectrometry (ICP-OES).…”

Section: Introductionmentioning

confidence: 99%

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Turbidimetric determination of sulfate in rainwater employing a LED based photometer and multicommuted flow analysis system with in-line preconcentration

Zárate

Pérez-Olmos

Reis

2011

J. Braz. Chem. Soc.

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No presente trabalho é proposto um procedimento automático para determinação turbidimétrica de sulfato em águas de chuvas, baseado no processo de multicomutação em análise em fluxo. O equipamento fotométrico foi desenvolvido no laboratório, e inclui um LED (λ = 420 nm), uma cela de fluxo com caminho óptico de 100 mm e um fotodiodo. Uma etapa de preconcentração foi incluída para melhorar a sensibilidade. Após estabelecer as condições operacionais adequadas, o procedimento apresentou as seguintes características: resposta linear na faixa de concentração entre 0,1 a 2,0 mg L -1 de sulfato, limite de detecção (critério 3s) de 0,04 mg L -1 de sulfato, desvio padrão relativo de 1,5% (n = 7) para uma solução com 0,5 mg L -1 de sulfato, consumo de 17,0 mg de cloreto de bário por determinação, volume de efluente de 7.3 mL por determinação e frquência de amostragem de 13 determinações por hora.In the present work, an automatic procedure for turbidimetric determination of sulfate in rainwater, based on the multicommuted flow analysis approach, is proposed. The photometer setup was developed at the laboratory, and includes: a LED (λ = 420 nm), a long pathlength flow cell (100 mm), and a photodiode. A preconcentration step is included in order to improve sensitivity. After establishing the adequate operational conditions, the proposed procedure presented the following useful features: a linear response ranging from 0.1 mg L -1 up to 2.0 mg L -1 sulfate, a detection limit (3s criterion) of 0.04 mg L -1 sulfate, a relative standard deviation of 1.5% for 0.5 mg L -1 sulfate solution (n = 7), barium chloride consumptions of 17.0 mg per determination, and waste generation of 7.3 mL per determination. Accuracy assessment was achieved by applying the paired t-test between results obtained using the proposed procedure and ICP-OES and showed that there is no significant difference at 95% confidence level.

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“…And 144 samples in Guiyang and 47 samples in Shangzhong were collected on an event basis from April 2006 to April 2007. The rainwater samples and the blank sample with deionized water were frozen to −18°C until analysis (Karlsson et al 1999;Fornaro and Gutzb 2003). Blank tests and stability tests performed for these samples show no detectable peaks.…”

Section: Sample Collection and Analysismentioning

confidence: 99%

Urban and rural observations of carboxylic acids in rainwater in Southwest of China: the impact of urbanization

Xu¹,

Lee

2009

J Atmos Chem

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Seven carboxylic acids in rainwater were simultaneously determined using ion chromatography for 13 months in two different sites, Guiyang and Shangzhong, southwest of China. Results showed formic, acetic and oxalic acids were the three predominant carboxylic acids. Their volume-weighted average concentrations were 14.24, 9.35, 2.79 μmol/L in Guiyang and 4.95, 1.35, 2.31 μmol/L in Shangzhong, respectively. A distinctive diurnal pattern in carboxylic acid concentrations (daytime>nighttime, t test, p<0.05) was observed during the growing season in Guiyang. Shangzhong witnessed higher concentration of these acids during the growing season than that during the non-growing season. Direct emissions from growing vegetation or soils probably account for the main provenance of the acids in the rural area. However, the opposite trend were found in Guiyang and the anthropogenic sources during the non-growing season were the main reason. By comparison of our result with the previous data about 20 years ago, we calculated that at least 42% of acetic acids and 69% of formic acid originated from the anthropogenic sources in Guiyang. Furthermore, the ratio of formate/acetate in gas phase larger than 1 suggest the oxidation of unsaturated hydrocarbons from the human activity and/or natural sources were the main origin of carboxylic acids in Guiyang. While The F/A ratio in gas phase was less than 1 in Shangzhong which indicate the direct emissions from biogenic sources. Oxalic acid was in similar amounts in both sites, indicating the common source of the acid.

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Wet deposition and related atmospheric chemistry in the São Paulo metropolis, Brazil: Part 2—contribution of formic and acetic acids

Cited by 96 publications

References 50 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

Turbidimetric determination of sulfate in rainwater employing a LED based photometer and multicommuted flow analysis system with in-line preconcentration

Urban and rural observations of carboxylic acids in rainwater in Southwest of China: the impact of urbanization

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