Sulfates as Pollution Particulates: Catalytic Formation on Carbon (Soot) Particles

Novakov, T.; Chang, Shuenn‐Yih; Harker, Alan B.

doi:10.1126/science.186.4160.259

Cited by 274 publications

(87 citation statements)

References 6 publications

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“…These newly created particles, composed of 2NH + 4 −SO 2− 4 −H 2 O, could then grow into the accumulation-mode particles by condensations of water and other species (e.g., NH 3 and H 2 SO 4 ). Furthermore, inside the smoke plumes from tropical forest burning, sulfate is very rapidly formed (∼1 min) at the surface of BC (black carbon) via heterogeneous pathways (Novakov et al, 1974;Meszaros and Meszaros;1989;Yamasoe et al, 2000). The sulfate produced in this manner could be rapidly neutralized by NH + 4 .…”

Section: Correlation Analysismentioning

confidence: 96%

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

Song

Orsini

et al. 2005

J Atmos Chem

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Abstract. In this study bulk airborne aerosol composition measured by the PILS-IC (integration time of 3 min 24 s) during TRACE-P P3B Flight 10 are used to investigate the ionic chemical composition and mixing state of biomass burning particles. A biomass burning plume, roughly 3-4 days old, moderately influenced by urban pollution aerosols recorded in the Philippine Sea is investigated. Focusing on the fine particle NO , and Organic anions, the measurements suggest that aerosols could be composed of biomass burning particles (KNO 3 ) mixed to a large degree externally with the (NH 4 ) 2 SO 4 aerosols. A "closed-mode" thermodynamic aerosol simulation predicts that a degree of external mixing (by SO 2− 4 mass) of 60 to 100% is necessary to achieve the observed ionic associations in terms of the existence of KNO 3 . However, the degree of external mixing is most likely larger than 90%, based on both the presence of KNO 3 and the amounts of NH 4 NO 3 . Calculations are also shown that the aerosol mixing state significantly impacts particle growth by water condensation/evaporation. In the case of P3B Flight #10, the internal mixture is generally more hygroscopic than the external mixture. This method for estimating particle mixing state from bulk aerosol data is less definitive than single particle analysis, but because the data are quantitative, it may provide a complementary method to single particle chemical analysis.

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Section: Correlation Analysismentioning

confidence: 96%

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

Song

Orsini

et al. 2005

J Atmos Chem

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“…As EC absorbs light, it may affect the earth's radiation balance and impact global climate (Yamamoto and Tanaka, 1972;Grassel, 1979). EC also has been investigated for its role in catalyzing the conversion of atmospheric SO, to sulfate (Novakov et al, 1974). Thus, the importance of particulate carbon in human health and air quality underscores the need to assess and control its levels in the atmosphere.…”

Section: Introductionmentioning

confidence: 99%

Particulate Carbon Speciation by MnO₂Oxidation

Fung¹

1990

Aerosol Science and Technology

120

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A selective thermal oxidation method was developed for the speciation of carbonaceous aerosols collected on filters into organic carbon (OC) and elemental carbon (EC). The technique is based on studying the thermal oxidation oi microcrystalline graphite by MnO, as well as various organic compounds. The procedure uses a modified Dohrmann DC-52 carbon analyzer with a flame ionization detector to detect the CO, resulting from the oxidation as methane after catalytic conversion. The results led to the selection of 525°C as the optimal temperature for the oxidation of OC while leaving EC intact. After the organic oxidation, the sample is heated at 850°C, at which EC is oxidized rapidly and completely by MnO,. Carbonates that may be present in either the particles or the filter medium are removed by acidification and heating to -120°C prior to performing the organic and EC measurements. Analysis of split ambient particulate samples in which the OC levels had been reduced by solvent extraction produced EC results statistically the same as the original untreated samples. These results suggest that the speciation is not sensitive to the level of organics in the sample. During the Carbonaceous Species Methods Comparison Study (CSMCS) in which the participants analyzed 20 blind samples, with four being triplicates, this technique yielded results in good agreement with the average results of the participants, with coefficients of variation (CV) derived from the triplicate analysis being 2.1%, 2.6%, and 8.1%, respectively, for total, organic, and elemental carbon.

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“…Partículas de poeira, material particulado gerado na exaustão de máquinas movidas à diesel e, também, os aerossóis formados durante a queima de biomassa funcionam como absorventes da radiação solar incidente e como suporte adsorvente para compostos químicos, como por exemplo, gotículas de vapor d'água condensado 3,19 , ou mesmo como catalisadores, podendo levar o SO 2 disperso na atmosfera a sulfato [20][21][22][23][24] . Os hidrocarbonetos aromáticos polinucleares (HPA) formados durante a combustão incompleta de materiais contendo carbono, em especial carvão e derivados do petróleo, mesmo na baixa concentração em que geralmente se apresentam, afetam incisivamente o equilíbrio atmosférico 3,16 .…”

Section: A Poluição Atmosférica E Suas Conseqüências Na Saúde Públicaunclassified

A poluição gerada por máquinas de combustão interna movidas à diesel - a questão dos particulados. Estratégias atuais para a redução e controle das emissões e tendências futuras

Braun¹,

Appel²,

Schmal

2004

Quím. Nova

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Recebido em 17/3/03; aceito em 2/9/03 THE POLLUTION FROM DIESEL ENGINES -THE PARTICULATE MATTER CURRENT EXPERIENCES AND FUTURE NEEDS. The exhaust emissions of vehicles greatly contribute to environmental pollution. Diesel engines are extremely fuelefficient. However, the exhaust compounds emitted by diesel engines are both a health hazard and a nuisance to the public. This paper gives an overview of the emission control of particulates from diesel exhaust compounds. The worldwide emission standards are summarized. Possible devices for reducing diesel pollutants are discussed. It is clear that after-treatment devices are necessary. Catalytic converters that collect particulates from diesel exhaust and promote the catalytic burn-off are examined. Finally, recent trends in diesel particulate emission control by novel catalysts are presented.Keywords: diesel particulates; soot; diesel exhaust after-treatment; catalysts. INTRODUÇÃODesde os tempos mais remotos, o homem vem se tornando cada vez mais consciente do perigo que representa uma atmosfera poluí-da, tanto aquela gerada de modo natural, por ocasião das erupções vulcânicas ou pelo efeito de pólen, como a provocada por ele mesmo, desde a invenção do fogo. Existem registros de que essa preocupação motivou várias disposições legislativas em alguns países, como a França, onde, em 1382, Carlos VI proibiu a emissão de gases féti-dos, ou a Inglaterra, onde existia, já no século XVII, uma disposição que proibia acender fogo durante as sessões do parlamento de Westminster 1,2 . A partir da explosão industrial e urbana do século XIX, a poluição atmosférica aumentou consideravelmente e de tal forma que as relações entre o homem e seu meio ambiente tornaram-se totalmente alteradas. A Revolução Industrial rompeu de vez com o equilíbrio que ainda era possível o homem manter com a natureza. Nas décadas de 60 e 70, o problema agravou-se muito, adquirindo proporções dramáticas, tanto pela sua intensificação como pela extensão geográfica, o que se constituiu, na época, em motivo de inquietação crescente nas zonas urbanas e industriais 1,3 . Atualmente, apesar de alguns autores considerarem que mesmo as investigações científicas altamente complexas ainda não são avançadas o suficiente para fornecerem conclusões irrefutáveis acerca de como controlar e retroceder a poluição ambiental, em especial, a poluição atmosférica 2-6 , pode-se verificar que muitas disposições adotadas em vários países estão sendo capazes de, ao menos, diminuir a taxa de aumento da concentração dos principais poluentes [6][7][8][9] . Londres e Califórnia são exemplos de localidades sob forte disposição legislativa, que mantém os níveis dos poluentes ambientais controlados 9 . Deve-se salientar que isso se tornou possível, principalmente, devido ao uso e contínuo desenvolvimento dos catalisadores de pós-combustão 9-15 . É patente, portanto, que a pesquisa científica tem contribuído de maneira inestimável para o estudo e a preservação do meio ambiente 16 . Entretanto, a tensão verificada na Conferência de Kioto ...

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Sulfates as Pollution Particulates: Catalytic Formation on Carbon (Soot) Particles

Cited by 274 publications

References 6 publications

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

Particulate Carbon Speciation by MnO₂Oxidation

A poluição gerada por máquinas de combustão interna movidas à diesel - a questão dos particulados. Estratégias atuais para a redução e controle das emissões e tendências futuras

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Sulfates as Pollution Particulates: Catalytic Formation on Carbon (Soot) Particles

Cited by 274 publications

References 6 publications

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

An Investigation into the Ionic Chemical Composition and Mixing State of Biomass Burning Particles Recorded During TRACE-P P3B Flight#10

Particulate Carbon Speciation by MnO2Oxidation

A poluição gerada por máquinas de combustão interna movidas à diesel - a questão dos particulados. Estratégias atuais para a redução e controle das emissões e tendências futuras

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Particulate Carbon Speciation by MnO₂Oxidation