Homologous series of C1–C10 monocarboxylic acids and C1–C6 carbonyls in Los Angeles air and motor vehicle exhausts

Kawamura, Kimitaka; Steinberg, Spencer M.; Kaplan, I. R.

doi:10.1016/s1352-2310(00)00212-0

Cited by 141 publications

(140 citation statements)

References 49 publications

Supporting

Mentioning

127

Contrasting

Unclassified

Order By: Relevance

“…According to Kawamura et al, if acids and aldehydes are significantly emitted from vehicles, it may be supposed that aldehydes are preferentially lost or, alternatively, that acids are preferentially formed by photochemical processes, resulting in an accumulation of acids in the air and leading to average ratios of acids/aldehydes higher than those of vehicle exhaust. 23 In the present study, average ratios of measured organic acid and aldehyde concentrations were equal to 0.29 for the MMT and 0.34 for the JQT. In our atmospheric samples collected in a previous experiment, the acid to aldehyde average ratio was 0.39 for the urban site near MMT and 0.60 for the urban site near JQT.…”

Section: Measurements Of Oxygenated Hydrocarbonssupporting

confidence: 42%

“…In a previous study, acetic acid was the most abundant carboxylic acid in gasoline motor exhaust emissions and formic acid was the most abundant carboxylic acid in diesel motor exhaust emissions. 23 Our tunnel formic/acetic ratios obtained at different collection periods were 0.28 in the morning, 0.11 in the midday and 0.28 in the afternoon for JQT samples; and 0.61 in the morning, 0.47 in the midday for MMT samples. Like carbonyl ratios, characteristics formic/acetic ratios were found for each tunnel (0.11 -0.28, JQT and 0.47 -0.61, MMT) and they appear to be also dependent on the type of engine and fuel utilized.…”

mentioning

confidence: 63%

“…Mixing ratios of benzaldehyde as high as formaldehyde or acetaldehyde have been found in gasoline vehicular motor exhausts. 23 Although crotonaldehyde appears to be also predominant in the JQT, it may not be suggested as a tracer of light-duty gasohol vehicular emissions due to its reactivity. For MMT, tracers of vehicular emissions were not proposed as a mixture of both gasohol and diesel vehicular emissions were predominantly presented inside this tunnel.…”

Section: Measurements Of Oxygenated Hydrocarbonsmentioning

confidence: 99%

See 2 more Smart Citations

Volatile organic compounds inside urban tunnels of São Paulo City, Brazil

Vasconcellos

Carvalho

Pool

2005

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

Compostos orgânicos voláteis, tais como hidrocarbonetos oxigenados, hidrocarbonetos alifáticos e aromáticos foram medidos no ar interno de dois túneis urbanos da cidade de São Paulo, Brasil. Nesses túneis são freqüentes os congestionamentos de tráfico com números expressivos de veículos com controle de emissão inadequada. São Paulo, uma cidade altamente poluída, apresenta uma frota atípica de veículos com uma variedade grande de misturas de combustíveis, incluindo os oxigenados. Nesse trabalho, foram feitas medidas no ar interno e externo do túnel para avaliar os níveis dos poluentes emitidos diretamente por veículos e aqueles formados fotoquimicamente na atmosfera. No túnel (A), onde circulam apenas veículos leves movidos principalmente por gasool, uma mistura contendo 78-80% (v/v) gasolina e 20-25% etanol, as razões de formaldeído/acetaldeído foram < 1; e no túnel (B), onde circulam veículos leves principalmente movidos a gasool e veículos pesados movidos a diesel, essas razões foram aproximadamente igual a 1. Em ambos os túneis, as razões ácido fórmico/ácido acético foram bem mais baixas do que 1. O benzaldeído foi sugerido como sendo um possível traçador de emissões de veículos leves movidos a gasool. Os n-alcanos foram os compostos mais abundantes (níveis semelhantes em ambos os túneis) e, em seguida os compostos carbonílicos (níveis mais altos em B) e os compostos aromáticos (níveis mais altos em A). Foram encontrados níveis semelhantes de ácidos orgânicos, espécies minoritárias, em ambos os túneis. Os resultados desse estudo mostram que poluentes tóxicos estão presentes em níveis significativos nos dois túneis. No túnel (A) foram encontrados razões de mistura de 39,2 e 24,8 ppbv para os agentes carcinogênicos formaldeído e benzeno; no túnel (B) um valor máximo de 34,5 ppbv foi encontrado para o acetaldeído, um provável agente carcinogênico. Estudos futuros devem ser feitos para estimar os níveis de exposição de poluentes tóxicos no ar para ocupantes de veículos, uma vez que essas pessoas passam um tempo significativo dentro de túneis urbanos.Volatile organic compounds, such as oxygenated hydrocarbons, aliphatic and aromatic hydrocarbons were measured in ambient air from two distinct urban tunnels in São Paulo City, Brazil, in special, at rush hours. In these tunnels, traffic jams with significant numbers of vehicles with inadequate emission controls are frequent. São Paulo, a highly polluted city, has an unconventional mix of vehicle types in that a variety of gasoline blends, including oxygenated ones are used. Inside and outside tunnel measurements were performed to evaluate pollutant levels originated from direct vehicular emissions and formed by atmospheric photochemistry. Formaldehyde/acetaldehyde ratios of tunnel (A) circulating only light-duty vehicles fueled mainly with gasohol, a mixture containing 78-80% (v/v) gasoline and 20-25% ethanol, were < 1; ratios of tunnel (B) circulating light-duty vehicles fueled mainly with gasohol and heavy diesel vehicles, were approximately equal to 1. Formic acid...

show abstract

Section: Measurements Of Oxygenated Hydrocarbonssupporting

confidence: 42%

mentioning

confidence: 63%

Section: Measurements Of Oxygenated Hydrocarbonsmentioning

confidence: 99%

See 1 more Smart Citation

Volatile organic compounds inside urban tunnels of São Paulo City, Brazil

Vasconcellos

Carvalho

Pool

2005

J. Braz. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Monocarboxylic acids (C 1 -C 10 ) were found in motor exhausts and used engine oils (Kawamura et al, 1985;Kawamura et al, 2000). However, photochemical oxidations of various organic precursors from anthropogenic sources in the urban atmosphere are suggested as a major source of C 1 -C 10 acids based on their diurnal daytime maxima and positive correlation to ambient temperature (Kawamura et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Low molecular weight (C1–C10) monocarboxylic acids, dissolved organic carbon and major inorganic ions in alpine snow pit sequence from a high mountain site, central Japan

Kawamura

Matsumoto

Tachibana

et al. 2012

Atmospheric Environment

Self Cite

View full text Add to dashboard Cite

Low molecular weight (C 1 -C 10 ) monocarboxylic acids, dissolved organic carbon and major inorganic ions in alpine snow pit sequence from a high mountain site, central Japan AbstractSnowpack samples were collected from a snow pit sequence (6 m in depth) at the Murodo-Daira site near the summit of Mt. Tateyama, central Japan, an outflow region of Asian dusts. The snow samples were analyzed for a homologous series of low molecular weight normal (C 1 -C 10 ) and branched (iC 4 -iC 6 ) monocarboxylic acids as well as aromatic (benzoic) and hydroxy (glycolic and lactic) acids, together with major inorganic ions and dissolved organic carbon (DOC). The molecular distributions of organic acids were characterized by a predominance of acetic (range 7.8-76.4 ng/g-snow, av. 34.8 ng/g) or formic acid (2.6-48.1 ng/g, 27.7 ng/g), followed by propionic acid (0.6-5.2 ng/g, 2.8 ng/g). were found to account for 1-6% of DOC (270-1500 ng/g, 630 ng/g) in the snow samples.

show abstract

“…Hexanal is prevalent in the atmosphere and has both primary sources, such as vegetation and the cracking of petroleum, as well as secondary sources such as the oxidation of longer chain organics (Kesselmeier and Staudt, 1999;Kawamura et al, 2000;Tadic et al, 2001;Muller et al, 2002). The relatively high vapor pressure of hexanal, 0.01 atm, suggests that it should not partition into the particle phase to any significant extent.…”

Section: Introductionmentioning

confidence: 99%

Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Garland

Elrod

Kincaid

et al. 2006

Atmospheric Environment

View full text Add to dashboard Cite

While it is well established that organics compose a large fraction of the atmospheric aerosol mass, the mechanisms through which organics are incorporated into atmospheric aerosols are not well understood. Acid-catalyzed reactions of compounds with carbonyl groups have recently been suggested as important pathways for transfer of volatile organics into acidic aerosols. In the present study, we use the aerodyne aerosol mass spectrometer (AMS) to probe the uptake of gasphase hexanal into ammonium sulfate and sulfuric acid aerosols. While both deliquesced and dry non-acidic ammonium sulfate aerosols showed no organic uptake, the acidic aerosols took up substantial amounts of organic material when exposed to hexanal vapor. Further, we used 1 H-NMR, Fourier transform infrared (FTIR) spectroscopy and GC-MS to identify the products of the acid-catalyzed reaction of hexanal in acidic aerosols. Both aldol condensation and hemiacetal products were identified, with the dominant reaction products dependent upon the initial acid concentration of the aerosol. The aldol condensation product was formed only at initial concentrations of 75-96 wt% sulfuric acid in water. The hemiacetal was produced at all sulfuric acid concentrations studied, 30-96 wt% sulfuric acid in water. Aerosols up to 88.4 wt% organic/11.1 wt% H 2 SO 4 /0.5 wt% water were produced via these two dimerization reaction pathways. The UV-VIS spectrum of the isolated aldol condensation product, 2-butyl 2-octenal, extends into the visible region, suggesting these reactions may impact aerosol optical properties as well as aerosol composition. In contrast to previous suggestions, no polymerization of hexanal or its products was observed at any sulfuric acid concentration studied, from 30 to 96 wt% in water. r

show abstract

Homologous series of C1–C10 monocarboxylic acids and C1–C6 carbonyls in Los Angeles air and motor vehicle exhausts

Cited by 141 publications

References 49 publications

Volatile organic compounds inside urban tunnels of São Paulo City, Brazil

Volatile organic compounds inside urban tunnels of São Paulo City, Brazil

Low molecular weight (C1–C10) monocarboxylic acids, dissolved organic carbon and major inorganic ions in alpine snow pit sequence from a high mountain site, central Japan

Acid-catalyzed reactions of hexanal on sulfuric acid particles: Identification of reaction products

Contact Info

Product

Resources

About