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ObjectiveTo characterize acetaldehyde and formaldehyde emissions, which are harmful gases to human health and not yet regulated for diesel engines. Methods Standardized tests were performed in four diesel light duty commercial vehicles, using a frame dynamometer and test procedure FTP-75. The pollutants were analyzed by high performance liquid chromatography. ResultsResults have shown acetaldehyde emission ranged from 5.9 to 45.4 mg/km, and formaldehyde emission from 16.5 to 115.2 mg/km. The average emission for aldehyde sum was 58.7 mg/km, ranging from 22.4 to 160.6 mg/km. The proportion between the two substances remained constant, close to 74% for formaldehydes and 26% for acetaldehydes. ConclusionsThe emission of diesel vehicle aldehydes was significant when compared with actual spark ignition vehicle emissions, or with the foresee limit for Otto cycle vehicles in Brazilian legislation. Establishing emission limits for these substances also in diesel vehicles is imperative in the light of the vehicle fleet growth, toxicity of these compounds, and their contribution as precursors in ozone gas formation reactions in low troposphere.

The exhaust emissions of 17 polychlorinated dibenzo-pdioxins and polychlorinated dibenzofurans (PCDD/Fs) were investigated in two spark-ignition light-duty vehicles, one gasohol-fueled and a flexible-fuel one fueled with hydrated ethanol. Gasohol is a mixture of gasoline and 22% ethanol. The influence of fuel type and quality, lubricant oil type, and use of fuel additives on the formation of these compounds was tested using standardized U.S. Federal Test Procedure (FTP)-75 cycle tests. The sampling of the PCDD/Fs followed the recommendations of a modified U.S. Environmental Protection Agency (EPA) Method 23 (www.epa.gov/ttn/ emc/promgate/m-23.pdf) and the analysis basically followed the U.S. EPA Method 8290 (http://www.epa.gov/osw/ hazard/testmethods/sw846/pdfs/8290a.pdf). Results showed that emission factors of PCDD/Fs for the gasohol vehicle varied from undetected to 0.068 pg international toxic equivalency (I-TEQ) km À1 (average of 0.0294 pg I-TEQ km À1), whereas in the ethanol vehicle they varied from 0.004 to 0.157 pg (I-TEQ) km À1 (average of 0.031 pg I-TEQ km À1

The emissions of seventeen 2,3,7,8 substituted Polychlorinated Dibenzo-pDioxins, Polychlorinated Dibenzofurans (PCDD/Fs) and sixteen Polycyclic Aromatic Hydrocarbons (PAH) [14] in the exhaust pipes of spark ignition light duty vehicles considered toxic to human health were investigated. The formations of these compounds were evaluated under the influence of variations of fuels and fuel additives.Standard tests in a gasohol (gasohol is pure gasoline plus 20% to 25% of anhydrous ethyl alcohol fuel (AEAF)) vehicle and in an ethanol vehicle were performed with variations in the quality of fuels. The sampling of the PCDD/Fs followed the recommendations of a modified 23 method and the analysis basically followed the 8290 method. The recommendations of the TO-13 method were followed for the PAH analysis, with the necessary modifications for a vehicular emission laboratory.The emission factors of the total PCDD/Fs varied between undetected and 0.157 pg I-TEQ/km. The emission factors of the total PAH varied from 0.01 µg TEQ/km to 4.61 µg TEQ/km.Significant and positive correlations were observed between the emissions of naphthalene, acenaphthylene, fluorene, phenanthrene, anthracene and fluoranthene and significant and negative correlations were observed between the emissions of CO 2 and fluoranthene in the gasohol vehicle. Significant and positive correlations between carbon monoxide and phenanthrene and between acenaphthylene, fluorene and fluoranthene in the alcohol vehicle were also observed, apart from significant and negative correlations between NOx and phenanthrene. In general way, significant correlations between PAH and PCDD/Fs were not observed, except in the ethanol vehicle considering phenanthrene.

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RESUMOOs primeiros estudos brasileiros de veículos utilizando como combustível o etanol ou álcool etílico, incluindo suas misturas com gasolina, datam da década de 1920, sendo representados pelo automóvel mais antigo que se tem notícia a rodar com etanol no Brasil. A partir deste marco, inúmeras foram as evoluções tecnológicas ligadas à indústria automobilística e a indústria do etanol, motivadas principalmente pelas crises do mercado de petróleo e por políticas de incentivo à indústria canavieira, e, mais recente, pela motivação ligada à forte necessidade de atendimento aos anseios dos consumidores em relação ao consumo de combustível e políticas mais rigorosas de controle de emissão de poluentes. Este trabalho tem o objetivo de realizar um breve levantamento histórico das informações citadas, por meio de fontes de referências e alguns testemunhos. Também se avalia como a utilização de etanol afeta a emissão de hidrocarbonetos pelo escapamento dos veículos rodoviários automotores leves, incluindo a emissão de aldeídos e do próprio etanol. [1,2]

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