Polycyclic aromatic compounds (PACs) are known due to their mutagenic activity. Among them, 2-nitrobenzanthrone (2-NBA) and 3-nitrobenzanthrone (3-NBA) are considered as two of the most potent mutagens found in atmospheric particles. In the present study 2-NBA, 3-NBA and selected PAHs and Nitro-PAHs were determined in fine particle samples (PM 2.5) collected in a bus station and an outdoor site. The fuel used by buses was a diesel-biodiesel (96:4) blend and light-duty vehicles run with any ethanol-to-gasoline proportion. The concentrations of 2-NBA and 3-NBA were, on average, under 14.8 µg g−1 and 4.39 µg g−1, respectively. In order to access the main sources and formation routes of these compounds, we performed ternary correlations and multivariate statistical analyses. The main sources for the studied compounds in the bus station were diesel/biodiesel exhaust followed by floor resuspension. In the coastal site, vehicular emission, photochemical formation and wood combustion were the main sources for 2-NBA and 3-NBA as well as the other PACs. Incremental lifetime cancer risk (ILCR) were calculated for both places, which presented low values, showing low cancer risk incidence although the ILCR values for the bus station were around 2.5 times higher than the ILCR from the coastal site.

A importância da produção de biodiesel, nos últimos cinco anos, é apresentada a partir de artigos científicos publicados e patentes depositadas. Foi realizada uma análise crítica sobre as fontes oleaginosas mais utilizadas como matéria-prima para produção de biodiesel, os catalisadores e os métodos de acompanhamento da reação de transesterificação. Também foram avaliados estudos comparativos entre emissões de diesel fossil e misturas, em várias proporções, com biodiesel. Finalmente, foram indicados desafios enfocando aspectos tecnológicos, agronômicos e de infraestrutura para produção de biodiesel.The importance of biodiesel production was analyzed based on scientific articles and patents. A critical analysis was presented on the most used oil sources, the catalysts and the methods to verify the transesterification yields. Also analyzed were the comparative studies on emissions from pure fossil diesel and mixtures with biodiesel in variable proportions. Finally some challenges and considerations focused on technological, agronomic and infrastructure aspects of biodiesel production were indicated.

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Carbonyl products have been identified and their yields measured in experiments involving the gas-phase reaction of ozone with eight simple alkenes in purified air. Sufficient cyclohexane was added to scavenge the hydroxyl radical (OH) in order to minimize the reaction of OH with the alkenes and with their carbonyl products. Formation yields of primary carbonyls (carbonyl formed/ozone reacted) were 1.060 ± 0.071 (one standard deviation) for formaldehyde from ethylene, 1.150 ± 0.104 for acetaldehyde from 2-butene (ca. 40% cis and 60% trans isomers), 1.011 ± 0.049 for propanal from trans-3-hexene, 1.006 ± 0.049 for acetone from 2,3-dimethyl-2-butene, 0.980 ± 0.036 for formaldehyde + propanal from 1-butene, 0.987 ± 0.020 for acetaldehyde + acetone for 2-methyl-2-butene, 1.300 ± 0.030 for formaldehyde + acetaldehyde from propene, and 1.290 ± 0.103 for formaldehyde + acetone from 2-methylpropene. After correction for the estimated contribution of biradical reactions to formaldehyde, primary carbonyl yields were ca. 1.22 ± 0.03 for acetaldehyde + formaldehyde from propene and 1.08 ± 0.11 for acetone + formaldehyde from 2-methylpropene. These yields are consistent with the value of 1.0 for primary carbonyl yields according to the reaction mechanism:  O3 + R1R2C = CR3R4 → α(R1COR2 + R3R4COO) + (1 − α)(R3COR4 + R1R2COO) which, for symmetrical alkenes, reduces to O3 + R1R2C = CR1R2 → one primary carbonyl (R1C(O)R2) + one biradical (R1R2COO). The results suggest modest preferential formation of the more substituted biradical for 1-butene (CH3CH2CHOO vs H2COO, α = 0.643 ± 0.039), 2-methyl-2-butene [(CH3)2COO vs CH3CHOO, α = 0.694 ± 0.024], 2-methylpropene [(CH3)2COO vs H2COO, estimated α = 0.68 ± 0.12], and perhaps propene (CH3CHOO vs H2COO, estimated α = 0.57 ± 0.03). Reaction of the biradicals resulted in the formation of carbonyls and of hydroxycarbonyls and/or dicarbonyls, which together accounted for ca. 0.25, 0.31, and 0.57 of the biradical reactions for CH3CHOO, CH3CH2CHOO, and (CH3)2COO, respectively. Carbonyls and hydroxycarbonyls and/or dicarbonyls from propene, 2-methylpropene, 1-butene, and 2-methyl-2-butene were consistent in nature and yields with those that form from the symmetrical alkenes that lead to the same biradicals.

This work relates the development of an analytical methodology to simultaneously determine three methylxanthines (caffeine, theobromine, and theophylline) in beverages and urine samples based on reversed-phase high-performance liquid chromatography. Separation is made with a Bondesil C18 column using methanol-water-acetic acid or ethanol-water-acetic acid (20:75:5, v/v/v) as the mobile phase at 0.7 mL/min. Identification is made by absorbance detection at 273 nm. Under optimized conditions, the detection limit of the HPLC method is 0.1 pg/mL for all three methylxanthines. This method is applied to urine and to 25 different beverage samples, which included coffee, tea, chocolate, and coconut water. The concentration ranges determined in the beverages and urine are: < 0.1 pg/mL to 350 microg/mL and 3.21 microg/mL to 71.2 microg/mL for caffeine; < 0.1 pg/mL to 32 microg mL and < 0.1 pg/mL to 13.2 microg/mL for theobromine; < 0.1 pg/mL to 47 microg/mL and < 0.1 pg/mL to 66.3 microg/mL for theophylline. The method proposed in this study is rapid and suitable for the simultaneous quantitation of methylxanthines in beverages and human urine samples and requires no extraction step or derivatization.

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O presente trabalho enfoca os níveis de formaldeído e acetaldeído em fase gasosa e a sua correlação com a frota veicular, em vários locais em Salvador, BA, Brasil. As amostras foram coletadas utilizando cartuchos Sep Pak C18 impregnados com uma solução ácida de 2,4-dinitrofenilidrazina (DNPH). As hidrazonas resultantes foram separadas e quantificadas através de cromatografia líquida de alta eficiência. As amostras foram coletadas durante períodos de 1 -2 h em seis locais na cidade de Salvador, Bahia: em uma estação de ônibus, no interior de um túnel, no estacionamento fechado de um shopping center, no estacionamento fechado de um prédio comercial, em um bairro residencial e em um bairro comercial; e em dois outros locais distantes de Salvador: Cacha Pregos e Lagoa Verde. As concentrações medidas de formaldeído e acetaldeído, estiveram, respectivamente, na faixa de 0,20 -88 ppbV and 0,40 -93 ppbV. A relação das concentrações formaldeído/acetaldeído determinadas nesses locais foram: 0,66 (estacionamento do shopping center); 0,65 (estacionamento do prédio comercial); 4,4 (estação de ônibus); 1,2 (túnel); 1,0 (bairro residencial) 1,7 (bairro comercial), 1,1 (Cacha Pregos) e 0,8 (Lagoa Verde). No caso do túnel, este representa a frota total da cidade. Contagens de tráfego, realizadas durante o período de amostragem, revelaram que 82% dos veículos que passaram pelo local eram leves e 18% veículos pesados (diesel). Um cálculo simples utilizando a composição da frota no túnel e a relação formaldeído/acetaldeído na estação de ônibus (como a assinatura dos veículos a diesel) e nos estacionamentos fechados (como a assinatura dos veículos leves), revelou uma relação formaldeído/acetaldeído igual a 1,3 a qual é muito próxima do valor medido 1,2. De forma idêntica, os valores calculados para os bairros comercial e residencial foram, respectivamente 1,7 e 0,62. Isto nos permite concluir que os níveis atmosféricos de formaldeído e acetaldeído em Salvador apresentam uma correlação com a composição da frota veicular.The present work is concerned with the formaldehyde and acetaldehyde content in the gas-phase and their concentrations correlation, with the vehicular fleet, at several sites in Salvador, BA, Brazil. The samples were collected using C-18 Sep Pak cartridges coated with an acidic solution of 2,4-dinitrophenylhydrazine (DNPH). The resulting hydrazones were separated and quantified using HPLC. Samples were collected during 1 -2 h periods at six sites located in the city of Salvador, Bahia: a bus station, a tunnel, a commercial mall parking lot, a business building parking lot a residential district and a commercial district; and at two other sites far from Salvador: Cacha Pregos and Lagoa Verde. The measured concentrations for formaldehyde and acetaldehyde ranged, respectively, from 0.20 to 88 ppbV and from 0.40 to 93 ppbV. The formaldehyde/acetaldehyde concentration ratio determined in these sites were: 0.66 (commercial mall parking lot); 0.65 (business building parking lot); 4.4 (bus station); 1.2 (tunnel); 1.0 (residen...

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