Comparison of emission of dioxins and furans from gasohol- and ethanol-powered vehicles.

The exhaust emissions of 17 polychlorinated dibenzo-p-dioxins 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 ( http://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-1 (average of 0.0294 pg I-TEQ km-1), whereas in the ethanol vehicle they varied from 0.004 to 0.157 pg (I-TEQ) km-1 (average of 0.031 pg I-TEQ km-1). In the gasohol-powered vehicle, the use of fuel additive diminished the emission of Octachlorodibenzo-p-dioxin (OCDD) significantly, whereas in the ethanol vehicle no significant associations were observed between the investigated variables and the emissions. [Box: see text].

Evaluation of mutagenic potential of contaminated atmosphere at Ibirapuera Park, São Paulo - SP, Brazil, using the Tradescantia stamen-hair assay.

Trad-SHM assay was used to check mutagenic potential of atmospheric contamination at Ibirapuera Park, located in São Paulo city, Brazil, and variation of risk along the year, besides determining which Tradescantia clone, BNL 4430 or KU-20, better indicates risk. Thirty pots of both clones were exposed during one-year period (September, 2002-August, 2003). Twenty inflorescences were taken from each clone twice a month in the morning, in order to estimate the frequency of mutations in stamen hairs. Results were compared to air pollution and climatic data measured next to the exposure site. KU-20 showed stamen-hair mutations greater than BNL 4430. Greatest mutation rates in KU-20 were observed in condition of high monthly mean of NO(2) and average peak concentrations of NO during the day, indicating that mutagenic effects originated from vehicular pollution. Clone KU-20 revealed to be more appropriate for biomonitoring purposes at the Park.

Chronic exposure to urban air pollution induces structural alterations in murine pulmonary and coronary arteries.

Epidemiological studies have shown that air pollution increases cardiovascular morbidity and mortality. Objective markers of cardiovascular risk have also been associated with increases in ambient pollution. This study was designed to assess whether prolonged exposure to ambient levels of air pollution may induce structural alterations of pulmonary and cardiac vessels. Mice were chronically exposed to ambient levels of air pollution in downtown São Paulo, Brazil. The animals were maintained in exposure chambers, 24 h/day, 7 days/wk, during 4 mo. One group was exposed to ambient air, and the control group was exposed to filtered air. Morphometric measurements of the ratio between the lumen and wall (L/W) areas were performed on transverse sections of renal, pulmonary, and coronary arteries. As expected, lumen/wall ratios increased with arterial caliber (p < .001). A significant decrease of L/W with exposure to air pollution was detected in pulmonary (p = .03) and coronary (p = .021) arteries, whereas no effects of air pollution were observed in renal vessels. Our results indicate that animals chronically exposed to ambient air pollution develop a significant thickening of the arterial wall in the coronary and pulmonary circulation.

[Emission of aldehydes from light duty diesel vehicles]. / Caracterização das emissões de aldeídos de veículos do ciclo diesel.

OBJECTIVE: To 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. RESULTS: Results 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. CONCLUSIONS: The 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.

Dioxins and furans in the atmosphere of São Paulo City, Brazil.

Air samples were collected simultaneously at three urban sites in São Paulo City, Brazil, in winter, spring, summer and fall (in 2000 and 2001). Andersen PUF samplers were used for gas and particles sequential sampling. Samples were analyzed using HRGC/HRMS according to US EPA Method 8290. The greater metropolitan area of São Paulo is the largest industrialized region of Latin America and has a highly polluted atmosphere. Concentrations of dioxins and furans, which are well-known toxic chemicals, ranged from 1.14 pg m-3 to 13.8 pg m-3 (0.047 pg I-TEQ m-3 to 0.751 pg I-TEQ m-3). Principal component analysis showed that all the variables are highly correlated with one another except the 2,3,7,8-TCDD one. This is consistent with the similar concentration profiles observed for the tetra, penta, hexa, hepta and octa-homologous groups of the three sampling sites studied. At all sites, the most abundant compounds were the hepta and octa congeners. The 2,3,4,7,8-PeCDF accounted for 37-46% of the total toxicity and the 2,3,7,8-TCDD accounted for 7-16%. Highest mass concentrations of PCDD/Fs were found in the site where there is influence of industrial activities and heavy vehicular traffic fueled by gasohol, diesel, and ethanol.