Quantification of personal exposure concentrations to gasoline vehicle emissions in high-end exposure microenvironments: Effects of fuel and season

Mobile-source air toxic (MSAT) levels increase in confining microenvironments (MEs) with numerous emission sources of vehicle exhaust or evaporative emissions or during high-load and cold-start conditions. Reformulated fuels are expected to reduce MSAT and ozone precursor emissions. This study, required under the Clean Air Act Section 211b, evaluated high-end exposures in cities using reformulated (methyl tertiary-butyl ether [MTBE] or ethanol [EtOH]) fuels and conventional gasoline blends. The study investigates 13 high-end MEs, sampling under enhanced exposure conditions expected to result in maximal fuel and exhaust component exposures to carbon monoxide (CO), carbon dioxide (CO₂), BTEX (benzene, toluene, ethylbenzene, xylenes), MTBE, 1,3-butadiene (1,3-BD), EtOH, formaldehyde (HCHO), and acetaldehyde (CH₃CHO). The authors found that day-to-day ME variations in high-end benzene, 1,3-BD, HCHO, and CO concentrations are substantial, but independent of gasoline composition and season, and related to the activity and emission rates of ME sources, which differ from day to day.

Implications: Mobile-source air toxic (MSAT) levels increase in confining microenvironments (MEs) in the presence of vehicular exhaust or evaporative emissions. This study, required under the Clean Air Act Section 211b, evaluated high-end exposures in cities using oxygenated (methyl tertiary-butyl ether or ethanol) and conventional gasoline blends. Personal exposure concentrations were quantified in selected MEs representing the upper end of the frequency distribution of potential population exposures. This work presents the first systematic look at high-end/maximal exposures to multiple contaminants, in multiple microenvironments, in multiple cities, over two seasons, for multiple fuels, making it a very complete evaluation of reformulated fuel impacts on MSAT concentrations in confined microenvironments. The study found that day-to-day ME variations of high-end pollutant concentrations are substantial, but independent of gasoline composition and season, and related to the variable daily activity and emission rates of ME sources. The data collected in this study may be used in bounding exposure modeling estimates that account for time spent in similar confining MEs.     

Characterization of solid-phase microextraction and gas chromatography for the analysis of gasoline tracers in different microenvironments

Gasoline tracers were collected on solid-phase microextraction (SPME) fibers and analyzed by capillary gas chromatography with photoionization detector (GC/PID). This was part of a larger study to quantify personal exposure to motor vehicle gasoline evaporative and combustive emissions in high-end exposure microenvironments (MEs). The SPME fiber selected for this application was a 75-microm carboxen/polydimethylsiloxane. Sequential 10-min samples were collected for measurement of benzene, toluene, ethylbenzene, and ortho-, meta-, and para-xylene in different MEs in Atlanta, GA, in summer 2002 and Reno, NV, in spring 2003. Field calibrations were performed with certified gas standards in 1-L Tedlar bags for varying concentrations and exposure times. SPME detection limits were approximately 0.2 ppbv with a precision of 3-17% and accuracy of 30%. A dynamic system was designed for temperature and relative humidity calibrations, with corrections for the effects of these variables performed when necessary. SPME data compared satisfactorily with integrated canister samples, continuous PID, and field portable mass spectrometer data.     

Evaluation of regional bioenergy recovery by local methane fermentation thermal recycling systems

This paper evaluates the potential for regional bioenergy recovery as electricity and heat by small-scale methane fermentation systems from organic waste matter generated from urban, industrial, and agricultural sectors. Biogas production functions of high-strength organic wastes are derived from data of implemented methane fermentation systems. The distributions of organic wastes from sewage, household, wholesale/retail, manufacturing, farming, and livestock activities in the Tokyo Bay region are calibrated into a disaggregated spatial database by compiling general activity statistics and emission intensity parameters using Geographic Information System (GIS). Three scenarios of organic matter circulation by co-digestion in sewage treatment plants (STPs) are designed and assessed. Surplus electricity and heat from methane fermentation systems are used for STP operations and household demand. The spatial database allows a preliminary examination for the suitability of locations for technology implementation from the aspects of bioenergy supply and balance. The results show that an additional 368,000-1,328,000MW of electricity would be generated, and 1300-3600TJ of heat could be used by households, reducing the annual emissions of CO(2) from fossil fuels by 307,000-798,000t.     

Relationship between traffic fatalities and drunk driving in Japan

OBJECTIVE: The present study was performed to clarify the relation between alcohol use and traffic fatalities in accidents involving motor vehicles in Japan. METHODS: Data on traffic accidents were collected from Fukuoka Prefectural Police records of traffic accidents which occurred in that prefecture between 1987 and 1996. Multiple logistic regression models were used to assess the effect of alcohol use on the risk of traffic-accident death. RESULTS: The data showed that 58,421 male drivers were involved in traffic accidents during the 10-year study period, and that 271 of these were killed as a result of the accident. Alcohol use was significantly associated with speed, seat belt use, time, and road form. Among male motorcar drivers, the odds ratio of alcohol use before driving, after adjusting for age, calendar year, time, and road form, was 4.08 (95% confidence interval, 3.08-5.40), which means that about 75% of fatalities (attributable risk percent among exposed) might have been prevented if drivers had not drunk before driving. CONCLUSIONS: Alcohol use before driving resulted in a 4.08-fold increase in the risk of death in a traffic accident. It is suggested that alcohol use is considered an important risk factor for fatality in traffic accidents.     

Estimating photophysiological condition of endosymbiont-bearing Baculogypsina sphaerulata based on the holobiont color represented in CIE L*a*b* color space

Symbiont-bearing large benthic foraminifers (LBFs) are widely distributed around coral reefs. If the physiological responses of LBFs to environmental changes can be recognized at an individual level, LBFs could serve as highly accurate bioindicators. In this study, chlorophyll a, respiration, and photosynthesis of Baculogypsina sphaerulata individuals were measured, and whether these physiological traits could be estimated based on the color of the holobiont (foraminifera and the diatom symbionts) was examined. Chlorophyll a content was estimated using a* and b* values of holobiont color represented in CIE L*a*b* color space. Photosynthetic performance decreased significantly with increasing whiteness (L*). These results indicated chlorophyll content as well as photosynthetic performance of Baculogypsina could be directly estimated using the holobiont color. The increased whiteness in color and decreased photosynthetic performance were mainly observed under low-light environment, possibly indicating symbiotic algae were shrunk into the central part of the host shell due to prolonged exposure to adverse conditions.     

Pharyngeal aspiration of single-wall carbon nanotubes aggravates allergic reaction to inhaled ovalbumin in mice

Single-wall carbon nanotubes are a major type of nano-objects that have industrial applications such as fuel cells. In this study, four types of single-wall carbon nanotubes and their abilities to aggravate allergic reactions were examined: those containing Fe, those containing Ni, and the corresponding purified metal-free ones. These were administered to mice via pharyngeal aspiration. Subsequently, the mice inhaled ovalbumin a total of eight times over three weeks. After inhalation of ovalbumin, the concentrations of total immunoglobulin E and ovalbumin-specific immunoglobulin E in serum increased in mice treated with purified metal-free and Fe containing single-wall carbon nanotubes while those containing Ni did not affect total and ovalbumin-specific immunoglobulin E levels. Additionally, the purified metal-free and Fe containing nanotubes caused the gene expression of heme oxygenase-1, chemokine (C-X-C motif) ligand 2, and tumor necrosis factor-α, suggesting that some kinds of single-wall carbon nanotubes have the potential to aggravate allergic reactions via oxidative stress and inflammation. Incorporated metals do not seem to be involved in the aggravation of allergic reactions. Other physical properties, such as fiber length and aggregation state, may be involved in enhancing allergic reactions.     

Evaluation of innovative municipal solid waste management through urban symbiosis: a case study of Kawasaki

Industrial symbiosis encourages the establishment of a broad eco-industrial network so that more synergy opportunities can be identified. By linking municipal solid waste management (MSWM) with local industries, i.e., urban symbiosis, new symbiotic opportunities can be generated from the geographic proximity of urban and industrial areas, transferring physical resources from urban refuse directly to industrial applications and improving the overall eco-efficiency of the city as a whole. Using a case study of Kawasaki, this paper simulates and evaluates an innovative waste management initiative in Kawasaki by an scenario simulation model based on the LCA approach. Results show that recycling mixed paper, mixed plastics, and organic wastes and utilizing the recycled materials in industrial production will potentially reduce about 69 kt CO₂(e) emissions and 8 kt incineration ashes to be landfilled in 2015. To achieve these outcomes, the total additional cost compared with the current practice is about 1.2 billion JPY.     

Pigments of meso- and bathypelagic chaetognaths

Pigments of the meso- and bathypelagic chaetognaths Sagitta macrocephala and Eukrohnia fowleri were studied by chromatographic analysis. Supplementary histological studies were also performed. Fat-soluble properties and absorption spectra of the chaetognath pigments indicated that all pigments were carotenoid, independent of chaetognath species or habitat. The major carotenoid in chaetognaths was very soluble in nonpolar solvents such as carotenes, although its absorption spectrum formed a single broad peak at around 460 nm. The characteristics of the carotenoids in the chaetognaths were different from those of the pigments in the plankton which formed their diet. It is therefore inferred that carotenoids in chaetognaths are not formed by the deposition of food pigments in the intestinal tissue, but are synthesized by the chaetognaths themselves.     

Diurnal and weekday variations in the source contributions of ozone precursors in California's South Coast Air Basin

For at least 30 years, ozone (O3) levels on weekends in parts of California's South Coast (Los Angeles) Air Basin (SoCAB) have been as high as or higher than on weekdays, even though ambient levels of O3 precursors are lower on weekends than on weekdays. A field study was conducted in the Los Angeles area during fall 2000 to test whether proposed relationships between emission sources and ambient nonmethane hydrocarbon (NMHC) and oxides of nitrogen (NOx) levels can account for observed diurnal and day-of-week variations in the concentration and proportions of precursor pollutants that may affect the efficiency and rate of O3 formation. The contributions to ambient NMHC by motor vehicle exhaust and evaporative emissions, estimated using chemical mass balance (CMB) receptor modeling, ranged from 65 to 85% with minimal day-of-week variation. Ratios of ambient NOx associated with black carbon (BC) to NOx associated with carbon monoxide (CO) were approximately 1.25 +/- 0.22 during weekdays and 0.76 +/- 0.07 and 0.52 +/- 0.07 on Saturday and Sunday, respectively. These results demonstrate that lower NOx emissions from diesel exhaust can be a major factor causing lower NOx mixing ratios and higher NMHC/NOx ratios on weekends. Nonmobile sources showed no significant day-of-week variations in their contributions to NMHC. Greater amounts of gasoline emissions are carried over on Friday and Saturday evenings but are, at most, a minor factor contributing to higher NMHC/NOx ratios on weekend mornings.     

Characterizing kinetics of transport and transformation of selenium in water-sediment microcosm free from selenium contamination using a simple mathematical model

This study developed a seven-compartment model for predicting the fate of selenium (Se) in an aquatic environment containing a water-sediment boundary. Speciation of Se in water-sediment microcosms under microaerobic conditions was measured to evaluate first-order kinetics of Se transportation and transformation. The microcosm consisted of a 10-ml solution containing 1mM soluble Se as selenate (Se6+) or selenite (Se4+) and 8 g wet sediment that was free from Se contamination, sampled from the Senri, Yamato, or Yodo Rivers in Osaka, Japan. Stepwise reaction coefficients describing transportation and transformation were determined using an inverse method on this model which includes: selenate (Se(W)6+) and selenite (Se(W)4+) in ponded water; selenate (Se(S)6+) and selenite (Se(S)4+), elemental Se (Se0), organic Se (Se2-) in sediment; and gaseous Se (DMSe). During this 1-month experiment, soluble Se was transported from ponded water to the sediment and Se was transformed sequentially to other Se species through biochemical reactions. Experimental and kinetic analyses indicated quantitatively that the Yamato River microcosm, with its high organic matter content, had a high adsorption rate of soluble Se. The Yodo River microcosm had a low adsorption rate for Se6+ and a low Se reduction rate. The Senri River microcosm had an apparent high volatilization rate of DMSe. The model developed in this study is extremely useful for predicting fate of Se in aquatic environment in the field.