Emission factors for high-emitting vehicles based on on-road measurements of individual vehicle exhaust with a mobile measurement platform

Fuel-based emission factors for 143 light-duty gasoline vehicles (LDGVs) and 93 heavy-duty diesel trucks (HDDTs) were measured in Wilmington, CA using a zero-emission mobile measurement platform (MMP). The frequency distributions of emission factors of carbon monoxide (CO), nitrogen oxides (NO(x)), and particle mass with aerodynamic diameter below 2.5 microm (PM2.5) varied widely, whereas the average of the individual vehicle emission factors were comparable to those reported in previous tunnel and remote sensing studies as well as the predictions by Emission Factors (EMFAC) 2007 mobile source emission model for Los Angeles County. Variation in emissions due to different driving modes (idle, low- and high-speed acceleration, low- and high-speed cruise) was found to be relatively small in comparison to intervehicle variability and did not appear to interfere with the identification of high emitters, defined as the vehicles whose emissions were more than 5 times the fleet-average values. Using this definition, approximately 5% of the LDGVs and HDDTs measured were high emitters. Among the 143 LDGVs, the average emission factors of NO(x), black carbon (BC), PM2.5, and ultrafine particle (UFP) would be reduced by 34%, 39%, 44%, and 31%, respectively, by removing the highest 5% of emitting vehicles, whereas CO emission factor would be reduced by 50%. The emission distributions of the 93 HDDTs measured were even more skewed: approximately half of the NO(x) and CO fleet-average emission factors and more than 60% of PM2.5, UFP, and BC fleet-average emission factors would be reduced by eliminating the highest-emitting 5% HDDTs. Furthermore, high emissions of BC, PM2.5, and NO(x) tended to cluster among the same vehicles.     

Environmental performance evaluation and strategy management using balanced scorecard

Recently, environmental protection and regulations such as WEEE, ELV, and RoHS are rapidly emerging as an important issue for business to consider. The trend of swinging from end-of-pipe control to product design, green innovation, and even the establishment of image or brand has affected corporations in almost every corner in the world, and enlarged to the all modern global production network. Corporations must take proactive environmental strategies to response the challenges. This study adopts balanced scorecard structure and aim at automobile industries to understand the relationships of internal and external, financial and non-financial, and outcome and driving factors. Further relying on these relationships to draw the “map of environment strategy” to probe and understand the feasibility of environmental performance evaluation and environmental strategy control.     

Experimental Evaluation of the Sustainability of Dwarf Bamboo (Pseudosasa usawai) Sprout-Harvesting Practices in Yangminshan National Park,Taiwan

Sustainable harvest of natural products that meets the needs of local people has been viewed by many as an important means for sustaining conservation projects. Although plants often respond to tissue damage through compensatory growth, it may not secure long-term sustainability of the populations because many plants enhance individual well-being at the expense of propagation. Sustainability may further be threatened by infrequent, large-scale events, especially ill-documented ones. We studied the impacts of sprout harvesting on sprout growth in a dwarf bamboo (Pseudosasa usawai) population that has seemingly recovered from an infrequent, large-scale masting event. Experimental results suggest that although a single sprout harvest did not significantly alter the subsequent abundance and structure of sprouts, culm damage that accompanied sprout harvesting resulted in shorter, thinner, and fewer sprouts. Weaker recovery was found in windward, continually harvested, and more severely damaged sites. These findings suggest that sprout growth of damaged dwarf bamboos is likely non-compensatory, but is instead supported through physiological integration whose strength is determined by the well-being of the supplying ramets. Healthy culms closer to the damage also provided more resources than those farther away. Sustainable harvesting of sprouts could benefit from organized community efforts to limit the magnitude of culm damage, provide adequate spacing between harvested sites, and ensure sufficient time interval between harvests. Vegetation boundaries relatively resilient to infrequent, large-scale events are likely maintained by climatic factors and may be sensitive to climate change. Continual monitoring is, therefore, integral to the sustainability of harvesting projects.     

Performance measurement for incineration plants using multi-activity network data envelopment analysis: The case of Taiwan

This study proposes the use of multi-activity network data envelopment analysis to appraise how incineration plants in Taiwan perform. Sample data from 2006 is used to examine the trade-offs between efficiency enhancement and pollution abatement. The respective efficiencies of the waste treatment and electricity generation are also assessed in a unified framework. The empirical results indicate that it is more important to improve the efficiency of waste treatment activity than of electricity generation activity in order to enhance the overall performance of Taiwan's incinerators. Since ownership, location and length of operations do not in general affect their performance, any improvement has to come from the careful monitoring of each process of the waste treatment operations. Furthermore, given that the policy in Taiwan has moved away from incineration to recycling, the problem of an over-supply of incinerators may become apparent in the near future. Our results indicate that the availability of capacity size may be an important factor when policy-makers consider whether to close down some existing incinerators.     

Multi-criteria analysis via the VIKOR method for prioritizing land-use restraint strategies in the Tseng-Wen reservoir watershed

It is important to adopt proper water and soil conservation and land-use planning in a watershed for lowering adverse impacts on reservoir water quality. Although reservoir watersheds occupy a large amount of land in Taiwan, high population density has exerted development pressures on such land. Therefore, the priority ranking of land-use restrictions for the subdivisions with different degrees of environmental vulnerability is necessary in watershed management. Since there are several criteria for evaluating the potential environmental impact from the subdivisions, multi-criteria analysis was applied as a technique for solving these problems in this study. The VIKOR method was applied to determine the best feasible solution according to the selected criteria, including geographical and meteorological factors. The objective of this study was to establish the priority ranking of land-use restrictions in the Tseng-Wen reservoir wastershed in southern Taiwan. The results show that subdivisions close to the outlet or reservoir area should have the priority of land-use restrictions.     

INVESTIGATION OF TURBIDITY MAXIMUM IN A MESOTIDAL ESTUARY,TAIWAN1

ABSTRACT: To comprehend the distributions of salinity, temperature, and suspended sediment in the Danshuei River estuary in Taiwan, monthly field surveys were conducted in 2003. These included several high and low slackwater surveys and intensive surveys. The results show that the Danshuei River estuary is predominately a partially mixed estuary. The highest concentration of suspended sediment is typically observed at the Chung‐Hsin Bridge, the most upstream sampling station. The suspended sediment concentration exhibits a general decreasing trend in the downstream direction. It may be concluded that the sediments mostly come from the upstream reach. A locally high concentration of suspended sediment is found at the Kuan‐Du station because of the local deep channel bathymetry and two‐layered estuarine circulation. A vertical two‐dimensional hydrodynamic and sediment transport model is applied to investigate the tidally averaged salinity distribution, residual circulation, and suspended sediment concentration. The modeling results reveal that, under the Q₇₅ flow condition (i.e., low flow), a turbidity maximum occurs at the Kuan‐Du station due to the strong estuarine circulation. The model simulation with a much higher river flow condition results in a weaker residual circulation and weaker turbidity maximum.     

Particle release transport in Danshuei River estuarine system and adjacent coastal ocean: a modeling assessment

A three-dimensional hydrodynamic model was created to study the Danshuei River estuarine system and adjacent coastal ocean in Taiwan. The model was verified using measurements of the time-series water surface elevation, tidal current, and salinity from 1999. We conclude that our model is consistent with these observations. Our particle-tracking model was also used to explore the transport of particles released from the Hsin-Hai Bridge, an area that is heavily polluted. The results suggest that it takes a much longer time for the estuary to be flushed out under low freshwater discharge conditions than with high freshwater discharge. We conclude that the northeast and southwest winds minimally impact particle dispersion in the estuary. The particles fail to settle to the bottom in the absence of density-induced circulation. Our model was also used to simulate the ocean outfall at the Bali. Our experimental results suggest that the tidal current dominates the particle trajectories and influences the transport properties in the absence of a wind stress condition. The particles tend to move northeast or southwest along the coast when northeast or southwest winds prevail. Our data suggest that wind-driven currents and tidal currents play important roles in water movement as linked with ocean outfall in the context of the Danshuei River.     

IMS Method Performance Analyses for Giardia in Water Under Differing Conditions

Immunomagnetic separation (IMS) has been specified as a standard method for the measurement of Giardia under USEPA Method 1623. In this study, IMS was evaluated on the basis of recovery efficiencies for Giardia cysts under various IMS operation conditions. Significant change in recovery was observed by altering the debris ratio of water samples. Notably, cyst recovery efficiencies utilizing IMS dropped with increased turbidity, and results for varying dosages of magnetic beads and cysts indicate that 1 / 100 immunomagnetic beads is sufficient to conjugate large numbers of cysts. Changing vessel volume and replacing the sample buffer had no significant effect on cyst recovery efficiencies.     

An occupational exposure assessment of polychlorinated dibenzo-p-dioxin and dibenzofurans in firefighters

Polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) are unintentional byproducts of combustion and industrial processes. Firefighters face the risk of occupational exposure to PCDD/Fs. Congener-specific analyses of 17 PCDD/Fs were performed on 20 serum samples collected from firefighters and fire scene investigators, and four soot samples that had deposited on the surfaces of the fire helmets and were collected after the firefighters had fought fires. The PCDD/F concentrations on the helmets that were contaminated by being worn at the fire scenes were 63-285 times higher than those on a clean helmet. The median serum PCDD/F concentration of the 16 firefighters (12 pg WHO₂₀₀₅-TEQ g⁻¹ lipid) was not different from those of the males from the general Taiwanese population (9.4 pg WHO₂₀₀₅-TEQ g⁻¹ lipid). However, the median PCDD/F level in the four fire scene investigators (15 pg WHO₂₀₀₅-TEQ g⁻¹ lipid) was higher than those in the male from the general Taiwanese population (Mann-Whitney U test, p < 0.01). Furthermore, the serum samples from the firefighters and fire scene investigators, and the soot samples from the fire scenes presented similarly distinctive PCDD/F profiles that had elevated proportions for 10 PCDF congeners. Limited data indicated that the fire scene investigators were occupationally exposed to PCDD/Fs at the fire scenes. We suggested that the firefighters were not occupationally exposed to PCDD/Fs at the fire scenes due to appropriate protection. However, the fire scene investigators may have had more occupational exposure to PCDD/Fs due to poor protection, and further research must be performed to confirm this.