Full-Scale Study of Plume Rise At Large Coal-Fired Electric Generating Stations

This paper reports on the plume rise research project conducted by TVA under sponsorship of the U. S. Public Health Service. Plume rise data were collected at six coal-fired, steam-electric generating stations within the TVA system over a 2-year period. Unit ratings ranged from 173 to 704 Mw with stack heights varying from 250 to 600 ft. An instrumented helicopter and special photographic equipment were used to obtain 1580 separate plume observations and significant related meteorological parameters during stable, neutral, and slightly unstable conditions. The 1580 observations were resolved and consolidated into 133 composite observation periods covering 30 to 120 min. Meteorological parameters and other compiled input data were entered into four principal equations for calculation of plume rise, and calculated plume rise values were compared with observed values. Most equations overestimated plume rise in low wind speed. For moderately high wind speeds, the Carson and Moses and the Concawe equations gave best fit.     

Air Pollution Damage to Exterior Household Paints

ABSTRACT

The present study focuses on the elemental characterization of fine and coarse particles collected at a coastal site of southwestern Italy, in a suburban area of the Calabria region. A chemical tracer analysis was carried out to identify the major emission sources influencing on the atmospheric aerosol levels. Size-resolved particulate samples were collected during three 2-week seasonal sampling campaigns: autumn (19 October to 2 November 2003), winter (19 January to 2 February 2004) and spring (26 April to 10 May 2004). Ambient concentrations of selected elements (Fe, Mn, Mg, Ca, V, Cu, Cr, Ni, Zn, Pb, and Cd) associated to fine and coarse size fractions were determined using atomic absorption spectrometry (AAS). The enrichment factor method was applied, suggesting a prevailing anthropogenic component for all the detected elements, with Fe, Mg, Mn, and Ca as exceptions. Trajectory sector analysis was used in order to discriminate the influence of different air mass origins and paths. Long-range transport from both the continental Europe and the Saharan region proved to be the main influencing factors. African dust outbreaks, whose occurrence frequency was greater during the autumn and spring seasonal monitoring periods, gave rise to a total of eight exceedances of the European Commission (EC) PM₁₀ daily limit value as well as an increase in values of the crustal-derived elements (Fe, Mg, and Ca). Long-range transport from the heavily industrialized area of Central/Eastern Europe contributed to the high levels of Zn, Cd, and Pb that were recorded during the winter sampling campaign. Seasonal trend and comparison with measurements previously performed across the Mediterranean basin were also presented and discussed.

IMPLICATIONS This paper, which investigates both natural and anthropogenic aerosol sources, contributes to the characterization of fine and coarse particles in a suburban area of the southern Italian region of Calabria whose air quality assessment is still being defined. The monitoring site involved in this study, located at the interface between continental Europe and the Mediterranean basin, offers an important platform to study the influence of seasonal meteorology and predominant circulation patterns on the aerosol concentration levels and their chemical composition.     

The Effect of Ethanol Fuel on the Emissions of Vehicles over a Wide Range of Temperatures

ABSTRACT

The emissions from a fleet of 11 vehicles, including three from the State of Alaska, were tested at 75, 0, and -20 °F with base gasolines and E10 gasolines, that is, gasolines with 10% by volume ethanol added. The data for the changes in emissions for the test run at 75 °F are included, since most other studies on the effects of E10 gasoline on emissions were run at that temperature. The three Alaskan vehicles were also tested at 20 °F. The testing followed the Federal Test Procedure, and regulated emissions—CO, total hydrocarbons (THC), and nitrogen oxides (NO_x)—CO₂, speciated organics, and fuel economy were measured. A total of 490 FTP tests were run. The data obtained indicated that with most vehicles, at the temperatures tested, improvements in both CO and THC emissions were obtained with the use of E10 fuel. At the lowest temperature used, -20 °F, most vehicles had an increase in NO emissions with the use of E10 fuel. At the other temperatures, however, more vehicles showed a decrease in NO_x emissions with the use of E10. With all vehicles at all temperatures tested, the emissions of acetaldehyde increased significantly when E10 fuel was used. The highest increase was about 8 to 1. Benzene, formaldehyde, and 1,3 butadiene showed both increases and decreases in the emissions when using E10 fuel. Unexpected results were obtained with the fuel economy, with about half of the tests showing an increase in fuel economy with the use of E10 fuel.     

Setting population-size targets for geese causing socio-economic conflicts

Most European goose populations have increased exponentially, and this has increasingly brought them into conflict with human activities. To manage this conflict, we used multi-criteria decision analysis to help set population targets for a super-abundant population of greylag geese (Anser anser). We relied on expert elicitation to assess the consequences of varying goose abundance on nine ecological, economic, and societal objectives. Representatives from national governments and from non-governmental organizations then weighted the objectives based on their perceived relative importance, and we used a consensus-convergence model to reach stakeholder agreement on the tradeoffs among objectives. The preferred population targets for two management units represent about a 20% reduction from current abundances, which from a management perspective would require considerable effort above and beyond current population-control measures. We believe that multi-criteria decision analysis can provide a systematic and transparent framework for building consensus among diverse stakeholders in a wide array of human-wildlife conflicts.     

Real-world vehicle emissions: a summary of the Sixteenth Coordinating Research Council On-Road Vehicle Emissions Workshop

The Coordinating Research Council held its 16th workshop in March 2006, with 83 presentations describing the most recent mobile source-related emissions research. In this paper, we summarize the presentations from researchers who are engaged in improving our understanding of the contribution of mobile sources to air quality. Participants in the workshop discussed evaluation of in-use emissions control programs, effects of fuels on emissions, emission models and emission inventories, results from gas- and particle-phase emissions studies from spark-ignition and diesel-powered vehicles, and efforts to improve our capabilities in performing on-board emissions measurements, as well as topics for future research.     

Not if,but when we need resilience in the workplace

Workplace resilience is a necessity for organizations and employees given it assists them in overcoming adversity and ultimately succeeding. However, organizational scholars have largely overlooked this construct. In this Incubator, we briefly summarize extant research on workplace resilience to highlight opportunities for theory building and advancement of empirical research. Copyright © 2015 John Wiley & Sons, Ltd.     

Deciding when to explore and when to persist: a comparison of honeybees and bumblebees in their response to downshifts in reward

As the distribution of food resources shifts over time, central place foragers are likely to be repeatedly faced with the question of when to abandon a forage site that is declining in value and to subsequently search elsewhere. Although there has been a great deal of investigation into how individual foragers allocate time between exploration and exploitation, few studies have sought to explore this issue within a larger functional context. We take a comparative approach to this problem by examining decision making in individual honeybees and bumblebees as they responded to a downshift in food reward. Our results show not only that honeybees and bumblebees have significantly divergent strategies with regards to abandoning a food source that is declining in value but also in terms of the subsequent tendency to seek an alternative food source. We interpret these results in terms of both biological and social distinctions between these species and highlight how group-level characteristics are likely to shape the evolutionarily derived foraging strategies of individual animals.     

When Are Peripheral Populations Valuable for Conservation?

A great deal of effort is spent protecting geographically peripheral populations of widespread species. We consider under what conditions it is appropriate to expend resources to protect these populations. The conservation value of peripheral populations depends upon their genetic divergence from other conspecific populations. Peripheral populations are expected to diverge from central populations as a result of the interwoven effects of isolation, genetic drift, and natural selection. Available empirical evidence suggests that peripheral populations are often genetically and morphologically divergent from central populations. The long-term conservation of species is likely to depend upon the protection of genetically distinct populations. In addition, peripheral populations are potentially important sites of future speciation events. Under some circumstances, conservation of peripheral populations may be beneficial to the protection of the evolutionary process and the environmental systems that are likely to generate future evolutionary diversity.     

Ergonomic evaluation of a new truck seat design: a field study

A postural evaluation of commercial licensed truck drivers was conducted to determine the ergonomic benefits of a truck seat prototype in comparison with an industry standard seat. Twenty commercially licensed truck drivers were recruited to perform a 90-min driving task. Postures were assessed using accelerometers and a backrest and seat pan pressure mapping system. Subjective discomfort measurements were monitored using two questionnaires: ratings of perceived discomfort (RPD) and the automotive seating discomfort questionnaire (ASDQ). Participants reported significantly higher discomfort scores when sitting in the industry standard seat. Participants sat with more lumbar lordosis and assumed a more extended thoracic posture when seated in the prototype. Pairing the gluteal backrest panel with the adjustable seat pan also helped reduce the average sitting pressure on both the seat pan and the backrest. The prototype provided several postural benefits for commercially certified truck drivers, as it did for a young and healthy population.