Measurements of primary trace gases and NOY composition in Houston,Texas

Concentrations of CO, SO₂, NO, NO₂, and NO_Y were measured atop the University of Houston's Moody Tower supersite during the 2006 TexAQS-II Radical and Aerosol Measurement Project (TRAMP). The lowest concentrations of all primary and secondary species were observed in clean marine air in southerly flow. SO₂ concentrations were usually low, but increased dramatically in sporadic midday plumes advected from sources in the Houston Ship Channel (HSC), located NE of the site. Concentrations of CO and NO_x displayed large diurnal variations in keeping with their co-emission by mobile sources in the Houston Metropolitan Area (HMA). CO/NO_x emission ratios of 5.81 ± 0.94 were observed in the morning rush hour. Nighttime concentrations of NO_x (NO_x = NO + NO₂) and NO_Y (NO_Y = NO + NO₂ + NO₃ + HNO₃ + HONO + 21N₂O₅ + HO₂NO₂ + PANs + RONO₂ + p-NO₃^? + …) were highest in winds from the NNW-NE due to emission from mobile sources. Median ratios of NO_x/NO_Y were approximately 0.9 overnight, reflecting the persistence and/or generation of NO_Z (NO_Z = NO_Y ? NO_x) species in the nighttime Houston boundary layer, and approached unity in the morning rush hour. Daytime concentrations of NO_x and NO_Y were highest in winds from the HSC. NO_x/NO_Y ratios reached their minimum values (median ca 0.63) from 1300 to 1500 CST, near local solar noon, and air masses often retained enough NO_x to sustain additional O₃ formation farther downwind. HNO₃ and PANs comprised the dominant NO_Z species in the HMA, and on a median basis represented 17–20% and 12–15% of NO_Y, respectively, at midday. Concentrations of HNO₃, PANs, and NO_Z, and fractional contributions of these species to NO_Y, were at a maximum in NE flow, reflecting the source strength and reactivity of precursor emissions in the HSC. As a result, daytime O₃ concentrations were highest in air masses with HSC influence. Overall, our findings confirm the impact of the HSC as a dominant source region within the HMA. A comparison of total NO_Y measurements with the sum of measured NO_Y species (NO_Yi = NO_x + HNO₃ + PANs + HONO + p-NO₃^?) yielded excellent overall agreement during both day ([NO_Y](ppb) = ([NO_Yi](ppb)11.03 ± 0.16) ? 0.42; r² = 0.9933) and night ([NO_Y](ppb) = ([NO_Yi](ppb)11.01 ± 0.16) + 0.18; r² = 0.9975). A similar comparison between NO_Y–NO_x concentrations and the sum of NO_Zi (NO_Zi = HNO₃ + PANs + HONO + p-NO₃^?) yielded good overall agreement during the day ([NO_Z](ppb) = ([NO_Zi](ppb)11.01 ± 0.30) + 0.044 ppb; r² = 0.8527) and at night ([NO_Z](ppb) = ([NO_Zi](ppb)11.12 ± 0.69) + 0.16 ppb; r² = 0.6899). Median ratios of NO_Z/NO_Zi were near unity during daylight hours but increased to approximately 1.2 overnight, a difference of 0.15–0.50 ppb. Differences between NO_Z and NO_Zi rarely exceeded combined measurement uncertainties, and variations in NO_Z/NO_Zi ratios may have resulted solely from errors in conversion efficiencies of NO_Y species and changes in NO_Y composition. However, nighttime NO_Z/NO_Zi ratios and the magnitude of NO_Z ? NO_Zi differences were generally consistent with recent observations of ClNO₂ in the nocturnal Houston boundary layer.     

An introduction to decision science for conservation

Biodiversity conservation decisions are difficult, especially when they involve differing values, complex multidimensional objectives, scarce resources, urgency, and considerable uncertainty. Decision science embodies a theory about how to make difficult decisions and an extensive array of frameworks and tools that make that theory practical. We sought to improve conceptual clarity and practical application of decision science to help decision makers apply decision science to conservation problems. We addressed barriers to the uptake of decision science, including a lack of training and awareness of decision science; confusion over common terminology and which tools and frameworks to apply; and the mistaken impression that applying decision science must be time consuming, expensive, and complex. To aid in navigating the extensive and disparate decision science literature, we clarify meaning of common terms: decision science, decision theory, decision analysis, structured decision-making, and decision-support tools. Applying decision science does not have to be complex or time consuming; rather, it begins with knowing how to think through the components of a decision utilizing decision analysis (i.e., define the problem, elicit objectives, develop alternatives, estimate consequences, and perform trade-offs). This is best achieved by applying a rapid-prototyping approach. At each step, decision-support tools can provide additional insight and clarity, whereas decision-support frameworks (e.g., priority threat management and systematic conservation planning) can aid navigation of multiple steps of a decision analysis for particular contexts. We summarize key decision-support frameworks and tools and describe to which step of a decision analysis, and to which contexts, each is most useful to apply. Our introduction to decision science will aid in contextualizing current approaches and new developments, and help decision makers begin to apply decision science to conservation problems.     

Pyrolysis-GC-MS analysis of crude and heavy fuel oil asphaltenes for application in oil fingerprinting

A Pyrolysis – Gas Chromatography – Mass Spectrometry (Py-GC-MS) method was developed for the analysis and profiling of crude and heavy fuel oil asphaltenes, for application in oil fingerprinting. Asphaltenes were precipitated from ten geographically different oils using n-pentane, and analysed by Py-GC-MS. Alkane profiles and sulphur/aromatic profiles were used to compare the oils, and to correctly differentiate oils from different geographical regions. Py-GC-MS could not differentiate a weathered oil sample and a fresh oil sample from the same source. The results of this study support the findings from a previously developed FTIR method for asphaltene profiling.     

Implications of Land Use/Land Cover Change in the Buffer Zone of a National Park in the Tropical Andes

The impacts of land use and land cover (LULC) change in buffer zones surrounding protected ecological reserves have important implications for the management and conservation of these protected areas. This study examines the spatial and temporal patterns of LULC change along the boundary of Rio Abiseo National Park in the Northern Peruvian Andes. Landscape change within four ecological zones was evaluated based on trends expected to occur between 1987 and 2001. Landsat TM and ETM imagery were used to produce LULC classification maps for both years using a hybrid supervised/unsupervised approach. LULC changes were measured using landscape metrics and from-to change maps created by post-classification change detection. Contrary to expectations, tropical upper wet montane forest increased despite being threatened by human-induced fires and cattle grazing of the highland grasslands inside the park. Within the park’s buffer zone, tropical moist forest remnants were fragmented into more numerous and smaller patches between 1987 and 2001; this was in part due to conversion into agricultural land. The methods used in this study provide an effective way to monitor LULC change detection and support the management of protected areas and their surrounding environments.     

Environmentalism and elitism: a conceptual and empirical analysis

The frequent charge that environmentalism is elitist is examined conceptually and empirically. First, the concept of elitism is analyzed by distinguishing between three types of accusations made against the environmental movement: (a)compositional elitism suggests that environmentalists are drawn from privileged socioeconomic strata, (b)ideological elitism suggests that environmental reforms are a subterfuge for distributing benefits to environmentalists and/or costs to others, and (c)impact elitism suggests that environmental reforms, whether intentionally or not, do in fact have regressive social impacts.The evidence bearing on each of the three types of elitism is examined in some detail, and the following conclusions are drawn: Compositional elitism is an exaggeration, for although environmentalists are typically above average in socioeconomic status (as are most sociopolitical activists), few belong to the upper class. Ideological elitism may hold in some instances, but environmentalists have shown increasing sensitivity to equity concerns and there is little evidence of consistent pursuit of self-interest. Impact elitism is the most important issue, and also the most difficult to assess. It appears that there has been a general tendency for environmental reforms to have regressive impacts. However, it is increasingly recognized that problems such as workplace pollution and toxic waste contamination disproportionately affect the lower socioeconomic strata, and thus reforms aimed at such problems will likely have more progressive impacts.This is Michigan Agricultural Experiment Station Journal article no. 11508.     

SIMULATION OF RUNOFF FROM URBAN WATERSHEDS1

ABSTRACT. .A mathematical model for urban watersheds is being developed in stages at the Utah Water Research Laboratory, Utah State University at Logan. In verifying the watershed as a unit, watershed coefficients are determined on the computer, and related to the urbanization characteristics. The second stage of verification consists of dividing the watershed into subzones, and determining the urban parameters within each subzone. Each subzone is then individually modeled, and outflow hydrographs are routed through succeeding downstream subzones to the gaging point. The model thus makes it possible to: (a) develop runoff models for subzone hydrographs within the urban watershed, and (b) account for spatial variations of storm and watershed characteristics. An attempt was also made to analytically model the outflow hydrograph based on storm and watershed characteristics.     

Collaborative learning for policy innovations: sustainable urban drainage systems in Leicester,England

ABSTRACT

Collaboration among multiple stakeholders is crucial in decentralised governance settings. The success of such collaboration hinges upon collaborative learning – the acquiring, translating, and disseminating of policy-relevant knowledge. However, despite much research, a knowledge gap persists in the public policy literature on the relationship between learning and policy change. It is debated whether learning is necessary and sufficient for policy change, and if so, under what conditions. To contribute to this debate, this paper examined whether collaborative learning has had any impact on the emergence and implementation of sustainable urban drainage systems (SuDS) in Leicester, England. We first examined implementation of SuDS in Leicester, and then study collaborative learning focused on SuDS. We found that implementation of SuDS in Leicester is marginal despite active collaborative learning that has resulted in the change in beliefs and attitudes towards SuDS among all policy actors in the setting. Social dynamics factors and leadership of two SuDS champions proved crucial for collaborative learning. We conclude that collaborative learning, while essential for legitimacy of a policy innovation, is not sufficient for policy change and a national legal and institutional framework is required to incentivise broader SuDS practices in Leicester and England.     

Investigation on chemical species of arsenic, selenium and antimony in fly ash from coal fuel thermal power stations

Investigations of the existing chemical forms and the concentrations of arsenic (As), selenium (Se) and antimony (Sb) in samples of fly ash obtained from six coal-fired power stations in various countries were carried out. The concentration of As was found to vary from 5.4 to 22.3 mg kg(-1), and the most common mode of occurrence of As in the fly ashes is in association with carbonates or Fe-Mn oxides. The concentrations of Se and Sb ranged from 2.3-5.2 and 1.0-3.9 mg kg(-1), respectively. The dominant chemical forms of Se and Sb in the fly ashes were as extractable species. Also, water-soluble As, Se and Sb in the fly ashes were extracted, and the chemical species of As, Se and Sb in the extract determined using HPLC-ICP-MS. This was done as the potential release of soluble As, Se and Sb through leaching of fly ash is of environmental concern. The most abundant form of As in the extract was the low toxicity As(V). The main species of Se was Se(IV), although it was found that the ratio of Se(VI) to Se(IV) in acidic fly ashes is higher than in alkaline fly ash samples. Antimony was mostly present as Sb(III).