Alkyl nitrate photochemistry during the tropospheric organic chemistry experiment

Alkyl nitrates (C₁–C₅) were measured at two sites (near urban and rural) in southeast England during the Tropospheric Organic Chemistry Experiment (TORCH). Methyl nitrate was the dominant species during both campaigns accounting for on average about one third of the total measured alkyl nitrates. High mixing ratios (>50 pptv) and variability of methyl nitrate were observed at the near urban site (TORCH1) that were not seen at the rural site (TORCH2) and which could not be explained by local photochemical production or direct emissions. The diurnal variation of methyl nitrate during TORCH1 showed a morning maximum that would be consistent with nighttime chemistry followed by transport to the surface by boundary layer dynamics. Similarly, elevated morning mixing ratios were also observed during TORCH2 although the magnitudes were much smaller. As a result, methyl nitrate could represent a tracer for nighttime chemistry seen at the ground the following day. At both campaigns, the dominant source of short chain alkyl nitrates and carbonyl precursor radicals (≤C₄) were from decomposition of larger compounds. The magnitude of the source increased with decreasing carbon number consistent with increasing total precursor abundance. Non-photochemical emissions of acetaldehyde and acetone could not be accounted for by automobile exhaust emissions alone and indicated that other direct sources are likely important in this environment.     

An improved dual channel PERCA instrument for atmospheric measurements of peroxy radicals

This paper describes a new dual-channel PEroxy RadiCal Amplification (PERCA) instrument, which has been designed to improve the time resolution and signal to noise and to reduce the interference caused by variations in ambient ozone concentrations. The instrument was run at the Weybourne Atmospheric Observatory (WAO), North Norfolk, during WAOWEX (Weybourne Atmospheric Observatory Winter Experiment) in January/February 2002 and INSPECTRO (Influence of clouds on the spectral actinic flux in the lower troposphere) in September 2002. The performance of the instrument is assessed and compared to that of a single channel instrument. In particular, it is shown how the precision is greatly improved in fluctuating background ozone conditions. In addition the improved time response of the instrument allows changes in peroxy radical concentrations to be related to rapid changes in nitric oxide concentrations and the ozone photolysis frequency, j(O(1)D).     

Cross-sensitivities of electrochemical detectors used to monitor worker exposures to airborne contaminants: false positive responses in the absence of target analytes

Ideally, the response of electrochemical detectors is proportional to the concentration of targeted airborne chemicals and is not be affected by concomitantly present substances. Manufacturers provide a limited list of cross-sensitivities but end-users have anecdotally reported unexpected interferences by other substances. Electrochemical detectors designed to measure airborne levels of CO, H(2)S, NO, NO(2), or SO(2), were challenged with potentially interfering substances in the absence of target analytes. Cross-sensitivities undocumented by the manufacturers were observed and were found to vary between different models of instruments for the same challenge chemical.     

Nature-based marine tourism in the Gulf of California and Baja California Peninsula: Economic benefits and key species

Ecotourism can incentivize social and environmental benefits through marine conservation, in parallel with efforts to better manage fisheries, coastal development, and other human pressures. In Mexico's Gulf of California and Baja California Peninsula (GCBP), marine ecosystems support tourism activities in many communities, but to date there have been no region-wide studies to estimate their benefits or identify key species. Based on data collected in this study, each year nature-based marine tourism in the GCBP results in 896,000 visits, US$518 million in expenditures and at least 3,575 direct jobs from formal operations. In interviews with operators, over 40 species groups were named as important; sea lions, whale sharks, whales, and marlin were the highest ranked, highlighting the importance of ecosystem-wide health for nature-based tourism sustainability. Local employment and the ability to make economic and conservation goals compatible were noted by operators as significant opportunities provided by nature-based marine tourism; challenges included pollution and declines in ecosystem health, a lack of infrastructure, poor resource management policies, and high operating costs. As nature-based marine tourism expands, a wider transition to true ecotourism, a focus on equitable benefits and collaboration between stakeholders and a cross-scale and ecosystem approach to management will be vital for achieving potential sustainable social, ecological and economic benefits.     

Trade‐offs and efficiencies in optimal budget‐constrained multispecies corridor networks

Conservation biologists recognize that a system of isolated protected areas will be necessary but insufficient to meet biodiversity objectives. Current approaches to connecting core conservation areas through corridors consider optimal corridor placement based on a single optimization goal: commonly, maximizing the movement for a target species across a network of protected areas. We show that designing corridors for single species based on purely ecological criteria leads to extremely expensive linkages that are suboptimal for multispecies connectivity objectives. Similarly, acquiring the least‐expensive linkages leads to ecologically poor solutions. We developed algorithms for optimizing corridors for multispecies use given a specific budget. We applied our approach in western Montana to demonstrate how the solutions may be used to evaluate trade‐offs in connectivity for 2 species with different habitat requirements, different core areas, and different conservation values under different budgets. We evaluated corridors that were optimal for each species individually and for both species jointly. Incorporating a budget constraint and jointly optimizing for both species resulted in corridors that were close to the individual species movement‐potential optima but with substantial cost savings. Our approach produced corridors that were within 14% and 11% of the best possible corridor connectivity for grizzly bears (Ursus arctos) and wolverines (Gulo gulo), respectively, and saved 75% of the cost. Similarly, joint optimization under a combined budget resulted in improved connectivity for both species relative to splitting the budget in 2 to optimize for each species individually. Our results demonstrate economies of scale and complementarities conservation planners can achieve by optimizing corridor designs for financial costs and for multiple species connectivity jointly. We believe that our approach will facilitate corridor conservation by reducing acquisition costs and by allowing derived corridors to more closely reflect conservation priorities.     

Mapping the public first‐aid training landscape: uptake,knowledge, confidence and willingness to deliver first aid in disasters/emergencies—a scoping review

The above article from Disasters, published online on 24 June 2019 in Wiley Online Library ( http://wileyonlinelibrary.com ) has been withdrawn by agreement among the authors, the Journal editors and John Wiley & Sons Inc. on behalf of ODI. The withdrawal has been agreed because this is a duplicate of an article that has been published in Disasters Volume 44 Issue 1.     

Land Use and Climate Variability Amplify Carbon,Nutrient, and Contaminant Pulses: A Review with Management Implications

Nonpoint source pollution from agriculture and urbanization is increasing globally at the same time climate extremes have increased in frequency and intensity. We review >200 studies of hydrologic and gaseous fluxes and show how the interaction between land use and climate variability alters magnitude and frequency of carbon, nutrient, and greenhouse gas pulses in watersheds. Agricultural and urban watersheds respond similarly to climate variability due to headwater alteration and loss of ecosystem services to buffer runoff and temperature changes. Organic carbon concentrations/exports increase and organic carbon quality changes with runoff. Nitrogen and phosphorus exports increase during floods (sometimes by an order of magnitude) and decrease during droughts. Relationships between annual runoff and nitrogen and phosphorus exports differ across land use. CH₄ and N₂O pulses in riparian zones/floodplains predominantly increase with: flooding, warming, low oxygen, nutrient enrichment, and organic carbon. CH₄, N₂O, and CO₂ pulses in streams/rivers increase due to similar factors but effects of floods are less known compared to base flow/droughts. Emerging questions include: (1) What factors influence lag times of contaminant pulses in response to extreme events? (2) What drives resistance/resilience to hydrologic and gaseous pulses? We conclude with eight recommendations for managing watershed pulses in response to interactive effects of land use and climate change.     

Designing sustainability for whom? Recent housing developments in Southwest Montréal

This paper sets out to show how urban sustainability issues have been addressed by social, political, and economic actors involved in housing production in Montréal. Specifically, it looks at how the environmental question has been incorporated into the practice and discourse of recent housing schemes. Principles of sustainable development such as adaptive reuse of industrial buildings and infill housing that allow for reinvestment in inner-city neighbourhoods, inclusion of affordable, or social housing in private housing developments to secure social mix, citizen participation, energy, water, and transportation matters have been increasingly circulated. By examining planning documents, design proposals, and briefs presented at public hearings on housing schemes in Southwest Montréal, a former working-class borough undergoing revitalisation, this paper shows that the values of sustainable development have been used by both private developers and local authorities to negotiate urban transformations with community groups.