Sulfur Control In Coal Fired Power Plants: A Probabilistic Approach to Policy Analysis

The optimum level of sulfur pollution control for a coal fired power plant is the point where the sum of societal costs, due to pollution, and control costs is minimized. This basic microeconomic concept has been of limited practical value due to considerable uncertainty in estimating both costs. A probabilistic approach is used to characterize these uncertainties quantitatively for a hypothetical 1000 Mw_e plant located near Pittsburgh, Pennsylvania. Only mortality effects within a distance of 80 km of the plant have been included. The results allow explicit consideration of attitude toward risk and appropriate level of investment to prevent deaths. Limitations of the findings are discussed. Implications are described for policy based on alternative sets of values and assumptions.     

Formation and Removal Reactions of Hazardous Air Pollutants

Current regulatory policies for hazardous air pollutants (HAPs) target the sources of direct emissions. In addition to direct emissions, some of the aromatic, nitrogenated, and oxygenated HAPs can be formed in the atmosphere. Formaldehyde and acetaldehyde, in particular, are produced by almost every hydrocarbon photooxidation reaction. Estimates have been made that, in some urban areas, in situ formation contributes as much as 85 percent of the ambient levels of formaldehyde and 95 percent for acetaldehyde. Over 40 percent of the HAPs being regulated under Title III of the 1990 Clean Air Act Amendments have atmospheric lifetimes of less than one day. The transformation products of these HAPs with low atmospheric persistence are important for assessing risks to human health, especially for cases where the transformation products are more toxic than the HAP itself.     

Field evaluations of newly available “interference-free” monitors for nitrogen dioxide and ozone at near-road and conventional National Ambient Air Quality Standards compliance sites

Long-standing measurement techniques for determining ground-level ozone (O₃) and nitrogen dioxide (NO₂) are known to be biased by interfering compounds that result in overestimates of high O₃ and NO₂ ambient concentrations under conducive conditions. An increasing near-ground O₃ gradient (NGOG) with increasing height above ground level is also known to exist. Both the interference bias and NGOG were investigated by comparing data from a conventional Federal Equivalent Method (FEM) O₃ photometer and an identical monitor upgraded with an “interference-free” nitric oxide O₃ scrubber that alternatively sampled at 2 m and 6.2 m inlet heights above ground level (AGL). Intercomparison was also made between a conventional nitrogen oxide (NO_x) chemiluminescence Federal Reference Method (FRM) monitor and a new “direct-measure” NO₂ NO_x 405 nm photometer at a near-road air quality measurement site. Results indicate that the O₃ monitor with the upgraded scrubber recorded lower regulatory-oriented concentrations than the deployed conventional metal oxide–scrubbed monitor and that O₃ concentrations 6.2 m AGL were higher than concentrations 2.0 m AGL, the nominal nose height of outdoor populations. Also, a new direct-measure NO₂ photometer recorded generally lower NO₂ regulatory-oriented concentrations than the conventional FRM chemiluminescence monitor, reporting lower daily maximum hourly average concentrations than the conventional monitor about 3 of every 5 days.

Implications: Employing bias-prone instruments for measurement of ambient ozone or nitrogen dioxide from inlets at inappropriate heights above ground level may result in collection of positively biased data. This paper discusses tests of new regulatory instruments, recent developments in bias-free ozone and nitrogen dioxide measurement technology, and the presence/extent of a near-ground O₃ gradient (NGOG). Collection of unbiased monitor inlet height–appropriate data is crucial for determining accurate design values and meeting National Ambient Air Quality Standards.     

Distribution of foraging habitats of male loggerhead turtles (Caretta caretta) as revealed by stable isotopes and satellite telemetry

Most studies on the foraging ecology of loggerhead turtles (Caretta caretta) have focused on adult females and juveniles. Little is known about the foraging patterns of adult male loggerheads. We analyzed tissues for carbon and nitrogen stable isotopes (δ¹³C and δ¹⁵N) from 29 adult male loggerheads tracked with satellite transmitters from one breeding area in Florida, USA, to evaluate their foraging habitats in the Northwest Atlantic (NWA). Our study revealed large variations in δ¹³C and δ¹⁵N and a correlation between both δ¹³C and δ¹⁵N and the latitude to which the loggerheads traveled after the mating season, thus reflecting a geographic pattern in the isotopic signatures. Variation in δ¹³C and δ¹⁵N can be explained by differences in food web baseline isotopic signatures rather than differences in loggerhead trophic levels. Stable isotope analysis may help elucidate residency and migration patterns and identify foraging sea turtle subpopulations in the NWA due to the isotopically distinct habitats used by these highly migratory organisms.     

Is there a role for not‐for‐profit or for‐purpose organizations in supporting governance professionals to engage with climate‐related opportunities and risks?

Climate change in Australia has become a political risk (for political parties) and a physical, transitional, and regulatory risk for businesses. Not‐for‐profits (NFPs) and for‐purpose (FPs) organisations, for example, Climate Alliance Limited, have acted in the absence of national climate risk policy, to support businesses to become better informed to manage their exposure to this risk, and helping them to set their own commitments and pathways to low and net zero carbon businesses. The objective of this article is to demonstrate, through the case study method, how one Australian NFP/FP has influenced the business sector and regulation. Climate Alliance Limited has done this through its interventions of (1) sharing case studies (best practices) on successful transitions to a low carbon business model and linking climate risk to business risk; (2) bringing thought leaders (advocacy) from the Bank of England and UK Prudential Regulator into the Australian finance and business sector; and (3) by offering a program (reward and recognition), showcasing how business leaders have and are adapting to climate risks and capturing business value.     

Ethanol emission from loose corn silage and exposed silage particles

Silage on dairy farms has been identified as a major source of volatile organic compound (VOC) emissions. However, rates of VOC emission from silage are not accurately known. In this work, we measured ethanol (a dominant silage VOC) emission from loose corn silage and exposed corn silage particles using wind tunnel systems. Flux of ethanol was highest immediately after exposing loose silage samples to moving air (as high as 220 g m^?2 h^?1) and declined by as much as 76-fold over 12 h as ethanol was depleted from samples. Emission rate and cumulative 12 h emission increased with temperature, silage permeability, exposed surface area, and air velocity over silage samples. These responses suggest that VOC emission from silage on farms is sensitive to climate and management practices. Ethanol emission rates from loose silage were generally higher than previous estimates of total VOC emission rates from silage and mixed feed. For 15 cm deep loose samples, mean cumulative emission was as high as 170 g m^?2 (80% of initial ethanol mass) after 12 h of exposure to an air velocity of 5 m s^?1. Emission rates measured with an emission isolation flux chamber were lower than rates measured in a wind tunnel and in an open setting. Results show that the US EPA emission isolation flux chamber method is not appropriate for estimating VOC emission rates from silage in the field.     

Enhanced phytoextraction of Pb and other metals from artificially contaminated soils through the combined application of EDTA and EDDS

Chemically enhanced phytoextraction is achieved by the application of chelates to soils. Using pot experiments, the effect of the combined application of EDTA and EDDS on the uptake of Cu, Pb, Zn and Cd by Zea mays L. was studied. Among the tested application ratios of 1:1, 1:2, and 2:1 (EDTA/EDDS), 2:1 of EDTA:EDDS was the most efficient ratio for increasing the concentrations of Cu, Pb, Zn and Cd in the shoots. The combined application of 3.33 mmol kg(-1) soil of EDTA+1.67 mmol kg(-1) soil of EDDS produced 650 mg kg(-1) of Pb in the shoots, which was 2.4 and 5.9 times the concentration of Pb in the shoots treated with 5 mmol kg(-1) of EDTA and EDDS alone, respectively. The total phytoextraction of Pb reached 1710 microg kg(-1) soil, which was 2.1 and 6.1 times the total Pb from 5 mmol kg(-1) EDTA and EDDS alone, respectively. The combined application of EDTA and EDDS also significantly increased the translocation of Pb from the roots to the shoots. The mechanism of enhancing the phytoextraction of Pb by the combined application of EDTA+EDDS did not involve a change in the pH of the soil. The increase in the phytoextraction of Pb by the shoots of Z. mays L. was more pronounced than the increase of Pb in the soil solution with the combined application of EDTA and EDDS. It was thought that the major role of EDDS might be to increase the uptake and translocation of Pb from the roots to the shoots of plants.     

Guiding principles for rewilding

There has been much recent interest in the concept of rewilding as a tool for nature conservation, but also confusion over the idea, which has limited its utility. We developed a unifying definition and 10 guiding principles for rewilding through a survey of 59 rewilding experts, a summary of key organizations’ rewilding visions, and workshops involving over 100 participants from around the world. The guiding principles convey that rewilding exits on a continuum of scale, connectivity, and level of human influence and aims to restore ecosystem structure and functions to achieve a self-sustaining autonomous nature. These principles clarify the concept of rewilding and improve its effectiveness as a tool to achieve global conservation targets, including those of the UN Decade on Ecosystem Restoration and post-2020 Global Biodiversity Framework. Finally, we suggest differences in rewilding perspectives lie largely in the extent to which it is seen as achievable and in specific interventions. An understanding of the context of rewilding projects is the key to success, and careful site-specific interpretations will help achieve the aims of rewilding.     

Characterizing species co-occurrence patterns of imperfectly detected stream fishes to inform species reintroduction efforts

Species reintroduction efforts can improve the recovery of imperiled species, but successful implementation of this conservation strategy requires a thorough understanding of the abiotic and biotic factors influencing species viability. Species interactions are especially understudied, in particular by omitting the effect of imperfect detection on negative, neutral, or positive associations within a community. Using repeat surveys from 5 southern Ontario, Canada, Great Lakes tributaries, we quantified species co-occurrence patterns with the eastern sand darter (ESD) (Ammocrypta pellucida), listed as federally threatened, and characterized how imperfect detection during sampling can influence inference regarding these relationships. We used a probabilistic framework that included 3 approaches of increasing complexity: probabilistic co-occurrence analysis ignoring imperfect detection; single-species occupancy models with subsequent co-occurrence analysis; and 2-species occupancy models. We then used our occupancy models to predict suitable sites for potential future reintroduction efforts while considering the influence of negative species interactions. Based on the observed data, ESD showed several positive associations with co-occurring species; however, species associations differed when imperfect detection was considered. Specifically, a negative association between ESD and rosyface shiner (Notropis rubellus) was observed only after accounting for imperfect detection in the Grand River. Alternatively, positive associations in the Grand River between ESD and northern hogsucker (Hypentelium nigricans) and silver shiner (Notropis photogenis) were observed regardless of whether imperfect detection was accounted for. Our models predicted several potential reintroduction sites for ESD in formerly occupied watersheds with high levels of certainty. Overall, our results demonstrate the importance of investigating imperfect detection and species co-occurrence when planning reintroduction efforts.     

The role of odds ratios in joint species distribution modeling

Environmental and Ecological Statistics - Joint species distribution modeling is attracting increasing attention these days, acknowledging the fact that individual level modeling fails to take into...