Air pollutant source characterization using the revised regional haze tracking metric and a photochemical grid model and implications for regional haze planning

The 2017 revisions to the Regional Haze Rule clarify that visibility progress at Class I national parks and wilderness areas should be tracked on days with the highest anthropogenic contributions to haze (impairment). We compare the natural and anthropogenic contributions to haze in the western United States in 2011 estimated using the Environmental Protection Agency (EPA) recommended method and using model projections from the Comprehensive Air Quality Model with Extensions (CAMx) and the Particulate Source Apportionment Tool (PSAT). We do so because these two methods will be used by states to demonstrate visibility progress by 2028. If the two methods assume different natural and anthropogenic contributions, the projected benefits of reducing U.S. anthropogenic emissions will differ. The EPA method assumes that episodic elevated carbonaceous aerosols greater than an annual 95th percentile threshold are natural events. For western U.S. IMPROVE monitoring sites reviewed in this paper, CAMx-PSAT confirms these episodes are impacted by carbon from wildfire or prescribed fire events. The EPA method assumes that most of the ammonium sulfate is anthropogenic in origin. At most western sites CAMx-PSAT apportions more of the ammonium sulfate on the most impaired days to global boundary conditions and anthropogenic Canadian, Mexican, and offshore shipping emissions than to U.S. anthropogenic sources. For ammonium nitrate and coarse mass, CAMx-PSAT apportions greater contributions to U.S. anthropogenic sources than the EPA method assigns to total anthropogenic contributions. We conclude that for western IMPROVE sites, the EPA method is effective in selecting days that are likely to be impacted by anthropogenic emissions and that CAMx-PSAT is an effective approach to estimate U.S. source contributions. Improved inventories, particularly international and natural emissions, and further evaluation of global and regional model performance and PSAT attribution methods are recommended to increase confidence in modeled source characterization.

Implications: The western states intend to use the CAMx model to project visibility progress by 2028. Modeled visibility response to changes in U.S. anthropogenic emissions may be less than estimated using the EPA assumptions based on total U.S. and international anthropogenic contributions to visibility impairment. Additional model improvements are needed to better account for contributions to haze from natural and international emissions in current and future modeling years. These improvements will allow more direct comparison of model and EPA estimates of natural and anthropogenic contributions to haze and future visibility progress.     

The ethics and politics of the caged layer hen debate in New Zealand

Changes in attitudes toward animal welfare, with a greater emphasis on the importance of allowing animals to express normal patterns of behavior has led to an examination of the practice of keeping hens in battery cages. There is widespread scientific consensus that the conditions of confinement and the barren nature of battery cages severely restrict hens’ behavioral repertoire, and are thus detrimental to their welfare. The New Zealand Animal Welfare Act 1999, stipulates that animals must have “the opportunity to display normal patterns of behaviour.” In spite of this provision, the New Zealand government has not acted in phasing out battery cages, arguing instead that there is insufficient evidence that welfare will be improved by a phase-out. There is evidence of strong industry pressure on the government, and the use of tactics common in policy considerations where changes are resisted by powerful interests. It is important that policy processes are better managed so that welfare changes are based on both public preferences and scientific knowledge, and ways of doing this are discussed.     

Measured gas emissions from four landfills in south africa and some implications for landfill design and methane recovery in semi-arid climates.

The magnitude of annual global emissions of methane from municipal solid waste landfills without landfill gas control systems implies that these landfills are significant contributors to the atmospheric load of greenhouse gases. There have been a number of field studies undertaken internationally to measure actual fluxes of methane and carbon dioxide from landfills, with a view to corroborating modelled predictions of the contribution of landfills to the global greenhouse gas budget. The vast majority of these studies have been undertaken in more temperate climates and in developed countries. This paper reports a study of landfill gas emissions from four large landfills located in the semi-arid interior of South Africa. A static accumulation chamber was used and measurements were made at each site over a period of two to three days. The results were analysed by three different methods, all of them leading to the same general conclusion that landfill gas emission rates were lower than expected. A common conclusion based on results from all four sites was that capping of landfills in semi-arid climates with low permeability covers would probably significantly retard the already low rate of waste degradation and thus gas generation. While this may be regarded as advantageous in the short term, it cannot be relied upon in perpetuity as clayey landfill covers will inevitably desiccate and crack in a semiarid environment. In addition, reasonable after-care periods for such landfills are likely to extend well beyond the currently stipulated 30-year period, and efforts to encourage energy recovery from landfills may be hampered because gas generation rates decrease as the waste dries out under conditions of minimal recharge from precipitation. A landfill cover that allows small amounts of percolation of rainfall into the waste may therefore in fact be beneficial in semiarid climates, although care would need to be taken to carefully regulate this infiltration.     

Niagara region farmers' markets: local food systems and sustainability considerations

This article presents the findings of a survey of farmers' markets customers in the Niagara region of Ontario, Canada. The recent growth of farmers' markets in North America and the association of these markets with local food systems development provoke examination to gain insights into consumer motivations for patronizing these markets, and to then reflect on their potential role within locally oriented and sustainable food production systems. The survey carried out on customers of three Niagara region farmers' markets corroborates previous studies that noted that socioeconomic and cultural factors such as the importance of food freshness, support of local farmers and the local farm economy, and social interaction—embeddedness—are key expressions of people's support and interest in farmers' markets. This work serves to heighten our understanding of consumer attitudes toward direct marketing via farmers' markets, yields useful speculation about these markets and their roles in sustainable local food systems progress, and also raises critical questions about such customer patronage and associated farmers' markets potential in local food system development.     

Issues Associated with Research on Sheep Parasite Control in New Zealand – a Descriptive Ethic

In common with much of theEnglish-speaking world, New Zealandersgenerally oppose the use of animalexperimentation where there is no demonstrableand immediate benefit for human, animal, orenvironmental health. Intrusive experiments onsheep internal and external parasites publishedbetween 1996 and 2000 are reviewed, anddiscussed in relation to these publicsensibilities. A total of 16 publishedexperiments on sheep parasites involvedsurgical manipulations or other intrusiveprocedures. Some of these experiments had noshort-term application, or the only applicationwas in increasing animal production. Otherscould have been modified at some extra expenseso that they were less intrusive. Still otherswere duplications of previous work. All thesemanipulations would be unacceptable accordingto the orthodox morality of the general public.Breeding programs, rotation of grazing,``low-tech' vaccination, and in vitromodels of sheep can provide insights intopreventing parasite infestation withoutintrusive experiments. Such research protocolsshould take priority over existing programs.The results also confirm earlier reports thatanimal ethics committees are not fulfillingtheir mandated objective of acting as watchdogsfor the public. Possible changes in New Zealandanimal welfare legislation and itsinterpretation by Animal Ethics Committees arediscussed.     

Methyl 2-(methylthio)benzoate: the unique sulfur-containing sex pheromone of<Emphasis Type="Italic"> Phyllophaga crinita</Emphasis>

The female-produced sex pheromone of Phyllophaga crinita (Burmeister) (Coleoptera: Scarabaeidae: Melolonthinae; the adult has no common name) is identified as methyl 2-(methylthio)benzoate. This is the first identification of a sulfur-containing, long-distance, female-produced sex attractant from any insect taxa. The root-feeding larvae of this species are serious pests in many crops in Texas and Mexico. In field tests, many P. crinita males were captured in traps baited with the authentic compound. Interestingly, a heteroatom analog, methyl 2-methoxybenzoate, also captured P. crinita males, but only at a dose 10,000 times higher than the lowest tested dose of the authentic pheromone.In memory of M.G. Villani, who died on 15 May 2001. His enthusiasm for soil-dwelling scarab beetles and contributions to their research are greatly missed.     

Prenatal ultrasound diagnosis of gastric outlet obstruction due to a pyloric web

Gastrointestinal tract atresia has an incidence of 1 in 10 000 live-births, while gastric outlet obstruction comprises only approximately 1 per cent of these malformations. A prenatally diagnosed case is described, followed by a discussion regarding the diagnosis and possible associated abnormalities.     

Cystic fibrosis prenatal diagnosis: Confirmation of an equivocal microvillar enzyme result by direct analysis of the common gene mutation

A child was tentatively diagnosed as having cystic fibrosis, based on neonatal presentation with severe gastrointestinal complications; the diagnosis was not confirmed biochemically and no tissues were available for DNA analysis. The mother presented in her subsequent pregnancy, and microvillar enzyme analysis of cell-free amniotic fluid at both 18 and 20 weeks gestation gave equivocal results. The pregnancy was terminated voluntarily because of a trend towards abnormal enzyme assay results on the second amniocentesis. Retrospectively, fetal tissues were found to be homozygous for the most common mutation of the cystic fibrosis gene (AF₅₀₈), which confirmed the prenatal assessment and suggested that the first infant of the couple was probably also affected by the disease.