A reevaluation of carbon monoxide: past trends,future concentrations,and implications for conformity "hot-spot" policies

Control of CO is one of the great air-quality management success stories of the past 20 years. This paper evaluates whether past progress will continue into the future and whether changes in microscale CO concentrations are comparable to reductions observed at the regional scale. Neighborhood and microscale CO concentrations were evaluated at six northern and southern California monitoring sites. The study also included a review of CO emission, concentration, and exposure trends and on-road motor vehicle-based CO emission control programs for California and the United States. Consistent with California and national trends, CO concentrations declined at each of the six study locations from 1988 through 1998. Microscale concentrations declined at the same rate as did neighborhood-scale concentrations. Rollback analyses demonstrated that microscale concentrations will continue to decline through at least 2010-2020. Within a few years, microscale violations of the CO National Ambient Air Quality Standards (NAAQS) will be unlikely in California except under extraordinary circumstances.     

Alternative policy instruments under uncertainty: A programming model of toxic pollution control

This paper presents the results of a programming model which examines the relative performance of different regulatory regimes under uncertainty in controlling toxic wastes discharged by industry to a central treatment plant when the central is subject to threshold-type losses in treatment performance. Four regulatory regimes are examined: non-market quantity, price, marketable permit, and mixed price-quantity. The theoretical framework of the model is based on the analysis of prices vs quantities by Weitzman in 1974 and its extension to the case of a discontinuous threshold effect. The data used are based on the situation of Bridgeport, Connecticut, which has a number of metal finishing firms.     

Dufour gland secretion in the harvester ant genus <Emphasis Type="Italic">Pogonomyrmex</Emphasis>

Summary. Dufour gland secretions of the harvester ants Pogonomyrmex barbatus, P. rugosus and P. maricopa were investigated. The glandular blends exhibit species specific patterns, but more importantly, based on indiviual profiles of Dufour gland contents of colony members it is possible to separate the colonies from each other in each species. It is possible that these collective colony specific cues serve as longer lasting trunk route markers. Behavioral tests demonstrate that workers of P. rugosus prefer homing routes marked by members of their own colony to routes marked by a foreign conspecific colony.     

Specificity and sensitivity of microsatellite markers for the identification of larvae

The identification of larval marine invertebrates to species or even higher taxonomic levels by morphological examination is notoriously difficult. Many diagnostic features are absent or poorly formed at early stages in development. This is particularly true for the larvae of bivalve molluscs, for which a routine and accurate method of identification would prove valuable to both ecologists and fishery managers. A simple molecular genetic method to identify specifically larvae of the European oyster, Ostrea edulis L., 1758, is presented. The test is based on PCR amplification of highly species-specific microsatellite loci and is sensitive enough to register the presence of a single larval individual (~200 µm width) in a mixed sample of 20 mg wet weight plankton (approximately 250 larval animals). This work demonstrates that microsatellite loci can be used as highly sensitive and specific taxonomic indicators, for studies of planktonic larvae. Details of three novel microsatellite loci are also given for O. edulis, increasing the suite of molecular tools available for use in population genetic studies of this commercially important species.     

Ecosystem Impacts of Geoengineering: A Review for Developing a Science Plan

Geoengineering methods are intended to reduce climate change, which is already having demonstrable effects on ecosystem structure and functioning in some regions. Two types of geoengineering activities that have been proposed are: carbon dioxide (CO(2)) removal (CDR), which removes CO(2) from the atmosphere, and solar radiation management (SRM, or sunlight reflection methods), which reflects a small percentage of sunlight back into space to offset warming from greenhouse gases (GHGs). Current research suggests that SRM or CDR might diminish the impacts of climate change on ecosystems by reducing changes in temperature and precipitation. However, sudden cessation of SRM would exacerbate the climate effects on ecosystems, and some CDR might interfere with oceanic and terrestrial ecosystem processes. The many risks and uncertainties associated with these new kinds of purposeful perturbations to the Earth system are not well understood and require cautious and comprehensive research.     

Proportional Sampling System for the Collection of an Integrated Auto Exhaust Gas Sample

Carbon baking process involves evolution of fumes containing hydrocarbons and soot particles which cannot be discharged directly into the atmosphere. An incinerator can be used to clean these fumes. However, length of the baking cycle, nature of the fumes and variations in fume volume and temperature may result in excessive auxiliary fuel usage and inefficient incineration, if the incinerator is not designed properly. This paper describes the application of fundamental knowledge of aerodynamics, reaction kinetics and combustion, together with clear understanding of the process, in design of a highly efficient, fully automated incinerator. The design incorporates a unique but simple control system which results in reduction of auxiliary fuel usage without endangering the safety and efficiency of the incineration process. Operations and economics of the incinerator are described by illustrating a typical baking cycle and comparing actual fuel usage with the thermal ratings of the incinerator. Operating experience from a number of installations in the U. S. and Canada is also noted.     

Relationship of Hydrocarbons to Oxidants in Ambient Atmospheres

The relation of ambient levels of hydrocarbons to the products of atmospheric photochemistry has proved to be an elusive problem. Models to account for the photochemical processes are available based on laboratory examination of simulated atmospheres. Likewise, dispersion models are available which, for nonreacting species, can predict air quality given knowledge of emission rates and meteorological variables. However, integration of the dispersion model with the photochemical model is as yet an unsolved problem. In this study an empirical approach was applied in which the only assumption made was that there exists a relationship between early morning average hydrocarbon concentrations and subsequent maximum hourly average oxidant concentrations. A direct examination of all available days in several cities shows that, at any given hydrocarbon level, there exists a limit on the amount of oxidant which can be generated. Specifically it shows that the average 6:00–9:00 A.M. concentration of 0.3 ppm C nonmethane hydrocarbon can be expected to produce a maximum hourly average oxidant concentration of up to 0.1 ppm.     

Measuring the impact of the pet trade on Indonesian birds

The trade in wild animals involves one‐third of the world's bird species and thousands of other vertebrate species. Although a few species are imperiled as a result of the wildlife trade, the lack of field studies makes it difficult to gauge how serious a threat it is to biodiversity. We used data on changes in bird abundances across space and time and information from trapper interviews to evaluate the effects of trapping wild birds for the pet trade in Sumatra, Indonesia. To analyze changes in bird abundance over time, we used data gathered over 14 years of repeated bird surveys in a 900‐ha forest in southern Sumatra. In northern Sumatra, we surveyed birds along a gradient of trapping accessibility, from the edge of roads to 5 km into the forest interior. We interviewed 49 bird trappers in northern Sumatra to learn which species they targeted and how far they went into the forest to trap. We used prices from Sumatran bird markets as a proxy for demand and, therefore, trapping pressure. Market price was a significant predictor of species declines over time in southern Sumatra (e.g., given a market price increase of approximately $50, the log change in abundance per year decreased by 0.06 on average). This result indicates a link between the market‐based pet trade and community‐wide species declines. In northern Sumatra, price and change in abundance were not related to remoteness (distance from the nearest road). However, based on our field surveys, high‐value species were rare or absent across this region. The median maximum distance trappers went into the forest each day was 5.0 km. This suggests that trapping has depleted bird populations across our remoteness gradient. We found that less than half of Sumatra's remaining forests are >5 km from a major road. Our results suggest that trapping for the pet trade threatens birds in Sumatra. Given the popularity of pet birds across Southeast Asia, additional studies are urgently needed to determine the extent and magnitude of the threat posed by the pet trade.