Does Engagement in Advocacy Hurt the Credibility of Scientists? Results from a Randomized National Survey Experiment

It is often assumed that issue advocacy will compromise the credibility of scientists. We conducted a randomized controlled experiment to test public reactions to six different advocacy statements made by a scientist—ranging from a purely informational statement to an endorsement of specific policies. We found that perceived credibility of the communicating scientist was uniformly high in five of the six message conditions, suffering only when he advocated for a specific policy—building more nuclear power plants (although credibility did not suffer when advocating for a different specific policy—carbon dioxide limits at power plants). We also found no significant differences in trust in the broader climate science community between the six message conditions. Our results suggest that climate scientists who wish to engage in certain forms of advocacy have considerable latitude to do so without risking harm to their credibility, or the credibility of the scientific community.     

The Capacity to Detect Change Stream Fish Communities Characteristics at the Site-Level in the Lake Ontario Basin

We investigate natural inter-annual variability of fish community measures within streams of the Lake Ontario basin. Given this variability, we examined coefficients of variation (CV) among the community measures and three scenarios pertaining to the capacity of biologists to detect changes in the fish community at the stream site level. Results indicate that Ontario's stream fish communities are highly variable in time. Young-of-the-year rainbow trout growth was the least variable whereas biomass density scored the highest CV of 0.50 among streams (range 0.22-0.99). Given the CVs and relatively equal sample sizes, our measures of the fish community can be ranked from least to most powerful: biomass, density, richness, diversity, and growth of young-of-the-year rainbow trout. Only large changes in measures can typically be detected. For instance, it would take 4-6 years of monitoring before and after a pulse perturbation to detect a 50 % change in species richness or diversity. We suggest that monitoring abundance is unlikely to result in the detection of small impacts within a short period of time and that large effects can be masked by low statistical power. This evidence voices the need for more research into better sampling methods, experimental designs, and choice of indicators to support monitoring programs for flowing waters.     

Emissions from Burning Grass Stubble and Straw

The emissions from burning the residue following grass-seed harvest were determined by means of a combined laboratory-field study. Samples of the straw and stubble residue were burned in the laboratory burning tower at the University of California at Riverside. Complete analyses were determined for gaseous and particulate emissions for the important grass species from the Willamette Valley of Oregon. Particulate emissions averaged 15.6 lb/ton of fuel burned. Carbon monoxide averaged 101 lb/ton of fuel burned. Hydrocarbon emission averages, in pounds per ton of fuel burned, were 1.74 for saturates plus acetylene, 2.80 for defines, and 1.68 for ethylene. The NO_x emission, at the temperature peak during the burn, averaged 29.3 ppm. Field studies, conducted by personnel from Oregon State University, measured only particulate emissions, carbon dioxide, and temperature over the burn. The carbon dioxide values were found to be similar to those obtained on the burning table at UCR and it was therefore concluded that the other gaseous emissions were similar and could be used as reasonably accurate for emission inventories. The temperature values obtained in the laboratory and field were also similar and further justifies extrapolating the burning table data to field situations. The particulate matter collected in the field studies averaged 15.55 lb of particulate per ton of fuel burned. This is the same average obtained for the burning table data which again serves to validate the emissions reported from Riverside. Much more variability was found in the particulate emissions obtained in the field which reflects the wider range of environmental conditions encountered in the field.     

Another Look at New York City’s Air Pollution Problem

An analysis of the ambient air quality in New York City over the past several years has been made. The various sources of the contaminants are identified and evaluated as to their effects on ambient air quality. Meteorological data have been analyzed to develop insight into the influence of weather conditions upon ground level pollution concentrations. The results of these analyses are employed to indicate the approaches that will be most effective in improving air quality.     

Coke Oven Pushing Emission Control System

This report deals with the entrapment, pickup, and transfer of hot gases during a typical coke oven push. Background information that led to the development of the Great Lakes Coke Oven Pushing Emission Control System is presented along with the problems that were encountered and solved during the design, construction, installation, and start-up of a pilot plant entrapment structure on a battery of 40 Simon Carves coke ovens. This unique entrapment structure has operated successfully since April 1972, and has been visited by representatives from almost all coke manufacturers in the U.S., as well as interested groups from several foreign countries. In addition to these operation groups, we have been visited by various state and federal pollution authorities, such as the Environmental Protection Agency, Battelle Institute, and National Institute of Occupational Safety and Health. At the present time we are erecting a similar entrapment structure on the north side of our plant, comprising 18 Koppers and 35 Wilputte ovens.     

Continuous Emission Monitoring: Objectives and Requirements

Regulations were recently proposed by the Environmental Protection Agency which, when promulgated, will require existing and new sources within certain specified source categories to install, operate, and maintain continuous emission monitoring systems. Major comments received on these proposed regulations are discussed as are the overall benefits that can be derived from the utilization of continuous emission monitoring systems.     

Simplified Models of U.S. Acid Rain Control Costs

Simplified algorithms are presented for estimating the cost of controlling sulfur dioxide (SO₂) emissions from existing coal-fired power plants on a state-by-state basis. Results are obtained using the detailed Utility Control Strategy Model (UCSM) to calculate the Impacts of emission reductions ranging from approximately 30 percent to 90 percent of projected 1995 emissions for 18 different scenarios and 36 states. Scenarios include the use of two dry SO₂ removal technologies (lime spray dryers and LIMB) as potential options for power plant retrofit, in addition to currently available emission control options including coal switching, coal cleaning and wet flue gas desulfurization (FGD). Technical assumptions relating to FGD system performance and the upgrading of existing cold-side electrostatic precipitators (ESP) for reduced sulfur levels are also analyzed, along with the effects of interest rates, coal prices, coal choice restrictions, plant lifetime, and plant operating levels. Results are summarized in the form of a 3-term polynomial equation for each state, giving total annualized SO₂ control cost as a function of the total SO₂ emissions reduction for each scenario. Excellent statistical fits to UCSM results are obtained for these generalized equations.