Influential Receptors in Targetted Emission Control Strategies

Emission abatement strategies which are targeted on environmental goals may provide cost-effective alternatives to flat-rate, source-oriented policies. It is not a trivial matter, however, to develop targeted strategies. Such strategies may require the numerical optimization involving large numbers of variables and constraints. These problems demand large computer resources. Moreover, the optimization process itself is likely to be obscure for all but the most technically competent decision-makers. In this paper, several techniques are presented which identify the receptors locations which influence the outcome of targeted emission abatement strategies. As only such "influential" receptors are needed in optimization problems, their identification may permit a dramatic reduction in the computational burden. These receptors also allow a more direct interpretation of the optimization problem. After developing these filters, influential receptors are identified for several policies related to the reduction of sulfur deposition in Europe

Estimating pollutant exposures from coal fired power plants in a rural region

A critical issue in epidemiological studies of ambient air pollution is the measurement of pollutant exposure in the study population. Accurate characterization of air quality is necessary in any study relating exposure to health effects, and is essential in attempting to quantify risk estimates for specific exposure concentrations. Despite the importance of accurate air quality data, most epidemiological investigations have used relatively crude estimates of pollutant exposure. Results from such investigations may be only qualitative at best.Early studies of air pollution health effects were limited by a lack of air pollution monitoring sites, and thus, exposures were often based on surrogate measures such as tons of coal consumed. With the introduction of reliable and reasonably accurate measurements of pollutant concentrations, several important constraints remained. These limitations include the relatively sparse siting of monitor sites and the variable relationship of monitor concentrations to the exposure experience of the study population. Other considerations in using monitor data include the selection of the pollutant specie(s), the duration of the sampling period, the use of short-term versus long-term averages, peak versus mean concentrations and the cyclical variation in pollutant levels.The Chestnut Ridge region of Pennsylvania is the site of an ongoing study of health effects from air pollution. This site was selected in part because of the extensive and well maintained air pollution monitoring network, and the previous studies of pollutant dispersion in the area. Several studies of respiratory symptoms and pulmonary function in women and school age children have been carried out in the area. The current study evaluated aspects of air pollution exposure estimates which are relevant to these epidemiologic studies. Subsequent papers will discuss findings of the various epidemiologic studies which employ these air pollution measures

Optimized Abatement Strategies Using Critical Loads: Suggested Deposition Criteria and Results

This paper addresses the use of critical loads in optimized emission abatement strategies. As deposition targets, critical loads can not be satisfied at all receptors. In Europe, consequently, there is a need for alternative criteria which still relate to ecological indicators, yet which are feasible, consistent and equitable. Two criteria are suggested: the relative critical load coverage and the relative deposition reduction. These criteria permit deposition goals to be set which guarantee that a specified fraction of ecosystems will attain critical loads, and thus be protected from adverse environmental impacts. In areas which can not achieve critical loads with the best available control measures, deposition is reduced to a specified fraction of the unabated level. After presenting examples which demonstrate their derivation, strengths and weakness of these criteria are discussed. The criteria have been implemented in the RAINS optimization model. Some preliminary examples show the sensitivity, interactions and utility of the criteria. Results obtained indicate that optimized emission strategies based on critical loads are similar to emission strategies based on deposition reductions, at certain levels of the criteria. This suggests that it may not be necessary to utilize critical loads to formulate deposition targets. A second example shows the effect of excluding countries from European cost minimization. A country's participation can save costs with moderate deposition targets, however, significant costs can be imposed with low (stringent) deposition targets. These preliminary results have significant implications for negotiations and multilateral negotiations. Suggestions for future analyses conclude the paper

Nonstationary spatiotemporal Bayesian data fusion for pollutants in the near‐road environment

Concentrations of near‐road air pollutants (NRAPs) have increased to very high levels in many urban centers around the world, particularly in developing countries. The adverse health effects of exposure to NRAPs are greater when the exposure occurs in the near‐road environment as compared to background levels of pollutant concentration. Therefore, there is increasing interest in monitoring pollutant concentrations in the near‐road environment. However, due to various practical limitations, monitoring pollutant concentrations near roadways and traffic sources is generally rather difficult and expensive. As an alternative, various deterministic computer models that provide predictions of pollutant concentrations in the near‐road environment, such as the research line‐source dispersion model (RLINE), have been developed. A common feature of these models is that their outputs typically display systematic biases and need to be calibrated in space and time using observed pollutant data. In this paper, we present a nonstationary Bayesian data fusion model that uses a novel data set on monitored pollutant concentrations (nitrogen oxides or NOx and fine particulate matter or PM2.5) in the near‐road environment and, combining it with the RLINE model output, provides predictions at unsampled locations. The model can also be used to evaluate whether including the RLINE model output leads to improved pollutant concentration predictions and whether the RLINE model output captures the spatial dependence structure of NRAP concentrations in the near‐road environment. A defining characteristic of the proposed model is that we model the nonstationarity in the pollutant concentrations by using a recently developed approach that includes covariates, postulated to be the driving force behind the nonstationary behavior, in the covariance function.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/151876/1/env2581.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151876/2/env2581_am.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/151876/3/ENV_2581-Supp-0001-BDF_supp_material.pd

X-Ray Synchrotron White Beam Excitation of Auger Electrons

Auger electron spectra have been measured at the Cornell High Energy Synchrotron Source (CHESS), using the full white beam x-ray spectrum as the excitation source. Ordinary Auger spectra obtained in the laboratory with an electron beam source must employ derivative techniques to distinguish the Auger structures from the large background due to the excitation beam. The synchrotron white beam eliminates this source of background and produces signal rates as high as 107 cps. Superior signal-to-background ratios are found for Auger peaks above a few hundred eV, and count rates are large enough to suggest microprobe applications. X-ray induced Auger satellite peaks were observed with intensities much greater than the electron-induced counterpart; this anomaly is not completely understood

Man-made noise in our living environments

The ITU’s (International Telecommunication Union’s) man-made noise levels are based on measurements performed in the 1970s. Some measurements have been carried out since then, showing that noise caused by automotive ignition systems has been reduced, but manmade noise in business areas and city centers increased, especially due to the widespread use of electronic systems. The interference scenario also changed, from analog communication systems in relatively free-space conditions, to digital systems in living areas, often semi-enclosed such as offi ces, industrial production plants, and even inside cars and trains. Several measurements have therefore been carried out to estimate the level of man-made noise in these semi-enclosed environments

Assessment of subsurface VOCs using a chemical microsensor array. Final report

This report describes the results of laboratory investigations of several performance parameters relevant to surface-acoustic-wave (SAW) chemical sensor arrays for the measurement of volatile organic compounds (VOCs) in contaminated soil and groundwater. The small size, low cost, sensitivity and selectivity of such instruments promise improvements in the quality and quantity of data used to guide site assessment and restoration efforts. In this investigation, calibrations were performed for 15 different coated SAW sensors. Each sensor was exposed to six VOCs selected to represent three chemical classes of contaminants that are commonly found at waste sites (i.e., aliphatic, aromatic and chlorinated hydrocarbons). A new pattern recognition method was developed for determining which coated sensors would maximize the selectivity and accuracy of quantitation for a given set of vapor contaminants. Using this method, an optimal subwet of four coated sensors was selected for testing in a prototype microsensor instrument. Additional laboratory experiments were performed with this optimized array to assess the limits of detection and linear response ranges for the representative vapors, as well as the additivity of responses to vapors in binary mixtures, temperature and humidity effects, aging effects, and other performance parameters related to the application of this technology to soil and groundwater VOC monitoring. Results demonstrate that SAW microsensor arrays can identify and quantify specific VOCs at concentrations in the {mu}g/L to mg/L range when present alone or in simple (e.g., binary) mixtures. SAW sensor technology offers a potentially effective alternative to existing field instrumentation for headspace analysis, soil vapor monitoring, and vacuum extraction process monitoring of VOCs in subsurface media

Ventilation rates in recently constructed U.S. school classrooms

Low ventilation rates (VRs) in schools have been associated with absenteeism, poorer academic performance, and teacher dissatisfaction. We measured VRs in 37 recently constructed or renovated and mechanically ventilated U.S. schools, including LEED and EnergyStarâ certified buildings, using CO2 and the steadyâ state, buildâ up, decay, and transient mass balance methods. The transient mass balance method better matched conditions (specifically, changes in occupancy) and minimized biases seen in the other methods. During the school day, air change rates (ACRs) averaged 2.0±1.3 hourâ 1, and only 22% of classrooms met recommended minimum ventilation rates. HVAC systems were shut off at the school day close, and ACRs dropped to 0.21±0.19 hourâ 1. VRs did not differ by building type, although costâ cutting and comfort measures resulted in low VRs and potentially impaired IAQ. VRs were lower in schools that used unit ventilators or radiant heating, in smaller schools and in larger classrooms. The steadyâ state, buildâ up, and decay methods had significant limitations and biases, showing the need to confirm that these methods are appropriate. Findings highlight the need to increase VRs and to ensure that energy saving and comfort measures do not compromise ventilation and IAQ.Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/138411/1/ina12384.pdfhttps://deepblue.lib.umich.edu/bitstream/2027.42/138411/2/ina12384_am.pd

Relationship of stream flow regime in the western Lake Superior basin to watershed type characteristics

To test a conceptual model of non-linear response of hydrologic regimes to watershed characteristics, we selected 48 secondand third-order study sites on the North and South Shores of western Lake Superior, MN(USA) using a random-stratified design based on hydrogeomorphic region, fraction mature forest, and fraction watershed storage (lakeCwetland area/watershed area). We calculated several commonly used hydrologic indices from discharge and velocity estimates, including daily flow indices, overall flood indices, low flow variables, and ratios or ranges of flow percentiles reflecting the nature of cumulative frequency distributions. Four principal components (PCs) explained 85.9 and 88.6% of the variation of flow metrics among second- and third-order stream sites, respectively. Axes of variation corresponded to a runoff vs. baseflow axis, flow variability, mean flow, and contrasts between flood duration and frequency. Analysis of velocity metrics for third-order streams yielded four PCs corresponding to mean or maximum velocity, Froude number, and inferred shear velocity, as well as spate frequencies vs. intervals associated with different velocity ranges. Using discriminant function analysis, we could discriminate among watershed classes based on region, mature forest, or watershed storage as a function of flow metrics. For second-order streams, median flow (Qs50) increased as watershed storage increased. North Shore streams showed a more skewed distribution and greater spread of discharge values than did South Shore streams for both stream orders, while third-order North Shore streams exhibited a higher frequency of spates. Independent of regional differences, loss of mature forest increased the range of variation between baseflow and peak flows, and depressed baseflow. Consistent with our initial model for watershed classification, Classification and Regression Tree (CART) analysis confirmed significant thresholds of change in flow metrics averaging between 0.506 and 0.636 for fraction mature forest and between 0.180 and 0.258 for fraction watershed storage