Soiling Potential—A New Method for Measuring Smoke Emission

There is a growing interest in effects of sub-micron, nonsettling particles in the atmosphere among air pollution control agencies throughout the country. This type of pollution, generally referred to as the “soiling index” of the atmosphere, is produced primarily by the incomplete combustion of fuels. The measurement procedure has been fairly well standardized, the values being reported as Cohs or Ruds per 1000 linear feet of air. Using a similar technique, a method of quantitating smoke emission in objective terms first demonstrated by W. C. L. Hemeon in 1953, has been applied to source testing at several operating plants by the Cincinnati Division of Air Pollution Control. The source strength will be called “soiling potential” while the effect in the general atmosphere is termed “soiling index.” The soiling potential unit is Rud-ft² per cubic foot exhaust gases or Rud-ft² per unit of fuel input. The “Soiling Potential” sampler is described and results of tests are given. Included is the use of soiling potential in quantitating smoke emission from single sources and for constructing area wide inventory of smoke emission. The use of an area wide smoke emission inventory in Rudft2 in a simple diffusion model for calculating the soiling index (Rud-ft²/1000 cu ft) in the general atmosphere at a given point is explored.     

The Plume Volume Molar Ratio Method for Determining NO2/NOx Ratios in Modeling—Part I: Methodology

ABSTRACT

During New Source Review modeling of proposed major sources of oxides of nitrogen (NO_x), maximum impacts are often predicted to occur very close to the source. At the same time, current modeling guidance recommends techniques that may be overly conservative in estimating the fraction of nitrogen dioxide (NO₂) in these plumes. A new technique called the Plume Volume Molar Ratio Method (PVMRM) is being proposed that simulates both chemistry and dispersion to better estimate the fraction of NO₂. This paper documents the methodology behind the technique. A follow-up pa-per¹ will evaluate its performance against a number of databases. This method is designed to realistically predict NO₂ fraction at close-in receptors yet still provide conservative estimates so that the air quality standards can be protected.     

The Plume Volume Molar Ratio Method for Determining NO2/NOx Ratios in Modeling—Part II: Evaluation Studies

ABSTRACT

A previous paper¹ discusses the methodology for a new method for deriving the nitrogen dioxide/nitrogen oxide (NO₂/NO_x) ratio in plumes that originally are composed mainly of (NO_x). It is called the Plume Volume Molar Ratio Method (PVMRM). This paper documents its performance against six different data sets. These performance evaluations show that the PVMRM can realistically predict the NO₂ fraction at close-in receptors yet still provide conservative estimates so that the air quality standards can be protected.     

A new challenge—development of test systems for the infochemical effect

Background, aim, and scope

Many—if not all—organisms depend on so-called infochemicals, chemical substances in their surroundings which inform the receivers about their biotic and abiotic environment and which allow them to react adequately to these signals. Anthropogenic substances can interfere with this complex chemical communication system. This finding is called infochemical effect. So far, it is not known to what extent anthropogenic discharges act as infochemicals and influence life and reproduction of organisms in the environment because adequate testing methods to identify chemicals which show the infochemical effect and to quantify their effects have not been developed yet. The purpose of this article is to help and find suitable test designs.

Main features

Test systems used in basic research to elucidate the olfactory cascade and the communication of environmental organisms by infochemicals are plentiful. Some of them might be the basis for a quantified ecotoxicological analysis of the infochemical effect. In principle, test systems for the infochemical effect could be developed at each step of the chemosensory signal transduction and processing cascade.

Results

Experimental set-ups were compiled systematically under the aspect whether they might be usable for testing the infochemical effect of single chemicals in standardized quantifying laboratory experiments. For an appropriate ecotoxicological assessment of the infochemical effect, experimental studies of many disciplines, such as molecular biology, neurobiology, physiology, chemical ecology, and population dynamics, should be evaluated in detail before a decision can be made which test system, respectively which test battery, might be suited best. The test systems presented here are based on the knowledge of the genetic sequences for olfactory receptors, binding studies of odorants, signal transmission, and reactions of the receivers on the level of the organisms or the populations. The following basic approaches are conceivable to identify the role of an infochemical: binding studies to the odorant-binding protein or to the odorant receptor binding protein (e.g., by in situ hybridization and immunohistochemical studies), measurement of electrical signals of the receptor cells in the tissue (e.g., electroolfactograms, electroantennograms), registration of phenotypic changes (e.g., observation under the microscope), behavioral tests (e.g., in situ online biomonitoring, use of T-shaped olfactometers, tests of avoidance responses), measurement of population changes (e.g., cell density or turbidity measurements), and multispecies tests with observation of community structure and community function. The main focus of this study is on aquatic organisms.

Discussion

It is evident that the infochemical effect is a very complex sublethal endpoint, and it needs further studies with standardized quantitative methods to elucidate whether and to what extent the ecosystem is affected. The collection of approaches presented here is far from being complete but should serve as a point of depart for further experimental research.

Conclusions

This article is the first to compare various approaches for testing the infochemical effect. The development of a suitable test system will not be easy as there are a multitude of relevant chemicals, a multitude of relevant receptors, and a multitude of relevant reactions, and it must be expected that the effective concentrations are very low. The chemical communication is of utmost importance for the ecosystem and justifies great endeavors to find solutions to these technical problems.

Recommendations and perspectives

The infochemical effect is a new chapter in ecotoxicology. Will a new endpoint, the so-called infochemical effect, be required in addition to the actual standard test battery of Annex 5 to Commission Directive 92/69/EEC (EC 1992)? Finding the answer to this question is a big challenge that could be met by a comprehensive research project.     

A comparison of numerical methods for solving the advection equation—II

Five algorithms and their variations for solving the advection equation were compared in terms of their accuracy, speed and storage requirements. The algorithms are a chapeau-function method including mass-lumping, Forester's method, a method called Filtering Remedy and Methodology, a Hermite-cubic orthogonal-collocation method and a quadratic function method. The test problem was the rotation of a cosine-shaped hill of concentration in a two-dimensional circular velocity field at three different time increments (or angular velocities). The forward-Euler time-integration scheme coupled with a balancing diffusion term was extensively used and was found to be superior to the Crank-Nicolson scheme in accuracy for the methods considered. Together with the results of Part I (Atmospheric Environment17, 11–24, 1983), Forester's method applied to the chapeau-function solution appears to be the best method for solving the advection equation in air-pollution modeling. The combined method retains the peak value well, has high accuracy with little or no negative concentration region, and requires short execution time and minimal memory storage.     

An Atmospheric Dispersion Model for the Environmental Impact Assessment of Thermal Power Plants in Japan—A Method for Evaluating Topographical Effects

Abstract

An atmospheric dispersion model was developed for the environmental impact assessment of thermal power plants in Japan, and a method for evaluating topographical effects using this model was proposed. The atmospheric dispersion model consists of an airflow model with a turbulence closure model based on the algebraic Reynolds stress model and a Lagrangian particle dispersion model (LPDM). The evaluation of the maximum concentration of air pollutants such as SO₂, NO_x, and suspended particulate matter is usually considered of primary importance for environmental impact assessment. Three indices were therefore estimated by the atmospheric dispersion model: the ratios (α and β, respectively) of the maximum concentration and the distance of the point of the maximum concentration from the source over topography to the respective values over a flat plane, and the relative concentration distribution [γ(x)] along the ground surface projection of the plume axis normalized by the maximum concentration over a flat plane. The atmospheric dispersion model was applied to the topography around a power plant with a maximum elevation of more than 1000 m. The values of α and β evaluated by the atmospheric dispersion model varied between 1 and 3 and between 1 and 0.4, respectively, depending on the topographical features. These results and the calculated distributions of γ(x) were highly similar to the results of the wind tunnel experiment. Therefore, when the slope of a hill or mountain is similar to the topography considered in this study, it is possible to evaluate topographical effects on exhaust gas dispersion with reasonable accuracy using the atmospheric dispersion model as well as wind tunnel experiments.     

The chemistry of carbonyl compounds in the atmosphere—A review

Carbonyl compounds are very important for the trophospheric physico-chemistry because they are the result of the first photo-oxidation stage of almost all organic compounds and they are the essential originators of the free radicals. In the present review we make a synthesis of the studies on the carbonyl compounds chemistry in the trophosphere by successively examining: measurement methods in the trophosphere, sources of primary carbonyl compounds, formation of secondary carbonyl compounds in the atmosphere, reactivity of carbonyl compounds in the atmosphere.     

A proposed strategy for reducing sulphate deposition in North America—II. Methodology for minimizing costs

A method is described for determining optimized emission reductions to reduce sulphate deposition in N America such that the cost of the emission reductions tends to be minimized. The method combines the use of source-receptor relationships produced by long range transport models and cost data for control steps at smelters, thermal generating stations and for fuel oil desulphurization. Emission reductions selected by this method cost less than those indicated by an optimization method which minimizes only the amount of sulphur removal. The savings are greater when the costs of the various control steps are spread over a wide range and not clustered about a mean value. In that case, the control costs, especially in the early to middle steps of the control program, may be only a fraction of what they would otherwise be.     

A proposed strategy for reducing sulphate deposition in North AmericA—I. Methodology for minimizing sulphur removal

Four schemes to reduce sulphate deposition in N America while minimizing sulphur removal are described and tested. These schemes utilize the source-receptor linkages, as described by the source-receptor matrices produced by long range atmospheric transport models, to select the source areas where emission reductions should take place. All four schemes indicate that most of the emission reductions should take place in the Ohio River Valley, northern Appalachia, the lower Great Lakes region and the St. Lawrence River Valley. Tests indicate that fluctuations in matrix elements have little effect upon the choice of the most important source regions but affect only the selection of the emission reductions in the less important fringe areas. The methodology is being continually refined with improved input data with respect to source-receptor relationships and control technology.     

A chamber study of photochemical smog in Melbourne,Australia—present and future

The present paper concludes a comprehensive program designed firstly to locate the source areas of emission responsible for the photochemical smog which impacts the central Melbourne urban area, secondly to determine the hydrocarbon and NO_x composition of these sources and finally to demonstrate by smog chamber simulations what benefit would be derived from a reduction in the emissions from the offending sources.The conclusions reached are that a reduction in NO_x emissions would lead to increased ozone levels in Melbourne but even a small reduction in hydrocarbon emissions would be beneficial. The implementation of Australia Design Rule 37 should, by restricting hydrocarbon emissions to 50% of the current 1985 level, reduce the photochemical ozone over the central metropolitan area to well below the acceptable level.In the course of this work it has been possible to validate the chamber technique by showing that the photochemical behaviour of a well-documented air parcel can be reproduced in a smog chamber operated under the same conditions of temperature, radiation, dilution and pollutant input as was experienced by the outdoor air parcel.     

A reactive transport model for mercury fate in soil—application to different anthropogenic pollution sources

Soil systems are a common receptor of anthropogenic mercury (Hg) contamination. Soils play an important role in the containment or dispersion of pollution to surface water, groundwater or the atmosphere. A one-dimensional model for simulating Hg fate and transport for variably saturated and transient flow conditions is presented. The model is developed using the HP1 code, which couples HYDRUS-1D for the water flow and solute transport to PHREEQC for geochemical reactions. The main processes included are Hg aqueous speciation and complexation, sorption to soil organic matter, dissolution of cinnabar and liquid Hg, and Hg reduction and volatilization. Processes such as atmospheric wet and dry deposition, vegetation litter fall and uptake are neglected because they are less relevant in the case of high Hg concentrations resulting from anthropogenic activities. A test case is presented, assuming a hypothetical sandy soil profile and a simulation time frame of 50 years of daily atmospheric inputs. Mercury fate and transport are simulated for three different sources of Hg (cinnabar, residual liquid mercury or aqueous mercuric chloride), as well as for combinations of these sources. Results are presented and discussed with focus on Hg volatilization to the atmosphere, Hg leaching at the bottom of the soil profile and the remaining Hg in or below the initially contaminated soil layer. In the test case, Hg volatilization was negligible because the reduction of Hg²⁺ to Hg⁰ was inhibited by the low concentration of dissolved Hg. Hg leaching was mainly caused by complexation of Hg²⁺ with thiol groups of dissolved organic matter, because in the geochemical model used, this reaction only had a higher equilibrium constant than the sorption reactions. Immobilization of Hg in the initially polluted horizon was enhanced by Hg²⁺ sorption onto humic and fulvic acids (which are more abundant than thiols). Potential benefits of the model for risk management and remediation of contaminated sites are discussed.     

PM2.5 concentrations in London for 2008–A modeling analysis of contributions from road traffic

We report on the analysis of contributions from road traffic emissions to fine particulate matter (PM_2.5) concentrations within London for 2008 with the OSCAR Air Quality Assessment System. A spatiotemporal evaluation of the OSCAR system has been conducted with measurements from the London air quality network (LAQN). For the predicted and measured hourly time series of concentrations at 18 sites in London, the medians of correlation, mean absolute error, index of agreement, and factor of two (FAC2) of all stations were 0.80, 4.1 μg/m³, 0.86, and 74%, respectively. Spatial evaluation of modeled and observed annual mean concentrations also showed a fairly good agreement, with all the values falling within the FAC2 range. According to model predictions, the urban increment (including the contributions from urban traffic and other urban sources) was evaluated to be on the average 18%, 33%, 39%, and 43% of the total PM_2.5 in suburban environments, in the urban background, near roads, and near busy roads, respectively. However, the highest values of the urban traffic increment can be around 50% of the total PM_2.5 concentrations near motorways and major roads. The total concentrations (including regional background, and the contributions from urban traffic and other urban sources) can therefore be almost three times the regional background. The total urban increment close to busy roads was around 7–8 μg/m³, in which the estimated traffic contribution is more than 2 μg/m³. On the average, urban traffic contributes approximately 1 μg/m³ of PM_2.5 to the urban background across London. According to modeling, approximately two-thirds of the traffic increment originated from exhaust emissions and most of the rest was due to brake and tire wear.

Implications: The urban increment and traffic contribution to the total PM_2.5 are significant and spatially heterogeneous across London. The highly heterogeneous distribution of PM_2.5 hence requires detailed modeling studies to be carried out at high spatial resolution, which can be particularly important for exposure and health impact assessment. This type of information can be used to quantify health impacts resulting from specific sources of PM_2.5 such as traffic emissions, to aid city and national decision makers when formulating pollution control strategies.     

Challenges in developing strategies for the valorization of lignin—a major pollutant of the paper mill industry

Environmental Science and Pollution Research - Apart from protecting the environment from undesired waste impacts, wastewater treatment is a crucial platform for recovery. The exploitation of...     

A review of bioretention components and nutrient removal under different climates—future directions for tropics

Bioretention systems have been implemented as stormwater best management practices (BMPs) worldwide to treat non-point sources pollution. Due to insufficient research, the design guidelines for bioretention systems in tropical countries are modeled after those of temperate countries. However, climatic factors and stormwater runoff characteristics are the two key factors affecting the capacity of bioretention system. This paper reviews and compares the stormwater runoff characteristics, bioretention components, pollutant removal requirements, and applications of bioretention systems in temperate and tropical countries. Suggestions are given for bioretention components in the tropics, including elimination of mulch layer and submerged zone. More research is required to identify suitable additives for filter media, study tropical shrubs application while avoiding using grass and sedges, explore function of soil faunas, and adopt final discharged pollutants concentration (mg/L) on top of percentage removal (%) in bioretention design guidelines.

     

Potential of Eucalyptus globulus for the phytoremediation of metals in a Moroccan iron mine soil—a case study

Environmental Science and Pollution Research - The contamination left by abandoned mines demands sustainable mitigation measures. Hence, the aim of this study was to examine the phytoremediator...     

A model for NOx–O3–terpene chemistry in chamber measurements of plant gas exchange

Cuvette measurements are a tool to analyse CO₂ exchange, transipiration and deposition/emission of different trace gases by plants. To verify these experimental methods and to use them efficiently we have developed a numerical model with atmospheric chemical reactions. The model includes reactions between 54 different chemical species in the gas phase. Using the model we are able to determine optimal size/flow rate ratios and cuvette cycles (closure times) from an experimental point of view. Using the cuvette model with atmospheric chemistry more accurate estimates for emissions/deposition rates of different species can be found. Some chemical reactions are significant, e.g. for NO and terpenes, as regards the analysis and interpretation of measured concentrations. With slower flow rates through a cuvette the significance of reactions is more pronounced. However, there are some species like ozone, where stomatal deposition is a dominant phenomenon and chemistry plays a minor role.     

Indoor and outdoor sources of size-resolved mass concentration of particulate matter in a school gym—implications for exposure of exercising children

Introduction  

It has been noticed many times that schools are buildings with high levels of particulate matter concentrations. Several authors documented that concentrations of particulate matter in indoor school microenvironments exceed limits recommended by WHO namely when school buildings are situated near major roads with high traffic densities. In addition, exercise under conditions of high particulate concentrations may increase the adverse health effects, as the total particle deposition increases in proportion to minute ventilation, and the deposition fraction nearly doubles from rest to intense exercise.     

Effectiveness in the Use of Natural Gas for the Reduction of Atmospheric Emissions: Case Study—Industrial Sector in the Metropolitan Region of Santiago,Chile

Abstract

The purpose of this investigation was to quantify the potential of natural gas to reduce emissions from stationary combustion sources by analyzing the case study of the metropolitan region of Santiago, Chile. For such purposes, referential base scenarios have been defined that represent with and without natural gas settings. The method to be applied is an emission estimate based on emission factors. The results for this case study reveal that stationary combustion sources that replaced their fuel reduced particulate matter (PM) emissions by 61%, sulfur oxides (SO_x) by 91%, nitrogen oxides (NO_x) by 40%, and volatile organic compounds (VOC) by 10%. Carbon mon-oxide (CO) emissions were reduced by 1%. As a result of this emission reduction, in addition to reductions caused by other factors, such as a shift to cleaner fuels other than natural gas, technological improvements, and sources which are not operative, emission reduction goals set forth by the environmental authorities were broadly exceeded.