Showing papers on "Air quality index published in 1988"

Receptor models: development and testing of such models has moved from the research domain into application to practical problems

Abstract: Air pollution authorities use models to develop optimal control strategies for air pollutants. According to the traditional approach, emissions inventories for various sources are used as inputs for plume, box, or grid models to predict ambient concentrations of total suspended particulate matter (TSP), SO/sub 2/, or other air pollutants. These methods, however, are inadequate for many purposes today and will be even less useful for many future needs. Even if dispersion models were accurate, the source emissions inventories upon which they rely are not. Source emission inventories, especially for sources equipped with pollution controls, usually do not include contributions from fugitive process emissions and dust. Furthermore, air quality standards are beginning to require knowledge of source of particles in certain size ranges, particles bearing certain toxic substances, or particles that have a special role in problems such as visibility degradation or climate modification.

S12 ambient air quality standards

Abstract: Conceptual methods of setting national ambient air quality standards in Japan are discussed in comparison with case of occupational exposure limits in industrial health. The air quality standards are set by the national government, based on recommendations of the Central Council on Countermeasures for Environmental pollution, in conformity with the Fundamental Act on Countermeasures for Environmental Pollution. In setting the standard values, thresholds and the existence of specific groups in the people with high susceptibility to a certain pollutant are taken into account. The standards are set following minimum effect reports in three branches of health effect studies on air pollution: animal experiments, human exposure, and epidemilogy. Safe levels take into account the absence of effects, suspicion of irreversible effects, dwellings of the elderly/infant/sick, epidemiologic growth of nonspecific diseases such as asthma, and so on. Under these conditions, air quality standards become far severer than in the case of industrial health limits.

Ozone air quality models. A critical review

Abstract: The field of ozone air quality modeling, or as it is commonly referred to, photochemical air quality modeling, has undergone rapid change in recent years. Improvements in model components, as well as in methods of interpreting model performance, have contributed to this change. Attendant with this rapid change has been a growing need for those developing and using air quality models and policy makers to have a common understanding of the use and role of models in the decision making process. This Critical Review highlights recent advances and continuing problem areas in photochemical air quality modeling. Emphasis is placed on the components and input data for such models, model performance evaluation, and the implications for their use in regulatory decisions.

Accuracy of Ozone Air Quality Models

Abstract: Photochemical grid model performance evaluation studies have been undertaken over the last decade as an integral part of ozone air pollution model development and application efforts and in support of model sensitivity analysis, monitoring program design, and applied research. These studies, sponsored by federal and state agencies, universities, and consulting firms, represent a significant body of information. A comprehensive review of past Eulerian model evaluation studies indicates that the overall accuracy of hourly averaged ozone predictions, paired in time and space, is of the order of 35–40%. However, considering the model’s ability to reproduce the maximum observed concentration, independent of time or space pairing, overall prediction accuracies of 10–20% are found. For single-day ozone simulations, the overall negative bias is -10%.

Air quality control systems

Abstract: Air quality control systems for rooms or other enclosed spaces relying on generators which supply charges to particles present in the air thereby purifying or otherwise controlling the condition of the air. A source of high voltage is connected to radiating surfaces of various configurations carrying electrostatic charges. A fan or other air circulating device including natural air movement insures adequate contact of the air with the charges generated to thereby achieve the desired quality control. Operating mechanisms provided in the system include voltage varying circuitry to permit adjustment of the generating intensity. A sensor is provided to detect variations in conditions thereby permitting automatic voltage variations. A remote control station is comtemplated where independent environments may be involved and where separate control of these environments is desired. Switching of the system polarity enable production of positive or negative electrostatic charges depending on the atmospheric conditions encountered.

Chance‐Constrained Dynamic Model of Air Quality Management

Abstract: This paper presents a modeling approach based on chanceconstrained programming, that determines least‐cost time‐linked air pollution emission controls, while accounting for the dynamic and stochastic character of meteorological conditions and respecting different averaging‐time ambient air quality standards with exogenously specified reliabilities. The methodology is numerically illustrated with actual meteorological data in the case of an isolated pollution source and of monthly and annual air quality standards. Areas for further research are also delineated.

Advances in instrumentation for atmospheric aerosol measurement

Abstract: Instruments for airborne particle sampling and measurement are important tools for the study of particulate air contaminants. As such they are important in air quality, air pollution and industrial hygiene studies. Particle measuring instruments are important also for various industrial processes, such as clean room monitoring and contaminant measurement in clean process gases used in semiconductor manufacturing. This paper reviews the advances in particle measuring and sampling instruments, with particular emphasis on instruments for atmospheric studies. Devices for particle generation needed for instrument calibration and experimental purposes are also covered in this review.

Olf and decipol: New units for perceived air quality

Abstract: In many offices, schools, dwellings and other non-industrial buildings the air is often perceived as annoying, unpleasant, stale, and stuffy. In many cases it has not been possible to identify the ...

The NCLAN Program for Crop Loss Assessment

Abstract: The Clean Air Act requires the US Environmental Protection Agency (EPA) to set National Ambient Air Quality Standards (NAAQSs) for “any air pollutant which, if present in the air, may reasonably be anticipated to endanger public health or welfare and whose presence in the air results from numerous or diverse mobile and/or stationary sources” (Padgett and Richmond, 1983). The Agency is responsible for developing and promulgating primary (to protect public health) and secondary (to protect public welfare) NAAQSs. The 1977 amendments to the Clean Air Act require that the criteria (scientific basis) for the standards be periodically reviewed and revised to include new information. In 1978, EPA reviewed the scientific literature to determine the impact of ozone on vegetation and published this analysis in the Air Quality Document for Ozone and Other Photochemical Oxidants (US EPA, 1978). The credibility of the secondary standard for ozone, based in part on these studies, suffered because there were insufficient data to determine reliably either the effects of ozone on the yield of major agronomic crops under field conditions or to determine resultant economic consequences.

High-ozone events in Atlanta, Georgia, in 1983 and 1984

Abstract: Measurements of ozone levels and meterological parameters were analyzed to determine the relative importance of transport-related processes and photochemical production in causing high-ozone events in and around the Atlanta metropolitan area. Back-trajectories calculated by the Branching Air Trajectory Model indicate that the air associated with high-ozone events had often traveled a significant distance within the previous 3 days: for days with ozone levels above 100 ppbv, half of the calculated trajectories showed that the air had traveled over 600 km, with half of those coming from the northwest quadrant. Six-hour vector-averaged winds were used to find that the concentrations of ozone in the air leaving the metropolitan area averaged 20-40 ppbv more than that entering the area.

Air pollution and wildlife toxicology: An overlooked problem

Abstract: Since the 1880s, there have been repeated reports worldwide of toxic effects to wildlife from air pollution. Incidents in North America were recorded as early as the 1920s and as recently as last year. The effects have ranged from death and injury to increased incidence of infectious diseases, and they are the result of exposure to both gaseous and particulate emissions. Compared with other threats to wildlife, for instance, pesticides, the toxicological relationship between air pollution and effects in wildlife is not well understood. Our limited understanding is based primarily on reports of symptoms observed in the field and on information extrapolated from studies in livestock and laboratory animals. Few controlled wildlife studies, such as those that have evaluated pesticide effects, have been conducted. Current air quality standards cannot be assumed to protect wildlife from the effects of air pollution. This article reviews the current state of knowledge of air pollution and wildlife toxicology and the continuing threat air pollution presents to wildlife. The available information on reported effects of gaseous and particulate pollutants (i.e., sulfur dioxide, hydrogen sulfide, oxidants, arsenic, cadmium, fluoride, lead and selenium) on terrestrial wildlife, along with similar toxicological data for domestic animals, is summarized. Information on the toxic effects, tolerance levels, pathways of contamination, and risks to wildlife from air pollution is given, and gaps in knowledge are pointed out. Areas where research is needed are identified.

Housing quality differentials in urban areas

Abstract: This paper applies an equilibrium quality theory for differentiated products to estimate the willingness to pay for improvements in the air quality of Chicago, Cleveland, Dallas, Houston, and Indianapolis. The empirical results show (i) that the structural approach and the standard non-structural approach give very different benefit figures even for small improvements in air quality, and (ii) that a uniform improvement in air quality implies significant distributional effects.

Air Quality Implications of Methanol Fuel Utilization

Abstract: Methanol fuel utilization has been proposed as a way to reduce ozone levels in urban areas experiencing concentrations in excess of the National Ambient Air Quality Standard. Since methanol is less reactive than the complex mixture of organic compounds emitted by gasoline engines, emissions from methanol fueled engines may form less ozone. A three-tiered modeling study has been developed to quantify the reduction in ozone attainable with methanol fuel utilization. The results of the final tier of the modeling program, use of an airshed model to calculate changes in basinwide ozone levels, are presented here. Results indicate that methanol fuel utilization reduces ozone levels to a greater extent than conventional control scenarios do, but the amount of reduction is somewhat sensitive to the amount of formaldehyde in the vehicle emissions.

Commercial building ventilation measurements using multiple tracer gases

Abstract: Researchers in the US have reported the results of measuring the nominal ventilation rate, i.e., outside air supply rate per unit building volume, in approximately 50 US commercial buildings. The nominal ventilation rate, and parameters that can be derived from the nominal ventilation rate, are sufficient for characterizing the rate of ventilation rate of ventilation only in buildings where the air is thoroughly mixed. Data that indicate the extent to which air is mixed in commercial buildings are largely unavailable. Mixing may depend on building size, internal configuration, the number and type of air handlers, and numerous other factors. When the indoor air is not fully mixed, indoor air quality and building energy consumption are influenced by such factors as local ventilation rates or ages of air, the extent and direction of interzonal air flow, the pattern of air flow between locations of air supply and removal, and the associated values of air exchange efficiency. We have obtained this detailed information on ventilation by labeling each airstream of entering outside air with a distinct tracer gas, appropriate monitoring of tracer gas concentrations, and specific procedures of data analysis. This describes the technical approach, methods of evaluating the data, and themore » results from two buildings. 8 refs., 4 figs., 2 tabs.« less