Showing papers on "Air quality index published in 1990"

PM-10 measurements using the tapered element oscillating microbalance

Abstract: In recent years the quality of the air we breathe has become a greater factor in important environmental issues. Both outdoor and indoor air quality are areas of interest and concern in this respect. Ambient air particulate matter in addition to gas species contribute to the assessment of air quality. In this regard, instrumentation to measure particulate concentration levels is available to quantify this parameter. Particulate concentration measurements, however, are notoriously difficult to standardise. Collection efficiency difficulties and vagaries concerning the definition of particulate matter combine to create substantial uncertainties when measurements from one method or type of instrument are compared with another.

Airborne particle sizes and sources found in indoor air. Rept. for Sep 89-Feb 90

Abstract: The paper summarizes results of a literature search into the sources, sizes, and concentrations of particles in indoor air, including the various types: plant, animal, mineral, combustion, home/personal care, and radioactive aerosols. The information, presented in a summary figure, has been gathered for use in designing test methodologies for air cleaners and other mitigation approaches and to aid in the selection of air cleaners. (NOTE: As concern about indoor air quality has grown, understanding indoor aerosols has become increasingly important so that control techniques may be implemented to reduce damaging health effects and soiling problems. Particle diameters must be known to predict dose or soiling and to determine efficient mitigation techniques.)

The Southern California air quality study

Abstract: During the 82nd Annual Air & Waste Management Association meeting in Anaheim, California, researchers presented preliminary results from the 1987 Southern California Air Quality Study (SCAQS), which was conducted in the South Coast Air Basin. This paper describes the background and study design for SCAQS, presents summaries of the papers presented in the SCAQS Symposium at the A&WMA meeting, and describes the data analysis and air quality modeling efforts currently in progress as part of the SCAQS program.

Emissions of some trace gases from biomass fires

Abstract: Airborne measurements of 13 trace gases from seven forest fires in North America are used to determine their average emission factors. The emission factors are then used to estimate the contributions of biomass burning to the worldwide fluxes of these gases. The estimate for NH3 (∼7 Tg N yr−1) is about 50% of the global emissions of this gas. Combined NH3 and emissions from biomass burning could be the most important component of the NH3 cycle. N2O from biomass burning (∼ 2 Tg N yr−1) is also significant worldwide. The estimate for NOx from biomass burning worldwide (∼ 19 Tg N yr−1), which is greater than previous estimates, is comparable to emissions from fossil fuel combustion. The estimate of the global flux of F12 (CF2Cl2) from biomass burning based on the complete data set (∼0.2 Tg yr−1) is ∼50% of the total global emission of F12. However, this estimate is strongly influenced by a very high emission of F12 from a fire in the Los Angeles Basin. Disregarding this fire yields a global flux of 0.06 Tg yr−1 (∼15% of total global emissions). The high emissions of NOx and F12 are due in whole or part to the resuspension of previously deposited pollutants. Since this can be the only source of F12 in the smoke from fires, deposition may be a significant sink for F12. Our estimate for NOx emissions from biomass burning in the South Coast Air Basin of California is much greater than previous estimates.

Procedure for controlling and maintaining air currents or equivalent in an air-conditioning installation, and an air-conditioning system according to said procedure

Abstract: The present invention concerns a procedure and apparatus for controlling and maintaining air currents or equivalent in an air-conditioning installation or equivalent. The air-conditioning installation comprises one or several air-conditioning machines (P) for producing the desired flows, and one or several duct systems for conducting the flows into the desired room spaces (H1, H2...) or equivalent and/or out from the room spaces (H1, H2...) or equivalent. The duct systems consist of requisite trunk, zone and room duct systems (R, Z, C). In the procedure the air flow rates required at any given time in the air-conditioning system are determined on the basis of the air temperature and/or air quality and/or air noise levels and/or air pressure conditions and/or other similar factors. On the basis of the respective air flow rates determined by calculation, a combination of the said values for all controll members (S1, S1.1, S1.2...) and air-conditioning machines (P) are thereafter determined at the same time, and the control members (S1, S1.1...) and the air-conditioning machines (P) are at the same time set to settings consistent with said set value combination, whereby the above-mentioned air flow rates will be realized.

Evaluating sources of indoor air pollution.

Abstract: Evaluation of Indoor air pollution problems requires an understanding of the relationship between sources, air movement, and outdoor air exchange. Research is underway to investigate these relationships. A three-phase program is being implemented: 1) Environmental chambers are used to provide source emission factors for specific indoor pollutants; 2) An IAQ (Indoor Air Quality) model has been developed to calculate indoor pollutant concentrations based on chamber emissions data and the air exchange and air movement within the indoor environment; and 3) An IAQ test house is used to conduct experiments to evaluate the model results. Examples are provided to show how this coordinated approach can be used to evaluate specific sources of indoor air pollution. Two sources are examined: 1) para-dichlorobenzene emissions from solid moth repellant; and 2) particle emissions from unvented kerosene heaters. The evaluation process for both sources followed the three-phase approach discussed above. Para-dichlorobenzen...

Air cleaner assembly

Abstract: A single compact air cleaner unit includes a motor and fan assembly, a mechanical pre-filter, an electrostatic precipitator, a main filter cartridge which is easily removable and which contains both a synthetic mesh media with electrical charges embedded therein and a plastic screen impregnated with activated carbon powder, ionizing needles positioned adjacent a fresh air outlet, an air quality sensing device having an adjustable control for selecting a level of air quality to be achieved, and an automatic control cooperatively associated with the air quality sensing device to keep the unit energized as long as the air being sampled does not meet the selected air quality level.

Air quality criteria for carbon monoxide. Draft report

Abstract: The revised air quality criteria document for carbon monoxide (CO) reviews and evaluates the scientific information on the health effects associated with exposure to the concentrations of CO found in ambient air. Although the document is not intended to be an exhaustive literature review, it is intended to cover all the pertinent literature through late 1989. The references cited in the document are, therefore, reflective of the current state of knowledge on those issues relevant to the subsequent review of the national ambient air quality standards (NAAQS) for CO, currently set at 9 ppm (10 mg/cu m) for 8 h and 35 ppm (40 mg/cu m) for 1 h. Major gaps in knowledge also are identified. Although emphasis is placed on the presentation of health effects data, other scientific data are presented and evaluated in order to provide a better understanding of the nature, sources, distribution, measurement, and concentrations of CO in the environment, as well as the measurement of population exposure to CO.

Root growth of Fagus sylvatica: impact of air quality and drought at a site in southern Britain.

Abstract: Transplants of beech, Fagus sylvatica, L. were planted in 1 m plastic tubes containing a mixture of peat and grit and sunk into the ground inside open-top chambers at a site in southern Britain. Chambers were ventilated with either charcoal-filtered or unfiltered air and water was withheld from half of the trees within each chamber. The influence of air quality on the growth and development of roots and interactions between air quality and drought were investigated. During May and June 1988 the growth of fine (diameter 1.5 m) was not significantly altered by air quality. A destructive harvest conducted in July revealed that trees exposed to ambient pollution had significantly longer roots (P During August 1988, water was withheld from half of the trees within each chamber. Well-watered trees exposed to unfiltered air had significantly less root dry weight (P These results illustrate the importance of measuring root length to complement estimates of dry weight, which may not be the best indicator of root function. The production of longer, thinner roots may be an important mechanism to compensate for reduced carbon allocation to, and dry matter accumulation by roots of trees exposed to pollution.

Exceedances of the National Ambient Air Quality Standard for Ozone Occurring at a “Pristine” Area Site

Abstract: The authors present ozone measurements for high elevation pristine area sites in the Mt. Mitchell, North Carolina State Park located in the southeastern United States. These data have been collected as part of an on-going project, one of the goals of which is to assess rural ozone exposure. They may also provide insight into those processes which affect rural ozone levels, and perhaps might guide policy makers in developing strategies for rural ozone control.

Roadway tunnel air quality models

Abstract: Quasi-steady-state, analytic air quality models for various types of roadway tunnels are presented. These models can be used to estimate the concentrations of pollutants in roadway tunnels and to determine vehicular emission rates. These models are used to evaluate formaldehyde concentrations resulting from the emissions of methanol-fueled vehicles. It is shown that, within the expected emission rates of methanol-fueled vehicles, formaldehyde concentrations in roadway tunnels are not likely to be a health concern for the general public. One possible exception is during heavily congested traffic conditions; during these conditions, formaldehyde concentrations may result in eye irritation for sensitive individuals.

Lichen Recolonization in the Upper Ohio River Valley

Abstract: Improvement in the air quality of the upper Ohio River valley has led to lichen recolonization at previously depauperate sites. Between 1973 and 1989 the number of lichen species in the area almost doubled and the mean species per site increased from 0.8 to 3.5. An indicator species, Flavoparmelia caperata, was completely absent in 1973 but occurred at half of the study sites in 1989. While many papers have detailed the loss of lichens in poor air quality, only a few have reported the recovery of lichens in improving air quality. Sulfur dioxide air quality is now improving in most areas of the United States. One source (Placet & Streets 1987) estimates that total SO2 emissions in the United States decreased from 26.8 million metric tons in 1975 to 21.2 million metric tons in 1985. Ohio showed a similar decrease in SO2 emissions from 2.99 to 2.43 million metric tons during the same period. The upper Ohio River valley was once reputed to have the dirtiest air in the nation. This area was heavily industrialized with coal-burning power plants, steel mills, foundries, and coking ovens. However, the region was severely affected by the recession of the late 1970's and the concomitant decline of the U.S. steel industry. Old plants were closed and modernization and fuel switching at other facilities led to reduced SO2 emissions. This decrease in emission has had a dramatic effect on the ambient SO2 levels. Data from the North Ohio Valley Air Authority (Robert T. Carducci, pers. comm.) show that in 1975, Steubenville, Ohio had an annual average SO2 concentration of 118 ~g/m3. By 1985 this had almost halved to 60 jig/m3. East Liverpool, Ohio reported an annual average of 120 ig/m3 in 1975 and 44 ig/m3 in 1985. For comparison, the National ambient air quality standard is 80 Ug/m3. Data from several different monitoring sites in the area consistently show a sharp decline from high to much lower values about 1981. Lichen studies in the upper Ohio River valley were first conducted in 1973 around Cardinal Power Plant, located between Wheeling, West Virginia and Steubenville, Ohio. After the initial study, it was apparent that the regional SO2 background overwhelmed any contribution to ground-level SO2 by the power plant. Lichens were depauperate throughout the study area with no apparent differences between sites upwind and downwind from Cardinal Plant. Thus, studies were continued to monitor the impact of regional SO2 on lichens. Lichen resurveys were performed in 1983, 1988, and 1989.

Upward vs. downward ventilation air flow in a swine house

Abstract: Several ventilation system designs are in common use, and very little is known about their relative performance in achieving an acceptable livestock building air quality. A ventilation system may be characterized quantitatively from the efficiency (p*) of the air exchange process and the effectiveness (€) of the contaminant removal process. The theoretical framework is summarized and applied in an intervention study of upward versus downward air flow in a swine house. The contaminants considered were NH3, CO2, dust, and excessive heat. It was concluded that the air exchange efficiency of upward air flow was superior to downward air flow. For some contaminants (CO2, excessive heat, dust) the ventilation effectiveness of upward air flow was superior to downward air flow..

An indoor air quality survey of twenty‐six (26) Swiss office buildings

Abstract: In an effort to characterize the major factors influencing air quality in buildings in Switzerland, a representative selection of 26 buildings was selected for this study. Each building was. subjected to the same indoor air quality survey methodology. The most significant cause of air quality problems was found to be poor ventilation followed by inadequate filtration and poor hygiene. Control of Legionella bacteria and asbestos containing materials may also need to be given high priorities in order to prevent immediate and long term hazards to building occupants.

Ground-based air-sampling measurements near the Nevada Test Site after atmospheric nuclear tests.

Abstract: Historical air-sampling data measured within 320 km (200 mi) of the Nevada Test Site (NTS) have been reviewed for periods following atmospheric nuclear tests, primarily in the 1950s. These data come mostly from high-volume air samplers, with some from cascade-impactor samplers. Measurements considered here are for beta radiation from gross fission products. The resulting air-quality data base is comprised of almost 13,000 samples from 42 sampling locations downwind of the NTS. In order to compile an accurate air-quality data base for use in estimating exposure via inhalation, raw data values were sought where possible, and the required calculations were performed on a computer with state-of-the-art algorithms. The data-processing procedures consisted of (1) entry and error checking of historical data; (2) determination of appropriate background values, air-sampling volumes, and net air concentrations; and (3) calculation of integrated air concentration (C) for each sample (considering fallout arrival times). Comparing C values for collocated high-volume and cascade-impactor samplers during the Upshot-Knothole series showed similar lognormal distributions, but with a geometric mean C for cascade impactors about half that for the high-volume air samplers. Overall, the uncertainty in C values is about a factor of three. In the past, it has been assumed that C could be related to ground deposition by a constant having units of velocity. In our data bases, simultaneous measurements of air concentration and ground deposition at the same locations were not related by a constant; indeed, there was a great amount of scatter. This suggests that the relationship between C and ground deposition in this situation is too complex to be treated adequately by simple approaches.

Groundwater treatment with zero air emissions

Abstract: Air emissions from the treatment of volatile organic compound (VOC) - contaminated groundwater are a growing problem in the US. Historically, air stripping has been used to remove VOCs from contaminated groundwater. Air stripping technology is a cross media treatment technique, i.e., it solves a groundwater problem by transferring contamination to the atmosphere. In response to the air pollution problem created by air stripping, the public, air quality regulatory agencies, the federal government and private industry are exerting pressure to eliminate and/or reduce air emissions from the clean-up of contaminated groundwater. These forces make it desirable to consider alternative and innovative technologies for the treatment of groundwater contaminated with VOCs.