Abstract
Air contamination by fluorides is one of our major air pollution problems. These compounds are released by industries processing clays, ores, phosphate rock, coal, or any other fluorine-containing materials. Aluminum reduction, ceramic, phosphate, chemical, steel, and thermal power generation works all release fluorides in their normal manufacturing processes. Both gaseous and particulate fluorides may be emitted.
Abstract
Growth chambers can be adapted in many ways to meet the special needs of plant stress studies. The purpose of this paper is to discuss special growth chambers and selected stress experiments requiring special techniques and extensive modification of growth chamber design. Use of growth chambers in air pollution, pesticide, radioisotope, and ultraviolet radiation research will be presented as examples.
Abstract
Atmospheric fluoride occasionally adversely affects foliage plants, especially intolerant species. The present report describes susceptibility to airborne fluoride damage of 34 foliage plants determined by comparative fumigation in compartmentalized greenhouses using 4 steady-state levels of hydrofluoric acid gas. Toxicity symptoms were recorded for diagnostic and damage evaluation purposes relative to air pollution effects.
Abstract
Bearing ‘Valencia’ orange trees growing in a commercial orchard adjacent to a known source of fluoride air pollution were sprayed periodically over a 3-year period with Ca(OH)2 and CaCl2 sprays. These materials in spray and dust forms have been used successfully in the Pacific Northwest to protect gladiolus and peaches from the harmful effects of fluoride-containing atmospheres. It has been postulated that calcium reacts with fluoride gases to produce insoluble and therefore nontoxic CaF2.
Results of these studies indicated that under conditions of high fluoride air pollution, application of lime sprays may improve citrus fruit production, but the mechanism of protection or improvement was not as simple as previously postulated. Immediately adjacent to the source where fluoride air pollution was at a maximum, applications of both Ca(OH)2 and CaCl2 were associated with increased internal fluoride accumulation by ‘Valencia’ orange foliage. With increased distance and therefore diminishing air pollution, an apparent reversal in effect was observed with the calcium sprays resulting in reduced internal accumulation of fluoride.
Although the effects of CaCl2 sprays on fluoride accumulation closely paralleled those obtained with Ca(OH)2, fruit production was not improved where CaCl2 sprays were applied, possibly as a result of induced chloride toxicity.
Abstract
Potato plants (Solanum tuberosum L.) were propagated in controlled environments from tubers or stem cuttings and exposed to SO2 and/or NO2. Cultivar, propagation method, and air quality affected intumescence formation on leaves. Tuber-propagated ‘Kennebec’ and ‘Russet Burbank’ plants developed intumescences in clean air, SO2, or NO2, but not in a SO2-NO2 mixture, whereas tuber-propagated ‘Superior’ and ‘Norchip’ had little or no intumescence formation. Cutting-propagated ‘Kennebec’, ‘Russet Burbank’, and ‘Norchip’ plants had no intumescence development. Intumescence development may be related to carbohydrate status of plants and maturity classification of cultivars.
Abstract
Eighteen cultivars representing 6 species (Poa pratensis L., Agrostis alba L., Agrostis palustris Huds., Agrostis tenuis Sibth., Festuca rubra Gaud., and Lolium perenne L.) of cool season turfgrass were exposed to 15 pphm ozone for 6 hours daily, 15 pphm sulfur dioxide continuously, 15 pphm nitrogen dioxide continuously, or a mixture of all three at these concentrations for 10 days. The most common symptoms of injury on sensitive cultivars in response to these gases were bleaching and necrosis of leaves with some cultivars exhibiting dark brown necrosis and stippling in response to O3 alone. Cultivars varied in sensitivity to O3 or SO2 from very sensitive to insensitive while few cultivars were sensitive to NO2 alone at the concentration used. Exposure of some cultivars resulted in less leaf area production but no visible injury symptoms, while other cultivars had leaf injury without reduction of area of uninjured leaves. The combined exposure caused more leaf injury and greater reduction in the leaf area production by most cultivars compared with plants exposed to single gases. Exposure to single pollutants could provide inaccurate estimates of turfgrass cultivar sensitivity outdoors where several pollutants may occur simultaneously.
Abstract
Air quality monitoring is carried out in Canada and the United States by air pollution control agencies in order to:
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provide information on the quality of the ambient air and determine long-term trends;
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identify pollutants and their sources, and determine the effects of emission controls on air quality levels;
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control episodes brought on by unique weather conditions by obtaining data on a real time basis and ordering emergency shutdowns of sources of pollution. Air pollution episodes during which hazardous air quality levels are reached may thus be prevented;
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determine background levels to assist in determining the transport diffusion and fate of the pollutants emitted, and the chemical reactions which take place in the atmosphere;
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research the effects of pollutants on health, property, and vegetation to enable the agencies to set meaningful air quality criteria and standards.
Abstract
Air pollutants influence the growth, yield and quality of many horticultural crops. It is difficult to determine and evaluate the impact of air pollution on the horticulture industry for the following reasons: The variable environments in which horticultural crops are grown markedly influence the amount of foliar injury caused by air pollutants. The large number of cultivars within horticultural crop species contribute to the magnitude of understanding necessary to evaluate pollutant effects. Genetic, morphological and physiological differences among species and cultivars within species also influence foliar injury and plant sensitivity. The amount of economic loss in horticultural crops due to air pollutants varies from year to year. This variation is probably most directly related to daily and seasonal variations in ambient concentrations of air pollutants. Horticultural crops may be subjected to high pollutant concentrations at different stages of plant maturity. These different stages of growth and development may be differentially affected by pollutant concentration and thus influence yield. Past estimates of crop yield losses have been based primarily on assessment of visual injury. Presently, there is a lack of suitable methodology to assess air pollution impacts under field conditions. Open-top chambers (40, 60) are an improvement but better techniques are needed. Finally, air pollution research is published in a variety of scientific journals and some of these references may not come to the attention of horticultural scientists.
Abstract
Urban Horticulture is a new area of scientific horticulture concerned with functional uses of plants to maintain and improve urban environments. “Functional uses” means that plants are used not only for beauty and ornamentation, but also as screens against wind, headlights, and unpleasant views, to influence climate, perhaps to reduce noise and combat forms of air pollution, for essential food and variation in human diet, and to improve the human psyche in densely populated areas. The constituent audiences for urban horticulture are people who utilize plants, primarily in landscape situations, including landscape maintenance and parks personnel, landscape architects, arborists, highway planters, nursery contractors, members of plant societies, and amateur horticulturists.
An Air Quality Learning and Demonstration Center has been developed within the Arboretum at Penn State Univ.. The Center provides opportunities where students (of all ages) and teachers (grade-school through to classes within the Univ.) can learn about air quality as one of our most important natural resources. A seasonally interactive display of air quality monitoring instrumentation, self guided walkways through gardens of air pollution sensitive plant species, innovative techniques for demonstrating the effects of air pollutants on plants, displays of recent research findings, industry supported displays of pollution abatement technologies, and a teaching pavilion are within the Center. A Pennsylvania Dept. of Environmental Protection air quality monitoring station with ozone, sulfur dioxide, nitrogen oxides, carbon dioxide, PM < 2.5 u mass and speciation samplers, and a complete meteorological station provide data on the immediate environmental parameters. These data are relayed to an LCD crystal display board that has been mounted on the outside of the monitoring building; visitors are able to see the various measures of the air quality on a real time basis. Pannier type fiberglass display panels provide understandings of the various facets of air pollution formation and transport phenomena, air quality monitoring methods, the functions of open-top chambers, foliar symptoms expressed by pollution sensitive plants within the bioindicator gardens, and the impacts of pollution on agricultural and forested ecosystems. Handicapped accessible walkways lead visitors throughout the Center to the Teaching Pavilion that easily accommodates 80 persons. The pavilion is equipped with drop down curtains, electric power, and internet connections.