共查询到20条相似文献,搜索用时 46 毫秒
1.
《Atmospheric environment(England)》1987,21(3):605-615
Ozone measurements are reported for five rural sites in the Tennessee Valley region of the southeastern U.S. for periods ranging from 18 to 83 months during the years 1977 through 1984. Rural ozone (O3) levels were found to equal or exceed urban values for the same region. The daily maximum 1-h average concentration was found to peak during the summer months, while the 24-h average concentrations were greatest in the spring. The annual cycle of daily maximum concentrations is related to the seasonal photochemical cycle. The annual cycle in 24-h average concentrations is best explained by the combined effects of the annual cycles in solar intensity and noctural O3 depletion. There was no indication that stratospheric intrusions exhibited a significant influence on the annual O3 cycles. Evidence was found for elevated O3 levels during touchdown of plumes from large power plants. No long-term trend in rural O3 concentrations, either daily maxima or means, was discernible. 相似文献
2.
《Atmospheric environment(England)》1987,21(12):2673-2679
Measurements of ozone concentration in the ambient air of the city of Baghdad were carried out for the period October 1983 to October 1984. The O3, probably of local origin, showed a typical diurnal and seasonal variation. Maximum daily 1-h O3 concentrations higher than the international ambient air quality standards were observed regularly during the summer months. High O3 concentrations during the night were also observed. Scatter diagrams were used to relate the O3 concentrations with temperature, solar radiation and humidity. 相似文献
3.
R. Rai M. Agrawal S.B. Agrawal 《Atmospheric environment (Oxford, England : 1994)》2007,41(40):9543-9554
The present study deals with the evaluation of effects of ambient gaseous air pollution on wheat (Triticum aestivum L. var. HUW-234) growing in a suburban area situated in eastern Gangetic plain of India, using open top chambers. Eight hourly air monitoring was conducted for ambient concentrations of SO2, NO2 and O3 in filtered chambers (FCs), non-filtered chambers (NFCs) and open plots (OPs). Various morphological, physiological and biochemical parameters were assessed during different developmental stages and finally yield parameters were quantified at the time of harvest.Mean concentrations of SO2, NO2 and O3 were 8.4, 39.9 and 40.1 ppb, respectively during the experiment in NFCs. Concentrations of SO2, NO2 and O3 reduced by 74.6%, 84.7% and 90.4%, respectively in FCs as compared to NFCs. Plants grown in FCs showed higher photosynthetic rate, stomatal conductance, chlorophyll content and Fv/Fm ratio as compared to the plants in NFCs and OPs. Lipid peroxidation, proline, total phenol and ascorbic acid contents and peroxidase activity were higher in plants grown in NFCs. There were improvements in morphological parameters of plants growing in FCs as compared to those in NFCs and OPs. Yield of plants also increased significantly in FCs as compared to those ventilated with ambient air (NFCs) or grown in OPs. During the vegetative phase, NO2 concentrations were higher than O3, but O3 became dominant pollutant during the time of grain setting and filling. The study concludes that O3 and NO2 are the main air pollutants in the sub-urban areas causing significant yield reductions in tropical wheat plants. 相似文献
4.
Manning WJ Paoletti E Sandermann H Ernst D 《Environmental pollution (Barking, Essex : 1987)》2011,159(12):3283-3293
Ethylenediurea (EDU) has been widely used to prevent ozone (O3) injury and crop losses in crop plants and growth reductions in forest trees. Successful use requires establishing a dose/response curve for EDU and the proposed plant in the absence of O3 and in the presence of O3 before initiating multiple applications to prevent O3 injury. EDU can be used to verify foliar O3 symptoms in the field, and to screen plants for sensitivity to O3 under ambient conditions. Despite considerable research, the mode of action of EDU remains elusive. Additional research on the mode of action of EDU in suppressing O3 injury in plants may also be helpful in understanding the mode of action of O3 in causing injury in plants. 相似文献
5.
R.J. Oshima M.P. Poe P.K. Braegelmann D.W. Baldwin V. Van Way 《Journal of the Air & Waste Management Association (1995)》2013,63(9):861-865
Ozone dose-crop loss conversion functions for alfalfa (Medicago sativa, L. var. Moapa 69) yield reduction and defoliation were developed using standardized field plots within an ambient O3 gradient in the South Coast Air Basin. Seasonal yields and defoliation values were tested with O3 dose, average daily maximum temperature, average daily minimum temperature, and average daily relative humidity in regression analyses to determine significant functional relationships. Only the ambient O3 dose variable was found to have a significant effect on alfalfa yield or defoliation (yield, r = –0.827, t-slope = 3.900**; defoliation, r = –0.890, t-slope = 5.190**). The ozone dose-crop loss conversion functions were calculated by converting the dose-response functions to dose-percent reduction functions. 相似文献
6.
Allen S. Lefohn H. Peter Knudsen Jennifer A. Logan Jeanne Simpson Chandrakant Bhumralkar 《Journal of the Air & Waste Management Association (1995)》2013,63(5):595-602
Using kriging, a statistical technique, the National Crop Loss Assessment Network (NCLAN) program estimated growing season 5-month (May-September) ambient 7-h mean O3 concentrations for each of the major crop growing areas of the United States for 1978-1982. The O3 estimates were used to predict economic benefits anticipated by lowering O3 levels in the United States. This paper reviews NCLAN’s use of kriging to estimate 7-h seasonal mean O3 concentrations for crop growing regions. Although the original kriging program used by NCLAN incorrectly calculated the diagonal elements of the kriging equations, this omission did not result in significant errors in the predicted estimates. Most of the data used in estimating the 7-h seasonal values were obtained from urban areas; the use of these data tended to underestimate the 7-h seasonal O3 concentrations in rural areas. It is recommended that only O3 data that are representative of agricultural areas and have been collected under accepted quality assurance programs be used In future kriging efforts. 相似文献
7.
The effects of elevated concentrations of atmospheric tropospheric ozone (O3) on DNA damage in five trembling aspen (Populus tremuloides Michx.) clones growing in a free-air enrichment experiment in the presence and absence of elevated concentrations of carbon dioxide (CO2) were examined. Growing season mean hourly O3 concentrations were 36.3 and 47.3 ppb for ambient and elevated O3 plots, respectively. The 4th highest daily maximum 8-h ambient and elevated O3 concentrations were 79 and 89 ppb, respectively. Elevated CO2 averaged 524 ppm (+150 ppm) over the growing season. Exposure to O3 and CO2 in combination with O3 increased DNA damage levels above background as measured by the comet assay. Ozone-tolerant clones 271 and 8L showed the highest levels of DNA damage under elevated O3 compared with ambient air; whereas less tolerant clone 216 and sensitive clones 42E and 259 had comparably lower levels of DNA damage with no significant differences between elevated O3 and ambient air. Clone 8L was demonstrated to have the highest level of excision DNA repair. In addition, clone 271 had the highest level of oxidative damage as measured by lipid peroxidation. The results suggest that variation in cellular responses to DNA damage between aspen clones may contribute to O3 tolerance or sensitivity. 相似文献
8.
We investigated the effects of ambient ultraviolet (UV) radiation on (i) the performance and chemistry of soybean plants, (ii) the performance of Spodoptera frugiperda and (iii) the foraging behavior of the herbivore's natural enemy Cotesia marginiventris which exploits herbivore-induced plant volatiles (VOC) for host location. The accumulation of protective phenolics was faster in plants receiving ambient UV than in controls exposed to sun light lacking UV. Accordingly, isorhamnetin- and quercetin-based flavonoids were increased in UV exposed plants. No UV effects were found on the performance and feeding behavior of S. frugiperda. Herbivore-damaged plants emitted the same VOC when grown under ambient or attenuated UV for 5, 10 or 30 days. Consequently, C. marginiventris was attracted but did not discriminate between exposed and unexposed soybeans. In summary, ambient UV radiation affected soybean morphology and physiology but did not destabilize interactions between trophic levels. 相似文献
9.
Effects of Chronic Doses of Ozone on Field-Grown Loblolly Pine: Seedling Responses in the First Year
Steven R. Shafer Allen S. Heagle Diane M. Camberato 《Journal of the Air & Waste Management Association (1995)》2013,63(10):1179-1184
A study was designed to examine responses of loblolly pine (Pinus taeda) to chronic exposure to ozone (O3) in the field. Seedlings of four full-sib families of loblolly pine were planted in a field near Raleigh, NC, and exposed daily (May 27 to October 24, 1985) in open-top chambers to O3 ranging from 0.5 to 1.96 times the O3 concentration in non-filtered (NF) air. One-fourth of the plants in each plot were removed during each of two harvests (August and October) to measure effects of O3 on plant growth. Plants of each family exhibited foliar symptoms characteristic of O3 injury after five months of exposure to any greater-than-ambient O3 concentration, and one family exhibited symptoms after five months of exposure to NF air. Ozone dose-plant response relationships were quantified by regression for stem height, stem diameter, biomass, and other plant morphological and yield characteristics. All relationships were linear for three families, but one family exhibited no significant growth response relationship of O3 dose. Dose-response equations suggest a maximum growth suppression of 10 percent for NF air compared to charcoal-filtered air (i.e., 0.5 × NF) in the first season of exposure. 相似文献
10.
Ellis F. Darley 《Journal of the Air & Waste Management Association (1995)》2013,63(3):198-199
Leaf injury data from acute and chronic exposure studies of Dare soybean were regressed against the logarithms of exposure time and O3 and SO2 concentrations to develop a new two-pollutant leaf injury model (which explains 88% of the variance) and to calculate the parameters of best fit for this new model and a previously developed one-pollutant model. Using the calculated parameters, the percentage of leaf surface Injured over a growing season by O3, SO2, or both simultaneously was estimated for an ambient air sampling site located 2 miles from a coal burning power plant. For this site, the one- and two-pollutant models predicted that SO2 effects would be negligible If SO2 concentrations never exceeded the National Ambient Air Quality Standard (NAAQS) of 0.50 ppm, averaged over 3 h. However, calculations suggest that O3 may injure up to 24% of Dare soybean leaf surface over a growing season even though the O3 NAAQS of 0.12 ppm, averaged over 1 h, is never exceeded. Because the 3 h SO2 standard is exceeded at very few places, the O3 model is usually sufficient to estimate Dare soybean leaf Injury. Leaf injury is estimated by taking the logarithm of the summation of each daytime hour’s exponentiated O3 concentration (c) measured at an ambient air sampling site over a growing season. This is expressed as: z = -0.0828 + 0.4876 in (Σco3 2.618), where z is the Gaussian transform of percent leaf injury. The methods developed in this paper, using Dare soybean data as an example, may apply to other plants. 相似文献
11.
Protection of plants from ambient ozone by applications of ethylenediurea (EDU): A meta-analytic review 总被引:1,自引:0,他引:1
Zhaozhong Feng Shuguang Wang Shuai Chen 《Environmental pollution (Barking, Essex : 1987)》2010,158(10):3236-3242
A meta-analysis was conducted to quantitatively assess the effects of ethylenediurea (EDU) on ozone (O3) injury, growth, physiology and productivity of plants grown in ambient air conditions. Results indicated that EDU significantly reduced O3-caused visible injury by 76%, and increased photosynthetic rate by 8%, above-ground biomass by 7% and crop yield by 15% in comparison with non-EDU treated plants, suggesting that ozone reduces growth and yield under current ambient conditions. EDU significantly ameliorated the biomass and yield of crops and grasses, but had no significant effect on tree growth with an exception of stem diameter. EDU applied as a soil drench at a concentration of 200-400 mg/L has the highest positive effect on crops grown in the field. Long-term research on full-grown tree species is needed. In conclusion, EDU is a powerful tool for assessing effects of ambient [O3] on vegetation. 相似文献
12.
Zhaozhong Feng Jing Pang Isamu Nouchi Takashi Yamakawa 《Environmental pollution (Barking, Essex : 1987)》2010,158(12):3539-3545
We studied leaf apoplastic ascorbates in relation to ozone (O3) sensitivity in two winter wheat (Triticum aestivum L.) varieties: Yangfumai 2 (Y2) and Yangmai 16 (Y16). The plants were exposed to elevated O3 concentration 27% higher than the ambient O3 concentration in a fully open-air field from tillering stage until final maturity. The less sensitive variety Y16 had higher concentration of reduced ascorbate in the apoplast and leaf tissue by 33.5% and 12.0%, respectively, than those in the more sensitive variety Y2, whereas no varietal difference was detected in the decline of reduced ascorbate concentration in response to elevated O3. No effects of O3 or variety were detected in either oxidized ascorbate or the redox state of ascorbate in the apoplast and leaf tissue. The lower ascorbate concentrations in both apoplast and leaf tissue should have contributed to the higher O3 sensitivity in variety Y2. 相似文献
13.
Analysis of the relationship between ambient levels of O3, NO2 and NO as a function of NOx in the UK
Monitoring data from the UK Automatic Urban and Rural Network are used to investigate the relationships between ambient levels of ozone (O3), nitric oxide (NO) and nitrogen dioxide (NO2) as a function of NOx, for levels ranging from those typical of UK rural sites to those observed at polluted urban kerbside sites. Particular emphasis is placed on establishing how the level of ‘oxidant’, OX (taken to be the sum of O3 and NO2) varies with the level of NOx, and therefore to gain some insight into the atmospheric sources of OX, particularly at polluted urban locations. The analyses indicate that the level of OX at a given location is made up of NOx-independent and NOx-dependent contributions. The former is effectively a regional contribution which equates to the regional background O3 level, whereas the latter is effectively a local contribution which correlates with the level of primary pollution. The local oxidant source has probable contributions from (i) direct NO2 emissions, (ii) the thermal reaction of NO with O2 at high NOx, and (iii) common-source emission of species which promote NO to NO2 conversion. The final category may include nitrous acid (HONO), which appears to be emitted directly in vehicle exhaust, and is potentially photolysed to generate HOx radicals on a short timescale throughout the year at southern UK latitudes. The analyses also show that the local oxidant source has significant site-to-site variations, and possible reasons for these variations are discussed. Relationships between OX and NOx, based on annual mean data, and fitted functions describing the relative contributions to OX made by NO2 and O3, are used to define expressions which describe the likely variation of annual mean NO2 as a function of NOx at 14 urban and suburban sites, and which can take account of possible changes in the regional background of O3. 相似文献
14.
《Journal of environmental science and health. Part. B》2013,48(4):585-594
Abstract This study investigated the toxicity of various concentrations of technical resmethrin and Scourge® on adult and larval Palaemonetes pugio, a common grass shrimp species. Two types of tests were conducted for each of the resmethrin formulations using adult and larval grass shrimp life stages, a 96-h static renewal aqueous test without sediment, and a 24-h static nonrenewal aqueous test with sediment. For resmethrin, the 96-h aqueous LC50 value for adult shrimp was 0.53 μg/L (95% confidence interval (CI): 0.46–0.60 μg/L), and for larval shrimp was 0.35 μg/L (95% CI: 0.28–0.42 μg/L). In the presence of sediment, technical resmethrin produced a 24-h LC50 value for adult shrimp of 5.44 μg/L (95% CI: 4.52–6.55 μg/L), and for larval shrimp of 2.15 μg/L (95% CI: 1.35–3.43 μg/L). For Scourge®, the 96-h aqueous LC50 for adult shrimp was 2.08 μg/L (95% CI: 1.70–2.54 μg/L), and for larval shrimp was 0.36 μg/L (95% CI: 0.24–0.55 μg/L). The 24-h sediment test yielded an LC50 value of 16.12 μg/L (95% CI: 14.79–17.57 μg/L) for adult shrimp, and 14.16 μg/L (95% CI: 12.21–16.43 μg/L) for larvae. Adjusted LC50 values to reflect the 18% resmethrin concentration in Scourge® are 0.37 μg/L (adult), 0.07 μg/L (larvae) for the 96-h aqueous test, and 2.90 μg/L (adult), 2.6 μg/L (larvae) for the 24-h sediment test. Larval grass shrimp were more sensitive to technical resmethrin and Scourge® than the adult life stage. The results also demonstrate that synergized resmethrin is more toxic to P. pugio than the nonsynergized form, and that the presence of sediment decreases the toxicity of both resmethrin and Scourge® 相似文献
15.
Ralph I. Larsen Thomas R. McCurdy Pamela M. Johnson Walter W. Heck 《Journal of the Air & Waste Management Association (1995)》2013,63(12):1497-1503
Soybean percent crop reduction was estimated as a function of ambient O3 concentrations for each of 80 agricultural sites in the National Aerometric Data Bank (NADB) for each available year of data for years 1981-1985. Fourteen O3 concentration statistics were calculated for each of the resulting 320 site-years of data. The two statistics that correlated best with estimated crop reduction were an effective mean O3 concentration (1 percent of variance unexplained) and an arithmetic mean O3 concentration (4 percent unexplained). The worst correlation of the 14 was for the statistic used in the present O3 National Ambient Air Quality Standard (NAAQS), the second highest daily maximum 1-h O3 concentration (42 percent unexplained). The number of site-years for estimated percent soybean yield reductions was plotted versus increasing O3 concentrations for each of the 14 O3 statistics. A maximum crop reduction line was drawn on each plot. These lines were used to estimate (and list) potential ambient O3 standards for each of the 14 statistics that would limit soybean crop reduction at agricultural. NADB sites to 5, 10, 15, or 20 percent. 相似文献
16.
Anthocyanins and tannins in ozone-fumigated guava trees 总被引:1,自引:0,他引:1
Psidium guajava “Paluma”, a tropical tree species, is known to be an efficient ozone indicator in tropical countries. When exposed to ozone, this species displays a characteristic leaf injury identified by inter-veinal red stippling on adaxial leaf surfaces. Following 30 days of three ozone treatments consisting of carbon filtered air (CF – AOT40 = 17 ppb h), ambient non-filtered air (NF – AOT40 = 542 ppb h) and ambient non-filtered air + 40 ppb ozone (NF + O3 – AOT40 = 7802 ppb h), the amounts of residual anthocyanins and tannins present in 10 P. guajava (“Paluma”) saplings were quantified. Higher amounts of anthocyanins were found in the NF + O3 treatment (1.6%) when compared to the CF (0.97%) and NF (1.30%) (p < 0.05), and of total tannins in the NF + O3 treatment (0.16%) compared to the CF (0.14%). Condensed tannins showed the same tendency as enhanced amounts. Regression analyses using amounts of tannins and anthocyanins, AOT40 and the leaf injury index (LII), showed a correlation between the leaf injury index and quantities of anthocyanins and total tannins. These results are in accordance with the association between the incidence of red-stippled leaves and ozone polluted environments. 相似文献
17.
18.
《Atmospheric environment(England)》1984,18(6):1207-1215
This study describes a quantitative relationship between mean O3 flux density and the length of exposure needed for the occurrence of visual injury to Phaseolus vulgaris L. Similar relationships were found for 14 day old and 6 week old plants using a whole leaf gas exchange cuvette system. Cultivars Seafarer (O3 sensitive) and Gold Crop (O3 resistant) exhibited similar responses at flux densities > 3 mg m−2 h−1 but only Seafarer was injured below this flux density. O3 concentration and length of exposure period alone did not contain sufficient information to describe the onset of visual foliar injury. The use of O3 concentrations in excess of normal ambient conditions compensated for low leaf conductances so that flux densities in the cuvette were similar to those found in the field. 相似文献
19.
Poonam Singh Shashi Bhushan Agrawal 《Environmental pollution (Barking, Essex : 1987)》2009,157(3):871-880
A field study was conducted to evaluate the impact of ambient ozone on mustard (Brassica campestris L. var. Kranti) plants grown under recommended and 1.5 times recommended NPK doses at a rural site of India using filtered (FCs) and non-filtered open top chambers (NFCs). Ambient mean O3 concentration varied from 41.65 to 54.2 ppb during the experiment. Plants growing in FCs showed higher photosynthetic rate at both NPK levels, but higher stomatal conductance only at recommended NPK. There were improvements in growth parameters and biomass of plants in FCs as compared to NFCs at both NPK levels with higher increments at 1.5 times recommended. Seed yield and harvest index decreased significantly only at recommended NPK in NFCs. Seed quality in terms of nutrients, protein and oil contents reduced in NFCs at recommended NPK. The application of 1.5 times recommended NPK provided protection against yield loss due to ambient O3. 相似文献
20.
Ameliorative effects of ethylenediurea (N-[2-(2-oxo-1-imidazolinidyl) ethyl]-N′ phenylurea, abbreviated as EDU) against ozone stress were studied on selected growth, biochemical, physiological and yield characteristics of palak (Beta vulgaris L. var Allgreen) plants grown in field at a suburban site of Varanasi, India. Mean eight hourly ozone concentration varied from 52 to 73 ppb which was found to produce adverse impacts on plant functioning and growth characteristics. The palak plants were treated with 300 ppm EDU at 10 days after germination at 10 days interval up to the plant maturity. Lipid peroxidation in EDU treated plants declined significantly as compared to non-EDU treated ones. Significant increment in Fv/Fm ratio in EDU treated plants as compared to non-EDU treated ones was recorded. EDU treated plants showed significant increment in ascorbic acid contents and reduction in peroxidase activity as compared to non-EDU treated ones. As a result of the protection provided by EDU against ozone induced stress on biochemical and physiological characteristics of palak, the morphological parameters also responded positively. Significant increments were recorded in shoot length, number of leaves plant−1, leaf area and root and shoot biomass of EDU treated plants as compared to non-EDU treated ones. Contents of Na, K, Ca, Mg and Fe were higher in EDU treated plants as compared to non-EDU treated ones. The present investigation proves the usefulness of EDU in partially ameliorating ozone injury in ambient conditions. 相似文献