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1.
《Atmospheric environment(England)》1986,20(2):361-366
Ozone fumigations that mimic ambient ozone distributions facilitate the development of links between
- 1.(1) vegetative effects results that are generated in the laboratory and the field and
- 2.(2) predictive effects models that depend upon ambient air quality data.
- 1.(a) the number of occurrences of hourly ozone concentrations equal to or above 0.07 ppm,
- 2.(b) the number of days of each episode,
- 3.(c) the number of days between episodes and
- 4.(d) the rate of rise and decline of the daily ozone concentrations.
2.
《Atmospheric environment(England)》1986,20(2):245-268
The status of knowledge on photochemical ozone formation and the effects of nitrogen oxides and peroxyacyl nitrates on such formation have been evaluated. The literature is reviewed on
- 1.(a) nonurban ozone and nitrogen oxide concentration distributions,(b) ozone lifetimes,(c) nitrogen oxide lifetimes, and(d) ozone formation in plumes as related to nitrogen oxide.
- 1.(a) with urban plumes,
- 2.(b) power plant plumes,
- 3.(c) high pressure systems, and
- 4.(d) during longerrange transport of ozone are discussed. In addition, models concerned with the contributions to ozone formation associated with reactions of natural hydrocarbons and nitrogen oxide near ground level and photochemical ozone formation associated with reactions of carbon monoxide and of more persistent organic species with nitrogen oxides in the free troposphere are considered.
3.
《Atmospheric environment(England)》1986,20(8):1517-1521
The effect of (a) fixing the time interval between cleaning pulses or (b) fixing the maximum pressure drop at which cleaning is started, on the performance of the fabric filter was investigated.A maximum pressure drop value of 2500 Pa:
- 1.(a) minimized the effect of the filter medium resistance;
- 2.(b) reduced the energy consumption by the filter;
- 3.(c) minimized the dust emission from the fabric filter to the surrounding atmosphere.
4.
《Atmospheric environment(England)》1987,21(9):1995-2004
Volatile organic compound levels (VOCs) in breath, personal air, fixed outdoor air and drinking water samples were measured and compared for a probability sample of individuals in Los Angeles and Antioch/Pittsburg, California during 1984. In addition, comparisons were made between seasons (winter vs spring) in Los Angeles for individuals sampled in both seasons. The statistics presented to compare the sites and seasons were primarily percent measurable and concentration levels (e.g. sample medians). For most comparisons, 13 VOC levels were examined for breath, personal and outdoor air samples and four VOCs for water samples.In addition to the results for VOC levels, the paper also briefly describes
- 1.(i) the sampling procedures used to obtain the study participants
- 2.(ii) the collection of air, breath and water samples
- 3.(iii) selected results from the quality assurance procedures used in this study.
- 1.(i) higher in personal air samples than in breath or outdoor air samples,
- 2.(ii) higher in Los Angeles in the winter for air and breath than in the, spring,
- 3.(iii) higher in Los Angeles for air and breath than in Antioch/Pittsburg,
- 4.(iv) quite different for water as compared with air and breath.
- 1.(i) outdoor air vs breath in the winter in Los Angeles (where outdoor air levels were much higher than in the spring),
- 2.(ii) in personal air vs outdoor air in the upper tails of the concentration distribution (90th percentile) compared to the 50th percentile. For the water samples, relatively high concentrations were noted for chloroform, bromodichloromethane and dibromochloromethane.
5.
《Atmospheric environment(England)》1987,21(11):2435-2444
The frequency of co-occurrences for SO2NO2, SO2/O3 and O3/NO2 at rural and remote monitoring sites in the United States was characterized for the months of May-September for the years 1978–1982. Minimum hourly concentrations of 0.03 and 0.05 ppm of each gas were used as the criteria for defining a ‘co-occurrence’. The objectives of this study were to:
- 1.(1) identify the types of co-occurrence patterns and their frequency;
- 2.(2) identify whether the frequency of hourly simultaneous co-occurrences increased substantially when the minimum concentration was lowered (e.g. from 0.05 to 0.03 ppm) for each pollutant; and
- 3.(3) determine whether the frequency of co-occurrences showed large year-to-year variation.
- 1.(1) hourly simultaneous and daily simultaneous-only co-occurrences are fairly rare and
- 2.(2) when co-occurrences are present, complex-sequential and sequential-only co-occurrence patterns predominate.
6.
《Atmospheric environment(England)》1985,19(4):611-622
A unique combination of an effective sampler and analysis of individual particles has been used in studying large particles (> 5 μm) at a rural site in eastern United States. The sampler is a modified ‘high volume’ rotary inertial impactor, which consists of four collectors of different widths, rotating at high speed and collecting particles by impaction. The collector surfaces were Mylar films coated with apiezon to ensure retention. After sampling, the collection surfaces were weighted to obtain the mass-size distribution. A section of the Mylar sample was transferred to a scanning electron microscope to study in detail the morphology and elemental content of individual particles.Results from two case studies indicated the following conclusions could be made:
- 1.(a) Natural sources, minerals and biologicals, were the main contributors to large particles (> 5 μm),
- 2.(b) Contribution of anthropogenic sources, mainly coal-fired power plants emitting fly ash particles, was limited to a few percent of the 5–10 μm size range,
- 3.(c) Pollen and some of the minerals were enriched in sulfur, probably as accumulation of sulfate on the particle surface,
- 4.(d) At low wind speeds the anthropogenic contribution was enhanced, whereas at high wind speeds natural sources were almost the only contributors to the large particle mode.
7.
《Atmospheric environment(England)》1986,20(10):1891-1895
A monitoring system for coal panicle dispersion at coal storage yards is necessary to meet environmental standards for the operation of coal fired power plants. We have developed a system having three functions as follows:
- 1.(1) To measure coal particle concentrations at the first connecting part of belt conveyors.
- 2.(2) To predict occurrence of coal particle dispersion during stacking.
- 3.(3) To moisten the coal at the second connecting part of belt conveyors when coal particle dispersion occurs.
8.
《Atmospheric environment(England)》1986,20(7):1501-1503
Evidence is presented to show that a serious leaf spot disease of potato which appeared each year in the Punjab since 1978 is primarily due to ozone:
- 1.(i) The symptoms of the leaf spot were similar to the ozone stipple of potato reported in the U.S.A.
- 2.(ii) Activated charcoal and ethylenediurea effectively controlled the spots.
- 3.(iii) Elevated ozone in the atmosphere was detected with the bioindicators Nicotiana tabacum var. Bel-W3 and potato variety Cherokee. This is the first report of ozone injury to a crop plant in India.
9.
《Atmospheric environment(England)》1987,21(11):2473-2480
This Report describes a tour from 2 to 14 January 1986 in Delhi and New Delhi. The principal objectives were:
- 1.(1) To participate in the Indian Science Congress Meeting.
- 2.(2) To present a paper in the section on ‘Recent advances in numerical modelling of the disperion of atmospheric pollutants’ and make an appraisal of the value of the meeting and suggestions for future meetings.
- 3.(3) Discuss the research programme of the Centre for Advanced Studies in Atmospheric and Fluid Sciences of the Indian Institute of Technology with staff and research students and make recommendations for the future direction and development of this programme.
- 4.(4) Participate in seminars and discussions at the Centre. A general impression of the Indian air pollution scene is also given, and its relationship to past and present situations in other parts of the world is discussed.
10.
《Atmospheric environment(England)》1987,21(3):531-549
The high density network component of the Oxidation and Scavenging Characteristics of April Rains (OSCAR) experiment combined aircraft, surface and sequential precipitation chemistry measurements to characterize the physicochemical and dynamic features of four storms sampled during an April 1981 field investigation. A surface network of 47 precipitation sampling stations, covering a region roughly 110 km by 110 km, was established in the area surrounding Fort Wayne, Indiana. The network provided temporal and spatial resolution of rainfall chemistry via the use of specially designed automatic sequential bulk precipitation collectors, while aircraft and surface sampling provided measurements of the major aerosols and trace gases in the boundary-layer inflow region.Composite concentration and ion ratio profiles for the events were analyzed to investigate potential pollutant scavenging pathways. This analysis led to the following observations:
- 1.(i) dryfall deposition during pre-rainfall exposure periods influenced initial sampler stage chemistry;
- 2.(ii) relative precipitation acidity increased throughout the events; SO42− and NO3− were the major contributors to this acidity;
- 3.(iii) evidence exists for the in-cloud oxidation of SO2 during Events 3 and 4, while scavenging of HNO3 and aerosol NO3− probably produced precipitation NO3−;
- 4.(iv) the non-frontal meteorology of Event 3 influenced the precipitation chemistry associated with this storm and led to distinct concentration profiles;
- 5.(v) an anomalous pattern of NH4+ concentrations observed during Event 1 cannot be explained by known NH4+ scavenging behavior or by non-scavenging related influences, such as local source contamination or NH3 volatilization;
- 6.(vi) Event 4 is more suitable for analysis by one- and two-dimensional diagnostic wet removal models. Analysis of the other events is complicated by more complex meteorological behavior and, in some cases, a less complete chemistry data set. This paper enlarges on these observations with comparisons of the major meteorological and chemical characteristics of the four events.
11.
《Atmospheric environment(England)》1986,20(9):1781-1789
In this paper the process by which a distributional model may be identified from a range of alternative models is examined. An assessment of the methods by which goodness-of-fit may be evaluated is presented. A procedure for selecting amongst the exponential, gamma, lognormal and Weibull distributions has been applied to 24-h average suspended particulates (β-scattering), ozone, carbon monoxide, sulphur dioxide, oxides of nitrogen, nitrogen dioxide and nitrogen oxide observations recorded in Melbourne, Australia. It is shown that
- 1.(a) lognormal distribution is appropriate for particulate data and the majority of the nitric oxide, oxides of nitrogen and sulphur dioxide data sets
- 2.(b) gamma distribution is best for both carbon monoxide, nitrogen dioxide and ozone
- 3.(c) Weibull distribution is appropriate for a significant number of carbon monoxide and ozone data sets.
12.
《Atmospheric environment(England)》1985,19(4):659-667
Observations of annual wet deposition of sulfur made during 1980 at 62 stations in northeastern America are interpreted using a statistical long-range transport model. This work is meant to demonstrate the role of an empirical model in the analysis of observations. Our analysis points to the following conclusions:
- 1.(1) The parameters that represent the conversion of SO2 to SO4 and the wet and dry removal of sulfur are insensitive to concentration levels,
- 2.(2) the variation of the wet deposition field is closely related to the distribution of sulfur emissions and
- 3.(3) observations demand efficient wet scavenging of SO2.
13.
《Atmospheric environment(England)》1987,21(9):1989-1994
Application of micro spot and electron microscopy techniques to individual particles in a coastal urban site revealed the following:
- 1.(a) sulfate particles, some of them mixed, dominated the sub-μm (0.3–0.8 μm) size range;
- 2.(b) nitrates were found mostly in the μm size range, in the form of NaNO3.
14.
《Atmospheric environment(England)》1988,22(6):1221-1227
This paper summarizes the discussions of a working group that was charged with the task of examining inherent uncertainty in air quality modeling. The major topics of the paper are:
- 1.1. Definition of inherent uncertainty in air quality models;
- 2.2. Determination of inherent uncertainty;
- 3.3. Role of inherent uncertainty in model evaluation.
15.
《Atmospheric environment(England)》1986,20(3):471-478
Numerous integral models describing the behaviour of buoyant plumes released into stratified crossflows have been presented in the literature. One of the differences between these models is the form assumed for the self-similar profile: some models assume a top-hat form while others assume a Gaussian. The differences between these two approaches are evaluated by
- 1.(a) comparing the governing equations on which Gaussian and top-hat models are based;
- 2.(b) comparing some typical plume predictions generated by each type of model over a range of model parameters.
16.
《Atmospheric environment(England)》1986,20(10):2047-2052
Discussions within COGAR during 1981 indicated that collective information on the types of meteorological conditions when large, single sources like power stations contributed to pollution episodes, the frequency with which they occurred and the implications for intermittent control procedures, was important to all member utilities. This paper summarizes the findings of a working group set up by COGAR to study these problems.The investigation was concerned with SO2 episodes and how feasible it would be to reduce their intensity by such measures as a substitution of low sulphur fuel or switching generation to areas where the probability of an episode developing is less.There has been a considerable reduction in SO2 emissions in most urban areas in the last two decades. Nevertheless, in many locations, 24-h air pollution episodes can still be attributed to small or medium-sized emissions from low or medium level stacks, rather than to power stations and other large industrial sources with tall stacks. The worst cases in flat terrain where power stations do contribute for many hours are either stagnant conditions persisting for 24 h or a steady wind blowing consistently from an area containing several power stations. Single stations can present problems when topography interferes with dispersion or the stack height is inadequate for the emissions.Data on the frequency with which episodes occur in a given location and the ability to forecast episode conditions in advance, so that if appropriate, preventative measures may be taken, are the desired objectives. Achievement of these objectives requires a detailed understanding of the role of each type of source in relation to different meteorological situations and the local topography. The end product of such studies should be either;
- 1.(a) the specification of a procedure for implementing intermittent emission control
- 2.(b) a demonstration that intermittent control is not an effective option in the area under study.
- 1.(i) the vertical structure of the atmosphere
- 2.(ii) ground level concentrations of pollutant plus, in complicated topography
- 3.(iii) the three-dimensional distribution of pollutant.
17.
《Atmospheric environment(England)》1986,20(6):1211-1215
In order to develop a diffusion denuder for the removal of NO2 from ambient atmospheric samples, a number of materials were screened for their ability to adsorb NO2:
- 1.(1) MgO;
- 2.(2) MnO2 on alpha-Al2O3;
- 3.(3) water-treated MnO2 on alpha-Al2O3; and
- 4.(4) MnO2 (activated).
18.
《Atmospheric environment(England)》1986,20(3):501-511
In Part I of this work, a deterministic model for development of acid rain abatement strategies was extended to a stochastic form through the incorporation of uncertainty in the transfer coefficients which describe long-range pollutant transport and transformation. The two extreme cases of:
- 1.(i) complete dependence between transfer coefficients (i.e. colinearity);
- 2.(ii) complete independence (noncolinearity) were developed.
19.
《Atmospheric environment(England)》1985,19(8):1263-1270
A statistical method is developed to determine the locations of major pollutant sources affecting a distant downwind receptor, provided that air trajectories can be estimated. Probability density functions are estimated which indicate
- 1.(1) the overall residence time of air parcels over a given geographic region as they travel toward a receptor and
- 2.(2) residence time for the case of high pollutant concentrations at the receptor.
20.
《Atmospheric environment(England)》1987,21(7):1623-1630
This paper is intended to be used by specialists engaged in air and precipitation quality management on regional and continental scales. Major goals are to establish definition, methodology and specific values of background air and precipitation quality for sulfur (S) and nitrogen (N) species to be used in practical applications of air resources management. Major findings are the following:
- 1.(a) 69% of SO2 and 63 % of NO2 concentration over Europe originate from continental scale anthropogenic sources,
- 2.(b) 15% of precipitation sulfate and 11% of precipitation nitrate over Europe are contributed by hemispheric background,
- 3.(c) hemispheric background pollution values for Europe were found as 1.25 μg (SO2-S)m−3, 0.80 μg (SO42−-S)m−3, 0.157 mg (SO42−-S)l−1 and 0.04 mg (NO3−-N)ℓ−1.