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1.
Inorganic emissions from livestock production and subsequent deposition of these ions can be a major source of pollution, causing nitrogen enrichment, eutrophication, acidification of soils and surface waters, and aerosol formation. In the poultry house, ammonia and hydrogen sulfide emissions can also adversely affect the health, performance, and welfare of both animals and human operators. The persistence and long life expectancy of ammonia, odors and toxic pollutants from poultry houses may be due to the ability of suspended particulate matter (SPM) to serve as carriers for odorous compounds such as ammonium ions and other inorganic compounds (e.g., phosphate, sulfate, nitrate, etc.). SPM is generated from the feed, animal manure, and the birds themselves. A large portion of odor associated with exhaust air from poultry houses is SPM that has absorbed odors from within the houses. Understanding the fate and transport processes of ammonia and other inorganic emissions in poultry houses is a necessary first step in utilizing the appropriate abatement strategies. In this study, the examination and characterization of ammonium ions, major components of odors and toxic gases from poultry operations, and other ions in suspended particulate matter in a broiler house were carried out using particle trap impactors. The SPM from the particle trap impactors was extracted and analyzed for its ionic species using ion chromatography (IC). The results showed concentrations of polyatomic ions in suspended particulate matter were found to increase with successive flocks and were highly concentrated in the larger size particulate matter. In addition, the ions concentrations appeared to reach a maximum at the middle of flock age (around the fourth week), tapering off toward the end in a given flock (possibly due to ventilation rates to cool off larger birds). Thus, it can be inferred that aged of bedding materials affects the ionic concentrations in aerosol particulate matter more than the age of the birds.

Implications: In the poultry house, toxic gas emissions can adversely affect the health, performance, and welfare of both animals and human operators. The persistence of these toxic pollutants from poultry houses may be due to the ability of suspended particulate matter (SPM) to serve as carriers for these compounds (inorganic ions). Our study showed that polyatomic ions in suspended particulate matter were found to increase with successive flocks and were highly concentrated in the larger size SPM. Understanding the effect of management practices on poultry air emissions will lead to innovative best management practices to safeguard the health and welfare of the animals as well as those of the poultry operators, along with reducing the impact of potential air pollution on the environment.  相似文献   

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For many national parks and wilderness areas with special air quality protections (Class I areas) in the western United States (U.S.), wildfire smoke and dust events can have a large impact on visibility. The U.S. Environmental Protection Agency’s (EPA) 1999 Regional Haze Rule used the 20% haziest days to track visibility changes over time even if they are dominated by smoke or dust. Visibility on the 20% haziest days has remained constant or degraded over the last 16 yr at some Class I areas despite widespread emission reductions from anthropogenic sources. To better track visibility changes specifically associated with anthropogenic pollution sources rather than natural sources, the EPA has revised the Regional Haze Rule to track visibility on the 20% most anthropogenically impaired (hereafter, most impaired) days rather than the haziest days. To support the implementation of this revised requirement, the EPA has proposed (but not finalized) a recommended metric for characterizing the anthropogenic and natural portions of the daily extinction budget at each site. This metric selects the 20% most impaired days based on these portions using a “delta deciview” approach to quantify the deciview scale impact of anthropogenic light extinction. Using this metric, sulfate and nitrate make up the majority of the anthropogenic extinction in 2015 on these days, with natural extinction largely made up of organic carbon mass in the eastern U.S. and a combination of organic carbon mass, dust components, and sea salt in the western U.S. For sites in the western U.S., the seasonality of days selected as the 20% most impaired is different than the seasonality of the 20% haziest days, with many more winter and spring days selected. Applying this new metric to the 2000–2015 period across sites representing Class I areas results in substantial changes in the calculated visibility trend for the northern Rockies and southwest U.S., but little change for the eastern U.S.

Implications: Changing the approach for tracking visibility in the Regional Haze Rule allows the EPA, states, and the public to track visibility on days when reductions in anthropogenic emissions have the greatest potential to improve the view. The calculations involved with the recommended metric can be incorporated into the routine IMPROVE (Interagency Monitoring of Protected Visual Environments) data processing, enabling rapid analysis of current and future visibility trends. Natural visibility conditions are important in the calculations for the recommended metric, necessitating the need for additional analysis and potential refinement of their values.  相似文献   

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The construction process contributes to pollutant emissions, particularly through the operation of diesel- and gasoline-powered equipment. In the past decade, a series of investigations were undertaken to quantify these emissions for a variety of non-road construction equipment performing different activities and undergoing different duty cycles, and a model to estimate quantities of six types of pollutant was developed. This paper uses that model to estimate emissions for four street and utility construction projects which no one has done previously. We combined information from company records with standard construction industry manuals to estimate total emissions for the projects and to examine the pollution patterns and magnitudes. The street construction projects all had similar emission profiles with a large peak at the beginning and a steady output of emissions throughout the duration of the project. For example, in two of the projects studied, half of all CO2 emissions were produced before the projects were 40% completed. Results showed that demolition and earthwork are the activities with the largest contribution. The equipment types with the largest contribution are backhoes, front-end loaders, bulldozers and trenchers. Trenchers, for example, produced 30% of all emissions on the projects on which they were used.  相似文献   
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Growing or shrinking cities can experience increases in vacant land. As urban populations and boundaries fluctuate, holes can open in once tight urban areas. Many cities chase growth-oriented approaches to dealing with vacancies. It is critical to understand land-use alteration to accurately predict transformations of physical change in order to make better informed decisions about this phenomenon. This research utilizes the land transformation model (LTM), an artificial neural networking mechanism in Geographic Information Systems, to forecast vacant land. Variable influence on vacant land prediction and accuracy of the LTM is assessed by comparing input factors and patterns, using time-series data from 1990 to 2010 in Fort Worth, Texas, USA. Results indicate that the LTM can be useful in simulating vacant land-use changes but more precise mechanisms are necessary to increase accuracy. This will allow for more proactive decisions to better regulate the process of urban decline and regeneration.  相似文献   
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Colloid-facilitated phosphorus (P) delivery from agricultural soils in different hydrological pathways was investigated using a series of laboratory and field experiments. A soil colloidal P test was developed that yields information on the propensity of different soils to release P attached to soil colloids. The relationship between turbidity of soil extracts and total phosphorus (TP) was significant (r2 = 0.996, p < 0.001) across a range of agricultural soils, and a strong positive relationship (r2 = 0.86, p < 0.001) was found between "colloidal P" (H2O-CaCl2 extracts) and turbidity. Linear regression of the proportion of fine clay (<2 microm) for each soil type evaluated against the (H2O-CaCl2) colloidal P fraction gave a weak but positive relationship (r2 = 0.38, p = 0.082). The relative contribution of different particle-size fractions in transporting P in agricultural runoff from grassland soils was evaluated using a randomized plot experiment. A significant difference (p = 0.05) in both TP and reactive phosphorus (RP) in subsurface flow was recorded for different particle-size fractions, with most TP transferred either in association with the 2-microm fraction or with the 0.001-microm or smaller fractions. Total P concentrations in runoff were higher from plots receiving P amendments compared with the zero-P plots; however, these differences were only significant for the >0.45-microm particle-size fractions (p = 0.05), and may be evidence of surface applications of organic and inorganic fertilizers being transferred through the soil either as intact organic colloids or attached to mineral particles. Our results highlight the potential for drainage water to mobilize colloids and associated P during rainfall events.  相似文献   
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The foraging areas and diets of the grey-headed albatross Thalassarche chrysostoma and wandering albatross Diomedea exulans were studied in March/April 2000 at Bird Island, South Georgia, during their respective chick-rearing and brood-guard periods. Oceanographically, March/April 2000 was abnormal, with warm conditions close to South Georgia. These conditions affected albatross foraging behaviour, particularly that of grey-headed albatrosses. Both species tended to forage in different areas of the ocean, with significant differences in trip durations. Grey-headed albatrosses (n=9) foraged mainly in Antarctic waters (predominantly shelf waters of the South Shetland Islands and Antarctic Peninsula, and also in oceanic waters around South Georgia), feeding mainly on krill (Euphausia superba; 77% by mass). Foraging trips lasted 13.3 days (range: 5–26 days), far longer than the 1–3 days found in previous studies. Only one grey-headed albatross was associated with the APF (Antarctic Polar Front), a reported foraging area in recent studies. Wandering albatrosses (n=9) foraged in Antarctic (South Georgia Shelf) and Antarctic Polar Frontal Zone (APFZ) waters, with trips of 1–4 days trip duration (usual for this species), feeding on fish (46% by mass) and cephalopods (32%). One bird was associated with the APF, and two birds foraged on the shelf/shelf break over the Patagonian shelf. These findings suggest that sea surface temperature anomalies, produced by movement of the APF closer to South Georgia or by eddies, may have had an effect on the foraging strategy of grey-headed albatrosses that year (the main prey of grey-headed albatrosses in previous studies, the ommastrephid Martialia hyadesi, is known to be associated with the APF). Also, when both albatross breeding periods overlap, their foraging areas were complementary, which reflected the prey taken.  相似文献   
10.
Cephalopods play an important role in the diet of many predators of the Southern Ocean. We investigated the cephalopod component of the diet of the wandering albatross, during breeding at South Georgia, from 269 boluses containing more than 34,000 beaks (corresponding to 19,452 individual cephalopods), collected between 1989 and 1999, and assessed the inter-annual variability of the cephalopod species, the level of scavenging on cephalopods by wandering albatrosses and the relationships between cephalopod availability and wandering albatross breeding parameters (breeding period, breeding success, fledging period, fledging success, egg mass and chick mass). We also proposed possible foraging areas of wandering albatrosses based on the cephalopods eaten. The cephalopod component of the diet of wandering albatrosses was relatively stable over the 11 years of the study. By number of lower beaks, three species predominated in the cephalopod component of the diet: Kondakovia longimana (29.5% of the total number of lower beaks; family Onychoteuthidae), Taonius sp. (20.4%; family Cranchiidae) and Histioteuthis sp. B (19.5%; family Histioteuthidae). K. longimana was consistently the predominant cephalopod species by mass in every year of the study (range 60.2-88.7% of mass contribution to diet). A minimum estimate of 30% of the number of cephalopods scavenged corresponded to 85% of the total mass of the cephalopods that contributed to the diet. Wandering albatrosses fed consistently more on "Antarctic" cephalopods than on "sub-Antarctic" or "subtropical" cephalopods in all years of the study, suggesting that Antarctic waters are an important foraging area for wandering albatrosses. Although some significant correlations between cephalopod abundance and wandering albatross breeding parameters existed (e.g. correlation between Taonius sp. by number and fledging success), none included K. longimana. When comparing groups of variables (using canonical analysis), no correlations were found between the most important cephalopod species (by number and by mass), total mass of squid consumed, cephalopod diversity index (H) for each year, and wandering albatross breeding parameters. This may reflect the possibility that other components in the diet (e.g. fish and carrion) are more important or, more likely, that the consistency across years of the wandering albatross breeding performance indicates that it is well buffered against fluctuations in prey availability.  相似文献   
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