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排序方式: 共有46条查询结果,搜索用时 15 毫秒
1.
Cities offer a large menu of possible employment and leisure opportunities. The gains from such consumer city leisure are likely to be lower on more polluted days. We study the association between daily consumption activity and outdoor air pollution in China and find evidence in favor of the hypothesis that clean air and leaving one's home for leisure trips are complements. Given the high levels of air pollution in cities in the developing world, regulation induced improvement in environmental quality is likely to further stimulate demand for the consumer city.  相似文献   
2.
Is urbanization good for the environment? This paper establishes a simple core–periphery model with monocentric cities, which comprises key forces that shape the structure and interrelation of cities to study the impact of the urban evolution on the environment. We focus on global warming and the potential of unfettered market forces to economize on emissions. The model parameters are chosen to match the dichotomy between average “large” and “small” cities in the urban geography of the United States, and the sectoral greenhouse gas emissions recorded for the United States. Based on numerical analyzes we find that a forced switch to a system with equally sized cities reduces total emissions. Second, any city driver which pronounces the asymmetry between the core and the periphery drives up emissions in the total city system, too, and the endogenous adjustment of the urban system accounts for the bulk of the change in emissions. Third, none of the city drivers gives rise to an urban environmental Kuznets curve according to our numerical simulations. Finally, the welfare‐maximizing allocation tends to involve dispersion of cities and the more so the higher is the marginal damage from pollution.  相似文献   
3.
Voluntary environmental programs (VEPs) have been used as a policy tool in the United States since the early 1990s and come in many forms. Early assessments of VEPs targeting changes in production processes showed that industrial participants improved their environmental performance and VEPs were celebrated as a viable alternative to more traditional regulation. Recent analyses using more sophisticated techniques, however, paint a less favorable picture. On the one hand, firms appear willing to sign up to VEPs, and in some cases, participants may be able to create a shield against future losses in shareholder value. On the other hand, these VEPs targeting production processes appear not to generate significant pollution abatement. The latter finding is particularly disturbing and this article discusses various explanations, including institutional failure and participant motivations. Future research needs to focus on understanding the firm motivation to invest in production‐related pollution abatement under a VEP. For policymakers, the research offers a warning on the limited impact to date of VEPs targeting production processes. However, the multitude of other VEPs, such as those which target new product development and changing market demands, merit a closer look to determine the overall potential of VEPs to engender positive environmental change.  相似文献   
4.
Metals present in the environment (soil, water and atmosphere) can affect food safety and human health through bio‐accumulation and bio‐magnification phenomena. Human exposure to the metals may take place through the environment and by ingesting contaminated food (including water), determining harmful effects usually detectable over the long term. Starting with the Industrial Revolution, local occurrence and concentration of metallic contaminants in the environment have been exponentially increasing: it has been assessed that, nowadays, daily absorption of lead, by North American people, is noticeably greater than that during prehistoric times. In this study, we measured concentrations of cadmium, lead and zinc in 153 bone samples (femurs) of Iron Age inhabitants of Central Italy (Abruzzo): the Samnites from the Alfedena Necropolis (2600–2400 bp ). The data found are in agreement with the results of similar published studies. Heavy metal concentrations varied widely among samples with the exception of zinc. A significant difference (p same Mann–Whitney test <0.05) in cadmium bone levels was found between male (0.08–1.8 mg/kg, median 0.31 mg/kg) and female samples (0.05–1.3 mg/kg, median 0.53 mg/kg). Copyright © 2014 John Wiley & Sons, Ltd.  相似文献   
5.
Bushfires (landscape fires) are a key Earth system process that affects humans and our societies and economies. In a recent article, we explored the coupling of humans to landscape fire through the lens of human health impacts of bushfire smoke. We noted that such an approach demands recognition of the indirect impacts and costs of bushfires that cannot be captured by simplistic proxies such as deaths directly attributable to a fire front. Evaluation of direct and indirect economic costs of bushfire disasters, and bushfire fire management remains a poorly developed research frontier that demands collaboration of expertise from a broad cross‐section of fields that often have limited experience of collaborating together. The need for such synthetic thinking about fire's place on Earth has spawned the discipline of pyrogeography.  相似文献   
6.
Risk perceptions are important to the policy process because they inform individuals’ preferences for government management of hazards that affect personal safety, public health, or ecological conditions. Studies of risk in the policy process have often focused on explicating the determinants of risk perceptions for highly salient, high consequence hazards (e.g., nuclear energy). We argue that it is useful to also study more routinely experienced hazards; doing so shows the relevance of risk perceptions in individuals’ daily lives. Our investigation focuses on the impact perceived risk has on citizens’ preferences over hazard management policies (as distinct from identifying risk perception determinants per se). We use a recursive structural equation model to analyze public opinion data measuring attitudes in three distinct issue domains: air pollution, crime, and hazardous waste storage and disposal. We find that citizens utilize perceived risk rationally: greater perceived risk generally produces support for more proactive government to manage potential hazards. This perceived risk–policy response relationship generally holds even though the policy options respondents were asked to consider entailed nontrivial costs to the public. The exception seems to be when individuals know less about the substantive issue domain.  相似文献   
7.
个旧锡业开发与生态环境变迁(1890-1949)   总被引:2,自引:0,他引:2  
随着1889年蒙自的开关,尤其是1910年滇越铁路的全线通车,极大地改善了云南的对外交通运输条件,推动了个旧锡业的迅速发展。在1890年至1949年的60年间,个旧共生产大锡323042吨,个旧锡业也取代铜业成为近代云南的矿业支柱。个旧锡业在推动云南矿业发展的同时,也对个旧及周边地区生态环境产生了巨大的影响。在1890年至1949年的60年间,个旧地区仅土法炼锡就至少消耗45万吨以上木炭。个旧、蒙自、建水、开远和石屏五县地区天然林平均覆盖率从清初的90%锐减至1940年的2.98%,近三百年间减少了80%以上,个旧锡业开发显然是五县天然林平均覆盖率急剧减少的重要原因。同时,锡矿的大量粗放开采和冶炼,也污染了个旧地区的土壤、水源和空气环境,带来了环境污染问题,影响了当地民众尤其是矿工的身体健康。因此,锡业开发是导致近代个旧及周边地区生态环境变迁的重要原因。  相似文献   
8.
博物馆文物环境因装饰材料所致甲醛污染以及由此产生对文物危害问题已被普遍关注.为了评价净化材料实际使用中对污染物去除净化能力,搭建了静态试验舱,建立了该环境中甲醛的定量分析方法.研究了甲醛溶液法和人造板散发法两种产生甲醛气体的方法,以及吸附材料不同加入方法等对净化材料评价结果的影响,研究试验舱内甲醛浓度随时间的变化规律,建立了净化材料脱附量检测方法,分别测定了活性炭和三种壳聚糖基净化材料的净化效果.结果表明,用人造板散发法产生甲醛气体方法能用于甲醛净化材料的评价,得到净化率指标反映了净化材料在实际文物环境中的应用效果,脱附量指标能直观比对和反映净化材料对污染物的吸附稳定性.  相似文献   
9.
The spatial and temporal variability of nitrogen dioxide (NO2) concentrations and their relationships with meteorology was evaluated in the Toronto–Hamilton urban airshed. NO2 concentrations were highest in the early morning and late evening. Mean concentrations were highest in winter, although individual one-hour NO2 concentrations were found to be highest in summer. Wind direction was the strongest control on hourly NO2 concentration, and temperature and wind speed also had an effect. Our analysis of NO2 concentration variation by wind direction showed that areas downwind of major highways, urban centres and industry were exposed to higher pollutant concentrations. Seasonal patterns of NO2 concentration displayed significant spatial heterogeneity, in particular, in Toronto. Onshore winds sheltered coastal inhabitants from the full extent of NO2 exposure they would otherwise experience. Seasonal variations in meteorology and emissions mean that the degree of spatial variability in NO2 concentrations changes from season to season. This study will help to improve existing land-use regression-based NO2 prediction models by incorporating meteorological controls on NO2 distributions for health effect studies.  相似文献   
10.
王瑞芳 《安徽史学》2012,(1):77-82,104
1973年第一次全国环境保护会议是新中国环保事业起步的标志。因环境污染主要是"三废"造成的,故环境保护的重点首先集中于"三废"综合利用,党和政府提出了"三十二字"方针,出台了"三同时"政策。随着对环境保护概念理解的深化,环境保护工作的重点开始从环境污染治理转向环境管理,进而转向自然环境保护。环境治理模式从单纯的行政手段,逐步转变为立法、经济、行政等多种手段并行,而以立法手段为主。把宣传教育同追究行政责任、经济责任直至刑事责任结合起来,成为一条行之有效的经验。治理环境污染经历了从治标到治本、从"三废"利用到环境保护的变化。这种变化,是由于环境逐渐恶化及污染日益严重的状况引起的,因此要求必须对环境保护进行全国性的总体规划,使环保工作计划化、制度化和法律化。  相似文献   
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