天津某老年社区夏冬季室内与个体暴露PM2.5对比

于2011年夏季(6月13日—7月2日)和冬季(11月30日—12月12日)在天津市某老年社区采集室内与老年人个体暴露PM_2.5样品,分析二者的质量浓度及化学组分特征. 结果表明:夏、冬季室内ρ(PM_2.5)分别为(138±103)和(173±136)μg/m3,二者差异显著(P<0.05);冬季室内ρ(PM_2.5)、ρ(SO₄2-)和ρ(OC)显著高于夏季(P<0.05),初步推断是由于冬季燃煤取暖排放的大量颗粒物渗透进入室内所致;冬季室内源(如清扫和吸烟)对某些室内PM_2.5组分(Al、Ca和Cd)的贡献较夏季显著. 对个体暴露与室内ρ(PM_2.5)的相关性分析发现,二者在夏、冬季均显著相关(P<0.05). 在受试老年人时间活动模式基础上,采用COD(分歧系数)评估室内和个体暴露PM_2.5化学组成的相似度,结果显示,室内与个体暴露PM_2.5的COD在夏、冬季分别为0.34±0.10和0.37±0.12;冬季受试老年人在交通微环境所处时间较长,致使COD大于0.5的样本数所占比例较夏季高. 室内和老年人个体暴露PM_2.5的ρ(OC)/ρ(EC)在夏、冬季均相近,说明二者的碳组分来源相似.      

露天矿排土场边坡自然恢复规律及其环境解释

露天矿排土场边坡水土流失严重,易发生地质灾害,急需开展生态恢复和土地复垦研究。为了解排土场边坡植物群落演替规律以及植物对生境因子的响应关系,本研究以阜新露天矿不同恢复年限排土场边坡为对象,调查不同坡向和坡位的植物组成、数量、高度和盖度,采用双向指示种法（TWINSPAN）对植物群落进行分类;同时分析边坡土壤物理、化学和生物学性质,采用去趋势典范对应分析（DCCA）方法研究群落分布格局与环境因子的关系。结果表明,排土场边坡共出现27种植物,物种数量小于平台。植物群落在阴坡和阳坡呈现出不同的演替格局,阴坡演替顺序为狗尾草（Setaira viridis）＋茵陈蒿（Artemisia capillaries）＋铁杆蒿（Artemisia sacrorum）→狗尾草＋铁杆蒿＋白蒿（Artemisia anethoides）→铁杆蒿＋狗尾草;恢复10 a后,铁杆蒿在中上坡位占据优势地位,植物种类和数量下降,植物群落呈逆向演替。阳坡演替顺序为蒺藜（Tribulus terrestris）＋旱稗（Echinochloa hispidula）＋狗尾草→狗尾草＋蒺藜＋白蒿→狗尾草＋页蒿（Carum carvi）＋白蒿,植被演替进程缓慢。DCCA排序表明,第一轴主要反映植物群落随坡位、土壤水分、氮元素有效性和周转的变化规律,其与土壤pH值和脲酶紧密相关;第二轴主要反映植物群落随着恢复年限和土壤磷素有效性的梯度变化,其与土壤容重、速效磷、蔗糖酶和碱性磷酸酶紧密相关。排土场边坡必须采取人工恢复措施,土壤酶活性对植物群落分布影响较大。     

Building resilience by challenging social norms: integrating a transformative approach within the BRACED consortia

Resilience is a complex phenomenon whereby a multitude of social and environmental factors, including gender, combine to shape the ways that shocks affect people. Looking at two BRACED (Building Resilience and Adaptation to Climate Extremes and Disasters) projects, in Burkina Faso and in Ethiopia, this article uses a desk review and primary data from partners and people at risk to explore how a gender‐transformative approach can be an integral part of resilience‐building projects, particularly those implemented by multi‐stakeholder consortia. It also suggests ways to incorporate a stronger gender component in similar future projects. The article argues that donors and programme managers must provide clear principles and guidelines for achieving gender equity within resilience‐building efforts. However, these must allow flexibility to adapt to norms, needs and resources as determined by implementing partners. The right balance can be achieved by facilitating spaces for individual and collective goal‐setting; assessing current capacity and trajectories; and lesson‐sharing as an iterative process for institutional learning.     

Looking forward: Disasters at 40

This paper reflects on contemporary studies of and responses to disasters, highlighting the importance of historical, spatial, and intersectional modes of analysis, and draws on the author's ongoing research on Southern‐led and local community responses to displacement in the Middle East. Acknowledging the plurality of ‘international communities of response’, it begins by critiquing the depiction of selected responses to disasters as ‘positive’ ‘paradigm shifts’, including in reference to the ‘localisation of aid, and the United Nations’ Regional Refugee and Resilience Plan for Syria. Next it turns to three key themes that are central to disasters studies: migration; forced displacement; and Southern‐led responses to disasters. Among other things, the paper argues that exploring the principles and modalities of South–South cooperation, rather than promoting the incorporation of Southern actors into the ‘international humanitarian system’ via the localisation agenda, presents a critical opportunity for studies of and responses to disasters.     

The social cost of carbon revisited

An estimate of the social cost of carbon (SCC) is crucial to climate policy. But how should we estimate the SCC? A common approach uses an integrated assessment model (IAM) to simulate time paths for the atmospheric CO₂ concentration, its impact on temperature, and resulting reductions in GDP. I have argued that IAMs have deficiencies that make them poorly suited for this job, but what is the alternative? I present an approach to estimating an average SCC, which I argue can be a useful guide for policy. I rely on a survey of experts to elicit opinions regarding (1) probabilities of alternative economic outcomes of climate change, but not the causes of those outcomes; and (2) the reduction in emissions required to avert an extreme outcome, i.e., a large climate-induced reduction in GDP. The average SCC is the ratio of the present value of lost GDP from an extreme outcome to the total emission reduction needed to avert that outcome. I discuss the survey instrument, explain how experts were identified, and present results. I obtain SCC estimates of $200/mt or higher, but the variation across experts is large. Trimming outliers and focusing on experts who expressed a high degree of confidence in their answers yields lower SCCs, $80 to $100/mt, but still well above the IAM-based estimates used by the U.S. government.     

Willingness to pay for clean air in China

We use a residential sorting model incorporating migration disutility to recover the implicit value of clean air in China. The model is estimated using China Population Census Data along with PM2.5 satellite data. Our study provides new evidence on the willingness to pay for air quality improvements in developing countries and is the first application of an equilibrium sorting model to the valuation of non-market amenities in China. We employ two instrumental variables based on coal-fired electricity generation and wind direction to address the endogeneity of local air pollution. Results suggest important differences between the residential sorting model and a conventional hedonic model, highlighting the role of moving costs and the discreteness of the choice set. Our sorting results indicate that the economic value of air quality improvement associated with a one-unit decline in PM2.5 concentration is up to $8.83 billion for all Chinese households in 2005.     

Environmental values and willingness to pay for a protected area: a segmentation of Italian university students

The study investigated students’ attitudes and willingness to pay (WTP) for the protection of some environmental values. The empirical study refers to a site located in Southern Italy and inserted into the Natura 2000 European Network. Students were segmented according to their appreciation of environmental values and the WTP for them. We considered two scenarios of the study site – of use and non-use – and four values – recreational, educational, bequest and existence. Five clusters, from the ‘unconcerned’ to the ‘committed’ one, reveal a diversity of profiles across the sample. Segmentation results point out the multifunctionality of the environmental heritage and highlight the heterogeneity of students’ environmental profiles.     

Large carnivore hunting and the social license to hunt

The social license to operate framework considers how society grants or withholds informal permission for resource extractors to exploit publicly owned resources. We developed a modified model, which we refer to as the social license to hunt (SLH). In it we similarly consider hunters as operators, given that wildlife are legally considered public resources in North America and Europe. We applied the SLH model to examine the controversial hunting of large carnivores, which are frequently killed for trophies. Killing for trophies is widespread, but undertaken by a minority of hunters, and can pose threats to the SLH for trophy-seeking carnivore hunters and potentially beyond. Societal opposition to large carnivore hunting relates not only to conservation concerns but also to misalignment between killing for trophies and dominant public values and attitudes concerning the treatment of animals. We summarized cases related to the killing of grizzly bears (Ursus arctos), wolves (Canis lupus), and other large carnivores in Canada, the United States, and Europe to illustrate how opposition to large carnivore hunting, now expressed primarily on social media, can exert rapid and significant pressure on policy makers and politicians. Evidence of the potential for transformative change to wildlife management and conservation includes proposed and realized changes to legislation, business practice, and wildlife policy, including the banning of some large carnivore hunts. Given that policy is ultimately shaped by societal values and attitudes, research gaps include developing increased insight into public support of various hunting policies beyond that derived from monitoring of social media and public polling. Informed by increased evidence, the SLH model can provide a conceptual foundation for predicting the likelihood of transient versus enduring changes to wildlife conservation policy and practice for a wide variety of taxa and contexts.     

Environmental hazards and waste management in Nsukka urban metropolis in Enugu State of Nigeria: how much are people willing to pay?

Solid waste management in Nsukka town in Enugu state of Nigeria has remained a major challenge despite the efforts of the state government through the Enugu State Waste Management Agency (ESWAMA). The current method whereby households dump refuse at designated locations by the road side to be cleared later has not yielded much improved sanitation of the town. In this study we propose an alternative waste management method that is believed to be superior to the status quo if properly managed. This study applies Contingent Valuation Method (CVM) to estimate the households’ willingness to pay (WTP) for this new method in order to ascertain its applicability in Nsukka urban. Data were collected from a sample of 500 households stratified according to major streets in the town. The results show that the mean WTP using different specifications of the model varies from N527.50 (about 2.68) to N530.90 (about 2.68) per month. The policy implication is that if the waste management agency adopts the proposed scenario and manages it well the average revenue realizable per month would be about N13,750,516 (about $69,800). The authorities can compare this with the cost of providing the service and see if it is worth the effort.     

北京与成都大气污染特征及空气质量改善效果评估

近年来我国空气质量持续改善,大气颗粒物浓度明显降低.为探究气象条件和减排措施对细颗粒物（PM_2.5）浓度的相对贡献,选取两个典型代表城市——北京和成都,对比分析两城市所处的地理环境条件、污染排放以及气象扩散条件.结果表明,北京与成都2013~2018年重污染天数及污染过程显著减少,SO₂和PM_2.5浓度降幅明显,与2013年相比,两城市2018年SO₂浓度的降幅分别为77.8%和70.9%,PM_2.5浓度分别降低了42.7%和48.5%.冬季PM_2.5浓度下降速率最大,每年分别以13.5μg·m^-3和14.1μg·m^-3的速率降低.2013~2018年成都较北京风速偏小,温度偏高约3℃,静小风日数偏多,冬季静小风频率高,混合层高度、大气容量指数以及通风系数明显偏小,大气扩散条件较差.综合静稳天气指数（SWI）和环境气象指数（EMI）结果表明北京大气扩散条件优于成都,但近几年的变化程度有所不同.2014~2018年两城市的EMI呈减小趋势,2018年成都地区EMI降幅最显著,气象条件明显好转.与2014年相比,2018年北京与成都全年大气污染减排对PM_2.5浓度的贡献分别为33.5%和24.0%,气象条件的贡献分别为7.2%和11.1%;冬季减排贡献分别为31.7%和32.5%,气象条件的贡献比全年的大.