Public transit and air pollution: Evidence from Canadian transit strikes

Little is known about the causal impacts of public transit on local air pollution. Exploiting variation in transit availability resulting from transit strikes in 18 Canadian cities between 1974 and 2011, this study identifies the short-run effect of public transit on air pollution. Our findings indicate that transit leads to a 3.5 part per billion increase in nitrogen oxides while having no statistically significant effect on carbon monoxide or PM_2.5. Estimates are robust to a series of specification tests and magnitudes are consistent with a calibrated simulation model. Overall, the results suggest that expanding the current configuration of public transit in North American cities is unlikely to yield improvements in local air quality.     

Does CTAP prior to hepatic resection improve patient survival rates?

The purpose of our study was to compare survival rates of colon carcinoma patients who had undergone attempted curative hepatic resection based on liver staging by computed tomographic angiography (CTA) or portography (CTAP) with previously reported survival rates of patients who underwent similar surgery without preoperative CTAP evaluations. A total of 404 CTAP studies performed at three institutions were reviewed. Of this group, 197 had colon carcinoma. Sixty-nine of the colon patients went to surgery. Actuarial adjusted yearly survival rates were calculated for the prior CTAP colon group and compared to historical controls. The control survival data were taken from reports published prior to the CTAP era. Our study demonstrated no difference in the 1-year survival data between the groups. However, the CTAP patients had greater survival in years 2–4. This greater survival may be multifactorial but in part due to better surgical selection caused by CTAP.     

替吉奥联合奥沙利铂在晚期结肠癌化疗中的临床效果及不良反应

目的 探讨晚期结肠癌患者应用替吉奥联合奥沙利铂化疗治疗的临床效果及不良反应发生情况.方法 选取2018年1—12月沈阳市肛肠医院收治的70例晚期结肠癌患者作为研究对象,采用随机双盲法分为观察组与对照组,各35例.观察组采用替吉奥联合奥沙利铂行化疗治疗,对照组采用奥沙利铂行化疗治疗,比较两组患者化疗期间不良反应发生率、治...     

雷替曲塞联合伊立替康治疗晚期结肠癌患者的疗效及安全性

目的 探讨雷替曲塞联合伊立替康治疗晚期结肠癌患者的疗效及安全性.方法 选取2018年1月至2019年12月沈阳市肛肠医院收治的50例晚期结肠癌患者作为研究对象,按治疗方案不同分为对照组与观察组,各25例.对照组采用伊立替康、5-氟尿嘧啶和亚叶酸钙治疗,观察组给予伊立替康联合雷替曲塞治疗,比较两组治疗效果及安全性.结果 ...     

洛杉矶的雾霾治理及其启示

1943年美国发生了著名的"洛杉矶雾霾"事件,直到20世纪70年代,该市区还被称为"美国烟雾城"。洛杉矶雾霾夏天主要起因于臭氧,冬天主要是源于细微颗粒物等。洛杉矶在治理雾霾方面的主要做法包括立法、排污许可证制度、推广先进环保技术、建立排污交易机制和成立跨部门专门机构等,其治理工作取得了明显成效:2012年,加州达到"不健康空气"水平的日子比2000年减少了约74%。我国治理雾霾,应更加重视空气污染的长期性预测分析,引入市场机制,成立跨地区的空气污染治理机构,同时,加强中美间环保科技的国际合作。     

Abdominal MR imaging following antegrade air introduction into the intestinal loops

Air was used to distend the gastrointestinal tract and act as a contrast medium to effectively delineate the other abdominal organs/masses and to outline intraluminal or mural lesions. We used a nasogastric tube to introduce air into the stomach. Metoclopramide was administered to propel air throughout the gastrointestinal tract. Bowel peristalsis was then controlled by scopolamine butylbromide. Most of the alimentary tract could be distended by air. The normal bowel walls were barely visible between intraluminal signal-void air and extraluminal high-signal fat. Intraluminal tumor, wall thickening, and adjacent structures could be clearly delineated.     

我国城市间航空客运量影响因素的实证分析

城市间航空客运需求是航空公司航线网络布局时需要参考的重要信息。文章分析了影响城市间航空客运量的因素,建立了描述城市间航空客运量的半对数形式的线性计量经济模型,并使用我国2002年的352个城市对的横截面数据对模型进行了估计。分析结果表明,城市间距离、机场旅客吞吐量、人口密度、邮政电信业务总量、人均拥有公共交通车辆数以及城市性质和GDP相比,与城市对航空客流有着更为密切的相关关系。文中所建立的城市对客运量的回归模型可以作为航空公司进行航线需求分析的基础。     

粤港澳大湾区SO2平均浓度与制造业、生产性服务业集聚的空间关联特征

厘清区域产业集聚与空气污染的关系与机制,是协调经济发展与环境污染矛盾的前提与基础。利用双变量空间自相关探讨产业集聚与SO2平均浓度的空间自相关关系,再通过构建空间面板STIRPAT模型,对这种空间关系进行计量检验。结果表明,2011—2017年,粤港澳大湾区生产性服务业集聚与SO2平均浓度存在正的空间关联关系,制造业集聚、两种产业协同集聚度同SO2平均浓度存在负的空间关联性,但是关联性不显著。单一产业、两种产业协同集聚与SO2平均浓度的关联性具有显著的空间溢出效应。得出以下结论:生产性服务业集聚可能加剧空气污染,制造业集聚、产业协同集聚度则可一定程度上缓解空气污染,但这种关系不显著;单一产业及协同产业集聚对空气污染的空间溢出效应是明显的。     

我国民航运输经济的区域划分

根据我国航空运输业自身的经济发展特征和规律对航空运输经济区域划分进行研究,不仅能够为制定合理的航空运输规划布局提供依据.同时也有助于认清我国民航运输业区域发展格局.为未来航空运输业投资规划和决策提供支持.文章以机场所在城市的经济特征、城市间的经济联系以及地理位置等为背景,尝试运用断裂点模型,和中心城市辐射的引力范围,以旅客吞吐量排名前十位的机场所在城市为中心进行民航运输经济区域划分,经过分析研究,划分出八大区域格局.     

The Value of Clean Air in China： Evidence from Beijing and Shanghai

We estimate the willingness to pay （WTP） of Beijing and Shanghai residents for improving the air quality of the two cities from their levels prior to the 2008 Beijing Olympic Games to the level achieved during the Olympics. The data are obtained from a contingent valuation study conducted through face-to-face interviews in June 2008 in Beijing and Shanghai prior to the Beijing Olympics, during which time there was intensive debate about Beijing＇s air quality. Residents in both cities are willing to pay more when they are more exposed to air pollution, when their disposable income increases, and when they have stronger beliefs that public opinion plays an important role in government policy making. Beijing residents are willing to pay more than Shanghai residents, due possibly to Beijing＇s poorer air quality. Overall, aggregate WTP for air quality improvement accounts for about 0.53% of the 2008 GDP in Beijing and 0.22% of the 2008 GDP in Shanghai.     

道路绿化隔离带消减颗粒物效应及配置参数研究

交通污染已成为城市空气颗粒物污染的主要来源之一,对居民的生活、工作、出行产生了严重影响,而绿化隔离带可作为优化非机动车道和人行道空气质量的一种有效且经济地措施。基于实验测定评价道路绿化隔离带对非机动车道空气颗粒物浓度的影响,并提出分层疏透度来表征样带垂直结构特征,分析绿化隔离带配置方式对街道空气颗粒物浓度的影响。研究结果显示,绿化隔离带可较好地改善街道空气质量,对TSP和PM10的消减效果较PM2.5好;颗粒物的消减效果与样带的植物配置结构有紧密联系,分析结果显示颗粒物消减效率均与0～2m高度区间内的疏透度呈显著负相关。在交通流量较大的城市干道上,应该减少或者避免使用冠大荫浓的高大乔木,多配置结构紧密和叶密度较大的灌木植物。本研究结果可为城市道路绿化参数化设计和优化提供理论支撑,为改善人居生活环境作出贡献。     

Livestock emissions regulation with unknown damages and strategic technology adoption

Livestock emissions have been identified as a contributor to greenhouse gas build-up yet have remained unregulated in the US. A game-theoretic model in the style of Tarui and Polasky (2005) was analysed where the dairy industry strategically chooses to abate air emissions with technology adoption and herd size decisions while a regulator chooses a tax rate on emissions to satisfy the desires of competing interest groups. This model allows the effects of potential air emission regulation on the dairy industry to be evaluated. Results demonstrate that dairy farms react to the increased cost of air regulation by decreasing herd size rather than investing in air emission abatement technology in the short run. This suggests that incentives may need to be put in place to induce adoption in emissions abatement technology at the livestock level in the long run.     

关于选择前室加压送风系统形式的计算分析

针对《高规》中,对于前室或合用前室加压送风口开启控制方式没有明确规定这一问题,采用压差法和流速法计算典型前宣的加压送风量,证明规范给定的风量宜用于设置常开型风口的加压送风系统。     

论我国大气污染生态补偿法律机制的完善

大气污染生态补偿法律机制对于促进区域大气污染联合治理、实现大气污染治理法律正义、创新与完善生态补偿法律机制等具有重要意义。我国现有法律法规就大气污染生态补偿进行了原则性规定,特别是山东、陕西、湖北等地方性法规更是对大气污染生态补偿进行了探索性规范,为大气污染生态补偿法律机制完善提供了有益经验。但从总体来看,我国大气污染生态补偿法律机制尚存在缺乏专门法律支撑、生态补偿主体过窄、补偿方式单一、补偿标准不合理、法律责任不完善等问题。为促进生态文明战略与强化大气污染生态补偿的法律保障,我国应以科学理念为指导,采取有效措施推进大气污染生态补偿法律机制完善。     

国家生态文明建设与空气质量改善——来自合成控制法与DID的双重验证

生态兴则文明兴,生态环境关系着生态文明体系的构建。2014年,我国设立第一批生态文明先行示范区,为生态文明建设在环境质量方面的成果评价提供了准自然实验环境。为了评价我国生态文明建设在空气质量改善方面的绩效,将江西、福建、贵州、云南和青海这5个省级生态文明先行示范区设定为处理组,运用合成控制法和DID模型对空气质量改善状况进行双重检验。结果表明:整体上,生态文明先行示范区建设对空气质量改善具有显著的效果;江西、贵州和云南的生态文明先行示范区建设均表现出对环境质量的改善作用,其中江西生态文明建设对空气质量改善成效尤为显著。因此,我国设立生态文明先行示范区对于空气质量改善具有显著效应,这对今后国家生态文明试验区建设尤其是在社会经济、资源环境等方面的协调发展具有重要的参考价值。     

Changing fuel use behavior: The Pittsburgh smoke control movement, 1940–1950

Local policy development in Pittsburgh brought about cleaner air by influencing change in the household use of fuel and combustion equipment. By a combination of media campaigns, voluntary organizations, technical advisers, and business and labor leaders, the public was convinced of the necessity to reduce air pollution. The unique aspect is that the public accepted the costs of a long-range policy decision through education and persuasion.     

The stock market effect of air pollution: evidence from China

In financial studies, environmental stimuli such as sunshine, temperature, and daylight are often used as proxies for people’s collective mood swings to test their effects on the stock market. China has experienced serious air pollution problems in recent years, and Chinese public awareness of air pollution has soared. In this paper, we use China as a natural experiment to investigate the effect on stock returns of depressed moods induced by air pollution. Daily air-pollution data from 2005 to 2014 are analysed and the results obtained from the empirical research show that a contemporaneous negative and a two-day lagged positive relationship exists between air pollution levels and stock returns over this time period. The relationship is mediated by the influence of air pollution on investment decisions. The results also indicate that the effect is weakened for companies that protect air quality, but no stronger effect is detected for polluting companies. The findings imply that air pollution is a behavioural factor with some connection to stock returns in China.     

媒体压力与空气质量改善

本文使用2014—2017年我国省级报纸对省份内地级市的空气污染报道数据,实证检验了媒体压力在促进空气质量改善中的作用。研究发现,媒体对污染报道的增加,显著促进了城市空气质量的改善,且这种改善的效果受污染报道发表报纸是否为省级党委机关报以及城市主政官员特征的影响。这意味着,媒体污染报道主要通过对政府官员形成的压力来促进地方政府进行污染治理、改善空气质量。进一步研究发现,环境治理投入的增加与工业污染排放的减少,是媒体压力促进城市空气质量改善的有效途径。本文的结论,对于理解新时代我国舆论监督的作用机制以及更好发挥新闻媒体监督在环境治理中的作用,提供了新的视角。     

我国航空货运网络结构研究

选取国内空港130个、航线317条,国际空港72个、航线237条,从空港和航线两个角度探讨我国航空货运机场分布格局和网络结构,结果发现:华东区、华北区、中南区是航空货物的主来源地、目的地和中转地,上海、广州和深圳、北京构成我国航空货运的"三极",形成货运三角;航空货运主要分布在少数枢纽空港间的航线上,呈现集中状态,前五位航线的货运量之和为43.83万t,占27.33%;航空货运高度集中在人口100万以上的城市间,人口100万以下的城市间航空货运联系很弱,所占市场份额之和不足1%,中等城市之间、大城市与中等城市、小城市之间无直航航线联系;我国对外航空货运联系主要集中在北美、日韩、西欧和港澳地区,与东欧、中东和南亚地区的航空货运联系较弱,与非洲和拉美地区目前还没有直通航班。     

基于ESDA的太湖流域空气质量时空异质性分析

以长三角核心区域——太湖流域对研究对象,对其2014—2018年空气质量进行了时空异质性分析,并利用相关性分析探索了太湖流域空气质量驱动机制。结果表明:(1)太湖流域空气质量的总体空间差异较小,流域东部沿海沿江地区以及西南部山林区域的空气质量普遍较好。上海、嘉兴两市空气质量相对较好,无锡、镇江两市则较差,局部聚集性尚不明显;(2)自然生态空间、污染治理技术及协同治理对策可使城市在经济社会发展的同时实现空气质量的稳步改善。最后结合流域实际针对性提出了相适应的对策建议。