‘Effortless Perfection:’ Do Chinese cities manipulate air pollution data?

This paper uses unique data on daily air pollution concentrations over the period 2001–2010 to test for manipulation in self-reported data by Chinese cities. First, we employ a discontinuity test to detect evidence consistent with data manipulation. Then, we propose a panel matching approach to identify the conditions under which irregularities may occur. We find that about 50% of cities reported dubious PM₁₀ pollution levels that led to a discontinuity at the cut-off. Suspicious data reporting tends to occur on days when the anomaly is least detectable. Our findings indicate that the official daily air pollution data are not well behaved, which provides suggestive evidence of manipulation.     

氢氧化镁对剩余污泥碱性发酵及脱水性能的影响

剩余污泥厌氧发酵可产出短链脂肪酸(SCFAs)发酵液用作碳源时,可改善污水脱氮除磷效果,但发酵液中的氮磷会增加污水厂的氮磷负荷.此研究分别采用Mg(OH)2和NaOH调节剩余污泥厌氧发酵时的pH值,考察Mg(OH)2能否促进剩余污泥碱性发酵同时去除发酵液中的氨氮和磷,及其对发酵后污泥脱水性能的影响.结果表明:Mg(OH)2可促进剩余污泥碱性发酵,发酵液最大SCFAs含量为2336.3mgCOD/L,同时Mg(OH)2能去除发酵液中的磷,在发酵的第4d,其磷含量接近0;Mg(OH)2调节碱性发酵后的剩余污泥脱水性能优于NaOH调节的,前者剩余污泥毛细吸水时间(CST)较后者短42.3s.     

滏阳河河流水体中重金属污染特征及其对青海弧菌和斜生栅藻的毒性效应

为调查滏阳河水系的重金属污染状况,研究河流重金属污染对水生生物的毒性,根据河流结构、水文条件、排污口分布并考虑空间分布的均匀性,选取66个采样位点,采集河水及对应的表层沉积物样品,分析了样品中的重金属含量。用斜生栅藻和青海弧菌Q67作为模式生物,根据滏阳河水重金属污染较严重的邯郸近郊2号采样点采集水样的重金属含量配制系列重金属浓度的模拟河水进行重金属污染河水的生态毒性测试。结果表明,在全部66个采样点中,29个采样点河水重金属含量超过国家地表水III类水体重金属含量标准,主要污染元素是Hg、Pb、Cr、Zn。几乎所有采样点河水Mn和Fe含量都大大高于国家集中式生活饮用水地表水源地补充项目规定的标准限值。根据2号采样点河水样品中的重金属含量配成的模拟河水对青海弧菌Q67的EC_(50)值为6.65%,为毒性极强的污染物。模拟河水样品对斜生栅藻的抑制作用较小,在实验的最高浓度下(1 000倍河水重金属含量)暴露4 d尚未引起半数藻细胞死亡。随河水重金属浓度上升,斜生栅藻超氧化物歧化酶(SOD)活性总体上呈现先升高后降低的趋势,丙二醛(MDA)含量变化则与此相反,反映河水重金属污染可引起藻细胞的氧化损伤。叶绿素a和b含量则随暴露浓度的提高逐渐降低。在重金属浓度达到2号采样点河水的10%时,斜生栅藻叶绿素a含量已有显著降低,MDA含量显著升高,海河流域重金属污染对生态系统的影响应予以重视。河水发光菌Q67的生长抑制率、斜生栅藻的叶绿素a和MDA含量可以作为评估河流重金属污染生态危害的指标。     

Removal,distribution and plant uptake of perfluorooctane sulfonate (PFOS) in a simulated constructed wetland system

• PFOS was removed by soil adsorption and plant uptake in the VFCW. • Uptake of PFOS by E. crassipes was more than that of C. alternifolius. • PFOS in wastewater can inhibit the removal of nutrients. • Dosing with PFOS changed the soil microbial community in the VFCW. A vertical-flow constructed wetland (VFCW) was used to treat simulated domestic sewage containing perfluorooctane sulfonate (PFOS). The removal rate of PFOS in the domestic sewage was 93%–98%, through soil adsorption and plant uptake, suggesting that VFCWs can remove PFOS efficiently from wastewater. The removal of PFOS in the VFCW was dependent on soil adsorption and plant uptake; moreover, the percentage of soil adsorption was 61%–89%, and was higher than that of the plants uptake (5%–31%). The absorption capacity of Eichhornia crassipes (E. crassipes) (1186.71 mg/kg) was higher than that of Cyperus alternifolius (C. alternifolius) (162.77 mg/kg) under 10 mg/L PFOS, and the transfer factor of PFOS in E. crassipes and C. alternifolius was 0.04 and 0.58, respectively, indicating that PFOS is not easily translocated to leaves from roots of wetland plants; moreover, uptake of PFOS by E. crassipes was more than that of C. alternifolius because the biomass of E. crassipes was more than that of C. alternifolius and the roots of E. crassipes can take up PFOS directly from wastewater while C. alternifolius needs to do so via its roots in the soil. The concentration of 10 mg/L PFOS had an obvious inhibitory effect on the removal rate of total nitrogen, total phosphorus, chemical oxygen demand, and ammonia nitrogen in the VFCW, which decreased by 15%, 10%, 10% and 12%, respectively. Dosing with PFOS in the wastewater reduced the bacterial richness but increased the diversity in soil because PFOS stimulated the growth of PFOS-tolerant strains.     

Motivations for the use and consumption of wildlife products

The dominant approach to combating the illegal wildlife trade has traditionally been to restrict the supply of wildlife products. Yet conservationists increasingly recognize the importance of implementing demand-side interventions that target the end consumers in the trade chain. Their aim is to curb the consumption of wildlife or shift consumption to more sustainable alternatives. However, there are still considerable knowledge gaps in understanding of the diversity of consumer motivations in the context of illegal wildlife trade, which includes hundreds of thousands of species, different uses, and diverse contexts. Based on consultation with multiple experts from a diversity of backgrounds, nationalities, and focal taxa, we developed a typology of common motivations held by wildlife consumers that can be used to inform conservation interventions. We identified 5 main motivational categories for wildlife use: experiential, social, functional, financial, and spiritual, each containing subcategories. This framework is intended to facilitate the segmentation of consumers based on psychographics and allow the tailoring of interventions—whether behavior change campaigns, enforcement efforts, or incentive programs—to the specific context in which they will be used. Underlining the importance of consumer research and collaborating with local actors is an important step toward promoting a more systematic approach to the design of demand reduction interventions.     

Competing land uses and fossil fuel,and optimal energy conversion rates during the transition toward a green economy under a pollution stock constraint

We study the transition to a carbon-free economy in a model with a polluting non-renewable resource and a clean renewable resource. Transforming primary energy into ready-to-use energy services is costly and more efficient energy transformation rates are more costly to achieve. Renewable energy competes with food production for land and the food productivity of land can be improved at some cost. To avoid catastrophic climate damages, the pollution stock is mandated to stay below a given cap. When the economy is not constrained by the cap, the efficiency of energy transformation increases steadily until the transition toward the ultimate green economy; when renewable energy is exploited, its land use rises at the expense of food production; food productivity increases together with the land rent but food production drops; the food and energy prices increase and renewables substitute for non-renewable energy. During the constrained phase, the economy follows a constant path of prices, quantities, efficiency rates, food productivity and land rent, a phenomenon we call the ‘ceiling efficiency paradox’.     

Environmental policy and human capital inequality: A matter of life and death

This paper analyzes the economic implications of an environmental policy when we account for the life expectancy of heterogeneous agents. In a framework in which everyone suffers from pollution but health status also depends on individual human capital, we find that the economy may be stuck in a trap in which inequality rises steadily, especially when the initial pollution intensity of production is too high. We emphasize that such inequality is in the long run costly for the economy in terms of health and growth. Therefore, we study whether a tax on pollution associated with an investment in pollution abatement can be used to address this situation. We show that a stricter environmental policy may allow the economy to escape from the inequality trap while enhancing the long-term growth rate when the initial inequality in human capital is not too large.     

The impact of flooding on property prices: A repeat-sales approach

In this paper we use a repeat-sales model to analyse the price path of properties affected by flooding in England between 1995 and 2014. Our dataset contains information on 4.8 million houses with at least one repeat-sale. This database is merged with high-definition GIS data delineating the spatial extent of all recorded flood incidents in England covering a total area of 2,654 km². Our results show that immediately after a flood event the price of property in a postcode entirely inundated by inland flooding is on average 24.9% lower than non-flooded property, whereas for property in a postcode entirely inundated by coastal flooding the price reduction is 21.1%. Nonetheless, we find that this discount is short-lived and the discount is no longer statistically significant for properties affected by inland flooding after 5 years, which falls to just 4 years for properties affected by coastal flooding. For lower-priced properties however, the post-flood price discount can be observed up to 6–7 years for both inland and coastal flooding. The magnitude of the impact also depends on the characteristics of the properties, the characteristics of the flood and the existence of flood protection assets.     

Infant health impacts of freshwater algal blooms: Evidence from an invasive species natural experiment

Economists are increasingly interested in causally interpretable estimates of environmental health externalities, particularly on infant health. This paper focuses on a specific case by investigating microcystin, a toxin produced by freshwater blue-green algal blooms. We exploit a natural experiment caused by a zebra mussel die-off in a large lake located in the state of Michigan, USA to identify changes in microcystin-related infant outcomes surrounding the lake. Using both the synthetic control method and a difference-in-differences strategy, we find that instances of low birth weight around the lake fell by 1.4 percentage points after lake water quality improved. Along the intensive margin, birth weight and length of gestation increased by 17.1 g and 0.47 weeks, respectively. Improvements to low birth weight result in $768,500 in average annual hospitalization cost savings. Many robustness and falsification tests are performed including using both annual and monthly data and accounting for possible weather confounders and seasonality. Results suggest that microcystin can affect infant health at levels below current water advisory guidelines.     

The price of innovation: An analysis of the marginal cost of green buildings

Energy efficiency plays an important role in reducing the carbon externality from buildings, but economic analyses of more efficient, green building have thus far ignored input costs. This paper finds that the average marginal cost of green-labeled construction projects is smaller than the value premiums documented in the literature. However, design fees, representing just a fraction of development costs but paid largely up-front, are significantly higher for green construction projects. These projects also take longer to complete. The results provide some insight into the market barriers and market failures that may explain the relatively slow adoption of otherwise economically rational green construction practices.