Immune parameters in female workers exposed to urban pollutants

Urban outside workers, such as traffic police, are daily exposed to air pollutants and psychosocial stressors: for these workers, the working environment corresponds to the living environment of the general population. Studies in the literature have shown that immune parameters could be affected by chronic exposure to various chemical pollutants. The aim of this study is to evaluate whether occupational exposure to urban pollutants can cause alterations in NK, IL-2, IFN-gamma and C3 plasma levels in female traffic police compared to a control group. After excluding subjects with the principal confounding factors, 86 female traffic police and 87 controls were matched by age, years of police work and habitual alcohol consumption. The distribution of NK values in female traffic police and controls was significantly different (p=0.000); NK values above the upper limit of the normal laboratory range were observed in 23 female traffic police and in 2 controls (p=0.000). IL-2 mean levels were higher in traffic police compared to controls, but the difference was not significant. The mean and the distribution of IFN-gamma values in female traffic police and controls were not different. C3 mean levels were higher in female traffic police versus controls, but the difference was not significant. Considering that the subjects with the principal confounding factors were excluded from the study and that female traffic police and controls were matched by the above-mentioned variables, our results suggest that chronic occupational exposure to low doses of chemical stressors, which may interact with and add to psychosocial ones, can affect both innate and adaptative immunity.     

The economic effects of facilitating the flow of rural workers to urban employment in China

Using a dynamic computable general equilibrium model of the Chinese economy we investigate the economic effects of relaxing China's household registration system over the period 2008 to 2020. The modelling results show that reducing the institutional restriction to rural labour movement will encourage rural workers to move from agricultural and rural non‐agricultural sectors into urban sectors. This enhanced labour movement will not only increase China's GDP and real consumption of households but it will also raise the real wages of agricultural and rural non‐agricultural workers. Although the real wage of rural migrant workers will increase at a slightly lower rate than in the baseline scenario, rural migrant workers remain considerably better paid than agricultural and rural non‐agricultural workers.     

Exposure to carbon monoxide in the Athens urban area during commuting

An extensive survey has been designed to provide detailed information on carbon monoxide (CO) concentration in the main transport modes and along heavy traffic routes in the Athens urban area. Specifically the study identifies the main factors affecting CO exposure during commuting. Several portable, electrochemical CO monitors (Solomat's MPM4100), were used to record the in-vehicle CO concentrations every 15 s. Measurements were performed during rush hour periods. Field monitoring was conducted in summer 1998 and winter 1998-1999. Exposure estimates were compared to WHO guidelines. The findings showed that the mean CO level over trips of 30 min was 21.4 ppm for private car against 10.4, 9.6, 4 and 11.5 ppm for bus, trolley, electric train and pedestrians, respectively. Transport mode, route, monitoring period and season had a significant influence on the measured CO concentrations. The study points out the importance of microenvironmental monitoring, instead of using fixed-site data in assessing commuter's CO exposure.     

Cocooning urban life: Exposure to diversity in neighbourhoods,workplaces and transport

Although one's neighbourhood is continuously structuring everyday lives and influences encounters between different people, place of residence is only partially the site where interactions and possibly integration between population categories occur. Another well-known domain is the place of work, where many spend hours per day and may meet various ‘others’. However, people's mobility is also strongly differentiated between class and ethnicity. Here too, different modes of transport may offer opportunities for encounter and engaging with others. In order to assess exposure to diversity of individuals from various ethnic and social class backgrounds to ‘the other’ we focus on these three important realms of daily life: neighbourhoods, workplaces and modes of transport. We use individual level data from the Mobilities Netherlands Database combined with detailed individual level register data from the Social Statistical Database. We found that, overall, higher income natives are, compared to the other combinations of country of origin and income category most frequently cocooning in homogeneous residential, workplace, and mobility spaces. However, native-Dutch with a low income stand out in the residential domain, where they are living more frequently in homogeneous neighbourhoods than high-income natives.     

Luteinizing hormone (LH) levels in male workers exposed to urban stressors

The aim of the study is to evaluate if occupational exposure to urban stressors could cause alterations in luteinizing hormone (LH) plasma levels in male traffic policemen vs. administrative staff of Municipal Police.After excluding the subjects with the main confounding factors, male traffic police and administrative staff of Municipal Police were matched by age, working life, body mass index (BMI), alcohol drinking habit, cigarette smoking habit and habitual consumption of Italian coffee.In 166 male traffic police mean LH values were significantly higher compared to 166 male administrative employees. The distribution of LH values in traffic police and in administrative employees was statistically significant.Our results suggest that recent exposure to urban stressors (chemical, physical and psycho-social) can alter the plasma concentration of LH. In agreement with our previous research, levels of plasma LH may be used as early biological markers, valuable for the group, used in occupational set before the appearance of the disease.     

浅谈城市道路无障碍设施建设

通过对城市道路无障碍设施概念的介绍,论述了城市道路中无障碍设施建设的必要性,并针对沧州市道路无障碍设施建设和使用中存在的问题,提出相关建议,为创造和谐、良好、以人为本的社会环境提供保障。     

Exposure of Chironomus riparius larvae to 17alpha-ethynylestradiol: effects on survival and mouthpart deformities

Evidence from field studies shows that mouthpart deformities in chironomid larvae are a sublethal response to pollution. Interest has been shown to use this end-point in programs for monitoring sediment quality. During laboratory studies, however, deformities were induced in only a few single pollutant exposures. These deformities develop at the endocrine regulated molting stage and disruption of this complex process is likely at the base of their ontogeny. Aiming to clarify the processes involved in the rise of such deformities, we tested the effects of ethynylestradiol (EE2) in an in vivo lab study. Chironomus riparius larvae were exposed to 1, 10 and 100 microg l(-1) EE2 (nominal concentrations). No adverse effects on the larvae, for the investigated end-points (survival and deformity induction), were found.     

Exposure assessment of organic solvents for aircraft paint stripping and spraying workers

The main objective of this study is to investigate the personal or area exposure of organic solvents during paint stripping and paint spraying. Three aircraft paint stripping/spraying workplaces in Taiwan were selected, and the Council of Labor Affairs and NIOSH recommended sampling/analytical methods used in this study. Activated charcoal tubes were used to investigate the personal and area exposure concentration of organic solvents in paint stripping and paint spraying operations. During aircraft paint stripping, experiment results show that methylene chloride personal exposure concentration at the ground area, 42.01+/-31.86 ppm, is higher than that at the working platform 4 M high above the ground, 20.41+/-11.43 ppm. Exposure concentration of methylene chloride in the initial paint stripping operation stage of every workplace is over the PEL (50 ppm) set by the Taiwan Council of Labor Affairs. Corrective actions are needed. During paint spraying, concentrations of all organic solvents were found to be below the PEL of OSHA.     

农民工居住环境的城市生态影响略论

以中国城市化进程中出现的农民工进城潮为背景,在观察农民工城市居住环境的基础上,结合城市生态学的基本原理,探讨农民工群体在城市中的生存状况对城市生态系统不可忽视的影响,指出构建和谐的城市生态环境建设急需关注农民工群体的居住环境并解决其中的问题。     

新生代农民工居住形态与城市融入——基于城市社会学视角

新生代农民工是我国城市化进程中需要面对的新群体,居住是新生代农民工进入城市后的基本活动之一,是其在城市生存、发展、进而转化为市民的基本条件。从城市社会学意义上讲,居住空间作为新生代农民工社会活动、社会关系的容器,是承载新生代农民工社会资本的重要载体,对于其融入城市具有重要影响。本文通过问卷调查的形式,对新生代农民工的群体特征、居住现状进行了调查研究,指出新生代农民工与市民之间存在着居住隔离与居住差异,并从城市社会学的角度,从经济融入、文化融入、心理融入三个方面对这种差异与隔离做了分析,指出居住形态的差异与隔离是造成新生代农民工与城市之间融入困境的重要原因,而改善新生代农民工的居住条件与居住环境,是促进新生代农民工融入城市的重要环节。     

Differential community effects on perception and use of urban greenspaces

The social profiles of residential communities exert differential effects on expectations and demands on urban greenspaces. We studied the diversity of public perception towards urban greenspaces in compact urban Hong Kong. Random household samples were selected from four dominant residential communities: old-core public housing (OP), old-core residential (OR), suburban residential (SR), and new-town public housing (NP). They denote gradations in income, housing quality, physical and social milieu, and development age. Face-to-face interviews were conducted using a structured questionnaire. Residents’ attitude, visiting pattern, greenspace preference, and assessment of neighborhood quality were investigated. SR presented distinctive results in comparison with others. The moderate differences between the remaining three communities were mainly linked to local traits in park environs. OP more emphasized the function of communal places for neighborly interactions associated with better social relationship of an older population. Parks in OR were the more frequently visited, even though its residents were sensitive to the negative impacts of urban greenspaces, which was related to urban blight in the environs. SR respondents highly appreciated greenspaces as pleasant settings for family activities and aesthetic enjoyment. NP residents were less frequent visitors despite generous park provision, due to the youthful population, weak social cohesion, and limited integration of new migrants. Community quality factors such as neighborhood relationship and urban density influenced the perception. Social qualities were more important than the physical aspects of parks in influencing visitorship. The findings suggest future research to deepen understanding of public perception towards urban greenspaces to inform park design.     

城市户外作业人员休息驿站规划建设研究

拟从规划的角度对城市户外作业人员休息驿站的规划建设进行研究,规范休息驿站的建设内容与配置标准,为此类设施的建设提供规划指导与技术支撑,并以合肥市蜀山区西部新城为例进行实证分析,以期能够为相关部门提供参考。     

Introduction to the special issue The regional and urban effects of high-speed trains

High-speed trains could be used to solve two different accessibility problems. In the first case, where a point to point link is dominant, they are a potential substitute for air travelling. In the second case it links together many cities and, hence, creates a new type of region or corridor with a high interregional accessibility. One important hypothesis for the discussion in this paper is the degree to which cities that are linked together into a band of cities by means of a high-speed train connection are transformed to an extended functional region or in other words an integrated corridor economy. This paper particularly examines economic integration in a corridor economy in the short, medium and long term. In considering the short-term perspective we discuss not only the integration of goods and service markets but also the integration of labour markets and markets for shopping, private services and leisure activities. The discussion of the medium term perspective is concentrated on the relocation of households and firms within a high-speed train corridor. To study the long-term integration effects of a high-speed train corridor we maintain that the analysis must be conducted using a genuinely dynamic model for the specialisation of production and, hence, for trade with and transport of goods and services and consequently transport of people. Received: December 1996 / Accepted: January 1997     

城市裸土地景观生态效应研究

研究了城市裸土地的分类、景观生态效应和景观生态修复方法,将其划分为季节性裸土地、点状裸土地和面状裸土地三个类别,探讨其对城市景观、生物多样性、环境质量和人体健康等的负面效应,提出了植物种植、有机无机物覆盖和硬质铺装等景观生态修复方法。     

Exposure and effects assessment of persistent organohalogen contaminants in arctic wildlife and fish

Persistent organic pollutants (POPs) encompass an array of anthropogenic organic and elemental substances and their degradation and metabolic byproducts that have been found in the tissues of exposed animals, especially POPs categorized as organohalogen contaminants (OHCs). OHCs have been of concern in the circumpolar arctic for decades. For example, as a consequence of bioaccumulation and in some cases biomagnification of legacy (e.g., chlorinated PCBs, DDTs and CHLs) and emerging (e.g., brominated flame retardants (BFRs) and in particular polybrominated diphenyl ethers (PBDEs) and perfluorinated compounds (PFCs) including perfluorooctane sulfonate (PFOS) and perfluorooctanic acid (PFOA) found in Arctic biota and humans. Of high concern are the potential biological effects of these contaminants in exposed Arctic wildlife and fish. As concluded in the last review in 2004 for the Arctic Monitoring and Assessment Program (AMAP) on the effects of POPs in Arctic wildlife, prior to 1997, biological effects data were minimal and insufficient at any level of biological organization. The present review summarizes recent studies on biological effects in relation to OHC exposure, and attempts to assess known tissue/body compartment concentration data in the context of possible threshold levels of effects to evaluate the risks. This review concentrates mainly on post-2002, new OHC effects data in Arctic wildlife and fish, and is largely based on recently available effects data for populations of several top trophic level species, including seabirds (e.g., glaucous gull (Larus hyperboreus)), polar bears (Ursus maritimus), polar (Arctic) fox (Vulpes lagopus), and Arctic charr (Salvelinus alpinus), as well as semi-captive studies on sled dogs (Canis familiaris). Regardless, there remains a dearth of data on true contaminant exposure, cause-effect relationships with respect to these contaminant exposures in Arctic wildlife and fish. Indications of exposure effects are largely based on correlations between biomarker endpoints (e.g., biochemical processes related to the immune and endocrine system, pathological changes in tissues and reproduction and development) and tissue residue levels of OHCs (e.g., PCBs, DDTs, CHLs, PBDEs and in a few cases perfluorinated carboxylic acids (PFCAs) and perfluorinated sulfonates (PFSAs)). Some exceptions include semi-field studies on comparative contaminant effects of control and exposed cohorts of captive Greenland sled dogs, and performance studies mimicking environmentally relevant PCB concentrations in Arctic charr. Recent tissue concentrations in several arctic marine mammal species and populations exceed a general threshold level of concern of 1 part-per-million (ppm), but a clear evidence of a POP/OHC-related stress in these populations remains to be confirmed. There remains minimal evidence that OHCs are having widespread effects on the health of Arctic organisms, with the possible exception of East Greenland and Svalbard polar bears and Svalbard glaucous gulls. However, the true (if any real) effects of POPs in Arctic wildlife have to be put into the context of other environmental, ecological and physiological stressors (both anthropogenic and natural) that render an overall complex picture. For instance, seasonal changes in food intake and corresponding cycles of fattening and emaciation seen in Arctic animals can modify contaminant tissue distribution and toxicokinetics (contaminant deposition, metabolism and depuration). Also, other factors, including impact of climate change (seasonal ice and temperature changes, and connection to food web changes, nutrition, etc. in exposed biota), disease, species invasion and the connection to disease resistance will impact toxicant exposure. Overall, further research and better understanding of POP/OHC impact on animal performance in Arctic biota are recommended. Regardless, it could be argued that Arctic wildlife and fish at the highest potential risk of POP/OHC exposure and mediated effects are East Greenland, Svalbard and (West and South) Hudson Bay polar bears, Alaskan and Northern Norway killer whales, several species of gulls and other seabirds from the Svalbard area, Northern Norway, East Greenland, the Kara Sea and/or the Canadian central high Arctic, East Greenland ringed seal and a few populations of Arctic charr and Greenland shark.     

Observations on renal function in workers exposed to lead

Renal function was studied in 40 workers chronically exposed to lead at a smelter. The geometric means of lead were 40 (range 24.0 - 63.0) micrograms/dl in blood and 47 (range 19 - 115) micrograms/g creatinine or 71 (range 20 - 250) micrograms/l in urine, respectively. There were no significant differences between the lead-exposed group and a control group in the concentrations of beta 2-microglobulin in serum, urinary total protein and IgG, whereas the level of beta 2-microglobulin in urine was significantly higher in the lead-exposed group (p less than 0.01). No individual lead worker showed abnormally increased level of urinary beta 2-microglobulin. The significance of increased excretion of beta 2-microglobulin on the basis of the group remains to be elucidated.     

Changing family systems in Ghana and its effects on access to urban rental housing: a study of the Offinso Municipality

Individualization of the family system in Ghana has implications for residential housing access particularly in urban areas. In this paper, the authors examined the effects of the changing family system on access, demand and supply of rental housing. The cross-sectional study design was adopted with Offinso Municipality as a case study. Through a multi-stage sampling approach, structured and unstructured questionnaires were used to collect data from 100 renters and 100 landlords. Findings revealed a reduction in the supply of rental housing while increasing demand as a result of the changing family system. Rental housing prices were also found to have increased by 86.17% between the years 2010 and 2015. Findings from the study based on preferences of new family systems for privacy and comfort are also likely to address the problem of scarcity of rental housing and associated escalating rental housing prices .     

Large-eddy simulation of wind effects on a super-tall building in urban environment conditions

A combined study of large-eddy simulation (LES), wind tunnel testing and full-scale measurement is conducted for the evaluation of wind effects on a super-tall building in a complex urban area. To validate the numerical simulations, the wind tunnel experiments including synchronous multi-pressure and high-frequency force balance model tests are conducted in a boundary layer wind tunnel laboratory. The numerical predictions are then compared with the experimental results, demonstrating that the LES can provide comparable predictions of the wind effects on the super-tall building. Furthermore, the cross-validation of the predicted displacement responses by the LES against the wind tunnel and full-scale measurements are presented and the agreement among them is reasonably good. The main objective of this study is to explore an effective numerical approach for the accurate estimation of wind effects on tall buildings in urban environment conditions and promote the practical use of the LES in the wind-resistant design of complex structures.     

Natural amenities and their effects on migration along the urban–rural continuum

The importance of natural amenities in promoting development and population change has been addressed in a large body of literature with recent studies identifying rather obvious spatial heterogeneity in the effects of natural amenities on migration. This said, the potential variation along the urban–rural continuum has not been addressed empirically. In this study, we examine and compare the migration effects of natural amenities in five specific urban–rural continuum types at the minor civil division level in the US state of Wisconsin. Results of spatial analysis suggest that natural amenities do indeed have differing effects on migration along this urban–rural continuum. Overall, natural amenities have the largest effect on in-migration into rural areas adjacent to metro areas and no effect on in-migration into urban areas. The effects of natural amenities on in-migration into remote rural areas rely more on growth trends within these regions. These findings have important implications for rural development, land use policy, and natural resource management.