The residential, area-specific prevalence and associated factors of suicidal ideation among South Korean adolescents.

Objectives: This study investigated the residential, area-specific prevalence and associated factors of suicidal ideation among adolescents in South Korea, based on nationally representative data. Methods: A secondary analysis was performed using the database of the 17th Korean Youth Health Behavior Survey, which contained data from 54,848 adolescents. Results: Female adolescents (more influential in counties), low economic status (more influential in metropolitan cities), perceived stress (more influential in metropolitan cities), depression (more influential in counties), loneliness (more influential in counties), and anxiety (more influential in counties) were influencing factors in all areas, and the factors associated with suicidal ideation differed by residential area. The factors related to suicidal ideation were similar by residential area, but the degree of relevance differed from area to area; in particular, the prevalence of variables related to mental health (depression, loneliness, and anxiety) was high in counties. Alcohol drinking was significant only in small- and medium-sized cities in terms of suicidal ideation. Conclusion: Suicide prevention programs for adolescents should be implemented given the higher incidence of suicidal ideation among female adolescents, the greater influence of mental health-related variables in counties, and the influence of smoking in cities. There were differences in the prevalence and risk factors of suicidal ideation by residential areas.

Improving the green space arrangement in residential areas from the perspective of tree leaf temperature utilizing scenario simulation in ENVI-met.

Studying the differences in leaf temperature and their mechanisms can help us accurately understand the microenvironment in which plants are located. In this paper, typical residential areas in Jianye District, Nanjing, Jiangsu Province, China, are selected as the research area, we investigated the suitability of green space configurations from the perspective of tree leaf temperature of residential areas based on the scenario simulation in ENVI-met. Firstly, twenty abstract models were constructed, including four kinds of aspect ratio of trees (ARTs) which can be used to indicate the different green space arrangement and two typical tree species, camphora tree and platanus tree. And then three aspects were discussed including impacts of different Aspect Ratio of Trees (ART), different house-side configurations on tree leaf temperature and the relationship between temperature of tree leaves and land surface temperature (ΔSurfT) and the thermal comfort index of physiological equivalent temperature (ΔPET). The results showed that B-1 (camphor tree, ART = 2) demonstrates the most effective cooling effect in summer, with ΔPET of 3.09 °C and ΔSurfT of 3.34 °C. In winter, A-1 (platanus tree, ART = 2) proves to be the most effective in enhancing thermal comfort (ΔPET = -0.15 °C), while B-1 excels in improving surface temperature (ΔSurfT = 0.55 °C). In all, for residential area, especially in summer, planting dense camphora trees is better than platanus trees and house-side green space was very necessary. This research can help to determine appropriate tree species and green space configuration strategies for future residential areas to enhance thermal comfort.

Regulation on air temperature by residential area morphology: A case study in Xuzhou City, China.

Due to woodlands and farmlands being replaced by residential areas in cities, continuous urbanization resulting in frequent urban heat island effects, especially in summer when high temperature seriously threaten health and lives of citizens. Although scientists realized that reasonable residential area morphology could effectively regulate air temperature and improve microclimate, it is lack of air temperature regulation-oriented specifications and requirements on morphology of residential areas. In this study, we used three types of morphological parameters of 15 residential areas in Xuzhou City and air temperature data via field investigation to analyze air temperature regulation caused by residential area morphology. The results showed that key morphological parameters of residential areas were different in morning and afternoon. In morning, independent effects of mean building height, street aspect ratio, and complete aspect ratio contributed 15.4%, 7.3%, and 6.8%, while those of building density, sky view factor, and the ratio of building surface area to floor area were 21.1%, 23.1%, and 6.9% in afternoon, respectively. Threshold values of efficiency of morphological parameters of residential areas were different between morning and afternoon. There were significant correlations between some morphological parameters of residential area. The results could provide data support and methodological reference for residential areas design in Xuzhou and surrounding cities.

Spatial factors for COVID-19 associated community deaths in an urban area of Lusaka, Zambia: an observational study.

We retrospectively analyzed spatial factors for coronavirus disease 2019 (COVID-19)-associated community deaths i.e., brought-in-dead (BID) in Lusaka, Zambia, between March and July 2020. A total of 127 cases of BID with geocoordinate data of their houses were identified during the study period. Median interquartile range (IQR) of the age of these cases was 49 (34-70) years old, and 47 cases (37.0%) were elderly individuals over 60 years old. Seventy-five cases (75%) of BID were identified in July 2020, when the total number of cases and deaths was largest in Zambia. Among those whose information regarding their underlying medical condition was available, hypertension was most common (22.9%, 8/35). Among Lusaka's 94 townships, the numbers (median, IQR) of cases were significantly larger in those characterized as unplanned residential areas compared to planned areas (1.0, 0.0-4.0 vs 0.0, 0.0-1.0; p=0.030). The proportion of individuals who require more than 30 minutes to obtain water was correlated with a larger number of BID cases per 105 population in each township (rho=0.28, p=0.006). The number of BID cases was larger in unplanned residential areas, which highlighted the importance of targeted public health interventions specifically to those areas to reduce the total number of COVID-19 associated community deaths in Lusaka. Brought-in-dead surveillance might be beneficial in monitoring epidemic conditions of COVID-19 in such high-risk areas. Furthermore, inadequate access to water, sanitation, and hygiene (WASH) might be associated with such distinct geographical distributions of COVID-19 associated community deaths in Lusaka, Zambia.

Relevance of Soil Heavy Metal XRF Screening for Quality and Landscaping of Public Playgrounds.

Heavy metals have become widespread urban pollutants, exposing vulnerable age groups such as children to potential risk. Specialists need feasible approaches that can routinely assist them in customizing options for sustainable and safer urban playgrounds. The aim of this research was to explore the practical relevance of the X-ray Fluorescence (XRF) method from the perspective of landscaping specialists, and the practical significance of screening for those heavy metals that currently present elevated levels across urban environments Europe-wide. Soil samples from six public children's playgrounds of different typologies from Cluj-Napoca, Romania, were analyzed. The results indicated that this method was sensitive to identifying thresholds stipulated in legislation for the screened elements (V, Cr, Mn, Ni, Cu, Zn, As, and Pb). Coupled with the calculation of pollution indexes, this method can serve as a quick orientation in landscaping options for urban playgrounds. The pollution load index (PLI) for the screened metals showed that three sites displayed baseline pollution with incipient deterioration in soil quality (PLI = 1.01-1.51). The highest contribution to the PLI among the screened elements, depending on the site, was due to Zn, Pb, As, and Mn. The average levels of the detected heavy metals were within admissible limits according to national legislation. Implementable protocols addressed to different categories of specialists could help to transition towards safer playgrounds and more research on accurate cost-effective procedures to overcome the limitations of existing approaches is currently needed.

Active school transport routines during school transitions: Socio-structural predictors of changes from childhood into early adulthood.

The purpose of this study is to investigate socio-structural predictors of active school transport (AST) change and to explore the stability and changes of transport modes during school transitions and into early adulthood in Germany. School transport mode, urbanicity level, socioeconomic status, and migration background were assessed in 624 children (8.9 ± 1.1 years, 51% female) and 444 adolescents (14.9 ± 1.7 years, 48% female) which were followed up longitudinally six years later. The results of multinomial logistic regressions and transition probability calculations indicated that residing outside of rural areas at baseline and follow-up predicts retaining or switching to AST in adolescence. Similarly, higher socioeconomic status at baseline predicted retaining or switching to AST in early adulthood. This research suggests that transition periods are crucial understanding AST behavior and may provide new opportunities for tailored AST promotion programs for different age groups.

Examining the association between the built environment and active travel using GPS data: A study of a large residential area (Daju) in Shanghai.

Automobile dependence and physical inactivity have become common health challenges for residents in large suburban residential areas. Limited literature has examined the associations between the built environment and active travel in such residential areas and the differences in these associations among residents from different neighborhoods. To avoid inaccurate results potentially derived from residence-based measures, we adopt a mobility-based approach for environmental exposure assessment. Using GPS data from 530 trips made by 98 participants in a large residential area in Shanghai, we investigate the relationships between neighborhood types, pollution perceptions, built environment features and active travel. The results indicate that residents in affordable and relocation housing make fewer active trips than those in market-rate housing, while the built environment seems to mitigate this difference. Sports facilities promote active travel while commercial facilities and road intersections discourage it. We identify significant interactions between the percentage of green space and neighborhood type, as well as floor area ratio and air pollution perception. Interventions promoting active travel include active-travel-friendly design for commercial facilities and road intersections, the provision of more sports facilities, a careful increase in floor area ratio, and the provision of more green space that is attractive to residents from different neighborhoods.

Analysis of Landscape Characteristics and Influencing Factors of Residential Areas on the Qinghai-Tibet Plateau: A Case Study of Tibet, China.

The Qinghai-Tibet Plateau is the largest ecological barrier and one of the most vulnerable areas of the ecological environmental system. However, the increasing frequency of human activities in the Qinghai-Tibet Plateau has led to strong interference. Residential areas are the main places in which human activities are carried out and, as such, can effectively reflect the intensity of activities. Based on this, this research takes the Tibet Autonomous Region as the study area and analyzes the distribution characteristics of Tibetan residential areas using Zipf's law and various landscape indices, as well as discussing the influences of altitude, hydrology, ecological environment, and location on residential area distribution. The obtained results indicate the following: (1) The residential areas in Tibet basically conform to the rank-size principle. The residential areas in central and northwest Tibet are concentrated in size distribution, and the relatively large residential areas are prominent, while the residential areas in the eastern Hengduan mountain region are relatively balanced in size distribution. (2) The landscape index results demonstrate that the counties with an unbalanced distribution of residential areas are mainly concentrated in the northwest of Tibet, while the residential areas in the counties and regions where the administrative stations of each prefecture-level city (or region) are located tend to present a polarization phenomenon, with large patches. The area distribution of residential areas showed a "medium-high-low" pattern from southeast to northwest. The residential areas in eastern Tibet have a high degree of fragmentation and a low degree of aggregation, while the residential areas in northwest Tibet have a low degree of fragmentation and a relatively high degree of aggregation. (3) The residential areas in Tibet are most concentrated in the altitude range of 3000-5000 m above sea level and their water affinity and road-affinity are strong, with the distribution of residential areas within 500 m of roads and water networks accounting for more than one-quarter. The vegetation coverage in the residential areas is low, inconsistent with the surface vegetation coverage rate over the whole of Tibet.

Resident Satisfaction of Urban Green Spaces through the Lens of Landsenses Ecology.

Residents' satisfaction of urban green space has been widely detected in living environments around the world. Most previous reports were performed with objective indicators to reflect the characteristics of vegetation and landscapes of residential green space. However, subjective senses as impact factors in the evaluation of residents' satisfaction based on landsenses ecology are scarce. To address this, in this study, physical perception, aesthetic cognition, and psychological cognition as latent variables in a structural equation model were investigated to determine the residents' satisfaction in Xiamen, in southeast China, a famously high green space coverage region. The results indicate that physical perception is the fundamental condition to improve residents' satisfaction, while aesthetic cognition and psychological cognition are the direct factors that influenced residents' satisfaction. Residents exhibit a preference for the residential green space which contains more biodiversity and landscape diversity, a higher biomass, and greater openness. In addition, the residents' perception significantly related to greenspace characteristics. The results provide a scientific basis for urban green space planning and optimization of ecological resources' allocation.

The Built Environment Assessment of Residential Areas in Wuhan during the Coronavirus Disease (COVID-19) Outbreak.

The COVID-19 epidemic has emerged as one of the biggest challenges, and the world is focused on preventing and controlling COVID-19. Although there is still insufficient understanding of how environmental conditions may impact the COVID-19 pandemic, airborne transmission is regarded as an important environmental factor that influences the spread of COVID-19. The natural ventilation potential (NVP) is critical for airborne infection control in the micro-built environment, where infectious and susceptible people share air spaces. Taking Wuhan as the research area, we evaluated the NVP in residential areas to combat COVID-19 during the outbreak. We determined four fundamental residential area layouts (point layout, parallel layout, center-around layout, and mixed layout) based on the semantic similarity model for point of interest (POI) picking. Our analyses indicated that the center-around and point layout had a higher NVP, while the mixed and parallel layouts had a lower NVP in winter and spring. Further analysis showed that the proportion of the worst NVP has been rising, while the proportion of the poor NVP remains very high in Wuhan. This study suggested the need to efficiently improve the residential area layout in Wuhan for better urban ventilation to combat COVID-19 without losing other benefits.

Estimating accumulation rates and health risks of PAHs in residential soils of metropolitan cities.

Predicting temporal changes in PAH concentrations in urban soils and their corresponding health risk is essential for developing appropriate management measures to prevent those risks. Concentrations of PAHs in soils of residential areas with different building ages in three metropolitan cities were determined to estimate the accumulation rates of PAHs in soil. The mean concentrations of total PAHs (∑PAHs) were 1297 ng/g in Shanghai, 865 ng/g in Beijing, and 228 ng/g in Shenzhen. The primary sources of the PAHs were traffic and coal combustion for industrial activity and space heating. The high PAH concentrations in Shanghai were attributed to the relatively high average building age of the sampled residential areas and the low annual temperature in the city. The overall annual accumulation rates of PAHs in the soils were estimated from linear regressions between the PAH concentrations and building age of the residential areas. The annual accumulation rate of PAHs in the soils was 64.7 ng/g in Beijing, 24.2 ng/g in Shanghai, and 3.3 ng/g in Shenzhen. The higher rate in Beijing was due to the higher intensity of PAH emissions and the lower temperature. The regression estimations suggest that health risks posed by PAHs in residential soils of the metropolitan cities increase considerably with time.

Source identification and health risk assessments of heavy metals in indoor dusts of Ilorin, North central Nigeria.

Background and Purpose: Exposure to heavy metals (HMs) in indoor dusts is a serious public concern that is linked to a myriad of deleterious health outcomes. The objectives of this study are to estimate the contamination levels of HMs in indoor dusts of different residential areas in Ilorin, Nigeria; identify HMs sources in different residential areas; and evaluate human health risks of HMs in selected residential areas. Methods: Indoor dust sampling was conducted in ten randomly selected from low, medium and high population density residential areas of Ilorin, Nigeria. Ten HMs concentration levels, their health risk implication and the associated potential ecological risks were evaluated. Results: The mean concentration levels measured for Fe, Pb, Zn, As, Co, Cr, Cu, Cd, Mn and Ni were 38.99, 5.74, 3.99, 0.08, 2.82, 2.13, 0.47, 0.60, 6.45 and 1.09 mg/kg, respectively. Positive Matrix Factorization (PMF) model was applied to ascertain sources of HMs in sampled indoor dust. Percentage contribution from oil-based cooking (29.82%) and transportation (29.77%) represented the highest source to HM concentrations among the six factors identified. The results of the various pollution indices employed showed that Pb, Zn, As, Co, Cr, Cu, Mn and Ni contributed moderately to HMs concentration levels in the sampled dusts. Cd had highest potential ecological risk factor E r i of between 160 and 320. The average values of Enrichment Factors (EFs) obtained aside from Fe used as the reference metal, ranged between 8.46 (As) and 2521.61(Cd). Health risk assessment results revealed that children are the most susceptible to the risks associated with HMs bound indoor dust than the adults. The percentage risk contributions of Hazard Quotient via ingestion route (HQing) in Hazard Index (HI) for non-cancer risk of indoor HMs were 93.17% and 69.87% in children and adults, respectively. Likewise, the percentage cancer risks contribution through ingestion pathway (CRing) were higher than cancer risks through inhalation and dermal pathways (CRinh and CRdermal), accounting for 99.84% and 97.04% of lifetime cancer risk in children and adults, respectively. The contamination level of Cd recorded is of great concern and signifies very strong contribution from anthropogenic sources. Conclusion: This study has further revealed the levels of HMs in typical African residential settings that could be used by relevant stakeholders and policy makers in developing lasting control measures. Supplementary Information: The online version contains supplementary material available at 10.1007/s40201-021-00778-8.

Health Risk Assessment for the Residential Area Adjacent to a Former Chemical Plant.

A health risk assessment was carried out for the residents of Legnowo-Wies settlement adjacent to a former Zachem Chemical Plant, Bydgoszcz, Poland. Due to the unique Zachem site history and contamination profile, an innovative strategy for soil sampling and contaminant selection was applied. The novelty in the developed strategy consisted of selecting substances for the health risk assessment, taking into consideration the location and boundaries of the groundwater contamination plumes in relation to contamination sources. This allowed limiting the number of the analysed contaminants. The risk assessment focused on the surface soil of a residential area, which was divided into 20 sampling sectors and 6 backyards with wells from which water was used for watering edible plants. A total of 80 inorganic and organic substances were determined, including metals, phenol, aniline, BTEX, diphenyl sulphone, chloroaniline, epichlorohydrin, hydroxybiphenyl, nitrobenzene, octylphenols, toluenediamine, toluidine, 16 polycyclic aromatic hydrocarbons, tetrachloroethylene and trichloroethylene. For the health risk assessment, the United States Environmental Protection Agency's deterministic method was applied. This applies conservative assumptions to obtain risk estimates protective for most of the potential receptors. Three exposure pathways were analysed: (1) incidental soil ingestion, (2) dermal contact with soil and (3) inhalation of fugitive soil particles and volatiles. In all sampling sectors and backyards, the total non-cancer risks (hazard index) were significantly lower than the acceptable level of 1. The acceptable cancer risk level for the single carcinogen of 1 × 10-5 was only insignificantly exceeded in the case of benzo(a)pyrene in three sectors and one backyard. The total cancer risks were lower than the acceptable level of 1 × 10-4 in all sampling sectors and all backyards. The findings show that the soil in the entire residential area is safe for the residents' health and no remedial actions are required. However, since not all possible exposure pathways were analysed in this study, further research focused on assessing the health risk resulting from the consumption of locally grown food is strongly recommended.

Bioaerosol exposure by farm type in Korea.

INTRODUCTION AND OBJECTIVE: Bioaerosols exist in almost every environment and are known to be risk factors for a variety of diseases. Agricultural work involves high exposure to bioaerosols and its workplace concentrations affect the surrounding areas. The study evaluates bioaerosol concentrations in agricultural workplaces and residential areas according to farm type. MATERIAL AND METHODS: In 2013-2015, a total of 381 samples were collected for endotoxin and microbial testing from three farm types: open field, greenhouse, and livestock facilities. Endotoxins were measured using a 37-mm glass fire filter connected to an air pump calibrated to 2 LPM. Microorganisms were measured using a gelatin filter and impaction (single-stage Andersen sampler). RESULTS: The concentration of endotoxins and microorganisms at the livestock facilities was significantly higher than in the open fields and greenhouses (p<0.05). Among the livestock farms, the concentrations of endotoxins and gram-negative bacteria were highest at hog farms, and the concentrations of total bacteria and fungi were the highest in poultry houses. In both greenhouses and livestock facilities, the concentrations of bioaerosols were higher in the workplace than in a nearby residential area, and the difference in concentration was significantly greater in the case of livestock facilities. CONCLUSIONS: The concentrations of bioaerosols in agricultural workplaces and nearby residential areas were higher than in the control and general areas. Therefore, measures should be taken to prevent exposure to bioaerosols at agricultural workplaces and their vicinities.

Using multiple isotopes to identify sources and transport of nitrate in urban residential stormwater runoff.

Increased nitrogen (N) from urban stormwater runoff aggravates the deterioration of aquatic ecosystems as urbanisation develops. The sources and transport of nitrate (NO3-) in urban stormwater runoff were investigated by analysing different forms of N, water isotopes (δD-H2O and δ18O-H2O), and NO3- isotopes (δ15N-NO3- and δ18O-NO3-) in urban stormwater runoff in a residential area in Hangzhou, China. The results showed that the concentrations of total N and nitrate N in road runoff were higher than those in roof runoff. Moreover, high concentrations of dissolved organic N and particulate N led to high total nitrogen (TN) concentrations in road runoff (mean: 3.76 mg/L). The high δ18O-NO3- values (mean: + 60 ± 13.1‰) indicated that atmospheric deposition was the predominant NO3- source in roof runoff, as confirmed by the Bayesian isotope mixing model (SIAR model), contributing 84-98% to NO3-. Atmospheric deposition (34-92%) and chemical fertilisers (6.2-54%) were the main NO3- sources for the road runoff. The proportional contributions from soil and organic N were small in the road runoff and roof runoff. For the initial period, the NO3- contributions from atmospheric deposition and chemical fertilisers were higher and lower, respectively, than those in the middle and late periods in road runoff during storm events 3 and 4, while an opposite trend of road runoff in storm event 7 highlighted the influence of short antecedent dry weather period. Reducing impervious areas and more effective management of fertiliser application in urban green land areas were essential to minimize the presence of N in urban aquatic ecosystems.

Relative contributions of different local sources to riverborne microplastic in a mixed landuse area within a tropical catchment.

Information on the relative contributions of microplastics coming from different sources is important to help prioritise measures to reduce river contamination levels and limit human and ecological health risks. This paper reports on work which aimed to quantitatively assess the relative concentrations and types of microplastic delivered from differed sources to a second order river. The study was undertaken in a mixed landuse area within a rapidly urbanising catchment in Malaysia. Over a six-week period, water samples were collected from road culverts and drains in residential and industrial areas across the area to assess microplastic concentrations, while inputs from atmospheric deposition and wastewater treatment plants (WWTPs) were also quantified. Microplastic fibres and fragments were the dominant material in all sources, with the majority consisting of styrene-butadiene rubber and nylon. Culverts draining main roads were the main contributor to riverborne microplastic, delivering 42.20 ± 35.29 particles/L directly to the river channel. Road inputs were up to seven times greater than those from residential (8.53 ± 9.91 particles/L) and industrial (5.67 ± 4.88 particles/L) areas. The five WWTPs had removal efficiencies of between 30.95 ± 5.51% and 69.94 ± 22.17%, with their outflows delivering microplastics to the river in concentrations similar to those in uncontrolled residential and industrial drains. Atmospheric deposition across the study area was estimated to be 76.07 ± 32.85 particles/m2/day (=8.35 ± 5.11 particles/L). Mitigation strategies in the study area should focus on improving management of water draining roads, and re-routing discharges from domestic and industrial areas to WWTPs rather than allowing them to flow directly to the river. The low efficiencies of some of the WWTPs are not unusual, and indicate the need for additional water treatment to deal with microplastic present in wastewater.

Association between exposure level of air pollutants and incidence rate of circulatory disease in residential and industrial areas of South Korea.

This study investigated the correlation between the concentration of air pollutants in two metropolitan cities, Seoul and Incheon, located in South Korea with different urban characteristics and the number of patients with circulatory diseases among residents exposed to air pollution. The residential area was selected as Eunpyeong-gu of Seoul Metropolitan City and the industrial area as Jung-gu of Incheon Metropolitan City. The evaluation period is between 2015 and 2016. The relevant data provide by the Korea governmental agency were analysed to derive the purpose of this study. It was confirmed that PM10, PM2.5, nitrogen dioxide, carbon monoxide, and sulfur dioxide among air pollutants had an increasing impact on the incidence rate of circulatory diseases. The PM2.5 was positively correlated with the incidence rate of all circulatory diseases in residential area (p < 0.05). The carbon monoxide showed a positive correlation with circulatory system diseases except for hypertension in residential area. (p < 0.05). The sulfur dioxide was positively correlated with all circulatory diseases in both residential and industrial area (p < 0.05). Based on the results obtained from this study, it was found that there are different types of air pollutants that affect circulatory diseases in residential and industrial areas.

Distribution and density of Aedes albopictus in Jiading District of Shanghai in 2020 / 上海预防医学

Objective To determine the seasonal fluctuation and population distribution of Aedes albopictus in Jiading District， and provide scientific evidence for the prevention and control of dengue fever and other Aedes-borne diseases. Methods In 2020， the mosq-ovitrap method and mosq-ovitrap index （MOI） were used to monitor and evaluate the density of Aedes albopictus in Jiading District. Spatial and temporal distribution of Aedes albopictus was determined. Chi-square test was used for statistical analysis. Results In 2020， the annual average MOI was determined to be 4.10， which was under safety threshold. The seasonal fluctuations showed a unimodal distribution， which peaked in July. The fluctuation trend in urban area was similar to the overall trend， while that in the non-urban area showed a bimodal distribution with peaks in June and August. The density of Aedes albopictus at different monitoring sites varied widely，with the highest MOI （6.64） at Anting town and the lowest MOI （2.09） at Huating town. The distribution of Aedes albopictus in different habitats also varied widely； the highest density was observed in environments as waste collection stations and construction sites， with the highest MOI 33.33 in waste collection stations in peak season. The MOI value of Aedes albopictus in residential areas was significantly higher than that in non-residential areas （χ2 = 6.082， P = 0.014）. Conclusion Aedes albopictus is quite common in Jiading District. In certain areas， Aedes density may exceed the safety threshold from May to September. More targeted mosquito control measures should be implemented in waste collection stations， construction sites and residential areas.

Spatial distribution, pollution level, and health risk of Pb in the finer dust of residential areas: a case study of Xi'an, northwest China.

The spatial distribution, pollution level, and exposure risk of Pb in the finer dust (particle size < 63 µm) of residential areas in Xi'an, northwest China were investigated in this study. Geographical information systems and geodetector methods were used to analyze the spatial variability of Pb content in the finer dust of Xi'an and its forming mechanism. The enrichment factor was used to assess the extent of Pb pollution, and the hazard index was used to evaluate the health risks to children and adults exposed to Pb. The results showed that the average content of Pb in the finer dust of residential areas in Xi'an was 99.9 mg kg-1. In the Xi'an urban area, a higher Pb content was mainly found in the finer dust near the Second Ring Road of Xi'an City, and the Pb content in the old town of Xi'an City was relatively lower than that near the Second Ring Road. The results of geodetector analysis indicate that the spatial variability of Pb in the finer dust of the Xi'an urban area was primarily controlled by the interaction among vehicle emissions, daily behavior of residents, and industrial emissions. Pb in the finer dust from residential areas in all districts showed moderate enrichment. The non-cancer risks of Pb in the finer dust were within the safe range for both children and adults. However, the prolonged exposure risk of Pb in the finer dust of residential areas should be considered for children.

Environmental and economic cost-benefit comparison of sponge city construction in different urban functional regions.

This study conducts a life cycle environmental and economic quantification comparison of urban runoff source control facilities (URSCFs) through construction and operation stages in two urban functional regions (i.e., residential area and campus). From the environmental perspective, URSCFs construction in residential area has both higher environmental impacts and benefits than that in campus. The operation stage of URSCFs can observe significant benefit for both residential area and campus. We then develop a set of monetized method to make a comprehensive benefit evaluation (i.e., environmental, economic, and social benefit) of URSCFs. Overall, the two areas have payback time less than thirteen years for their investment which is acceptable when compared with the assumed total service period (30 years). Specifically, the payback time of campus is 5.62 years and residential area is 12.44 years. This implies that the campus has great potential to achieve high cost-benefit ratio and thus the Sponge City construction in campus can implement URSCFs with less engineering and material consumption due to its more spacious site than residential area with high building density. For both residential area and campus, permeable pavement has the highest environmental impact and economic cost because of the concrete consumption. Thus, we recommend that it should be cautious of the construction of concrete permeable pavement and find environmentally and economically alternatives in future URSCFs projects.