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Urban rail development can increase land value, reduce commute time, and increase accessibility, as reported in the literature. However, little is known about the impact of opening urban rail transit stations on people's sentiment, particularly in the context of large metropolises where population density is significantly high. This paper investigates such impact by studying six new transit stations opened in Hong Kong. People's sentiment and activity in station nearby areas are estimated by tweet sentiment and tweet activity. We use the difference-in-difference model to study the impact of opening new transit stations. Tweet sentiment, tweet activity, tweet content, and footprints of people who visit the station-influenced area ‘before and after’ the opening of transit stations are analyzed. The results suggest that, in general, the introduction of transit stations causes a positive change in tweet activity, and the change is statistically significant after six months. Regarding tweet sentiment, new transit stations tend to pose a mixed effect in a short-term, a positive influence on areas with high-density residential places, yet a negative influence on areas with a large proportion of nature reserve areas. These short-term effects, positive or negative, become not significant in the long term (after twelve months). Our analysis also confirmed that the introduction of new transit stations increased accessibility from (to) other parts of the city to(from) the station's nearby area, which was shown by the expanded locations sustaining users visited. These findings indicate that the urban rail transit system in Hong Kong promotes more active neighborhoods yet does not always promotes positive influence on people's sentiment. Further studies are needed to make future urban rail transit systems promoting active and happy neighborhoods. The study is relevant to the Belt and Road Initiative (BRI) in methodologies, data, and findings. The social media analysis method used in this study, including text mining and sentiment analysis, can be easily extended to multiple language analysis for Singapore, Malaysia, as well as other regions in the belt and road plan. The developed tools could contribute to analyzing the influence of cross-country projects on local neighborhoods in the belt and road plan.

Background Cowpea (Vigna unguiculata L. Walp.) is an economically important crop. It is nutritious and popular with consumers. However, it has been listed as one of the agricultural products of critical concern about safety in China and cyromazine is the major risk factor. Objectives This study analyzed the dissipation and permeation kinetics of cyromazine residue in cowpea, to offer a scientific basis for the rational use of pesticide and ensure the safety of agricultural products. Materials and methods The dissipation and residue level of the systemic insecticide cyromazine on cowpea under field and stored conditions were investigated. Subsequently, the spatial distribution of cyromazine was studied using mass spectrometry imaging to visualize the dynamic processes of permeation and migration in the tissues post pesticide application. Results The dissipation processing of cyromazine in cowpea was shown to follow the first-order kinetics and half-life was 7.76 d in the field. In cowpea, the permeation and migration rate of cyromazine was faster than that in kidney beans and accumulation was mainly in the pulp. It is not safe to apply cyromazine to cowpeas with reference to the application method on kidney beans. Conclusions These findings present vital data for the determination of risks linked with cowpea consumption and pesticide intake.

Trees provide cooling benefits through shading and evapotranspiration; they are regarded as an important measure in heat-resilient urban planning and policies. Knowing where to plant trees for maximum cooling benefits, given practical and resource constraints, remains a challenge in both practice and research. Literature in the field of tree modelling and location optimization is limited, either by the incompleteness in accounting for tree shading, evapotranspiration, and the modifying effect of wind, or by the slow-running speed of the Computational Fluid Dynamics model, making them less applicable in practice. This paper describes a novel method to search for the optimal locations for trees to maximize their cooling benefits in an urban environment. A non-CFD simulation model was applied to assess on-site heat stress under the influences of trees, which was evaluated using field measurements conducted under hot, temperate, and cool weather conditions in an urban park in Hong Kong. It was then linked to a genetic algorithm in search of a near-optimal tree layout. The proposed method was tested in the same park, and it can automatically identify locations to plant new trees to minimize heat stress, subject to practical constraints such as avoiding existing buildings and utilities. It can also identify the optimal layout to rearrange the existing 55 trees, hypothetically, which is expected to cool the park (around 30,000 m2) by up to 0.3 ℃ in the site average UTCI equivalent temperature compared with the worse scenario. Trees can cool the most if they are concentrated on the leeward side of the park relative to the prevailing wind, rather than spread evenly. The new method runs significantly faster than existing approaches, and it can inform research and landscape design practices concerning park cooling as a goal.

A green building is believed to promote green behaviors from energy-saving to waste recycling. Green building certifications have attracted wide interest, and some were made mandatory for publicly funded developments in cities such as Hong Kong. Policymakers debate whether the city’s expanding public housing stock should be exempted from the green certification mandate for reasons of cost, while evidence of behavioral benefits in green residential buildings is thin, or non-existent for public housing estates. This paper describes a post-occupancy evaluation study on self-reported green behaviors in Hong Kong’s public housing estates. The study subjects are 400 occupants from two pairs of public rental housing estates with or without green certifications. A natural experiment was conducted, in which surveyed occupants were allocated to certified and uncertified estates via a random lottery, without significant differences in socioeconomic characteristics and propensity to green behaviors a priori. The results show that green-certified housing estates partially induced energy-saving behaviors, but not water saving or waste recycling, nor does it enhance satisfaction or green awareness. A certification alone is insufficient to induce behavioral changes, rather, efforts should be invested in conveying the green message, public education, and appropriate fiscal incentives.

The Delta variant of SARS-CoV-2 has inflicted heavy burdens on healthcare systems globally, although direct evidence on the quantity of exhaled viral shedding from Delta cases is lacking. Literature remains inconclusive on whether existing public health guidance, formulated based on earlier evidence of COVID-19, should respond differently to more infectious viral strains. This paper describes a study on an outbreak of the Delta variant of COVID-19 in an auditorium, where one person contracted the virus from three asymptomatic index cases sitting in a different row. Field inspections were conducted on the configuration of seating, building and ventilation systems. Numerical simulation was conducted to retrospectively assess the exhaled viral emission, decay, airborne dispersion, with a modified Wells-Riley equation used to calculate the inhalation exposure and disease infection risks at the seat level. Results support the airborne disease transmission. The viral emission rate for Delta cases was estimated at 31 quanta per hour, 30 times higher than those of the original variant. The high quantity of viral plume exhaled by delta cases can create a risky zone nearby, which, for a mixing ventilation system, cannot be easily mitigated by raising mixing rates or introducing fresh air supply. Such risks can be reduced by wearing an N95 respirator, less so for social distancing. A displacement ventilation system, through which the air is supplied at the floor and returned from the ceiling, can reduce risks compared with a mixing system. The study has implications for ventilation guidelines and hygiene practices in light of more infectious viral strains of COVID-19.

Aims We estimated the association between outdoor light at night at the residence and risk of coronary heart disease (CHD) within a prospective cohort of older adults in Hong Kong. Methods and results Over a median of 11 years of follow-up, we identified 3772 incident CHD hospitalizations and 1695 CHD deaths. Annual levels of outdoor light at night at participants’ residential addresses were estimated using time-varying satellite data for a composite of persistent night-time illumination at ∼1 km2 scale. We used Cox proportional hazards models to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) of the association between outdoor light at night at the residence and risk of CHD. The association between light at night and incident CHD hospitalization and mortality exhibited a monotonic exposure-response function. An interquartile range (IQR) (60.0 nW/cm2/sr) increase in outdoor light at night was associated with an HR of 1.11 (95% CI: 1.03, 1.18) for CHD hospitalizations and 1.10 (95% CI: 1.00, 1.22) for CHD deaths after adjusting for both individual and area-level risk factors. The association did not vary across strata of hypothesized risk factors. Conclusion Among older adults, outdoor light at night at the residence was associated with a higher risk of CHD hospitalizations and deaths. We caution against causal interpretation of these novel findings. Future studies with more detailed information on exposure, individual adaptive behaviours, and potential mediators are warranted to further examine the relationship between light at night and CHD risk.

Poor housing conditions are known to be associated with infectious diseases such as high Coronavirus disease 2019 (COVID-19) incidences. Transmission causes of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in poor housing conditions can be complex. An understanding of the exact mechanism of transmission can help to pinpoint contributing environmental issues. Here, we investigated a Hong Kong COVID-19 outbreak in early 2021 in four traditional Tong Lau houses with subdivided units. There are more than 80 subdivided units of less than 20 m2floor area each on average. With a total of 34 confirmed COVID-19 cases, the outbreak had an attack rate of 25.4%, being one of the highest attack rates observed in Hong Kong, and ranked among the highest attack rates in reported outbreaks internationally. Tracer gas leakage and decay measurements were performed in the drainage system and in the subdivided units to determine the transport of infectious aerosols by the owner-modified sophisticated wastewater drainage pipe networks and the poor ventilation conditions in some subdivided units. The results show that the outbreak was probably due to multiple transmission routes, i.e. by the drainage pipe spread of stack aerosols, which is enhanced by poor ventilation in the subdivided units.

Urban heat disrupts the use of parks, although the extent of such disruptions remains disputed. Literature relies on “small data” methods, i.e., questionnaires, field observations, or human-subject experiments, to capture the behavioural response to heat. Their findings are often in contradiction with each other, possibly due to the small sample sizes, the short study period, or the few sites available in a single study. The rise of “big data” such as social media offers new opportunities, yet its reliability and usefulness remain unknown. This paper describes the first study using Twitter data (tweets) to study park attendance under the influence of hot weather. Some 700,000 tweets with GPS coordinates inside major parks were obtained in Hong Kong over a period of three years. Field measurements were conducted in parallel in a large park covering the hot and cool seasons. Both the “small” and “big data” were analyzed and compared to each other. Findings suggest that a 1 ℃ increase in temperature was associated with some 4% drop in park attendance and some 1% drop in park tweets. The differences between the two data sources be explained by the ‘leakage’ of indoor tweets to parks caused by GPS drift near buildings. The Universal Thermal Climate Index can better predict self-reported thermal sensations, compared with other biometeorological indicators. This study has contributed to methodologies and new evidence to the study of behaviors and thermal adaptations in an outdoor space, and geo-coded tweets can serve as a powerful data source.

Traffic congestion and accidents take a toll on commuters' daily experiences and society. Locating the venues prone to congestion and accidents and capturing their perception by public members is invaluable for transport policy-makers. However, few previous methods consider user perception toward the accidents and congestion in finding and profiling the accident- and congestion-prone areas, leaving decision-makers unaware of the subsequent behavior responses and priorities of retrofitting measures. This study develops a framework to identify and characterize the accident- and congestion-prone areas heatedly discussed on social media. First, we use natural language processing and deep learning to detect the accident- and congestion-relevant Chinese microblogs posted on Sina Weibo, a Chinese social media platform. Then a modified Kernel Density Estimation method considering the sentiment of microblogs is employed to find the accident- and congestion-prone regions. The results show that the 'congestion-prone areas' discussed on social media are mainly distributed throughout the historical urban core and the Northwest of Pudong New Area, in reasonably good agreements with actual congestion records. In contrast, the 'accident-prone areas' are primarily found in locations with severe accidents. Finally, the above venues are characterized in spatio-temporal and semantic aspects to understand the nature of the incidents and assess the priority level for mitigation measures. The outcomes can provide a reference for traffic authorities to inform resource allocation and prioritize mitigation measures in future traffic management.

Background Nanoplastics have been recently found widely distributed in our natural environment where ubiquitously bacteria are major participants in various material cycles. Understanding how nanoplastics interact with bacterial cell membrane is critical to grasp their uptake processes as well as to analyze their associated risks in ecosystems and human microflora. However, little is known about the detailed interaction of differentially charged nanoplastics with bacteria. The present work experimentally and theoretically demonstrated that nanoplastics enter into bacteria depending on the surface charges and cell envelope structural features, and proved the shielding role of membrane lipids against nanoplastics. Results Positively charged polystyrene nanoplastics (PS-NH2, 80 nm) can efficiently translocate across cell membranes, while negatively charged PS (PS-COOH) and neutral PS show almost no or much less efficacy in translocation. Molecular dynamics simulations revealed that the PS-NH2 displayed more favourable electrostatic interactions with bacterial membranes and was subjected to internalisation through membrane penetration. The positively charged nanoplastics destroy cell envelope of Gram-positive B. subtilis by forming membrane pore, while enter into the Gram-negative E. coli with a relatively intact envelope. The accumulated positively charged nanoplastics conveyed more cell stress by inducing a higher level of reactive oxygen species (ROS). However, the subsequently released membrane lipid-coated nanoplastics were nearly nontoxic to cells, and like wise, stealthy bacteria wrapped up with artifical lipid layers became less sensitive to the positively charged nanoplastics, thereby illustrating that the membrane lipid can shield the strong interaction between the positively charged nanoplastics and cells. Conclusions Our findings elucidated the molecular mechanism of nanoplastics’ interaction and accumulation within bacteria, and implied the shielding and internalization effect of membrane lipid on toxic nanoplastics could promote bacteria for potential plastic bioremediation. Graphical Abstract

BACKGROUND: Hemorrhagic shock is the leading cause of early traumatic death. Research and discussion on restrictive fluid resuscitation have been ongoing for many years. The purpose of this study was to explore whether restrictive resuscitation can inhibit the shedding of vascular endothelial glycocalyx in the prehospital treatment of traumatic hemorrhagic shock pigs. METHODS: Landrace pigs were randomly divided into a restrictive resuscitation group (restrictive group) and a conventional resuscitation group (conventional group), with 6 pigs in each group. The gunshot caused a rupture of the pig’s receding right femoral artery, and the average arterial pressure was 40–45 mmHg stable for 30 minutes, which was defined as a successful shock model. The end point of resuscitation in the restrictive group was a mean arterial pressure (MAP) of 55–60 mmHg for 30 minutes, and the end point of resuscitation in the conventional group was a MAP of 70–75 mmHg for 30 minutes. The results of arterial blood gas analysis, hemodynamic indicators, endothelial glycocalyx damage and shedding marker Syndecan1 and soluble thrombomodulin (sTM) expression levels were compared between the two groups of experimental pigs after resuscitation. RESULTS: The two groups of experimental pigs had the same baseline levels before injury in age, body weight, blood loss, cardiac output index, cardiac function index (CFI), extravascular lung water index (ELWI), and pulmonary vascular permeability index (PVPI). The arterial blood gas analysis of the two experimental pigs showed no significant difference in carbon dioxide partial pressure, oxygen partial pressure, blood oxygen saturation, or blood lactic acid after resuscitation. The difference in cardiac output index and CFI at the end of resuscitation between the two groups was not statistically significant; the absolute value and percentage of Syndecan1 level increase in the restrictive resuscitation group were lower than those in the conventional resuscitation group, and the difference was statistically significant. CONCLUSIONS: Compared with full resuscitation in a short period of prehospital treatment, restrictive resuscitation can achieve a similar effect in maintaining tissue oxygen supply and can reduce the loss of vascular endothelial glycocalyx to a certain extent.

Vertical transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) along a vertical column of flats has been documented in several outbreaks of coronavirus disease 2019 (COVID-19) in Guangdong and Hong Kong. We describe an outbreak in Luk Chuen House, involving two vertical columns of flats associated with an unusually connected two-stack drainage system, in which nine individuals from seven households were infected. The index case resided in Flat 812 (8th floor, Unit 12), two flats (813, 817) on its opposite side reported one case each (i.e., a horizontal sub-cluster). All other flats with infected residents were vertically associated, forming a vertical sub-cluster. We injected tracer gas (SF

Stimuli-responsive nano-immunochemotherapy modulates the tumor microenvironment to enhance antitumor immunity., Mounting evidence suggests that immunotherapies are a promising new class of anticancer therapies. However, the immunosuppressive tumor microenvironment (TME), poor immunogenicity, and off-target toxicity hinder the broader implementation of immunotherapies. Here, we describe a novel strategy combining chemotherapy and immunotherapy to modulate the TME by systemically and concurrently delivering the chemotherapeutic agent SN38 (7-ethyl-10-hydroxycamptothecin) and the STING agonist DMXAA (5,6-dimethylxanthenone-4-acetic acid) into tumors using triblock copolymer nanoparticles, named PS3D1@DMXAA, which enhances antigen cross-presentation and induces the conversion of the immunosuppressive TME to immunogenic TME through the newly found synergistic function between SN38 and STING activation. PS3D1@DMXAA thus shows potent therapeutic efficacy in three mice tumor models and elicits remarkable therapeutic benefit when combined with anti–PD-1 therapy. Our engineered nanosystem offers a rational design of an effective immunotherapy combination regimen to convert uninflamed “cold” tumors into “hot” tumors, addressing the major challenges immunotherapies faced.

Solar energy building applications are attracting increasing attention from researchers, engineers, businessmen and officials due to their significant benefits in sustainable development, such as energy saving, cost reduction and environmental protection. Trombe wall, as a classical passive solar heating technique, has been studied for many years. A variety of concepts, methodologies and experiences have been developed during relevant research. Especially in recent years, numerous studies on Trombe wall have been published, which implies a rising attention to this technique. This review focuses on the classification, experimental assessment, modeling methods, and evaluation metrics for Trombe wall. In detail, nine types of Trombe walls are introduced according to their materials, structures and functions. Four experimental methods and two modeling methods of Trombe wall are discussed based on their functions, advantages, disadvantages, and applicability. Three aspects of evaluation metrics for Trombe wall are summarized in terms of technique, economy and environment. Moreover, the current and future research of Trombe wall are discussed at the end. The authors consider this article would be useful for their peers and can facilitate the technical development of Trombe wall.

Accumulating evidence suggests that stromal modifications improve chemotherapeutic outcomes in pancreatic ductal adenocarcinoma (PDAC). However, combination regimens of stroma-modifying agents and small-molecule cytotoxic drugs have achieved only limited improvements in the clinic, probably due to unsatisfactory pharmacokinetic profiles and restricted drug distribution in tumors. Here, we developed self-assembled prodrug nanoparticles integrating a stromal reprogramming inducer, calcipotriol (CAL), and a potent chemotherapeutic agent, 7-Ethyl-10-hydroxycamptothecin (SN38), to treat PDAC. While SN38 is conjugated to the block polymer backbone, CAL is loaded into the inner hydrophobic space during polymer self-assembly into nanoparticles. To achieve an efficient drug co-package, a planar and hydrophobic cholesterol domain was introduced to stabilize the hydrophobic CAL. Notably, the blood circulation time of CAL significantly improved as CAL|SN38 nanoparticle (CAL|SN38 NP). In addition, CAL|SN38 NP treatment significantly decreased the expression of N-cadherin, collagen, and fibronectin in tumors, which play critical roles in PDAC metastasis. Potent inhibition of primary tumor growth and vigorous anti-metastasis effects were observed after systemic administration of CAL|SN38 NP to stroma-rich PDAC orthotopic tumor-bearing mice. These findings provide a promising paradigm for developing tailor-made nanoparticles with potent stroma-modification capability to combat metastatic cancer.

District Heating Systems (DHS) have received renewed attention in relation to their environmental, economic, and health benefits. Research literature on DHS tends to focus separately, either on the thermo-hydrological modelling or building energy demand. Rarely are there combined simulation approaches that consider the interactions between the district heating system and the buildings they serve. There is a practical need for a coupled simulation model to inform operation and energy retrofit strategies, such as, building insulation, water leakage prevention, and achieving comfortable indoor air temperatures. In this study, a novel simulation model, BETHS, is developed to predict the time-varying energy performance and occupant thermal comfort of a cluster of buildings served by a DHS in the urban context. The simulation results are compared with field measurement data collected for a secondary network consisting of 12 buildings and 2788 m of pipeline network over a 10-day period, in Shenyang, Liaoning, China. Predicted water temperature and indoor air temperature showed reasonable agreements with measured data. Simulation results suggested an energy saving of 35% for improved building insulation, 32% for switching from coal to gas, 18% for reduced indoor temperature, 14% for water leakage prevention, and 67% if all are combined. The BETHS model can be a valuable extension to a building energy simulation framework, and support retrofit strategies and operational decisions for existing DHS networks.

Stack aerosols are generated within vertical building drainage stacks during the discharge of wastewater containing feces and exhaled mucus from toilets and washbasins. Fifteen stack aerosol-related outbreaks of coronavirus disease 2019 (COVID-19) in high-rise buildings have been observed in Hong Kong and Guangzhou. Currently, we investigated two such outbreaks of COVID-19 in Hong Kong, identified the probable role of chimney effect-induced airflow in a building drainage system in the spread of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). We injected tracer gas (SF6) into the drainage stacks via the water closet of the index case and monitored tracer gas concentrations in the bathrooms and along the facades of infected and non-infected flats and in roof vents. The air temperature, humidity, and pressure in vertical stacks were also monitored. The measured tracer gas distribution agreed with the observed distribution of the infected cases. Phylogenetic analysis of the SARS-CoV-2 genome sequences demonstrated clonal spread from a point source in cases along the same vertical column. The stack air pressure and temperature distributions suggested that stack aerosols can spread to indoors through pipe leaks which provide direct evidence for the long-range aerosol transmission of SARS-CoV-2 through drainage pipes via the chimney effect., Graphical Abstract ga1

“The Image of the City” by Kevin Lynch is a landmark planning theory of lasting influence; its scientific rigor and relevance in the digital age were in dispute. The rise of social media and other digital technologies offers new opportunities to study the perception of urban environments. Questions remain as to whether social media analytics can provide a reliable measure of perceived city images? If yes, what implication does it hold for urban planners? This paper describes a study on the perception of city images using a combination of “big data” and “small data” methods in the Tri-City Region in Poland. The aims were to 1) test the hypothesis whether social media analytics can elicit Lynchian elements of city image in consistency with conventional methods, and 2) develop and evaluate social media-based indicators of Imageability for planning practice. Geo-tagged images and texts were collected from Instagram and Twitter, two popular social media platforms in Poland. Text-Mining, Image Processing, Clustering Analysis, Kernel Density Estimation, and Sentiment Analysis were used. Results were compared with benchmarks constructed from official GIS database, questionnaire responses and sketch maps. “District”, “landmark”, and “path” identified on social media were in good agreements with benchmarks, less so for “edge” and “node”. Two social media-based indicators have influenced the perception of a place: Instagramability, the frequency of a place captured on Instagram, was linked to its perception as an architectural landmark and tourist attraction, while Twitterability, the frequency of a place mentioned on Twitter by name, was linked to its perceived niceness and relevance to everyday life of communities. Methods developed in this study have theoretical and practical implications for urban planners.

The outdoor thermal environment correlates with occupant behaviors in open spaces. The appropriate range of thermal environment that is conducive to outdoor activities, however, remains inadequately defined. Existing studies fail to characterize the behavioral responses to thermal environments in important dimensions including activity types, age or gender. We conducted field studies on six open spaces in Wuhan, China, a city with humid subtropical climate and ideal for this research. Data based on field observations, questionnaires, and measurement were collected under a variety of weather conditions over 4 years. We renovated a playground by adding shading shelters and vegetation cover to reduce summertime heat stress. On-site thermal environment were assessed using the Universal Thermal Climate Index (UTCI). Findings are as following: the outdoor thermal environment is a strong predictor of mean attendance over a period of time, but not spontaneous occupancy at a specific time or space; the Optimum Thermal Environment (OTE), defined as the range in which an open space is well-attended (attendance above 90% of peak value), is more consistent than the self-reported Thermal Acceptable Range (TAR) in this study. Behavioral responses to thermal environment differ by gender, age, and types of activities. The experiment confirmed the causality between outdoor thermal environment and activities: the renovated playground attracted 80% more occupants in summer; people stayed longer, reported less heat stress, and interacted with each other more often. Results remained significant after controlling for weather, air quality, daily and weekly routines. Findings had implications for the design of open spaces.

Quantitative structure-property relationship (QSPR) models were firstly established for the hydrophobic substituent constant (πX) using the theoretical descriptors derived solely from electrostatic potentials (EPSs) at the substituent atoms. The descriptors introduced are found to be related to hydrogen-bond basicity, hydrogen-bond acidity, cavity, or dipolarity/polarizability terms in linear solvation energy relationship, which endows the models good interpretability. The predictive capabilities of the models constructed were also verified by rigorous Monte Carlo cross-validation. Then, eight groups of meta- or para-disubstituted benzenes and one group of substituted pyridines were investigated. QSPR models for individual systems were achieved with the ESP-derived descriptors. Additionally, two QSPR models were also established for Rekker's fragment constants (foct), which is a secondary-treatment quantity and reflects average contribution of the fragment to logP. It has been demonstrated that the descriptors derived from ESPs at the fragments, can be well used to quantitatively express the relationship between fragment structures and their hydrophobic properties, regardless of the attached parent structure or the valence state. Finally, the relations of Hammett σ constant and ESP quantities were explored. It implies that σ and π, which are essential in classic QSAR and represent different type of contributions to biological activities, are also complementary in interaction site.

The microclimate of a high-density city affects building energy consumption and thermal comfort. Despite the practical needs in building design and urban planning to predict conditions inside street canyons, literature is sparse for physics-based models that can support early stage design. Existing tools such as the Computational Fluid Dynamics (CFD) method is computationally expensive and cannot easily be coupled with other simulation models to account for solar heat gains at urban surfaces and anthropogenic heat from traffic and building HVAC systems. This paper describes a zonal model developed to assess airflow and air temperature in street canyons in high-density cities. The model takes into account 3D urban geometries, external wind, buoyancy, convective heat transfers from urban surfaces; it can simulate zonal air temperature, pressure, and airflow patterns by interactively solving mass, pressure and energy balance equations. The model was evaluated using field measurement on a 'mock-up' site consisted of movable concrete bins mimicking buildings and street canyons in high-density cities. Experiments were conducted on 3 alternative street layouts of various height-to-width aspect ratios: moderate (H/W = 1), dense (H/W = 2), and high-density (H/W = 3). Agreements between predicted and measured air temperatures were satisfactory across 3 layouts (RMSE < 0.0041). Temperature differences between simulated and measured results were largely within 1 K. The model can provide a reliable and quick assessment of the impact of street canyons on urban heat island (UHI) in high-density cities. The next step is to couple this model with building energy models.

The energy performance of a building in a dense city depends to some extent on its surroundings. The impact of the built form, together with anthropogenic heat gains from traffic and building HVAC exhaust, determines external environmental conditions at the Urban Canopy Layer. Existing building energy models are limited in accounting for micro-scale variations of the urban microclimate, which may significantly modify a building's energy performance in density cities. This paper presents the Urban Building Energy and Climate (UrBEC) model, a coupled urban microclimate model (UMM) and building energy model (HTB2) developed to assess the time varying energy performance of a cluster of buildings and the combined heat gains to the external space from direct and reflected solar radiation, traffic and the exhaust from HVAC systems in a high-density city. The simulation results were evaluated by comparison with field measurement data collected from the Sai Ying Pun neighbourhood in Hong Kong, on a summer and winter day. Predicted and measured air and surface temperature at the four locations were found to be in reasonable agreement. Simulation results indicate an average of 1-3 ºC of temperature rise in street canyons compared with the ambient air in summer. Street level air is predicted to be 0.6 ºC warmer than those at higher levels (20m +). Anthropogenic heat from traffic and building HVAC exhaust are the dominant contributors to temperature rise in street canyons in summer, exceeding the contribution from urban surfaces. The predicted building cooling demand is expected to increase up to 15 % in summer due to the warming effect in street canyons. The UrBEC model runs significantly faster than current CFD-based approaches. Therefore, the model has the potential to support early stage design and planning decisions in a dense city.

This paper introduces CityComfort+, a new method to simulate the spatial variation of the mean radiant temperature (Tmrt) in dense urban areas. This method derives the Tmrt by modeling five components of radiation fluxes—direct solar radiation, diffuse solar radiation, reflected solar radiation, long-wave radiation from the atmosphere, and long-wave radiation from urban surfaces—each weighted by view factors. The novelty of CityComfort+ lies in a new algorithm to model surface temperature and associated long-wave radiation as well as the application of RADIANCE, a ray-tracing algorithm that can accurately simulate 3-D radiation fluxes in a complex urban space (Ward, et al, 1998). CityComfort+ was evaluated in field studies conducted in a dense urban courtyard (mean sky view factor of 0.4) in Boston, Massachusetts, USA under winter, spring, and summer (cold, warm, and hot) weather conditions. Simulation results yielded close agreement with measured Tmrt. Also, predicted mean surface temperature agreed well with the measurement data. A sensitivity test using CityComfort+ revealed that Tmrt on the study site will be mostly affected by the heat capacity and emissivity of surface material, not albedo. This study is subject to limitations from sensor accuracy and the thermal inertia of the grey ball thermometer, and the CityComfort+ method is still under development. The next step is to compare its performance with existing methods.

In many dense cities, urban heat and the interaction of buildings with their immediate urban environment emerges as a pressing issue due to growing urban heat island effect and climate change. Informed evidence based design decisions to mitigate heat stress becomes a priority for urban planning and design practitioners. The aim of the study is to develop informed design and development decisions using computer simulation tools concerning urban microclimate performance. In this study, academic researchers have worked with industrial partners in an urban renewal project in Hong Kong’s high density urban area. In-house developed simulation software such as CityComfort+ and HTB2-Virvil were applied to assess urban microclimate conditions and risks of pedestrian thermal stress throughout key seasons. Simulation results were provided as feedback to project designers and managers at early stage, allowing timely design modification to improve performance while maintaining code compliance and design and fiscal priorities. The procedure is iterative until performance attributes converge. Preliminary results show that the informed design can deliver significant microclimate benefits compared with “business-as-usual scenarios”. By shaping building mass, orientation, and strategic placement of shading and vegetation, the improved design is expected to reduce summer-time outdoor heat stress by 1°C measured in UTCI equivalent temperature, thus bringing the average conditions for the hot season into the “comfort zone” for the local community. Energy simulation can predict overall energy demand and the potential for renewable energy supply at an urban scale. The simulation-designer workflow shows promising potentials to improve urban microclimate performance of design outcomes and the potential for zero carbon urban blocks. The early-stage action, forward-looking partnership, and computing efficiency of the simulation tools are the keys.

Road traffic noise is an environmental health hazard in Hong Kong and other high-density cities. The dense built environment modifies noise propagation, reflects, absorbs or diffracts sound depending on building morphology, road configuration, and open space layout, etc. Mitigation of urban traffic noise is of growing concerns to planning and design practitioners. Existing assessment methods are limited in reliably accounting for localized variations in noise exposure associated with a high-density city. The aim of this research is to 1) develop a 3D database of road traffic noise exposure for a large number of households in a high-density city; 2) explore the linkages between built environment attributes and road traffic noise exposure. A 3D built environment database was constructed for Hong Kong using building geometries, topography and urban traffic noise data. Window coordinates for each household were extracted using address and building floor plans. Computer simulation was conducted to determine traffic noise exposure at window locations using CadnaA for a random sample of 8,158 households across the city. Results revealed that 76.3% of the households are exposed to excessive road traffic noise by WHO standards. Household traffic noise exposure are significantly associated with proximity to secondary road, story-level of the flat, and other urban form attributes. The 3D database is of value for public health research in relation to noise and urban noise mitigation measures. The next step is to develop an efficient and reliable simulation tool to support planning and design decisions in traffic noise mitigation.

The quality of outdoor spaces in a residential community affects the quality of life of its residents. This paper presents the findings of a study on outdoor thermal comfort and space usage at a residential community in Wuhan, central China, through the monitoring of microclimate conditions, interviews with residents, and recording of occupants’ activities. The data were used to develop a thermal sensation vote (TSV) model and a space usage rate model. An alternative design strategy was proposed for considering thermal environment and usage rate. The results show that thermal comfort is the most important factor in the quality of outdoor spaces. Other significant factors include air quality, acoustic environment, functionality, and convenience. The study provided valuable information for the design of outdoor spaces in residential communities.

A novel silicon-containing arylacetylene resin (MSAR) modified by dipropargyl ether of bisphenol A (DPBPA) and dipropargyl ether of perfluorobisphenol A (DPPFBPA) was prepared separately. The curing behaviors of modified resins, DPBPA/MSAR and DPPFBPA/MSAR, were characterized with differential scanning calorimeter (DSC). The kinetic parameters of modified resins were obtained by the Kissinger and Ozawa methods. The results of dynamic mechanical analysis (DMA) revealed that the glass transition temperature (Tg) of the cured DPBPA/MSAR reached 486 °C. According to the thermogravimetric analysis (TGA), the decomposition temperature (Td5) of the cured resins and char yield (Yc, 800 °C) decreased as the dipropargyl ether loadings increased, especially in air. With the same weight loading, thermal stability of DPBPA/MSAR was better than that of DPPFBPA/MSAR. The carbon fiber (T300) reinforced composites exhibited excellent flexural properties at room temperature with a high property retention at 300 °C.

This study investigates the dissipation and residue of a metalaxyl and dimethomorph mixed formulation in grape and soil. A high-performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS) analytical method was developed to determine the residue of metalaxyl and dimethomorph in grape and soil. The results showed that the average recoveries are in the range of 86.84 percent to 97.30 percent. The dissipation rate of metalaxyl in grape (with half life of 4.9 days) was faster than in soil (with half life of 8.7 days). The dissipation rates of E- and Z-isomers of dimethomorph in grape were almost the same (with half lives of 9.0 and 9.8 days, respectively). However, the dissipation rate of the E-isomer in soil was much faster than that of the Z-isomer (with half lives of 10.3 and 31.5 days, respectively). Moreover, the terminal residue of metalaxyl and dimethomorph were significantly below the available maximum residue limits (MRL). However, a difference was observed between the concentration of the Z- and E-isomers either in grape or soil. The ratio of E-isomer to Z-isomer in grape was higher than in soil, which may due to the different water solubilities and polarities of the two isomers.

A residue analytical method to detect pyrimethanil in tomatoes and soil was developed by using high-performance liquid chromatography with a diode array detector. The dissipation and residue level of pyrimethanil in tomatoes and soil were also investigated. Results showed that the average recoveries are in the range of 87.2 to 90.0 % with a relative standard difference of 2.22 to 7.61 % in tomatoes and soil. In Guangdong, Shandong, and Yunnan, the half-lives of pyrimethanil in tomatoes were 1.8, 3.6, and 4.2 days and those in soil were 4.0, 3.3, and 3.9 days, respectively. The dissipation rate of pyrimethanil in tomatoes and soil was affected by temperature, precipitation, and soil type. The terminal residue results showed that when pesticide pyrimethanil was used under the experiment design, all the results were far below the available maximum residue limits. Low residues in tomatoes and soil suggest that this pesticide is safe to use under the recommended dosage.