Spatial-temporal distribution and emission of urban scale air pollutants in Hefei based on Mobile-DOAS.

As a significant city in the Yangtze River Delta regions, Hefei has experienced rapid changes in the sources of air pollution due to its high-speed economic development and urban expansion. However, there has been limited research in recent years on the spatial-temporal distribution and emission of its atmospheric pollutants. To address this, this study conducted mobile observations of urban roads using the Mobile-DOAS instrument from June 2021 to May 2022. The monitoring results exhibit a favourable consistent with TROPOMI satellite data and ground monitoring station data. Temporally, there were pronounced seasonal variations in air pollutants. Spatially, high concentration of HCHO and NO2 were closely associated with traffic congestion on roadways, while heightened SO2 levels were attributed to winter heating and industrial emissions. The study also revealed that with the implementation of road policies, the average vehicle speed increased by 95.4%, while the NO concentration decreased by 54.4%. In the estimation of urban NOx emission flux, it was observed that in temporal terms, compared with inventory data, the emissions calculated via mobile measurements exhibited more distinct seasonal patterns, with the highest emission rate of 349 g/sec in winter and the lowest of 142 g/sec in summer. In spatial terms, the significant difference in emissions between the inner and outer ring roads also suggests the presence of the city's primary NOx emission sources in the area between these two rings. This study offers data support for formulating the next phase of air pollution control measures in urban areas.

Quantitative analysis of influencing factors to aerosol pH and its responses to PM2.5 and O3 pollution in a coastal city.

Aerosol acidity (pH) plays an important role in the multiphase chemical processes of atmospheric particles. In this study, we demonstrated the seasonal trends of aerosol pH calculated with the ISORROPIA-II model in a coastal city of southeast China. We performed quantitative analysis on the various influencing factors on aerosol pH, and explored the responses of aerosol pH to different PM2.5 and O3 pollution levels. The results showed that the average aerosol pH was 2.92 ± 0.61, following the order of winter > spring > summer > autumn. Sensitivity tests revealed that SO42-, NHx, T and RH triggered the variations of aerosol pH. Quantitative analysis results showed that T (37.9%-51.2%) was the main factors affecting pH variations in four seasons, followed by SO42- (6.1%-23.7%), NHx (7.2%-22.2%) and RH (0-14.2%). Totally, annual mean meteorological factors (52.9%) and chemical compositions (41.3%) commonly contributed the aerosol ΔpH in the coastal city. The concentrations of PM2.5 was positively correlated with aerosol liquid water content (R2 = 0.53) and aerosol pH (R2 = 0.26), indicating that the increase in pH was related with the elevated NH4NO3 and decreased SO42-, and also the changes of T and RH. The Ox (O3 + NO2) was moderately correlated with aerosol pH (R2 = -0.48), attributable to the fact that the proportion of SO42- increased under high T and low RH conditions. The study strengthened our understanding of the contributions of influencing factors to aerosol pH, and also provided scientific evidences for chemical processes of atmospheric particles in coastal areas.

Source apportionment of black carbon using an advanced Aethalometer model in a typical industrial city of China.

Black carbon (BC) aerosol can lead to adverse health effects and drive climate change; therefore, the characteristic research and identification of BC sources are essential for lowering emissions. In this study, equivalent black carbon (eBC) measurement was performed using a seven-wavelength Aethalometer (AE33) at an urban site in a typical industrial city (Zibo) of Northern China for the first time. The monitoring was performed from February 2021 to January 2022. The mass absorption cross-section (MAC) of AE33 was optimised using the online elemental carbon (EC) data, and eBC was corrected using the MAC. The corrected annual BC concentration was 1.72 ± 1.18 µg/m3. The diurnal variation of BC depicted a bimodal distribution. Furthermore, the BC concentration on weekends was 18% lower than on weekdays. The diurnal variation and weekend effect reflect the critical contributions of traffic emission to BC concentration. The source apportionment of BC was calculated by a constraining Aethalometer model, which restricted the Ångström exponent using the online potassium ions. The results revealed that BC was not significantly affected by biomass burning (BCbb) in Zibo. The relative contribution of BCbb was higher in winter than in other seasons. The daily morning peak of BC was primarily influenced by traffic sources, whereas the contribution of biomass burning increased after 17:00 in the evening peak. Our findings suggest that it is more important to control fossil fuel sources for BC emission reduction in Zibo, while it is necessary to strengthen the control of biomass combustion sources in winter.

Analyzing carbon emissions and influencing factors in Chengdu-Chongqing urban agglomeration counties.

Majority of carbon emissions originate from fossil energy consumption, thus necessitating calculation and monitoring of carbon emissions from energy consumption. In this study, we utilized energy consumption data from Sichuan Province and Chongqing Municipality for the years 2000 to 2019 to estimate their statistical carbon emissions. We then employed nighttime light data to downscale and infer the spatial distribution of carbon emissions at the county level within the Chengdu-Chongqing urban agglomeration. Furthermore, we analyzed the spatial pattern of carbon emissions at the county level using the coefficient of variation and spatial autocorrelation, and we used the Geographically and Temporally Weighted Regression (GTWR) model to analyze the influencing factors of carbon emissions at this scale. The results of this study are as follows: (1) from 2000 to 2019, the overall carbon emissions in the Chengdu-Chongqing urban agglomeration showed an increasing trend followed by a decrease, with an average annual growth rate of 4.24%. However, in recent years, it has stabilized, and 2012 was the peak year for carbon emissions in the Chengdu-Chongqing urban agglomeration; (2) carbon emissions exhibited significant spatial clustering, with high-high clustering observed in the core urban areas of Chengdu and Chongqing and low-low clustering in the southern counties of the Chengdu-Chongqing urban agglomeration; (3) factors such as GDP, population (Pop), urbanization rate (Ur), and industrialization structure (Ic) all showed a significant influence on carbon emissions; (4) the spatial heterogeneity of each influencing factor was evident.

Investigation of spatiotemporal distribution and formation mechanisms of ozone pollution in eastern Chinese cities applying convolutional neural network.

Severe ground-level ozone (O3) pollution over major Chinese cities has become one of the most challenging problems, which have deleterious effects on human health and the sustainability of society. This study explored the spatiotemporal distribution characteristics of ground-level O3 and its precursors based on conventional pollutant and meteorological monitoring data in Zhejiang Province from 2016 to 2021. Then, a high-performance convolutional neural network (CNN) model was established by expanding the moment and the concentration variations to general factors. Finally, the response mechanism of O3 to the variation with crucial influencing factors is explored by controlling variables and interpolating target variables. The results indicated that the annual average MDA8-90th concentrations in Zhejiang Province are higher in the northern and lower in the southern. When the wind direction (WD) ranges from east to southwest and the wind speed (WS) ranges between 2 and 3 m/sec, higher O3 concentration prone to occur. At different temperatures (T), the O3 concentration showed a trend of first increasing and subsequently decreasing with increasing NO2 concentration, peaks at the NO2 concentration around 0.02 mg/m3. The sensitivity of NO2 to O3 formation is not easily affected by temperature, barometric pressure and dew point temperature. Additionally, there is a minimum [Formula: see text] at each temperature when the NO2 concentration is 0.03 mg/m3, and this minimum [Formula: see text] decreases with increasing temperature. The study explores the response mechanism of O3 with the change of driving variables, which can provide a scientific foundation and methodological support for the targeted management of O3 pollution.

Physicochemical characteristics of airborne microplastics of a typical coastal city in the Yangtze River Delta Region, China.

Airborne microplastics (MPs) are important pollutants that have been present in the environment for many years and are characterized by their universality, persistence, and potential toxicity. This study investigated the effects of terrestrial and marine transport of MPs in the atmosphere of a coastal city and compared the difference between daytime and nighttime. Laser direct infrared imaging (LDIR) and polarized light microscopy were used to characterize the physical and chemical properties of MPs, including number concentration, chemical types, shape, and size. Backward trajectories were used to distinguish the air masses from marine and terrestrial transport. Twenty chemical types were detected by LDIR, with rubber (16.7%) and phenol-formaldehyde resin (PFR; 14.8%) being major components. Three main morphological types of MPs were identified, and fragments (78.1%) are the dominant type. MPs in the atmosphere were concentrated in the small particle size segment (20-50 µm). The concentration of MPs in the air mass from marine transport was 14.7 items/m3 - lower than that from terrestrial transport (32.0 items/m3). The number concentration of airborne MPs was negatively correlated with relative humidity. MPs from terrestrial transport were mainly rubber (20.2%), while those from marine transport were mainly PFR (18%). MPs in the marine transport air mass were more aged and had a lower number concentration than those in the terrestrial transport air mass. The number concentration of airborne MPs is higher during the day than at night. These findings could contribute to the development of targeted control measures and methods to reduce MP pollution.

Real-road NOx and CO2 emissions of city and highway China-6 heavy-duty diesel vehicles.

The emission of heavy-duty vehicles has raised great concerns worldwide. The complex working and loading conditions, which may differ a lot from PEMS tests, raised new challenges to the supervision and control of emissions, especially during real-world applications. On-board diagnostics (OBD) technology with data exchange enabled and strengthened the monitoring of emissions from a large number of heavy-duty diesel vehicles. This paper presents an analysis of the OBD data collected from more than 800 city and highway heavy-duty vehicles in China using remote OBD data terminals. Real-world NOx and CO2 emissions of China-6 heavy-duty vehicles have been examined. The results showed that city heavy-duty vehicles had higher NOx emission levels, which was mostly due to longer time of low SCR temperatures below 180°C. The application of novel methods based on 3B-MAW also found that heavy-duty diesel vehicles tended to have high NOx emissions at idle. Also, little difference had been found in work-based CO2 emissions, and this may be due to no major difference were found in occupancies of hot running.

Changes in source contributions to the oxidative potential of PM2.5 in urban Xiamen, China.

The toxicity of PM2.5 does not necessarily change synchronously with its mass concentration. In this study, the chemical composition (carbonaceous species, water-soluble ions, and metals) and oxidative potential (dithiothreitol assay, DTT) of PM2.5 were investigated in 2017/2018 and 2022 in Xiamen, China. The decrease rate of volume-normalized DTT (DTTv) (38%) was lower than that of PM2.5 (55%) between the two sampling periods. However, the mass-normalized DTT (DTTm) increased by 44%. Clear seasonal patterns with higher levels in winter were found for PM2.5, most chemical constituents and DTTv but not for DTTm. The large decrease in DTT activity (84%-92%) after the addition of EDTA suggested that water-soluble metals were the main contributors to DTT in Xiamen. The increased gap between the reconstructed and measured DTTv and the stronger correlations between the reconstructed/measured DTT ratio and carbonaceous species in 2022 were observed. The decrease rates of the hazard index (32.5%) and lifetime cancer risk (9.1%) differed from those of PM2.5 and DTTv due to their different main contributors. The PMF-MLR model showed that the contributions (nmol/(min·m3)) of vehicle emission, coal + biomass burning, ship emission and secondary aerosol to DTTv in 2022 decreased by 63.0%, 65.2%, 66.5%, and 22.2%, respectively, compared to those in 2017/2018, which was consistent with the emission reduction of vehicle exhaust and coal consumption, the adoption of low-sulfur fuel oil used on board ships and the reduced production of WSOC. However, the contributions of dust + sea salt and industrial emission increased.

Chemical characteristics and sources apportionment of volatile organic compounds in the primary urban area of Shijiazhuang, North China Plain.

VOCs (Volatile organic compounds) exert a vital role in ozone and secondary organic aerosol production, necessitating investigations into their concentration, chemical characteristics, and source apportionment for the effective implementation of measures aimed at preventing and controlling atmospheric pollution. From July to October 2020, online monitoring was conducted in the main urban area of Shijiazhuang to collect data on VOCs and analyze their concentrations and reactivity. Additionally, the PMF (positive matrix factorization) method was utilized to identify the VOCs sources. Results indicated that the TVOCs (total VOCs) concentration was (96.7 ± 63.4 µg/m3), with alkanes exhibiting the highest concentration of (36.1 ± 26.4 µg/m3), followed by OVOCs (16.4 ± 14.4 µg/m3). The key active components were alkenes and aromatics, among which xylene, propylene, toluene, propionaldehyde, acetaldehyde, ethylene, and styrene played crucial roles as reactive species. The sources derived from PMF analysis encompassed vehicle emissions, solvent and coating sources, combustion sources, industrial emissions sources, as well as plant sources, the contribution of which were 37.80%, 27.93%, 16.57%, 15.24%, and 2.46%, respectively. Hence, reducing vehicular exhaust emissions and encouraging neighboring industries to adopt low-volatile organic solvents and coatings should be prioritized to mitigate VOCs levels.

Evaluating complementaries among urban water, energy, infrastructure, and social Sustainable Development Goals in China.

Urban areas' performance in water, energy, infrastructure, and socio-economic sectors is intertwined and measurable through Sustainable Development Goals (SDGs) 6-13. Effective synergy among these is critical for sustainability. This study constructs an indicator framework that reflects progress towards these urban SDGs in China. Findings indicate underperformance in SDGs 8-11, suggesting the need for transformative actions. Through network analysis, the research reveals complementarities among these SDGs. Notably, the SDG space divides into socio-economic and ecological clusters, with SDG 6 (Clean Water and Sanitation) central to both. Additionally, SDG 8 (Decent Work and Economic Growth) and SDG 9 (Industry, Innovation, and Infrastructure) act as bridges, while greater synergies exist between SDG 12 (Responsible Consumption and Production) and SDG 13 (Climate Action). An in-depth view at the indicator-level shows a core-periphery structure, emphasizing indicators like SDG 6.2 (Wastewater Treatment Rate) and SDG 6.6 (Recycled Water Production Capacity per capita) as pivotal. This study confirms the urban SDG space's stability and predictiveness, underscoring its value in steering well-aligned policy decisions for sustainable growth.

Exploring the HONO source during the COVID-19 pandemic in a megacity in China.

HONO is a critical precursor of •OH, but its sources are controversial due to its complex formation mechanism. This study conducted comprehensive observations in Zhengzhou from April 26 to May 11, 2022. Low NOx concentrations were observed during the Covid epidemic period (EP) (10.4 ± 3.0 ppb), compared to the pre-epidemic period (PEP) (12.5 ± 3.8 ppb). The mean HONO concentration during EP (0.53 ± 0.34 ppb) was 0.09 ppb lower than that during PEP (0.62 ± 0.53 ppb). The decrease in HONO concentration during EP came mainly at night due to the reduction in the direct emission (Pemi) (0.03 ppb/hr), the homogeneous reaction between •OH and NO (POH+NO) (0.02 ppb/hr), and the heterogeneous conversion of NO2 on the ground (0.01 ppb/hr). Notably, there was no significant change in daytime HONO concentration. The daytime HONO budget indicated that the primary HONO sources during PEP were the nitrate photolysis (Pnitrate), followed by the POH+NO, Pemi, the photo-enhanced reaction of NO2 on the ground (Pground+hv) and aerosol surface (Paerosol+hv). The primary HONO sources were Pnitrate, POH+NO, Pemi, and Paerosol+hv during EP, respectively. The missing source has a high correlation with solar radiation, there might be other photo-related HONO sources or the contributions of photosensitized reactions were underestimated. In the extremely underestimated cases, HONO production rates from the Pnitrate, Pground+hv, and Paerosol+hv increased by 0.17, 0.10, and 0.10 ppb/hr during PEP, 0.23, 0.13, and 0.16 ppb/hr during EP, and Pnitrate was still the primary source during both PEP and EP.

Spatio-temporal pattern and coordinated development of eco-compensation performance of 101 cities in the Yangtze River Economic Belt.

Eco-compensation is an important component of ecological civilization construction. Therefore, it is of great significance to elucidate the spatial and temporal pattern of eco-compensation performance and its internal coupling and coordinated features to promote ecological civilization construction. We proposed that eco-compensation performance consists of benefit and efficiency, and used the projection pursuit and super-efficiency SBM-DEA models to measure the eco-compensation benefit and efficiency of 101 cities in the Yangtze River Economic Belt from 2010 to 2021 and to analyze their spatial and temporal patterns. Finally, we used the coupling coordination degree model to reveal the coupling and coordinated features of eco-compensation performance. The results showed that the temporal trends of eco-compensation benefit and efficiency were "W" and "U" shaped. The eco-compensation benefit in eastern or mega-cities was the highest, whereas the eco-compensation efficiency in western or small/medium-sized cities was the highest. Coupling coordination degree of eco-compensation performance was in the coordinated development stage from 2010 to 2012, with a concentration of agglomeration effects in the central region. It was in the transition/adjustment stage from 2013 to 2020, with low-value areas concentrated and scattered high-value areas, and smaller regional differences. It was in the coordinated development stage in 2021, with a clear agglomeration effect in the eastern region. Cities in the Yangtze River Economic Belt should incorporate the eco-compensation performance coupling coordination mechanism into their optimized eco-compensation policy plans based on the stage of coordinated development, to achieve their environmental improvement goals.

Assessing the nonlinear impact of green space exposure on psychological stress perception using machine learning and street view images.

Introduction: Urban green space (GS) exposure is recognized as a nature-based strategy for addressing urban challenges. However, the stress relieving effects and mechanisms of GS exposure are yet to be fully explored. The development of machine learning and street view images offers a method for large-scale measurement and precise empirical analysis. Methods: This study focuses on the central area of Shanghai, examining the complex effects of GS exposure on psychological stress perception. By constructing a multidimensional psychological stress perception scale and integrating machine learning algorithms with extensive street view images data, we successfully developed a framework for measuring urban stress perception. Using the scores from the psychological stress perception scale provided by volunteers as labeled data, we predicted the psychological stress perception in Shanghai's central urban area through the Support Vector Machine (SVM) algorithm. Additionally, this study employed the interpretable machine learning model eXtreme Gradient Boosting (XGBoost) algorithm to reveal the nonlinear relationship between GS exposure and residents' psychological stress. Results: Results indicate that the GS exposure in central Shanghai is generally low, with significant spatial heterogeneity. GS exposure has a positive impact on reducing residents' psychological stress. However, this effect has a threshold; when GS exposure exceeds 0.35, its impact on stress perception gradually diminishes. Discussion: We recommend combining the threshold of stress perception with GS exposure to identify urban spaces, thereby guiding precise strategies for enhancing GS. This research not only demonstrates the complex mitigating effect of GS exposure on psychological stress perception but also emphasizes the importance of considering the "dose-effect" of it in urban planning and construction. Based on open-source data, the framework and methods developed in this study have the potential to be applied in different urban environments, thus providing more comprehensive support for future urban planning.

Hypertension risk pathways in urban built environment: the case of Yuhui District, Bengbu City, China.

Introduction: The rapid development of urbanization has brought about changes in residents' living environment and behavior, leading to health challenges such as hypertension. An improvement in the built-up environment in the community could contribute to the construction of a healthy city, promote the active life of the residents, and prevent and relieve hypertension. However, there is little research on the relationship between the built environment of the community and hypertension. This cross-sectional study aims to evaluate the relationship between communities' built environment, health behavior, and hypertension grade of residents in Yuhui District of Bengbu City. Methods: This study is based on data from the 2022 Health Survey of Residents in 21 communities. To investigate the impact of the community's built environment on residents' hypertension and the underlying mechanisms, regression and structural equation modeling were employed. Results and discussion: The results show that the built environment of urban communities has a significant impact on the residents' hypertension. The presence of high densities of supermarkets, convenience stores, parks and plazas, but low densities of clinics and hospitals, has been identified as a significant risk factor for the development of high blood pressure among the residents. Nevertheless, the adoption of healthy behaviors, including regular walking, physical activity, and a diet rich in fruit and vegetables, can play an important role in reducing the risk of hypertension. The findings of this study show that enhancements to the built environment in urban neighborhoods could contribute to a reduction in the prevalence of hypertension among residents. Furthermore, the implementation of efficacious health interventions in urban settings would facilitate the alteration of residents' health behaviors and enhance their overall health status.

Bioaccumulation, contamination and health risks of trace elements in wild fish in Chongqing City, China: a consumer guidance regarding fish size.

Trace elements generally contaminate wild fish, particularly in megacities, necessitating guided consumption practices. This study investigated the bioaccumulation of trace elements in wild fish from Chongqing City in June 2021. We evaluated their contamination and associated health risks to establish consumption guidance based on fish size. Our results indicate that the concentrations of Zn, Pb, Cr, and As were relatively high, with some fish exceeding the maximum residue limits. Herbivorous and pelagic fish generally exhibited lower bioaccumulation of most trace elements, except for Cr and As, which were higher in pelagic species. The contamination indices (Pi) for Cr, Pb and As were consistently above 0.2, indicating widespread contamination. The most contaminated fish typically measured around 19 cm in length and weighed approximately 90 g. Only the maximum target hazard quotients (THQ) for As, Cr, and Hg exceeded 1, with a notably high ratio of THQ(As) > 1, highlighting concerns over arsenic contamination. The THQ(As) remained below 1 for adults across all fish species, whereas for children, species such as Onychostoma sima, Pseudohemiculter dispar, and Parabramis pekinensis exceeded this threshold. Fish safe for adult consumption generally measured 13 cm in length and weighed 20 g, and for children, 16 cm and 25 g. Consequently, selecting larger fish is likely to reduce the consumption of contaminated fish, thereby decreasing health risks to the public. The centralization of contaminated fish with high risk in specific size range confirmed fish size could be used to gauge the contamination and health risk of fish.

Effects of a large-scale bioretention installation on the species composition of an urban bird community as determined by passive acoustic monitoring.

As urbanization accelerates worldwide, municipalities are attempting to construct new green spaces within their borders. The perceived ecological value of these places is frequently tied to their ability to attract urban wildlife, such as birds, which can easily be observed and enjoyed. As one strategy, stormwater is now frequently managed with green infrastructure: planted areas that retain and treat stormwater rather than merely directing it to surface waters. While these practices have the potential to provide habitat for urban wildlife, the ecological effects of these systems are largely unknown. To assess whether one green infrastructure project increases habitat value, we used passive acoustic monitoring to survey urban bird communities in and near a large green infrastructure project in Columbus, Ohio (USA). Bird communities near bioretention cells (rain gardens) were compared to those at nearby lawns and remnant or restored natural areas. We found that recently installed bioretention cells tended to support more omnivores, lower-canopy foraging species, and species from a higher diversity of feeding guilds than did nearby lawn control sites. We were unable to detect effects of nearby bioretention installations on bird species richness at other sites. The observed differences in species richness were fairly small, and we urge caution when anticipating the habitat value of bioretention cells, at least for bird species. However, the results that we observed suggest that bioretention cells could have a more positive impact on bird communities in different contexts or using different design strategies. The bioretention cells surveyed in this study were small and only planted in grasses and forbs, potentially limiting their ability to offer complex habitat. They were also relatively young, and future work is needed to determine their long-term effect on avian communities and biodiversity of other taxa.

Evaluation of statistical process control charts for infant mortality monitoring in Brazilian cities with different population sizes.

OBJECTIVES: The control chart is a classic statistical technique in epidemiology for identifying trends, patterns, or alerts. One meaningful use is monitoring and tracking Infant Mortality Rates, which is a priority both domestically and for the World Health Organization, as it reflects the effectiveness of public policies and the progress of nations. This study aims to evaluate the applicability and performance of this technique in Brazilian cities with different population sizes using infant mortality data. RESULTS: In this article, we evaluate the effectiveness of the statistical process control chart in the context of Brazilian cities. We present three categories of city groups, divided based on population size and classified according to the quality of the analyses when subjected to the control method: consistent, interpretable, and inconsistent. In cities with a large population, the data in these contexts show a lower noise level and reliable results. However, in intermediate and small-sized cities, the technique becomes limited in detecting deviations from expected behaviors, resulting in reduced reliability of the generated patterns and alerts.

Capacity analysis of short-distance continuous diversion areas on mountainous urban expressways.

The short-distance continuous diversion area plays a crucial role within mountainous urban expressway systems, significantly enhancing the efficiency of specialized road sections through capacity analysis. This study develops a capacity calculation model tailored to the diversion area's unique characteristics and principal capacity-influencing factors. Initially, the research focuses on a specific short-distance continuous diversion area of a mountainous urban expressway, employing video trajectory tracking technology to gather trajectory data. This data serves as the basis for analyzing road and traffic characteristics. Subsequently, the model computes the capacity influenced by eight variables, including diversion point spacing and deceleration lane length, using VISSIM simulation experiments. A gray correlation analysis identifies key factors, which guide the establishment of the model's fundamental structure through two-factor surface fitting results. Mathematical statistical methods are then applied to resolve the model's parameters, culminating in a robust capacity calculation model. The findings reveal that diversion point spacing, along with primary and secondary diversion ratios, significantly influence capacity. Notably, the capacity exhibits a marked quadratic polynomial relationship with the primary diversion ratio and diversion point spacing, and a linear relationship with the secondary diversion ratio. The model's validity is confirmed through a case study at the diversion area north of Huacun Interchange in Chongqing Municipality, where the discrepancy between calculated and actual capacities is under 5%, underscoring the model's high accuracy. These results offer valuable theoretical and methodological support for the planning, design, and traffic management of diversion areas.

Extensive investigation of seasonal and spatial fluctuations of BTEX in an industrial city with a health risk assessment.

There are many pollutants in the air that can be harmful to human health. Their impact varies based on factors such as the kind of pollutant, duration of exposure, and concentration levels. Volatile organic compounds are particularly significant carcinogens among the various pollutants present in the air. Consequently, people who are exposed to these harmful airborne pollutants suffer permanent consequences. This study examines the properties of BTEX compounds-benzene, toluene, ethylbenzene, and xylene-as well as their sources and risk assessments throughout a one-year period from March 21, 2019, to March 20, 2020, in Karaj, Iran's largest industrialized city. First, utilizing a geographical information system that covered the entire city, 17 locations within Karaj were chosen for this purpose. Then, samplings were carried out in the spring, summer, autumn, and winter months with the NIOSH 1501 method. During the research period, 68 samples of BTEX compounds were collected. The adsorption of these contaminants on the activated carbon adsorbents was performed using an environmental sampling pump with a flow rate of 0.2 L/min for 1 h. The samples were subsequently prepared using a carbon disulfide solution and injected into a GC-FID for analysis. In this research, the average annual concentration of BTEX compounds in the air of Karaj city was obtained at 33.01 µg/m3. Autumn and spring had the highest and lowest average concentrations of BTEX compounds, respectively. In addition, sites 5 and 8 had the highest average annual concentrations of these pollutants. The sourcing conducted in this study showed that transportation and fuel consumption, as well as industries, were the primary sources of pollution in the city. In addition, the excess lifetime cancer risk was higher than the guideline value in some sites and lower in others. Furthermore, the Hazard Quotients were lower than 1, but in general, the citizens of Karaj were at serious risk from exposure to this group of pollutants.

Variance in odds ratios for estimating the deterrent effect of darkness on cycling: Variation due to the choice of case and control hours.

Comparing the counts of cyclists travelling at specific times of day is one approach to measuring the impact of ambient light level. Here we investigate one source of variance in the magnitude of change seen in previous research-the choice of case and control hour. This was done through an analysis of cyclist flows using data from multiple automated cyclist counters in five cities (Arlington, Bergen, Berlin, Birmingham and Leeds) to determine the odds ratios (OR) for each combination of case and control hour. The results tend to reveal odds ratios above 1.0 indicating that cycling can be deterred by darkness. The odds ratios varied with the choice of case and control hour. For two cities (Birmingham and Leeds), the impact was small, with little difference in ORs between any case and control hour combination. For three cities the variance in ORs was larger. To represent the impact of darkness on cycling flows across the range of case and control hours we suggest the Mantel-Haenszel pooled odds ratio is used, in which the odds ratio for each combination of case and control hour is weighted by the total number of cyclists in that combination. This suggested a statistically significant (p<0.001) deterrent effect of darkness in all five cities.