Concentrations In Urban Areas Research Articles

Summertime tropospheric ozone source apportionment study in the Madrid region (Spain)

Abstract. The design of emission abatement measures to effectively reduce high ground-level ozone (O3) concentrations in urban areas is very complex. In addition to the strongly non-linear chemistry of this secondary pollutant, precursors can be released by a variety of sources in different regions, and locally produced O3 is mixed with that transported from the regional or continental scales. All of these processes depend also on the specific meteorological conditions and topography of the study area. Consequently, high-resolution comprehensive modeling tools are needed to understand the drivers of photochemical pollution and to assess the potential of local strategies to reduce adverse impacts from high tropospheric O3 levels. In this study, we apply the Integrated Source Apportionment Method (ISAM) implemented in the Community Multiscale Air Quality (CMAQ v5.3.2) model to investigate the origin of summertime O3 in the Madrid region (Spain). Consistent with previous studies, our results confirm that O3 levels are dominated by non-local contributions, representing around 70 % of mean values across the region. Nonetheless, precursors emitted by local sources, mainly road traffic, play a more important role during O3 peaks, with contributions as high as 25 ppb. The potential impact of local measures is higher under unfavorable meteorological conditions associated with regional accumulation patterns. These findings suggest that this modeling system may be used in the future to simulate the potential outcomes of specific emission abatement measures to prevent high-O3 episodes in the Madrid metropolitan area.

Fine Particle Formation and Dependence of Wet Deposition on Precipitation Intensity in an Urban Area

ABSTRACT In order to understand the characteristics of the change of aerosol concentration in an urban area and the impact of meteorological conditions on aerosol concentration in urban areas, particle concentration and size distribution were measured using an aerosol particle counter and an aerosol spectrometer in Hefei, China in spring 2017. Meteorological data, such as temperature, relative humidity, wind speed, wind direction, and shortwave radiation, were measured on a meteorological tower. The concentration of coarse mode (d > 2.5 μm, d is particle diameter), accumulation mode (0.25 μm<d < 2.5 μm), and ultrafine (Aitken and nucleation mode, d < 0.25 μm) particles under different meteorological conditions were recorded. Results show that, approximately 10–20 min after the solar downward shortwave radiation decreases (rises), the ultrafine particles (UFPs) concentration decreases (rises). Diurnal change in radiation causes daily change in the concentration of UFPs, and when the relative humidity was low, UFP generation easily occurs. On wet deposition, the concentration of coarse mode particles is significantly reduced during precipitation, and the concentration of accumulation mode particles varies during heavy precipitation and slight precipitation. Because of the combined action of wet deposition and hygroscopic growth, the concentration of accumulation mode particles first increases and then decreases. And during the slight precipitation, the concentration only increases with the relative humidity.

Advancing nuanced pollution control: Local improvements and spatial spillovers of policies on key enterprises

This paper examines the impact of air pollution control policies targeting key polluting enterprises, highlighting a strategic shift towards precision pollution control that concentrates on high-emission, high-risk businesses. The paper explores the efficacy of these policies and their potential spatial spillover effects, utilizing panel data from 259 Chinese cities from 2013 to 2021. Employing the difference-in-differences (DID) model and spatial Durbin model, the study analyzes both the direct local effects and the broader spatial consequences of these regulatory measures on air quality. The findings indicate a significant reduction in air pollutant concentrations in urban areas, attributing this improvement to factors such as industrial restructuring, increased investment in science and technology, and economic growth. Spatial econometric analysis further reveals a substantial positive correlation in air quality among Chinese cities. However, estimates of the spillover effect indicate that while such policies successfully reduce pollution locally, they could unintentionally degrade air quality in adjacent areas. The study highlights the need for nuanced policy strategies to mitigate unintended spatial spillovers and enhance overall effectiveness. It recommends tailored policies that integrate environmental and socioeconomic objectives, national and regional coordination for consistent enforcement, technology-driven compliance strategies, and incentives for sustainable enterprise practices.

Investigation of ambient BTEX concentrations along a bus rapid transit route in Tabriz: Spatio-temporal variations and health risk assessment

Urgent actions are imperative to assess ambient BTEX concentration in urban areas and increase awareness of the significant health risks linked to exposure to these volatile compounds. This study examines the spatiotemporal variations of BTEX concentration in BRT stations and provides a health risk assessment in Tabriz, located in the northwest of Iran. We collected samples repeatedly from four BRT stations and three areas between stations (N = 86). The mixture BTEX compounds had average concentrations ranging from 6.7 to 52.9 μg/m3, with the highest concentration belonging to o-xylene. Additionally, the average ratios of toluene/benzene, m-xylene/benzene, and o-xylene/benzene were 2.4, 2.3, and 3.0, respectively. Total BTEX concentrations were significantly higher in BRT stations than areas between stations. Furthermore, the concentration of total BTEX doubled in the evening compared to the morning. Although the maximum concentrations of BTEX were recorded in winter, there were no significant seasonal differences. The lifetime cancer risk (LCR) of benzene exposure was 1.07 × 10−7 and 1.52 × 10−5 for passengers and residents located in the vicinity of the BRT lane, respectively. In conclusion, this study suggests that emissions from BRT buses are one of the main contributors to BTEX in Tabriz.

ANALISIS KONSENTRASI PARTIKEL MIKRO AMBIENT PADA FUNGSI PARU POPULASI URBAN JAKARTA

Introduction: The potential impact on lung function due to high exposure to ambient microparticles in cities such as Jakarta has not been comprehensively studied. The background of this research is based on the lack of studies regarding the impact of high micro-particle exposure in major cities like Jakarta on lung function. Research Objective: The purpose of this study is to investigate the relationship between the dominant levels of ambient micro-particle concentration in urban areas of Jakarta and changes in spirometry indices among its residents. Method: A cross-sectional approach was used to determine the relationship between ambient micro-particle concentration and irregularities in spirometry indices among the urban population of Jakarta. This study involved 187 adults, aged between 20 to 65 years, mostly from the busy urban sectors of Jakarta. Statistical techniques of association and logistic regression were used for the assessment of the collected data. Results: The average exposure to ambient micro-particles was 315 µg/m³. Aberrations in spirometry indices were detected in 41.2% of participants. A significant relationship was found between high micro-particle concentrations and anomalies in spirometry readings among urban residents of Jakarta. This correlation remained significant after considering confounding factors such as gender, duration of exposure, local ventilation quality, smoking habits, and prevailing humidity. Conclusion: The results of this analysis suggest that the dominant levels of ambient micro-particles in the urban areas of Jakarta may play an important role in causing variations in spirometry results among its inhabitants..

Особенности концентраций аэроаллергенов в городах и влияние на них температуры воздуха

Aim: to examine the content of plant pollen and fungal spores in the air of Karakol city (Kyrgyz Republic) during the seasons from 2015 to 2017. Materials and Methods: in the course of the aerobiological study, samples containing bioparticles (plant pollen and fungal spores) were collected from the air. The samples were identified to the genus or family level, or, in some cases, to the species level, and quantified by visual counting in the field of view of a microscope. A Lanzoni volumetric pollen and spore trap was placed on the roof of a building within the city borders (Karakol) at a height of 13 m above ground level, away from park areas and industrial enterprises. A total of 630 atmospheric air samples were collected from April to September in 2015-2017. Results: the taxa Artemisia spp., Poaceae, Chenopodiaceae, and Pinus spp. exhibited the greatest abundance in the aerobiological spectrum of Karakol. Among the fungi, Alternaria, Cladosporium, and Fusarium were the most prevalent. The majority of fungal spores (60–76%) were observed during the period from June to August. The absolute maximum of pollen in the air coincided with high temperature values in the area. The highest concentrations of Artemisia pollen were observed from mid to late July, which corresponded to an increase in the average daily air temperature over the study seasons. The highest Artemisia pollen content in the air (61–72%) for the study seasons was observed in Karakol at air temperatures ranging from 28.3 to 33.4°C. High temperatures contribute to the release of spores into the atmosphere. It can be observed that allergenic species of fungi are accumulated in urban environments rather than in natural areas. Conclusion: the quantitative and qualitative profile of pollen from the dominant species of allergenic plants and fungal spores in the air environment of Karakol city was determined in order to contribute to the study of the aerobiological situation. It is important to determine the impact of meteorological factors on the concentration of plant pollen and fungal spores. This will allow for the prediction of the behavior of aeroallergens in a changing climate. KEYWORDS: plant pollen, fungal spores, aerobiological monitoring, climate change, air temperature, biological air particles, aeroallergens. FOR CITATION: Osmonbaeva K.B., Churyukina E.V., Dzhambekova G.S., Nazarova E.V. Aeroallergen concentrations in urban areas and the effect of air temperature. Russian Medical Inquiry. 2024;8(3):124–131 (in Russ.). DOI: 10.32364/2587-6821-2024-8-3-2.

A SCREENING OF THE HYDROGEN SULFIDE LEVELS IN PLOIEȘTI CITY, ROMANIA

Oil refineries and petrochemical facilities contribute to the pollution of the environment either air, water, or soil releasing hazardous and toxic air pollutants into the atmosphere. These include nitrogen oxides (NOx), carbon monoxide (CO), hydrogen sulfide (H2S), sulfur dioxide (SO2), and particulate matter (PM), affecting both environment and human health. In the range of air pollutants, hydrogen sulfide is less monitored and reported despite its importance in determining adverse effects. Background H2S concentrations in air were found to range commonly from 0.11 ppb to 0.33 ppb. The concentrations in urban areas can reach 1 ppb (~1.4 g m-3) up to more than 90 ppb (~125 g m-3) near sources of H2S emissions. In Romania, the standard for the air in protected areas for the hydrogen sulfide pollutant provides an admissible concentration, over a maximum interval of 30 minutes, of 15 µg/m³. Everything that exceeds this value is considered harmful to human health. The statistics for the H2S time series recorded in Ploiești City by the mobile laboratory of the Environmental Protection Agency Prahova between 2019 and 2021 with a sampling rate of 30 minutes showed that the mean ranged between 1.51 and 3.74 µg/m³, while the maximum reached 59.36 µg/m³ in the east of Ploiești in 2019. Overall, the highest variance occurred in the East and North parts due to the presence of the concentration peaks. Hydrogen sulfide must be considered on the public health agenda, both from the occupational perspective and for the ambient concentrations near significant H2S sources and in background urban areas. The monitoring infrastructure needs to be improved to allow continuous surveillance to ensure reliable databases that support research regarding the health effects of H2S across the concentrations occurring in the urban environment.

Characterization of spatial-temporal distribution and microenvironment source contribution of PM2.5 concentrations using a low-cost sensor network with artificial neural network/kriging techniques

Low-cost sensors (LCS) network is widely used to improve the resolution of spatial-temporal distribution of air pollutant concentrations in urban areas. However, studies on air pollution sources contribution to the microenvironment, especially in industrial and mix-used housing areas, still need to be completed. This study investigated the spatial-temporal distribution and source contributions of PM2.5 in the urban area based on 6-month of the LCS network datasets. The Artificial Neural Network (ANN) was used to calibrate the measured PM2.5 by the LCS network. The calibrated PM2.5 were shown to agree with reference PM2.5 measured by the BAM-1020 with R2 of 0.85, MNE of 30.91%, and RMSE of 3.73 μg/m3, which meet the criteria for hotspot identification and personal exposure study purposes. The Kriging method was further used to establish the spatial-temporal distribution of PM2.5 concentrations in the urban area. Results showed that the highest average PM2.5 concentration occurred during autumn and winter due to monsoon and topographic effects. From a diurnal perspective, the highest level of PM2.5 concentration was observed during the daytime due to heavy traffic emissions and industrial production. Based on the present ANN-based microenvironment source contribution assessment model, temples, fried chicken shops, traffic emissions in shopping and residential zones, and industrial activities such as the mechanical manufacturing and precision metal machining were identified as the sources of PM2.5. The numerical algorithm coupled with the LCS network presented in this study is a practical framework for PM2.5 hotspots and source identification, aiding decision-makers in reducing atmospheric PM2.5 concentrations and formulating regional air pollution control strategies.

NH3 emissions from the human body in central Tokyo decreased during the COVID-19 pandemic lockdown

Atmospheric NH3 is emitted from various sources, such as agriculture, automobile exhaust, industrial activities, and human bodies (dermal and respiratory). Although the contribution from automobile exhaust to NH3 concentrations in urban areas is well understood, the contribution from human body emissions has not been clarified, even in densely populated areas far from agricultural and industrial sources. Tokyo, Japan, is the one of the most populated megacities in the world. During April and May 2020, socioeconomic activities in Tokyo were severely restricted to prevent the spread of the coronavirus disease (COVID-19), resulting in significant changes in human flow and automobile traffic. The sudden decrease in emissions presented a unique opportunity to clarify the contributions of human body emissions to NH3 levels. NH3 concentrations observed in central Tokyo from 2018 to 2021 decreased significantly, by about 20%, during the lockdown in 2020. No significant differences were found in wind speed or rainfall during the same period. Air quality model simulations of NH3 concentrations in the area were performed for 2019 and 2020. The simulation results for 2019 reproduced the observed NH3 concentrations and temporal variations well. However, the simulation results were overestimated for 2020. To evaluate the differences in emissions' contributions during the lockdown, sensitivity tests of NH3 emissions’ strength were conducted for 2020. The simulation in which NH3 emissions from automobiles and human bodies were reduced by 20% and 80%, respectively, reproduced the observed results well. These results indicate that emissions from human bodies and automobile traffic contribute significantly to NH3 concentrations in central Tokyo. The contributions from human body emissions to NH3 concentrations revealed in this study should be applied to update emissions factors for human bodies; clarifying human emissions factors under various conditions will improve the accuracy of air quality simulations over densely populated megacities.

Complex study of air pollution based on tree species in Vienna

Plants are especially useful as biological indicators to assess air pollution and the effects of urbanisation. The aim of this study was to investigate tree species’ sensitivity to air pollution using the Air Pollution Tolerance Index (APTI), the dust content (PM10) of leaves, and the heavy metal concentration of leaves. Sampling sites were in a city park (urban area), a location on the edge of the city (suburban area), and a forested location (rural area) along an urbanisation gradient in the city of Vienna in Austria. Leaf samples were collected from Acer platanoides, Fraxinus excelsior, and Quercus robur tree species. The APTI was determined by measuring the content of relative water ascorbic acid and chlorophyll, and the pH of leaf extracts. We found significant difference among species in their relative water content, pH, and content of ascorbic acid and chlorophyll Additionally, we found significant differences in chlorophyll content and pH based on sampling site. The highest chlorophyll content was found in A. platanoides. There was a significant difference among species in Al, Ba, Cr, Ni, and Zn concentrations in each stage of urbanisation. Based on APTI values, the studied species were sensitive indicators of air pollution; thus, they are useful bioindicator species, and they are suitable for air pollution monitoring. We demonstrated the effects of urbanisation with these bioindicator species with elevated PM10, Al, Ba, Cu, Fe, Sr, and Zn concentrations in urban area samples.Graphical abstract

Seasonal variations of microplastics in surface water and sediment in an inland river drinking water source in southern China

The aim of this study was to examine microplastic (size distribution of 0.05–5 mm) occurrence and distribution in drinking water source of XJ River during both flooding and dry periods. Surface water and sediment samples were collected from the CS City section of the river in August and December 2020. During the flooding period, microplastic abundances were observed at 0.72–18.6 (7.32 ± 2.36) items L−1 in surface water and 26.3–302 (150 ± 75.6) items kg−1 dry weight (dw) in sediment. In the dry period, abundances were slightly higher at 2.88–17.7 (11.0 ± 3.08) items L−1 and 27.0–651 (249 ± 182) items kg−1 dw, respectively. Microplastics were found in higher concentrations in urban areas and downstream of wastewater treatment plants, suggesting anthropogenic sources. The diversity in shapes, colors, and types of microplastics in surface waters and sediments indicates specialized enrichment processes and persistent sources of microplastic pollution. Approximately 60 % of the microplastic particles identified fall within the 50–100 μm range. Furthermore, a significant correlation was observed between these smaller-sized particles and the overall prevalence of microplastics. Fourier-transform infrared spectroscopy and scanning electron microscopy indicated that the microplastics had been subjected to weathering in the environment, contributing to the production of oxygen-containing functional groups and surface cleavage features. The utilization of energy dispersive spectroscopy revealed the presence of microplastics associated with various heavy metals, highlighting the intricate nature of microplastic pollution. Moreover, the high abundance of microplastics may pose a potential ecological risk to the aquatic environment of the XJ River. The results of this study demonstrate concerning levels of microplastics in the XJ River, despite its status as a high-quality water source.

A two-way coupled regional urban–street network air quality model system for Beijing, China

Abstract. Owing to the substantial traffic emissions in urban areas, especially near road areas, the concentrations of pollutants, such as ozone (O3) and its precursors, have a large difference compared to regional averages, and their distributions cannot be captured accurately by traditional single-scale air quality models. In this study, a new version of a regional urban–street network model (an Integrated Air Quality Modeling System coupling regional urban–street: IAQMS-street v2.0) is presented. An upscaling module is implemented in IAQMS-street v2.0 to calculate the impact of mass transfer to regional scale from street network. The influence of pollutants in the street network is considered in the concentration calculation on the regional scale, which is not considered in a previous version (IAQMS-street v1.0). In this study, the simulated results in Beijing during August 2021, using IAQMS-street v2.0, IAQMS-street v1.0, and the regional model (Nested Air Quality Prediction Modeling System, NAQPMS), are compared. On-road traffic emissions in Beijing, as the key model input data, were established using intelligent image-recognition technology and real-time traffic big data from navigation applications. The simulated results showed that the O3 and nitrogen oxide (NOx) concentrations in Beijing were reproduced by using IAQMS-street v2.0 on both the regional scale and street scale. The prediction fractions within a factor of 2 (FAC2s) between simulations and observations of NO and NO2 increased from 0.11 and 0.34 in NAQPMS to 0.78 and 1.00 in IAQMS-street v2.0, respectively. The normalized mean biases (NMBs) of NO and NO2 decreased from 2.67 and 1.33 to −0.25 and 0.08. In the coupled model, the concentration of NOx at the street scale is higher than that at the regional scale, and the simulated distribution of pollutants on a regional scale was improved in IAQMS-street v2.0 when compared with that in IAQMS-street v1.0. We further used IAQMS-street v2.0 to quantify the contribution of local on-road traffic emissions to the O3 and NOx emissions and analyze the effect of traffic regulation policies in Beijing. Results showed that heavy-duty trucks are the major source of on-road traffic emissions of NOx. The relative contributions of local traffic emissions to NO2, NO, and O3 concentrations were 53.41 %, 57.45 %, and 8.49 %, respectively. We found that traffic regulation policies in Beijing largely decreased the concentrations of NOx and hydrocarbons (HC); however, the O3 concentration near the road increased due to the decrease consumption of O3 by NO. To decrease the O3 concentration in urban areas, controlling the local emissions of HC and NOx from other sources requires consideration.

Reducing PM 2.5 seasonal concentration in urban areas could reduce the number of hospital admissions in Cote d'Ivoire

Reducing PM 2.5 seasonal concentration in urban areas could reduce the number of hospital admissions in Cote d'Ivoire

Modelled atmospheric concentration of tyre wear in an urban environment

Microplastics are emitted to the environment from many sources, and transported via water, soil and air. The airborne component is less well studied and measurements often focus on particles larger than 10 μm, while smaller particles are worse from a health perspective and likely more abundant. Measurement studies do often not include tyre wear, which is a large source of microplastics in urban areas. To improve the understanding of the microplastics concentration in urban areas, simulations of emissions and concentrations of atmospheric tyre wear particles (TWP) over Stockholm are performed. The results show that TWP are ubiquitous in urban areas, with highest concentrations along busy highways and in poorly ventilated street canyons. Yearly average roof level concentrations of TWP-PM10 range from 0.2 μg m−3 in areas with moderate traffic to 1.2 μg m−3 close to busy highways. Average yearly concentrations at three selected street canyons range from 0.7 to 1.1 μg m−3. The modelled concentrations correspond to 4–6% of the total measured PM10 concentration. TWP emissions are expected to increase with increasing traffic in future, and possibly also with the increase in vehicle weight with electric vehicles and SUV:s.

Radon Concentration in Urban Areas in the North and West of Morocco

Radon is a colorless, odorless radioactive gas produced by the decay of uranium and radium. It is the second cause of cancer of the lungs after smoking. It has been present in Earth's crust since the creation of Earth. Uranium-rich rocks in the deep crust are the main source of radon. Its emanation from the ground surface varies from one point to another depending on the physical characteristics of the terrain crossed as observed in this study between North and West Morocco. A dosimetric study of those emanations was performed by using the LR-115 solid-state nuclear track detector (SSNTD) which was subsequently processed by techniques developed and calibrated in the laboratory. The study revealed high concentrations of this gas in confined spaces at ground level and, in particular, in basements and less-ventilated ground floor rooms. In order to reduce these concentrations of radon and the probability of carcinogenic attacks by these accumulations of this gas, it is recommended to ventilate these premises well. Good air circulation allows the removal of this harmful gas.

The effect of spatial distribution on the composition of the middle social class in the Kingdom of Saudi Arabia: A spatial econometric analysis

This article examines the formation of the Saudi middle class using econometric models and a national survey of household budget and consumption data from 44,000 households in 2019. The study compares the spatial offset model (SAR) and spatial error model (SEM) with the Space Turbine Model (SDM) and Space Turbine Error Model (SDEM), finding that the SDM and SDEM models offer better benefits and options. The SDEM model exhibits the best-fit quality based on the Akaike information criterion. The results reveal a positive spatial effect indicating that human capital accumulation is vital in knowledge diffusion and technological transfer. The study also identifies spatial inequalities in the distribution of the middle class, with a concentration in urban areas like Riyadh and the Eastern Province. While the poor class is concentrated in rural areas which surround the main cities such (e.g., Rumah, Tawala, Hanak, Araar and Aljof) while the wealthy class is concentrated in urban areas, particularly Riyadh. The article emphasizes the importance of regional development and suggests measures to reduce inequality and enhance the middle class's role in the economy. In effect, the Saudi government should increase access to quality education and training by investing in the education system to provide citizens with the skills needed for a modern economy, including higher education, vocational training, and apprenticeships. Nevertheless, the Kingdom should promote entrepreneurship by creating an environment that encourages entrepreneurship and supports small business growth through tax incentives, access to capital, and start-up support. Moreover, the most important is improving access to finance by making it easier for businesses, especially small ones, to access finance through loan guarantees and support programs.

Vertical exchange and cross-regional transport of lower-tropospheric ozone over Hong Kong

In recent years, the escalating ozone concentrations in urban areas of China have raised significant public concern. Due to the lack of long-term vertical observation, the characteristics of vertical distribution and long-range transport of ozone are still not well understood. This study utilized 27 years (1994–2020) of ozone sounding observations in Hong Kong, in conjunction with the ERA5 reanalysis data and HYSPLIT backward model, to examine the vertical structure and three-dimensional cross-regional transport of tropospheric ozone over Hong Kong. During spring, ozone concentrations above 850 hPa are found to be higher than those observed during other seasons. Conversely, ozone concentrations below 850 hPa are comparatively elevated in autumn. The stratospheric-tropospheric exchange (STE) process is a crucial factor contributing to high ozone concentrations in the upper troposphere, with 46.2% of trajectories crossing the tropopause and becoming concentrated mainly in the eastern Yunnan–Guizhou Plateau. The study identified two obvious peaks in the lower troposphere above Hong Kong, with higher concentrations observed at approximately 700 hPa. The springtime ozone maximum is linked to the long-range cross-regional ozone transport from higher elevations in the Bay of Bengal and the Indo–China Peninsula, which moves eastward and downward under the influence of the southern branch trough. Additionally, transboundary transportation of fire emissions in Southeast Asia, influenced by monsoon circulation, also contributes to the high ozone concentrations during the observation. The autumn ozone maximum occurrs at approximately 925 hPa and is linked to boundary layer dynamics and the southward cross-regional transport of low-altitude ozone from the Pearl River Delta and Yangtze River Delta regions under the influence of the northeasterly Asian monsoon flow. The study advances our knowledge in understanding the vertical profile of ozone and emphasizes the importance of regionally-joint emission control particularly when meteorology-induced cross-regional transportation occurs.

The use of Nature-Based Solutions in the fight against Urban Floods: trends, actors and solutions adopted

The growing and accelerated population concentration in urban areas, which was not accompanied by proper planning, resulted in several problems, which are even more profound in developing countries. With the elimination of natural vegetation cover, the waterproofing of the soil and other human actions that did not respect environmental dynamics, it is possible to observe increases in the number of occurrences and in the intensity of phenomena, such as floods and urban floods. Such problems affect especially the population layer in conditions of greater socio- environmental vulnerability, since they often occupy risk areas, such as the river plains. In order to combat this problem, alternative actions are being used to the detriment of conventional actions linked to gray infrastructure. In this sense, Nature-Based Solutions emerge as an alternative way to avoid and reduce the intrinsic impacts of urban floods in cities, as well as being implemented in different ways and in different locations. Therefore, this work sought to identify actions that are being used by several cities in the world with ways to combat urban floods through Nature- Based Solutions. Therefore, a Systematic Literature Review was carried out, with bibliometric analysis, in order to identify processes, actors and trends related to the theme. In this way, it is concluded that, despite the importance given to the subject having grown in the last 6 years, mainly due to the increase in scientific production and the amount of solutions implemented in several countries, such trends are concentrated, to a large extent, in European cities and observed by European actors.

Structural Causality Between Road Traffic and Particulate Matter Concentrations in Urban Areas

Road traffic makes a major contribution to air pollution by emitting solid and liquid particles, also known as particulate matter, into the air. However, the causal relationship between road traffic and particulate matter emissions has not been adequately explored, primarily because traffic is the result of dynamic interactions involving many real-time variables, such as volume and speed. This study used structural equation modeling to quantify this complex causal relationship. A one-year survey using a mobile laboratory was conducted to collect data on particulate matter concentrations and traffic, which were then combined with weather statistics provided by the Korea Meteorological Administration. The key finding of this study suggests that greater attention in research and policy should be directed toward non-exhaust particulate matter emissions from road traffic.

A review of the sources, distribution sequences, and health risks associated with exposure to atmospheric polycyclic aromatic hydrocarbons

Atmospheric polycyclic aromatic hydrocarbons (PAHs) are associated with adverse health effects in exposed populations. Understanding PAH pollution in ambient air and its adverse impacts is essential for developing effective actions for combating air pollution. This review paper summarised and discussed the findings of research work that determined the concentrations, distribution sequence, and health risk exposure levels of atmospheric PAHs in cities worldwide. It also gave an overview of the sources and the methodology for appraising the health risk of exposure to atmospheric PAHs. Eighty-five articles published in peer-reviewed journals from 2010 to 2023 were identified in academic research databases, with 55 reporting on sources and distribution of atmospheric PAHs, while 30 evaluated the health risk of exposure to PAHs in ambient air. The narrative review approach was employed to critically analyse and produce descriptive summaries of distribution patterns and health risk exposure levels of atmospheric PAHs in a tabular form. The review showed that the total PAH concentration in urban areas was about eight times greater than in rural environments and emanated from diverse sources. However, vehicle exhaust and industrial emissions were the primary sources of atmospheric PAHs. The distribution sequence of PAHs in particulate and gas phases was HMW>MMW>LMW PAHs and LMW>MMW>HMW PAHs, respectively. Chronic exposure to PAHs in the environment increased the risk of asthma, cardiovascular disease, and lung cancer. Adoption of stricter emission standards, cleaner energy sources, and more efficient industrial technology will aid in the reduction of particulate PAH pollution and its negative health consequences in urban areas.