Air Quality In Urban Areas Research Articles

Editorial: Indoor environmental air quality in urban areas

Editorial: Indoor environmental air quality in urban areas

Environmental friendly energy resources improving air quality in urban area

The article concerns a very important issue related to the air quality in Kraków, a historic city with a rich history and cultural tradition. Kraków is the capital of the Małopolska Voivodeship, located in southern Poland. Due to the common phenomenon of smog in winter and the related problem of significant exceedances of permissible air pollutants, Kraków was the first city in Poland which implemented a complete ban on the combustion of solid fuels (coal, wood and also all types of biomass). It is allowed to use only district heat, gaseous fuels, light fuel oil, electricity and renewable energy sources as heat pumps, solar collectors and photovoltaics. The article attempts to analyze the results of air quality tests in the period after the implementation of restrictions on the type of energy sources used in relation to the previous years. The starting point for this analysis is the presentation of emissions of combustion products of energy carriers with various calorific values in heating devices with various energy efficiency. Environmental aspects are also analyzed, such as average annual temperatures, wind speeds and directions, precipitation, and the number of days with fog. Thanks to this, the picture of the changes introduced in Kraków becomes complete and allows you to understand the environmental effects that have occurred. The analysis of air quality was carried out with regard to six pollutants: TSP (total suspended particulate), PM10 and PM2.5 particulate matter, benzo(a)pyrene, sulfur dioxide (SOx), and nitrogen oxides (NOx). Additionally equivalent emission has been calculated. The obtained results indicate an improvement in air quality in relation to the previous heating periods, which allows to draw a conclusion that regulatory actions such as a ban on the burning of solid fuels was justified and that this sector (individual heat generation) has a significant impact on the state of the environment. A significant reduction in all analyzed pollutants – TSP, PM10 and PM2.5, B(a)P and SOx is evident, and the only the exception is NOx.

Towards zero pollution vehicles by advanced fuels and exhaust aftertreatment technologies

Vehicular emissions deteriorate air quality in urban areas notably. The aim of this study was to conduct an in-depth characterization of gaseous and particle emissions, and their potential to form secondary aerosol emissions, of the cars meeting the most recent emission Euro 6d standards, and to investigate the impact of fuel as well as engine and aftertreatment technologies on pollutants at warm and cold ambient temperatures. Studied vehicles were a diesel car with a diesel particulate filter (DPF), two gasoline cars (with and without a gasoline particulate filter (GPF)), and a car using compressed natural gas (CNG). The impact of fuel aromatic content was examined for the diesel car and the gasoline car without the GPF. The results showed that the utilization of exhaust particulate filter was important both in diesel and gasoline cars. The gasoline car without the GPF emitted relatively high concentrations of particles compared to the other technologies but the implementation of the GPF decreased particle emissions, and the potential to form secondary aerosols in atmospheric processes. The diesel car equipped with the DPF emitted low particle number concentrations except during the DPF regeneration events. Aromatic-free gasoline and diesel fuel efficiently reduced exhaust particles. Since the renewal of vehicle fleet is a relatively slow process, changing the fuel composition can be seen as a faster way to affect traffic emissions.

Observing Downwind Structures of Urban HCHO Plumes From Space: Implications to Non‐Methane Volatile Organic Compound Emissions

AbstractNon‐methane volatile organic compounds (NMVOCs) have a significant impact on air quality in urban areas. Detecting NMVOCs emission with its proxy HCHO on urban scales from space, however, has been limited by the lack of discernible enhancement. Here we show clear urban HCHO plumes from 16 cities over the globe by rotating TROPOspheric Monitoring Instrument HCHO pixels according to wind directions. We fit the downwind structure of the plumes with the exponentially modified Gaussian approach to quantify urban HCHO effective production rates between 7.0 and 88.5 mol s−1. Our results are in line with total NMVOC emissions from the EDGAR inventory (r = 0.76). Our work offers a new measure of total NMVOC emissions from urban areas and highlights the potential of satellite HCHO data to provide new information for monitoring urban air quality.

Unlocking Urban Insights: A Case Study on Impact of Urban Vegetation on Volatile Organic Compounds (VOCs) Variability Across Different Areas of Reggio Emilia, Italy

The Po Valley is one of the European regions most severely affected by air pollution. Within the spectrum of airborne molecules, Volatile Organic Compounds (VOCs) represent a significant component, derived from both natural processes and anthropogenic sources. All VOCs influence air quality, as they are precursors to ozone (O3), secondary organic aerosol (SOA), and particulate matter (PM). While naturally occurring VOCs contribute to the formation of air pollutants, they also have beneficial effects on human health. Furthermore, vegetation plays a fundamental role in air purification and improvement of air quality both directly, through the metabolic processes of leaves, and indirectly, through physical mechanisms.
 This study aims to evaluate the qualitative and quantitative fluctuations of VOCs in different zones within the city of Reggio Emilia (Italy), characterized by varying percentages of vegetation cover and proximity to high-traffic roads. The collected data suggest that air quality may be influenced by the spatial distribution and type of urban area, with urban parks and green zones showing lower concentrations of total VOCs compared to areas with less vegetation cover. These observations can contribute to formulating strategies to improve air quality in urban areas and emphasize the importance of vegetation in an urban context.

Smart logistic for sustainable cities

The United Nations has agreed on sustainable cities to be one of a series of sustainable development goals (SDGs) as the eleventh goal. This shows the seriousness of the world government in viewing the role of cities to participate in building the concept of sustainability. However, on the other hand, the phenomenon of urbanization continues to increase from year to year. The increase in urbanization is followed by an increase in the number of motorized vehicles, including logistics activities in it. The increase in logistics and transportation activities has a negative impact on air quality in urban areas with its CO2 emissions. Poor air quality will certainly hamper a city's efforts in achieving the concept of sustainability or sustainable cities. Thus, solutions to improve logistics activities are needed in an effort to achieve the sustainability of a city. In today's digital era, the role of technology is enormous including in the field of logistics, by integrating technology with logistics activities, more optimal solutions related to efficiency and so on will be more easily recorded. This integration concept is known as smart logistics. This research presents the results of a review of various literatures to define the concept of sustainable cities, the concept of smart logistics, and what logistics solutions have been studied before and how these solutions can answer the challenges posed in the development of the concept of sustainable cities

Human Health Risks and Interference of Urban Landscape and Meteorological Parameters in the Distribution of Pollutant: A Case Study of Nakhon Si Thammarat Province, Thailand

Recently, the air quality in urban areas has declined because of increasing traffic emissions. This paper aimed to determine the toxicity from exposure to pollutants among three sensitive groups of residents in urban areas. Moreover, this study also estimated the impacts of landscape and meteorological conditions on the accumulation of air pollutants in these areas. The results showed that the annual average concentration in the town exceeded the WHO air quality guidelines. Other areas that had a high traffic density also presented unacceptable levels according to the hazard quotient (HQ value ≥ 1). It was found that the air quality in the town had declined. This study also found that people living in a tropical monsoon climate should avoid exposure to air pollution in both the summer and rainy seasons; even though the pollutant concentration is lower in the rainy season, the longer exposure time causes unacceptable health risks. Humidity showed a strong impact on gas pollutant reduction (rs = −0.943). The pollutants tended to increase in areas with a high density of main roads. Additionally, building density affected the accumulation of pollutants in near-source areas and blocked pollutants in receptor areas. Therefore, this study suggests that local authorities should provide vegetation infrastructure for a sustainable air quality improvement in urban areas.

The Landscape Urban Planning Approach for Improving Urban Air Quality, Case Study of Algiers, Algeria

Gardens and urban parks are areas of great importance for the support of the urban ecosystem, in addition to their psychological and therapeutic values; they provide the urban environment with a large amount of oxygen. Trees produce oxygen through the operation of photosynthesis; one hectare of eucalyptus tree annually produces oxygen for 37 to 80 people, and absorbs 25, 000 kg of carbon dioxide for the same period of time. Wooded zone in urban areas significantly improve and purify the quality of the air that we breathe and make living environments healthier. A recent study carried out by the World Health Organization (WHO) revealed that the MENA region (Middle East and North Africa) is one of the most polluted in the world, air polluted by particulate matter smaller than 2.5µm (PM2.5). For the case of Algiers, measurements were taken during the first two months of the year 2023 by the station of the United States Embassy in Algiers, showed that daily average of 14 µm/m3 for particulate matter less than 2.5 µm/m3 and a daily average of 50 for the IQA, air quality index. According to the US EPA's NAAQS, any measurement above 12.0 μg/m 3 (US AQI 50) may be hazardous to human health. Several factors of an exogenous and endogenous nature act directly on the quality of the air in large urban concentrations, CO2 emissions, modes and nature of urban mobility, uncontrolled urban sprawl. High population densities, urban forms, morphology, the size of cities, which getting larger and larger, the choice of urbanization models, and the surface of wooded areas, all are, factors responsible for air quality. This study will be particularly interested in the contribution of gardens, parks and wooded areas in improving air quality, and consequently on the quality of the living environment in urban areas. In this respect, and to understand the situation, we take the city of Algiers as a case study. The field work will allow us to understand in a qualitative and quantitative way the contribution of the tree and the choice of tree species, understanding co-relation between landscape architecture decision and results obtained on the urban air quality, and try to research on how it would possible to improve air quality in urban areas by using trees new essence.

Towards Cleaner Cities: An Analysis of the Impact of Bus Fleet Decomposition on PM and NOX Emissions Reduction in Sustainable Public Transport

The problem of poor air quality in urban areas has a negative impact on the health of residents. This is especially important during periods of smog. In Poland, as in other countries, the problem of poor air quality, especially during the winter season, is associated with a high concentration of particulate pollutants in ambient air (PM10, PM2.5). Sources of particulate emissions, in addition to solid-fuel boilers, include means of transportation, especially those equipped with diesel engines. In turn, during periods of strong sunshine (spring and summer), the problem of photochemical smog, whose precursors are nitrogen oxides NOX, arises in urban areas. Their main sources of emissions are internal combustion engines. Therefore, to improve air quality in urban areas, changes are being made in the transport sector, among which is upgrading the fleet of urban transport vehicles to low- or zero-emission vehicles, which are more environmentally friendly. In addition, measures that reduce the harmfulness of the transportation sector to air quality include the introduction of clean transportation zones, as well as park-and-ride (P&R) systems. The purpose of this article is to present the results in terms of PM10, PM2.5, and NOx emission reductions, implemented over a period of two years (2021–2022) in the area of the Rzeszow agglomeration, related to the modernization of the suburban bus fleet and the implementation of a P&R system for passenger cars. The results of the study were compared with the value of estimated emissions from coal-fired boilers used for residential heating and hot water, which also contribute to smog. Thanks to the implementation of the project, i.e., the replacement of 52 old buses with new buses of the Euro VI emission class and the construction of new P&R spaces, the total average annual reduction in emissions amounted to approximately 703.6 kg of PM10, approximately 692.7 kg of PM2.5, and a reduction of approximately 10.4 tons of NOX.

Vertical distribution of air pollutants in an urban street canyon during winter air pollution episodes in Shenyang, China

Understanding the vertical distribution of air pollutants in urban street canyons is crucial to improve air quality in urban areas. Previous studies on air pollutants during air pollution episodes primarily focused on their distribution in rural areas, but rarely considered urban street canyons. To investigate such episodes in urban environments, we recorded concentrations of particulate matter (PM) with diameters of less than 2.5 μm and 10 μm (PM2.5 and PM10, respectively), ozone (O3), and carbon monoxide (CO), as well as air temperature, relative humidity, wind speed, wind direction, and atmospheric pressure, every minute, at bottom, middle, and roof levels in an urban street canyon in Shenyang, China, between December 2018 and March 2019. The study period included three air pollution episodes. Results indicated that PM was the primary contributor to air pollution during all episodes. During air pollution episodes, PM concentrations were higher at roof level, with increasing PM concentration differences between the bottom, middle, and roof height levels; O3 concentrations decreased; CO concentrations did not vary significantly. Additionally, higher relative humidity and lower air temperature enhanced particle formation but slowed photochemical reactions, yielding lower O3 concentrations. Finally, we established that wind speed in the street canyon depended more on canyon morphology than on the pollution level.

Patterns and Influencing Factors of Air Pollution at a Southeast Chinese City

Ambient air pollution is a pressing global environmental problem. To identify the source of air pollution and manage air quality in urban areas, the patterns of air pollutants under different traffic conditions and the impact of weather on air quality were explored in Hangzhou, China, a city experiencing rapid growth in vehicles. Data for particulate matters (PM10, PM2.5, PM1.0, and UFP), gaseous pollutants (CO, SO2, O3, and NO), and weather parameters (temperature, relative humidity, wind speed, and air pressure) were collected at two venues with different traffic conditions. An exploratory factor analysis was employed to identify the main factors contributing to air quality. The results showed that PMs, particularly PM1.0 and UFP, significantly contributed to air quality in monitoring venues, especially at Venue 2. As the leading factor, PMs contributed 40.85%, while gaseous pollutants and traffic (particularly fuel type) contributed 30.46% to air quality. The traffic was an independent contributor at Venue 2. Temperature and wind speed had negative influences on air pollutants. The outcomes of the study suggest that exhaust emissions from vehicles, particularly PM1.0 and UFP from heavy-duty vehicles, contributed significantly to ambient air quality. The contribution of meteorological factors to air quality varied at different venues and should not be ignored.

Monitoring Aerosol Optical Depth for Air Quality Through Himawari-8 in Urban Area West Java Province Indonesia

Air quality is a crucial parameter in human life. One air quality indicator can be observed through Aerosol Optical Depth (AOD). If these substances are pollutants such as particulate matter, aerosols, and ozone, it is confident that air quality will deteriorate, threatening human health and causing climate change. AOD monitoring can be used as a basis for policymakers and related parties to maintain the stability of air quality in the atmosphere. Many ground observation stations monitor air quality by obtaining data on PM2.5 and PM10 aerosol particles. However, the number of ground stations is limited, resulting in incomplete data. Fortunately, remote sensing satellites have the advantage of covering large areas and providing continuous observations, with the ability to gather information on large-scale aerosol and obtain spatiotemporal distribution. Therefore, this research aims to obtain AOD through Himawari-8 and analyze the spatiotemporal air quality in urban areas of West Java based on AOD. The research methodology used in this study is descriptive analysis with an empirical research approach. Assisted by remote sensing technology and Geographic Information Systems, this research generates AOD data extraction that can be obtained from the new generation satellite of Himawari-8. The distribution of AOD levels and spatiotemporal monitoring in urban areas of West Java is very dynamic depending on anthropogenic activity in a particular area and time. Keywords: Aerosol Optical Depth (AOD), Air Quality, Himawari-8

The Impact of Shipping on Air Quality in the Port Cities of the Mediterranean Area: A Review

Shipping emissions contribute significantly to air pollution at the local and global scales and will do so even more in the future because global maritime transport volumes are projected to increase. The Mediterranean Sea contains the major routes for short sea shipping within Europe and between Europe and East Asia. For this reason, concern about maritime emissions from Mediterranean harbours has been increasing on the EU and IMO (International Maritime Organization, London, UK) agenda, also supporting the implementation of a potential Mediterranean Emission Control Area (MedECA). Many studies are concerned with the impact of ship emissions in port cities. Studies of the contributions of ship emissions to air quality at the local scale include several monitoring and modelling techniques. This article presents a detailed review of the contributions of ship emissions of NO2, SO2, PM10, and PM2.5 on air quality in the main ports in the Mediterranean area. The review extracts and summarises information from published research. The results show a certain variability that suggests the necessity of harmonisation among methods and input data in order to compare results. The analysis illustrates the effects of this pollution source on air quality in urban areas, which could be useful for implementing effective mitigation strategies.

Estimasi Emisi Kendaraan Bermotor untuk Memprediksi Beban Pencemar Udara CO dan NOx di Tempat Pelelangan Ikan Kota Kendari

Transportation has a positive impact in supporting community activities and helps determine regional development through the distribution of goods and services, besides that it also has a negative impact on the environment, especially air quality in urban areas. Fish Auction Place is a place that is usually located in a port or fish landing base and in that place, there is a sale of fish and marine products either by auction or not. This study aims to observe the prediction of motor vehicle emission load by using analytical prediction studies and simple statistical data about the possible estimates of vehicle emissions produced by motorized vehicles at the Kendari City Fish Auction Place. Based on the results of the study, the volume of vehicle traffic passing at the Kendari City Fish Auction Place was 1,774 vehicles/hour, 8,517 vehicles/day, and 3,100,664 vehicles/year. The type of motorcycle vehicle is the vehicle that passes the most while the bus is the vehicle that passes the least at the research location. It is known that the largest CO emission load is produced by motorcycle vehicles, which is 3.8981 tons/year, and the smallest is produced by buses at 0.0011 tons/year. While the largest NOx emission load is generated by diesel-fueled cars, which is 0.1369 tons/year and the smallest is generated by bus vehicles, which is 0.0012 tons/year.

Noise impact evaluations of an outdoor air filter tower in urban blocks

Although air filter towers are commonly used to improve air quality in urban areas, their operation often produces significant noise levels, and their noise impact is unknown. In this research paper, a case study on the noise impacts of an outdoor air filter tower in city open areas and on building façades is conducted by noise mapping. Noise levels around the filter tower were first measured in situ, and a prediction model for noise mapping was built and well-calibrated by comparing the predicted and measured results. Noise mapping was then carried out to investigate noise exposure in city open areas and on façades in four typical urban blocks with different morphology. Simulated results highlight noise level improvement with the increase of façade height at some high-rise buildings whose heights are higher than the neighboring ones. In addition, urban morphology, including building height and density, as well as the distance between the source and the building, has an impact on noise exposure. The utilization of sound-absorbing building envelopes has been identified as an effective means of reducing noise on building façades, with a maximum attenuation of approximately 4 dB(A) observed, but the effectiveness of this method is limited at certain positions. This study provides valuable insights into the impact of filter towers on noise levels and offers suggestions for urban sound planning.

The use of radon as a tracer for air quality assessment: a case study in Bratislava, Slovakia

Air quality in urban areas is mainly controlled by emission sources and dispersion conditions. The mixing layer height (MLH) within which the pollutants are dispersed plays an important role in air pollution assessment. In this study, the MLH was determined based on the daily radon flux obtained from the European radon flux map and outdoor radon concentration measured in Bratislava, Slovakia. The radon-based MLH was compared with the boundary layer height obtained from the ERA-5 reanalysis dataset, showing good agreement. Using the Sturges grouping method and regression analysis, radon-based MLH showed significant correlations with the concentration of various atmospheric pollutants.

Smart solutions for urban health risk assessment: A PM2.5 monitoring system incorporating spatiotemporal long-short term graph convolutional network

Current spatial-temporal early warning systems aim to predict outdoor air quality in urban areas either at short or long temporal horizons. These systems implemented architectures without considering the geographical distribution of each air quality monitoring station, increasing the uncertainty of the forecasting framework. This study developed an integrated spatiotemporal forecasting architecture incorporating an extensive air quality PM2.5 monitoring network and simultaneously forecasts PM2.5 concentrations at all locations, allowing the monitoring of the health risk associated with exposure to these levels. First, this study uses a graph convolutional layer to incorporate the spatial relationship of the neighboring stations at their current state with real-time measurements. Then, it is coupled to a deep learning temporal model to form the long- and short-term time-series graph convolutional network (LSTGraphNet) model, anticipating high pollutant concentration events. This work tested the proposed model with a case study of an existing ambient air quality monitoring network in South Korea. LSTGraphNet model showed prediction performances of PM2.5 at multiple monitoring stations with a mean absolute error (MAE) of 1.82 μg/m3, 4.46 μg/m3, and 4.87 μg/m3 for forecasting horizons of one, three, and 6 h ahead, respectively. Compared to conventional sequential models, this architecture was superior among the state-of-the-art baselines, where the MAE decreased to 41%, respectively. The results of the study showed that the proposed architecture was superior to conventional sequential models and could be used as a tool for decision-making in smart cities by revealing hotspots of higher and lower PM2.5 concentrations in the long term.

Photocatalytic Oxidation of NO2 on TiO2 : Evidence of a New Source of N2 O5.

N2 O5 is an important intermediate in the atmospheric nitrogen cycle. Using a flow tube reactor, N2 O5 was found to be released from the TiO2 surface during the photocatalytic oxidation of NO2 , revealing a previously unreported source of N2 O5 . The rate of N2 O5 release from TiO2 was dependent on the initial NO2 concentration, relative humidity, O2 /N2 ratio, and irradiation intensity. Experimental evidence and quantum chemical calculations showed that NO2 can react with the surface hydroxyl groups and the generated electron holes on the TiO2 , followed by combining with another NO2 molecule to form N2 O5 . The latter was physisorbed on TiO2 and had a low adsorption energy of -0.13 eV. Box model simulations indicated that the new source of N2 O5 released from TiO2 can increase the daytime N2 O5 concentration by up to 20 % in urban areas if abundant TiO2 -containing materials and high NOx concentrations were present. This joint experimental/theoretical study not only demonstrates a new chemical mechanism for N2 O5 formation but also has important implications for air quality in urban areas.

Photocatalytic Oxidation of NO2 on TiO2: Evidence of a New Source of N2O5

AbstractN2O5 is an important intermediate in the atmospheric nitrogen cycle. Using a flow tube reactor, N2O5 was found to be released from the TiO2 surface during the photocatalytic oxidation of NO2, revealing a previously unreported source of N2O5. The rate of N2O5 release from TiO2 was dependent on the initial NO2 concentration, relative humidity, O2/N2 ratio, and irradiation intensity. Experimental evidence and quantum chemical calculations showed that NO2 can react with the surface hydroxyl groups and the generated electron holes on the TiO2, followed by combining with another NO2 molecule to form N2O5. The latter was physisorbed on TiO2 and had a low adsorption energy of −0.13 eV. Box model simulations indicated that the new source of N2O5 released from TiO2 can increase the daytime N2O5 concentration by up to 20 % in urban areas if abundant TiO2‐containing materials and high NOx concentrations were present. This joint experimental/theoretical study not only demonstrates a new chemical mechanism for N2O5 formation but also has important implications for air quality in urban areas.

Effects of Urban Form on Ambient Air Filter Noise Exposure in Open Areas

Although ambient air filters are commonly used to improve air quality in urban areas, their operation often produces significant noise levels. In this study, we investigated and addressed the issue of ambient air filter noise exposure in open areas of Chinese cities, with a focus on various typical urban forms. Firstly, fifteen common urban blocks with different forms and of 250 × 250 m each were chosen as sample sites, for which urban form indices and noise distribution indices were defined. Then noise mapping was conducted to investigate air filter noise exposure in open areas and the effects of urban form indices on noise distribution indices. Results show that urban form has considerable effects on filter noise exposure in open areas. Among the six urban form indices examined, the distance between the first-row building and the air filter was found to be the most critical factor affecting noise levels with the highest correlation coefficient (R = 0.754). The orientation of the first-row building shows the significant resisting effect on both average and background noise levels. Furthermore, the resisting effect of first-row buildings can create a maximum reduction of 12.0 dB (A) for peak noise. These indices could be profiled and used as an “a priori” tool for urban sound environment planning.