Trends of Urban Air Pollution in Zhengzhou City in 1996-2008

Urban air pollution is a commonly concerned environmental problem in the world. Identification of air quality trend using long-term monitoring data is helpful to understand the effectiveness of pollution control strategies. This study, using data from six monitoring stations in Zhengzhou City, analyzed the changing trend in concentrations of SO2, NOJNO2 and TSP/PM10 in 1996-2008, based on non-parametric Mann-Kendall test and Sen＇s slope estimator, and evaluated the comprehensive air pollution level using Multi-Pollutant Index （MPI）. It was found that the concen- tration of each pollutant exceeded obviously the World Health Organization （WHO） guideline value, but the changing trend varied： SO2 and NO2 were significantly increased mainly due to an increase in coal consumption and vehicle number, while NOx, TSP and PM10 decreased. The air pollution was serious, and differed markedly among the three functional regions： it is the most severe in the Industrial and Residential Area （IRA）, followed by the Transportation Hub and Business District （THBD）, and then the High-tech, Cultural and Educational Area （HCEA）. Different from NO2 concentration that had a similar change trend/rate among the function regions, the change rate of PM10 concentra- tion differed spatially, decreased much more obviously in THBD than other two regions. For the whole city, the com- prehensive air pollution level declined gradually, illustrating that the air quality in Zhengzhou was improved in the last decade.

A Framework of Environmental Modelling and Information Sharing for Urban Air Pollution Control and Management

More effective environmental pollution control and management are needed due to the increasing environ-mental impacts from a range of human activities and the growing public demands for a better living environment. Urban air pollution is a serious environmental issue that poses adverse impacts on the health of people and the environment in most metropolitan areas. In this paper,we propose a geoinformatics augmented framework of environmental modelling and information sharing for supporting effective urban air pollution control and management. This framework is out-lined in terms of its key components and processes including: 1) an integrated,adaptive network of sensors for envi-ronmental monitoring; 2) a set of distributed,interoperable databases for data management; 3) a set of intelligent,robust algorithms and models for environmental modelling; 4) a set of flexible,efficient user interfaces for data access and in-formation sharing; and 5) a reliable,high capacity,high performance computing and communication infrastructure for integrating and supporting other framework components and processes.

Study on the Layout of Urban Planning in Rapid Urbanization Areas under the Background of Air Pollution

China＇s urbanization has been over the medium-term process,which has made great achievements,but also triggered a huge problem of air pollution. Air pollution has become a big problem after the water pollution in China,and a serious threat to people＇s life and health. Under the background of ＂ the construction of beautiful China＂ and rapid urbanization,how to build a beautiful home has become the focus of attention. Taking Shenyang as an example,the author contrastively analyses the spatial distribution of the main air pollutants（ PM10,PM2. 5,and SO2） and the present situation of land use,and thus finds out the rules between pollutants distribution and land use. Then combining the urban planning scheme and the rules obtained above,reasonable suggestions are proposed for the scheme to improve the air quality,and reduce or avoid air pollution,and providing the basis for the construction of a piece of blue sky. The conclusions are as follows： 1 air pollutants concentration above Light Oil Gas Making Factory in south vice city of Shenyang reaches the peak value,and industrial point source is the main air pollutants emission source; 2 pollutants concentration above greenbelt is the lowest; 3 the overall spatial structure of urban planning can insulate the industrial agglomeration areas to some extent; greenbelt planning covers 40%- 50% of the area with high concentration of air pollutants,and it is suggested to achieve full coverage; traffic planning can achieve shunt most of the pollutants in many regions,but it can also expand the scope of pollutants in some certain regions,in such regions,it should reduce the road density.

The effect of hosting international mega-events on urban haze pollution in China:Based on a quasi-natural experiment

With the rapid economic and social development of China,more and more Chinese cities are hosting important international events.However,the long-term effects of hosting international events on urban haze pollution are rarely discussed in existing literature.Based on the quasi-natural experiment of China hosting the G20 Hangzhou Summit in 2016,this paper applies the synthetic control method (SCM) for the first time to evaluate the impact of the G20 Hangzhou Summit on urban haze pollution in China.Compared with the traditional method,SCM measures the long-term impact of hosting the G20 Summit on haze pollution more scientifically.The results show that hosting the G20 Summit did improve the haze pollution in Hangzhou.The effectiveness and robustness of the above conclusions are objectively confirmed by multi-dimensional tests such as placebo test,permutation test,iterative test and difference-in-differences model.Further mechanism analysis shows that foreign direct investment and technological innovation are important channels for the G20 Summit to curb haze pollution in Hangzhou.At the same time,this paper employs a series of methods to systematically evaluate the impact of the G20 Hangzhou Summit on haze pollution in both time and space dimensions.This paper provides a credible basis and empirical support for the impact of international mega-events on air pollution in China.

Impact of Remote and Local Sources on Particulate Matter in Urban Environment

In this paper, the impact of natural and anthropogenic sources on particulate matter with diameter less than 10 μm (PM10) was investigated in Jeddah urban area, Saudi Arabia to identify and quantify the major particle pollution source classes. Hourly data of PM10 and other gaseous pollutants (NOx, CO, SO2 and O3) and meteorological factors (temperature, relative humidity, atmospheric pressure, wind speed and wind direction) were collected at two air quality monitoring sites for the period of March 2008 to February 2009. The air mass origin was determined using 5-day backward trajectories arriving to Jeddah by using HYSPLIT model. Results show that the PM10 Daily Limit Value was exceeded. The most frequent air masses entering Jeddah and thereby influencing PM10 concentrations come from the East, specifically the SE and NE directions, 84% of the trajectories were originated over the Arabian Peninsula including Saudi Arabia mainland and the Arabian Gulf. The Mediterranean Sea and southern Europe were the origin source of 8% of the air mass trajectories, another 8% were originated from North Africa and Sahara Desert. The majority of PM10 episodes were attributed to the intrusion of dust to Jeddah urban air.

Spatio-Temporal Air Pollutant Characterization for Urban Areas

Urban pollution has now become increasingly recognized as an important determinant of air pollution in developed countries. The effect of urban air pollution in developing countries, on the other hand, has not been adequately addressed in the data Spatio-temporal time series. Thus, this study was intended to characterize the effect of urbanization on air pollution for an urbanized Klang Valley, Malaysia using Spatio-temporal data from 2008 to 2017. The Air Pollution Index (API) data and local pollutant concentration were employed to establish the links between urban air pollution. The analysis will be supported by determining the source of pollutants during the study period using Principal Component Analysis (PCA). The study identified that Carbon monoxide (CO), Nitrogen Dioxide (NO2), and Ozone (O3) are the major air pollution that has contributed to degrading air quality in the Klang Valley due to the vehicles, combustion process, and industries.

New approaches to characterizing urban air particles in central London

Atmospheric particles in central London during July 1996 have been apportioned to sources by two complimentary techniques: (1) morphological characteristics, determined using high power light microscopy; (2) chemical composition determined by energy dispersive spectroscopy. During the study period, the majority of particles were found to be either biological in origin, or from vehicle related combustion processes. Trends in the latter group of particles are explored further. Numbers of particles per cubic metre were determined at an hourly resolution over a period of six days, and were found to be significantly correlated with other traffic pollutants such as benzene and 1,3 butadiene, although there is no relationship with mass of PM10 as measured by a nearby UK Government monitoring station. We suggest in this paper that numbers of particles from car exhausts are more representative of traffic pollution than current estimates which use monitoring by mass.

A Microscale Model for Air Pollutant Dispersion Simulation in Urban Areas： Presentation of the Model and Performance over a Single Building

A microscale air pollutant dispersion model system is developed for emergency response purposes. The model includes a diagnostic wind field model to simulate the wind field and a random-walk air pollutant dispersion model to simulate the pollutant concentration through consideration of the influence of urban buildings. Numerical experiments are designed to evaluate the model＇s performance, using CEDVAL （Compilation of Experimental Data for Validation of Microscale Disper- sion Models） wind tunnel experiment data, including wind fields and air pollutant dispersion around a single building. The results show that the wind model can reproduce the vortexes triggered by urban buildings and the dispersion model simulates the pollutant concentration around buildings well. Typically, the simulation errors come from the determination of the key zones around a building or building cluster. This model has the potential for multiple applications; for example, the prediction of air pollutant dispersion and the evaluation of environmental impacts in emergency situations; urban planning scenarios; and the assessment of microscale air quality in urban areas.

Random walk modeling of wake dispersion for the exhaust tower of an underground tunnel in urban area

In this paper, some experimental studies on the impact of effluent from an exhaust tower of an underground tunnel with special construction are reported. By measuring the flow field downstream of the tower in NJU meteorological wind tunnel, some flow characteristics in the make area were established. Based on these, an advanced random\|walk dispersion model was set up and applied successfully to the simulation of dispersion in the wake area. The modelling results were in accordance with wind tunnel measurements. The computed maximum of ground surface concentration in the building case was a factor of 3-4 higher than that in the flat case and appeared much closer to the source. The simulation indicated that random walk modelling is an effective and practical tool for the wake stream impact assessment.

Effects of Aeration on Nitrification Process in a Polluted Urban River

[Objective] The study aimed to discuss the effects of aeration on nitrification process in a polluted urban river, [Metbod] Through indoor simulation experiments, the effects of different aeration conditions （aerating water named Ew, aerating sediment named Es ） on nitrification process in a polluted urban river were studied.[ Result]The nitrification of the control group named Ec proceeded slowly, while two kinds of aeration promo- ted the process of nitrification, that is, the peak values of nitrate nitrogen of Ew and Es group were respectively 5.15 and 3.83 times that of Ec group. During aeration, NO2 --N accumulation in the overlying water of Ew and Es group lasted for 10 and 14 days separately, and the maximum concentrations reached 11.41 and 7.41 mg/L respectively. Nitrification process was not consistent during the two aeration conditions, that is, the rate of nitrite oxidation in Ew group was faster than that in Es group. Denitrification process was significant after aeration, and the concentration of nitrate nitrogen in Ew and Es group was 1.26 and 2.82 mg/L respectively at the end of the experiment. [ Conclusion]The research could provide scientific references for the restoration of polluted urban rivers.

Assessment of Pollution Levels of Suspended Particulate Matter on an Hourly and a Daily Time Scale in West African Cities: Case Study of Ouagadougou (Burkina Faso)

In Western countries, research works on air quality have reinforced in recent years because of the links between the level of particulate pollution in numerous cities and the appearing of various health disorders including cardio-respiratory pathologies, acute bronchopneumonia, lung cancer, etc. In sub-Saharan Africa countries, particularly Burkina Faso, there is very few similar research. In the present work, the pollution levels of airborne particle in the city of Ouagadougou have been assessed through two campaigns of in situ measurements of suspended particulate matter concentrations. These measurements which have concerned PM1, PM2.5 and PM10 were performed using a portable device (AEROCET531S) at nine sites in 2018 and at ten sites in 2019. These sites are located on roadside, administrative services, secondary education establishments and outlying districts. The results show that: 1) the PM1 concentrations values presented no significant variation between days, seasons or sampling sites;2) the 24-hour PM2.5 concentrations often exceeding WHO recommended concentrations and, 3) the 24-hour PM10 concentrations exceed WHO recommended concentrations regardless of the season or the sampling site. In indeed, the average 24-hour concentrations are 20 ± 4, 87 ± 16 and 951 ± 266 μg·m−3 for the PM1, PM2.5 and PM10, respectively. They are 17 ± 3, 29 ± 5 and 158 ± 43 μg·m−3, respectively, in 2018 dry season and, 12 ± 1, 22 ± 9 and 187 ± 67 μg·m−3, respectively, in 2019 rainy season.

Variability in the Levels of BTEX at a Pollution Hotspot in New Delhi, India

It is a matter of concern that despite taking measures to control aromatic content in gasoline in India, the levels of volatile organic compounds are rising again in many of the Indian cities. The transport sector has been one of the major sectors which are re-sponsible for worsening the air quality of Delhi city. While thousands of toxic com-pounds are emitted from automobiles, industries, gasoline stations as well as service stations, however, volatile organic compounds are important due to their significant contribution to ozone formation, cancer, and non-cancer health risks. In this study, roadside levels of benzene, toluene, ethylbenzene and xylenes (BTEX) were investi-gated at the one of the major arterial road of Delhi city. Air samples were collected by activated coconut shell charcoal adsorbent tubes. The BTEX concentrations were de-termined by gas chromatography-flame ionization detector (GC-FID) technique. The mean concentrations of benzene, toluene, ethylbenzene and xylenes were, respectively, 60.22, 162.68, 49.42 and 25.25 μg/m3. The relative concentration distribution pattern and mutual correlation analysis indicated that in BTEX had sources other than vehicle emission at the study site. The samples collected, showed that BTEX had significantly higher concentrations in winter than those in spring and summer.

Estimating Exposure to Traffic-Related Air Pollution and Its Consequences on Respiratory Health in Population Working or Living along the Trunk Road: A Systematic Review

Introduction: Urban Air pollution is increasingly becoming a major health and sustainable development issue. Several studies showed that Traffic-related air pollution (TRAP) is one of the main sources of urban air pollution and has serious consequences on respiratory health. As no systematic review focused on the traffic-related air pollution and respiratory health in the target population of individuals working in a shop or in an office or individuals living along the trunk road, the authors conducted the current study to try to fill this gap. Methods: A systematic review search was conducted using MEDLINE (PubMed), Scientific Research Publishing: SCIRP, Web of Science, Google scholar. Studies were included if they meet the following selection criteria: 1) focus on population working or living along a major/trunk road; 2) studies had reported clearly at least on the exposure variables related to TRAP; 3) the association between TRAP and development of respiratory symptoms or respiratory diseases was established. Results: 13 articles were selected on the 192 articles that were retrieved in the initial research. Exposure to traffic-related air pollution was determined by using distance to road, traffic intensity and pollutants measured. The main respiratory health problems found were cough, wheeze, asthma and bronchitis. No article discussed about roundabouts in characterizing exposure to traffic-related air pollution. Conclusion: Distance to road, traffic density and pollutants measured are the usual methods to characterize the exposure to traffic-related air pollution and its consequences on respiratory health. Regarding the context of area occupations in African cities, it is necessary to focus on population around roundabouts and see if they are not more exposed to TRAP.

Development and experience in the monitoring,assessment and control of environmentalpollutants in Hong Kong

The late start of environmental protection in Hong Kong was discussed in the light of problems encountered during the development of environmental protection legislation in Hong Kong for the past 20 years. The collaboration in monitoring and assessment of environmental pollutants between the University of Hong Kong and various governments were descrbed in parallel with the progress in environmental protection in Hong Kong. The developments of new analytical techniques for environmental monitoring and analysis is given and their application in environmental control described. The joint projects in assessment and control of environmental pollutants carried out in collaboration with local industries and other organizations within and without the university are given and discussed. The problems and possible solution facing Hong Kong in development control equipment for small scale industries are discussed and areas of development identified. The development and experience in the monitoring assessment and control of environmental pollutants in Hong Kong are summarized and areas of difficulties are illustrated.

Positive and negative turbulent heat diffusivity observed on a 325-m meteorological tower in Beijing

Turbulent diffusion efficiently transports momentum,heat,and matter and affects their transfers between the atmosphere and the surface.As a key parameter in describing turbulent diffusion,the turbulent heat diffusivity KH has rarely been studied in the context of frequent urban pollution in recent years.In this study,KH under urban pollution conditions was directly calculated based on K-theory.The authors found an obvious diurnal variation in K_(H),with variations also in the vertical distributions between each case and over time.Interestingly,the height corresponding to the high occurrence frequency of negative K_(H) rises gradually after sunrise,peaks at noon,falls near sunset,and concentrates around 140 m during most of the night.The KH magnitude and fluctuation are smaller in the pollutant accumulation stage(CS)at all levels than in the pollutant transport stage and pollutant removal stage.Turbulent diffusion may greatly affect PM_(2.5) concentrations at the CS because of the negative correlation between PM_(2.5) concentrations and the absolute value of KH at the CS accompanied by weak wind speeds.The applicability of K-theory is not very good during either day or at night.These problems are inherent in K-theory when characterizing complex systems,such as turbulent diffusion,and require new frameworks or parameterization schemes.These findings may provide valuable insight for establishing a new turbulence diffusion parameterization scheme for KH and promote the study of turbulent diffusion,air quality forecasting,and weather and climate modeling.

Assessment of Organic Compounds as Vehicular Emission Tracers in the AburráValley Region of Colombia

The Aburrá Valley region in Colombia, with Medellín as its main city, is an urban centre with about three million people. An investigation was carried out to deter-mine a set of baseline concentrations for VOC compounds associated with diesel fuel and gasoline, as vehicular emission tracers in the region. The VOC measurement campaigns, based on TENAX tube sampling and analysis according to TO-17 EPA method, were done in areas of low and high vehicular flow as well as on-board measurements covering major Medellín road networks during 24 hours. The results showed that there was a relation between VOCs concentrations and vehicular activi-ty. The diesel fuel sulfur content was also found as an important factor on VOC hy-drocarbon formation.

Intercomparison of NO_x, SO_2, O_3, and Aromatic Hydrocarbons Measured by a Commercial DOAS System and Traditional Point Monitoring Techniques

A field-based Intercomparison study of a commercial Differential Optical Absorption Spectroscopy (DOAS) instrument (OPSIS AB, Sweden) and different point-sample monitoring techniques (PM, based on an air monitoring station, an air monitoring vehicle, and various chemical methods) was conducted in Beijing from October 1999 to January 2000. The mixing ratios of six trace gases including NO, NO2, SO2, O3, benzene, and toluene were monitored continuously during the four months. A good agreement between the DOAS and PM data was found for NO2 and SO2. However, the concentrations of benzene, toluene, and NO obtained by DOAS were significantly lower than those measured by the point monitors. The ozone levels monitored by the DOAS were generally higher than those measured by point monitors. These results may be attributed to a strong vertical gradient of the NO-O3-NO2 system and of the aromatics at the measurement site. Since the exact data evaluation algorithm is not revealed by the manufacturer of the DOAS system, the error in the DOAS analysis can also not be excluded.

Particulate matter geochemistry of a highly industrialized region in the Caribbean:Basis for future toxicological studies

Air pollution has become an important issue,especially in Caribbean urban areas,and,particulate matter(PM)emitted by different natural and anthropogenic sources causes environmental and health issues.In this work,we studied the concentrations of PM_(10) and PM_(2.5) sources in an industrial and port urban area in the Caribbean region of Colombia.PM samples were collected within 48-h periods between April and October 2018 by using a Partisol 2000 i-D sampler.Elemental geochemical characterization was performed by X-ray fluorescence(XRF)analysis.Further,ionic species and black carbon(BC)were quantified by ion chromatography and reflectance spectroscopy,respectively.Using the Positive Matrix Factorization(PMF)receptor model,the contributions of PM sources were quantified.The average concentration of PM_(10) was 46.6±16.2μg/m^(3),with high concentrations of Cl and Ca.For PM_(2.5),the average concentration was 12.0±3.2μg/m^(3),and the most abundant components were BC,S,and Cl.The receptor model identified five sources for PM_(10) and PM_(2.5).For both fractions,the contributions of marine sea spray,re-suspended soil,and vehicular traffic were observed.In addition,PM_(2.5) included two mixed sources were found to be fuel oil combustion with fertilizer industry emissions,and secondary aerosol sources with building construction emissions.Further,PM_(10) was found to also include building construction emissions with re-suspended soil,and metallurgical industry emissions.These obtained geochemical atmospheric results are important for the implementation of strategies for the continuous improvement of the air quality of the Caribbean region.

Influence of urban air pollution on the population in the Klang Valley,Malaysia:a spatial approach

Background:Urban air pollution resulting from economic growth as well as urbanization impacts the health of inhabitants.This study aims to examine the spatial distribution of particulate matter(PM_(10))and the risk of exposure for the population in the Klang Valley,an urban conglomeration centred in Kuala Lumpur,Malaysia.Methods:The inverse distance weighted(IDW)interpolation technique in the ArcGIS platform was used to map the air quality from five air monitoring stations.Spatial statistics of the Global Moran’s I Spatial Autocorrelation and Optimized Hot Spot Analysis were used to estimate the spatial clustering of PM_(10).The population-weighted exposure level(PWEL)technique was used to calculate the population density susceptible to PM_(10)and the AirQ+model was applied to estimate the proportion of the adult population at risk of chronic bronchitis due to long-term exposure to PM_(10)concentrations in the Klang Valley.Results:The highest annual mean PM_(10)concentrations at the Klang station ranged between 80 and 100μg/m^(3)from 2000 to 2009 and exceeded the New Malaysia Ambient Air Quality Standard(NMAAQS)and the World Health Organi-zation Air Quality Guidelines(WHOAQG)levels of 40 and 20μg/m^(3),respectively.The Moran’s I results indicated that the statistically significant clusters of high PM_(10)in Klang present a health risk to the local community.The PWEL results showed that levels of PM_(10)in Petaling Jaya exceeded the WHOAQG limits,potentially posing a health risk to the high-density population.The AirQ+model found Klang to be a significantly high-risk area for chronic bronchitis among the adult population with 804,240 people(with a relative risk of 1.85)in 2009.Conclusion:These high-risk values are due to rapid urbanization and high motor vehicle usage in the Klang Valley and therefore the impact of PM_(10)on the population needs to be reduced.This situation should be taken seriously by the Department of Environment and Kuala Lumpur City Hall in addressing air pollution issues through stricter rules on emissions and implementing low-carbon policies to improve the well-being of residents.