Urban Pollution Sources Research Articles

Interlocked Dual‐Network and Superelastic Electrospun Fibrous Sponges for Efficient Low‐Frequency Noise Absorption

Traffic noise is a major source of urban noise pollution, with severe threats to the physiological and psychological health of humans. Fibrous sound absorption materials are extensively applied in the control of traffic noise pollution; however, the larger fiber diameters and monotonous internal structure of such materials result in poor low‐frequency sound‐absorbing properties or unsatisfied mechanical properties. Herein, a biomimetic and robust strategy to design ultrastrong and superelastic fibrous sound absorption sponges is reported, which is achieved by integrating a one‐step forming technique of interlocked micro/nano dual fiber networks and an in situ crosslinking approach. The obtained vine‐like interlocked structured fibrous sponges can withstand a tensile force 10 000 times their weight without deformation. Furthermore, the materials also show outstanding compression fatigue resistance and a lightweight feature (8.70 mg cm−3). Most importantly, the interlocked dual‐network‐induced stable fluffy‐stacked structure endows the fibrous sponges with an enhanced low‐frequency sound‐absorbing property (absorption coefficient of 0.93 at 1000 Hz), which is superior to those of commercial and reported sound absorption materials. In addition, the materials also possess good hydrophobicity and temperature resistance. This work opens new pathways for the further development of highly efficient sound‐absorbing materials.

Spatiotemporal Patterns in River Water Quality and Pollution Source Apportionment in the Arid Beichuan River Basin of Northwestern China Using Positive Matrix Factorization Receptor Modeling Techniques.

Deteriorating surface water quality has become an important environmental problem in China. In this study, river water quality was monitored in July (wet season) and October (dry season) 2019 at 26 sites, and a water quality index (WQI) and positive matrix factorization (PMF) model were used to assess surface water quality and identify pollution sources in the Beichuan River basin, Qinghai Province, China. The results showed that 53.85% and 76.92% of TN, 11.54% and 34.62% of TP, 65.38% and 76.92% of Fe, and 11.54% and 15.38% of Mn samples in the dry and wet seasons, respectively, exceeded the Chinese Government’s Grade III standards for surface water quality. The spatial variation in water quality showed that it gradually deteriorated from upstream to downstream as a result of human activity. The temporal variation showed that water quality was poorer in the wet season than in the dry season because of the rainfall runoff effect. The PMF model outputs showed that the primary sources of pollution in the wet season were mineral weathering and organic pollution sources, domestic and industrial sewage, and agricultural and urban non-point pollution sources. However, in the dry season, the primary sources were mineral weathering and organic pollution sources, industrial sewage, and domestic sewage. Our results suggest that the point pollution sources (domestic and industrial sewage) should be more strictly controlled, as a priority, in order to prevent the continued deterioration in water quality.

Nanodomains in cardiopulmonary disorders and the impact of air pollution.

Air pollution is a major environmental threat and each year about 7 million people reported to die as a result of air pollution. Consequently, exposure to air pollution is linked to increased morbidity and mortality world-wide. Diesel automotive engines are a major source of urban air pollution in the western societies encompassing particulate matter and diesel exhaust particles (DEP). Air pollution is envisioned as primary cause for cardiovascular dysfunction, such as ischemic heart disease, cardiac dysrhythmias, heart failure, cerebrovascular disease and stroke. Air pollution also causes lung dysfunction, such as chronic obstructive pulmonary disease (COPD), asthma, idiopathic pulmonary fibrosis (IPF), and specifically exacerbations of these diseases. DEP induces inflammation and reactive oxygen species production ultimately leading to mitochondrial dysfunction. DEP impair structural cell function and initiate the epithelial-to-mesenchymal transition, a process leading to dysfunction in endothelial as well as epithelial barrier, hamper tissue repair and eventually leading to fibrosis. Targeting cyclic adenosine monophosphate (cAMP) has been implicated to alleviate cardiopulmonary dysfunction, even more intriguingly cAMP seems to emerge as a potent regulator of mitochondrial metabolism. We propose that targeting of the mitochondrial cAMP nanodomain bear the therapeutic potential to diminish air pollutant — particularly DEP — induced decline in cardiopulmonary function.

Modeling Emission Flow Pattern of a Single Cruising Vehicle on Urban Streets with CFD Simulation and Wind Tunnel Validation.

Transportation has become one of the primary sources of urban atmospheric pollutants and it causes severe diseases among city residents. This study focuses on assessing the pollutant dispersion pattern using computational fluid dynamics (CFD) numerical simulation, with the effect and results validated by the results from wind tunnel experiments. First, the wind tunnel experiment was carefully designed to preliminarily assess the flow pattern of vehicle emissions. Next, the spatiotemporal distribution of pollutant concentrations around the motor vehicle was modeled using a CFD numerical simulation. The pollutant concentration contours indicated that the diffusion process of carbon monoxide mainly occurred in the range of 0−2 m above the ground. Meanwhile, to verify the correctness of the CFD simulation, pressure distributions of seven selected points that were perpendicular along the midline of the vehicle surface were obtained from both the wind tunnel experiment and the CFD numerical simulation. The Pearson correlation coefficient between the numerical simulation and the wind tunnel measurement was 0.98, indicating a strong positive correlation. Therefore, the distribution trend of all pressure coefficients in the numerical simulation was considered to be consistent with those from the measurements. The findings of this study could shed light on the concentration distribution of platoon-based vehicles and the future application of CFD simulations to estimate the concentration of pollutants along urban street canyons.

Technology and the Effectiveness of Regulatory Programs over Time: Vehicle Emissions and Smog Checks with a Changing Fleet

Personal automobile emissions are a major source of urban air pollution. Many U.S. states control emissions through mandated vehicle inspections and repairs. But there is little empirical evidence directly linking mandated inspections, maintenance, and local air pollution levels. To test for a link, we estimate the contemporaneous effect of inspections on local air quality. We use day-to-day, within-county variation in the number of vehicles repaired and recertified after failing an initial emissions inspection, with individual-level data from 1998–2012 from California’s inspection program. Additional re-inspections of pre-1985 model year vehicles reduce local carbon monoxide, nitrogen oxide, and particulate matter levels, while re-inspections of newer vehicles with more modern engine technology have no economically significant effect on air pollution. This suggests emissions inspections have become less effective at reducing local air pollution as more high-polluting vehicles from the 1970s and 1980s leave the road, and provides an example of how the social efficiency of programs can change under improving technologies. We also estimate the importance of station quality, using a metric devised for California’s new STAR certification program. We show re-inspections of older vehicles conducted by low quality inspection stations do not change air pollution, while inspections at high quality stations have a moderate effect on pollution concentrations, which suggests the potential for ineffective monitoring at low quality inspection stations. We find little effect on ambient ozone levels, regardless of station quality or vehicle age.

Urban forests near municipal solid waste incinerators do not show elevated trace metal or rare earth element concentrations across three cities in the northeast USA.

With the World Bank estimating global municipal solid waste MSW to increase to 3.4 billion tonnes by 2050, municipal solid waste incineration (MSWI) needs to be considered as part of sustainable waste management. In spite of major advancements in air pollution control systems and emission regulations, emissions of trace metals (TMs) (As, Cd, Cu, Ga, Mn, Ni, Pb, V, W, Zn) and rare earth elements (REEs) (La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Yb) may occur. Here, leaves, wood, forest floor, and A horizons in urban forests were assessed to determine if TM and REE concentrations show enrichment near MSWI relative to other urban areas for three cities in the northeastern USA. Vegetation and soil concentrations measured were generally comparable to concentrations observed in previous studies in non-urban sites. Overall, higher TM and REE in forest floor, A horizons, leaves, and wood were not observed consistently for MSWI sites when compared to city sites. Although pooled forest floor Ni and V and A horizon La and Nd concentrations were significantly different, they were not consistent but driven by a large difference at one of the three cities. This indirect study suggests air pollution control systems have prevented or have reduced TM and REE emissions to local urban forests to negligible amounts. Further studies are needed to evaluate potential interferences from other urban air pollution sources, and conduct direct emission measurements to validate MSWIs are not emitting TMs and REEs.

State-of-the-art outlook for light-duty vehicle emission control standards and technologies in China

A surge in the size of the automobile population has caused vehicular emissions to become a major source of urban atmospheric pollution. Elevating standards is an effective method of controlling vehicular emissions and improving air quality. Light-duty vehicles are the major contributors to HC and CO emissions as they constitute a large proportion of all vehicles. Consequently, controlling light-duty vehicular emissions has been the primary means of air pollution prevention in China. This paper first reviews the progress of emission control standards in mainland China. Second, it analyzes features of the China 6 emissions standards, namely the continuation of European standards, the harmony of global technology regulations, and fusion with the standards of the USA. This is followed by a description and discussion of the status of research on mainstream after-treatment technologies such as the gasoline particulate filter, lean-NOx trap, and selective catalytic reduction. Finally, this study argues that the technical routes for implementing three-way catalysts, gasoline particulate filters, and onboard refueling vapor recovery in gasoline vehicles and diesel oxidation catalysts, diesel particulate filters, and selective catalyst reduction in diesel vehicles meet China 6 standards. Moreover, onboard diagnostics-based control of light vehicle emissions is introduced, and the development directions of vehicle gasoline (the reduction in sulfur, olefin, and aromatic content and vapor pressure control in summer) and vehicle diesel (an increase in the Cetane number and reduction in the forecasted polycyclic aromatic content) are discussed. State-of-the-art outlook for light-duty vehicle emission control standards in China

Indoor sound level spectra of public entertainment premises for rating airborne sound insulation.

Public entertainment premises are significant sources of urban noise pollution. In this paper, indoor sound level spectra for different types of entertainment premises have been analyzed. While most of the spectra lie between two standardized curves proposed by the ISO 717-1:2013 (The International Organization for Standardization) standard, spectra recorded in discotheques show a pronounced spectral level below 160 Hz as a result of an intensive use of subwoofers. This indicates potentially inappropriate rating of sound insulation against such specific low-frequency noise by standardized spectrum adaptation terms. A modified spectrum adaptation term for a single-number rating of sound insulation under such circumstances has been proposed.

Application of a combined standard deviation and mean based approach to MOPITT CO column data, and resulting improved representation of biomass burning and urban air pollution sources

This work presents a new methodology to simultaneously account for both the mean and variance of 17 years of Carbon Monoxide [CO] measurements from the MOPITT satellite (from 2000 to 2016) over Southeast and East Asia. We demonstrate that the new technique is stable and produces a set of results which are both consistent with the understood geographical and temporal distribution of CO sources, as well as those of some other co-emitted species. These regions were chosen because they have high levels of CO loadings and complex factors driving their underlying emissions profiles. We first successfully categorize the region, based on the total CO column measurements, into those locations impacted by intense urbanization (high climatological mean, low climatological variance, high loading throughout most of the year, and variation mostly due to global-scale chemistry and climatology), large-scale biomass burning (low climatological mean, high climatological variance, mostly clean but with short and intense peak events occurring around a similar time year-to-year), those regions undergoing a significant change from one type to another, and those regions which are clean. We further reproduce the temporal and spatial distributions of other co-emitted species measured by other measurement platforms, including aerosols (AOD) and gasses (NO2), and demonstrate consistency across all three platforms. Third of all, we produce an important scientific finding using these new results, in terms of a significant geographic expansion of the known biomass burning regions from Myanmar through Northern Vietnam, as compared with previous research. Fourth, we also find that urbanization dominates emissions of CO over both known urban agglomerations in East and Southeast Asia, including around Beijing, Shanghai, the Pearl River Delta, Seoul, Shandong, Chengdu, Chongqing, Hanoi and Bangkok, but also extend into otherwise unclassified or recently emerging mega-cities including Shanxi Province, Henan Province, and Liaoning Province. Additionally, we have found that there is a 37% overlap with emissions from FINN, providing both validation of the technique over known biomass burning regions, and an ability to quantify regions that are burning but not presently identified. Finally, we have a consistent and value-adding comparison and contrast with an EOF/PCA analysis in terms of both our regions classified as biomass burning and mixed/urban, with each approach offering its unique advantages and drawbacks. Although our approach has made some very simple assumptions in terms of cutoff that can and should be improved by the community, its robust results provide new insights into the rapid changes impacting CO throughout Asia, and will allow models to have an improved chance at representing peak events or areas undergoing rapid change.

Characterizing Elevated Urban Air Pollutant Spatial Patterns with Mobile Monitoring in Houston, Texas.

Diverse urban air pollution sources contribute to spatially variable atmospheric concentrations, with important public health implications. Mobile monitoring shows promise for understanding spatial pollutant patterns, yet it is unclear whether uncertainties associated with temporally sparse sampling and instrument performance limit our ability to identify locations of elevated pollution. To address this question, we analyze 9 months of repeated weekday daytime on-road mobile measurements of black carbon (BC), particle number (PN), and nitrogen oxide (NO, NO2) concentrations within 24 census tracts across Houston, Texas. We quantify persistently elevated, intermittent, and extreme concentration behaviors at 50 m road segments on surface streets and 90 m segments on highways relative to median statistics across the entire sampling domain. We find elevated concentrations above uncertainty levels (±40%) within portions of every census tract, with median concentration increases ranging from 2 to 3× for NO2, and >9× for NO. In contrast, PN exhibits elevated concentrations of 1.5-2× the domain-wide median and distinct spatial patterns relative to other pollutants. Co-located elevated concentrations of primary combustion tracers (BC and NOx) near 30% of metal recycling and concrete batch plant facilities within our sampled census tracts are comparable to those measured within 200 m of highways. Our results demonstrate how extensive mobile monitoring across multiple census tracts can quantitatively characterize urban air pollution source patterns and are applicable to developing effective source mitigation policies.

Vehicle atmospheric pollution evaluation using AERMOD model at avenue in a Brazilian capital city

One of the most complex environmental problems is the air pollution, and automotive vehicles are one of the main sources of urban air pollution. Aracaju-SE, Sergipe’s capital in the northeast of Brazil, faces frequent congestion in traffic and does not have a monitoring network of air quality, so mathematical models are useful for impact assessment. This work consisted of an unusual application of AERMOD View software for vehicular pollution evaluation at Tancredo Neves Avenue in Aracaju’s city. The modeling was performed for the two avenue tracks, considered as urban linear sources. The rate of emission source was calculated from emission factors, average speed, and the number of vehicles accounted for footage circulating on the promenade at peak times. Concentrations distributions of total suspended particles (TSP), carbon monoxide (CO), and nitrogen oxide (NOx) on the mesh receptors were determinated from weather, topographic, and sources of emission data. The dispersion maps showed that the pollutants were concentrated around the sources; the estimated TSP concentrations were within the standards of CONAMA 491/2018 law. The CO concentration values exceeded the standard due to the high rate of emission sources. NO2 concentrations also exceeded the standard for hourly average, attributed to the contribution of heavy vehicles and the emission rates of light vehicles and motorcycles. The simulations showed that the meteorological and topographical conditions of Aracaju favor the atmospheric pollutants dispersion, that vehicles significantly affect air quality in the region and that the mathematical modeling is a useful tool for the study of atmospheric dispersion.

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.

Sustainability Impact Assessment of Waste to Energy Technologies in Iran

Introduction: Current energy sources are coming to end and one of the main priorities of the country’s management is the energy recovery from renewable energy. Considerable quantity of municipal solid waste (MSW) is one of the most serious urban pollution sources. Impact assessment matrix is a new and fast tool for Environmental Impact Assessment (EIA). Materials and Methods: In this regard, renewable energy like waste-to-energy was investigated. Environmental assessment method was performed to evaluate the environmental impacts of common Waste to Energy (WTE) technologies by Wooten and Rau matrix. Most available WTE technologies (anaerobic digestion, sanitary landfill with gas recovery, waste incineration, and gasification) were environmentally assessed and compared. Results: Results showed that anaerobic digestion could be most environmental friendly WTE technology for production of renewable energy from organic waste and could be considered. Furthermore, executives as green minded managements can improve the quality of waste management by finding new solutions. Other technologies such as landfill by gas recovery and gasification will be ranked second and third in terms of environmental effect. Conclusion: Results showed that performing anaerobic digestion technology will produce less environmental impact in long term. Then landfilling by gas recovery and gasification technologies will be ranked second and third in terms of environmental effect.

Urban air pollution monitoring using scanning Lidar

We have developed a scanning Lidar system in this work to detect urban air pollution changes in real time and locate the sources of urban air pollution. We first proposed an algorithm to retrieve atmospheric extinction coefficients, which we used to create Lidar maps. Using Lidar map of the average extinction coefficients, we identified the locations of the local maximum values, and hence, the positions of the urban air pollution sources. Experimental results indicate that this method is effective for urban air pollution monitoring.

Urban and Rural Differences in Gut Microbial Diversity

PDS 75: Microbiome, infections and respiratory effects, Johan Friso Foyer, Floor 1, August 27, 2019, 1:30 PM - 3:00 PM Background: The link between the external and internal microbiological communities on host health is an emerging area of scientific inquiry. Gut dysbiosis or the unequal balance of healthy and unhealthy microbes has been associated with numerous inflammatory, metabolic and immune disorders. Urban environments are thought to be less diverse than rural environments, but the health impacts of these differences are poorly understood. The aim of this study is to examine urban and rural factors predicting gut microbial diversity among a randomly selected population-based sample of adults. The geographically diverse sample includes unique opportunities to explore differences in both urban and rural communities in which air pollution and drinking water sources vary considerably. Methods: Participants included adults over the age of 18 from the 2016 Survey of the Health of Wisconsin (SHOW) and its ancillary microbiome study. SHOW is a general population-based health examination survey, collecting a wide range of health determinants including drinking water sources and filtration, as well as objective measurements of body habitus, and biological specimens. Residents can be linked to numerous extant data including downscaled air monitoring and drinking water source data. Data for this analysis came from participants who also submitted a stool sample and completed a microbiome survey questionnaire. Results: Using carefully adjusted models, among 466 participants, gut microbial α-diversity and richness were associated with higher income, older age, and urbanicity. Water filtration use was only associated with α-diversity among rural residents, 98% private-well users. Similarly, β-diversity was associated with water filter use for those with increasing income level. In contrast, low-level ambient-air pollution was not associated with an altered gut microbial composition in either context. Conclusion: Results suggest urban and rural sources of water and air pollution may contribute to differences in microbial diversity, additional research is needed to fully understand the health impacts.

PM2.5 concentrations in the greenbelt near the Lin’an toll station of the Hang Rui expressway and related influencing factors

Expressways in China are developing rapidly, as is traffic pollution, which is one of the major sources of urban pollution. In this study, we chose the greenbelt in the idle zone near the Lin’an toll station along the Hang Rui expressway as our sampling area. Five points in the sampling area along Qianjin road were marked vertically at distances of 0, 15, 30, 45 and 60 m to monitor concentrations of PM2.5 and learn the varying patterns of these concentrations and influencing factors. The results showed that in spring (March, April and May), the average PM2.5 concentrations in the greenbelt were 32.56 ± 22.51, 77.71 ± 32.11 and 64.15 ± 29.00 μg m–3, respectively. The ranking of concentrations at different monitoring points in the same period was 0 > 15 > 60 > 30 > 45 m. The average concentrations in winter (November and December 2017, and February 2018) were 33.56 ± 9.34, 60.78 ± 17.67 and 124.71 ± 43.19 μg m–3, respectively. However, the ranking of concentrations at different monitoring points in the same period revealed some differences. Except at 0 m, the concentrations of PM2.5 in the other four positions were higher in winter than in spring. The reduction rate at 45 m reached its maximum in both spring and winter. PM2.5 concentrations were significantly correlated with meteorological factors, the structure of the plant community and traffic flow. PM2.5 concentrations were negatively correlated with temperature, positively correlated with relative humidity and was not significantly correlated with wind speed. The correlations of PM2.5 concentrations with the canopy density and degree of porosity differed greatly due to different seasons, and concentrations were significantly correlated with the amount of traffic flow, especially when there were large trucks.

DEVELOPMENT OF A SELF-ADJUSTING METHOD FOR CALCULATING RECURRENT DIAGRAMS IN A SPACE WITH A SCALAR PRODUCT

A self-adjusting method for calculating recurrence diagrams has been developed. The proposed method is aimed at overcoming the metric-threshold uncertainty inherent in the known methods for calculating recurrence diagrams. The method provides invariance to the nature of the measured data, and also allows to display the recurrence of states, adequate to real systems of various fields. A new scientific result consists in the theoretical justification of the method for calculating recurrence diagrams, which is capable of overcoming the existing metric-threshold uncertainty of known methods on the basis of self-adjusting by measurements by improving the topology of the metric space. The topology is improved due to the additional introduction of the scalar product of state vectors into the operation space. This allowed to develop a self-adjusting method for calculating recurrence diagrams with increased accuracy and adequacy of the display of recurrence states of real systems. Moreover, the method has a relatively low computational complexity, providing invariance with respect to the nature of the irregularity of measurements. Verification of the proposed method was carried out on the basis of experimental measurements of concentrations of gas pollutants of atmospheric air for a typical industrial city. The main gas pollutants of the atmosphere are formaldehyde, ammonia and nitrogen dioxide, caused by stationary and mobile sources of urban pollution. The obtained experimental verification results confirm the increased accuracy and adequacy of the display of the recurrence of atmospheric pollution states, as well as the invariance of the method with respect to the nature of the irregularity of measurements. It has been established that the accuracy of the method is influenced by the a priori boundary angular dimensions of the recurrence cone. It was shown that with a decrease in the boundary angular dimensions of the recurrence cone, the accuracy of the recurrence mapping of the real states of dynamical systems in the calculated diagrams increases. It was experimentally established that the accuracy and adequacy of the mapping of the recurrence states of real dynamical systems acceptable for applications is provided for a boundary angular size of the recurrence cone of 10° or less.

Noise attenuation provided by hedges

During the past few decades, urban areas have experienced increasing environmental stress. Noise is considered as one of the most important sources of urban pollution with adverse effects on human health. Urban vegetation provides many ecosystem services including the reduction of noise pollution. Hedges are widespread in cities and have the peculiarity of being often grown close to the source of noise. The study investigated the noise reduction due to hedges of Prunus laurocerasus and Laurus nobilis and the effect of the vegetation on sound spectra. Four different trials were carried out, including the use of two different noise sources and the measurement of noise at different distances both from the green barrier and from the noise source. During one trial, the influence of the type of ground surfaces between the noise source and the receiver was also evaluated. In the three trials where a significant attenuation of the noise occurred, the porosity of hedges measured less than 4.6% and an average noise reduction of about 2.7 dB(A) (max 7.0 dB(A)) was observed. This effect was particularly relevant in the range of higher frequencies (between 2 and 20 kHz). This study can contribute to plan and design hedges in the urban context.

Residential property price differentials of waste plants: evidence from Beijing, China

ABSTRACTAs a primary source of urban pollution, waste plants release toxic gases and polluted waste water that can cause great harm to human health and contaminate water resources. The adverse impact of waste plants on environmental threaten the quality of life of surrounding residents which will be reflected in residential property values. In this study, we develop a hedonic price model to estimate the environmental externalities of waste plants based on a panel dataset for real-estate transactions in Beijing from 2011 to 2015. We apply fixed effects and a Heckman selection model to control for omitted variable bias and sample selection bias and then construct price counterfactuals for properties. The price differentials between expected and counterfactual prices are then calculated. Our empirical results suggest that waste plants negatively influence residential property prices. Additionally, the influences of other factors, such as school district, traffic convenience, and average housing area, on property prices are consistent with common sense, though they are weakened for properties within three kilometers of waste plants.

Use of Multi-Rotor Unmanned Aerial Vehicles for Fine-Grained Roadside Air Pollution Monitoring

With increasing numbers of motor vehicles, vehicle exhaust gas has become one of the most important sources of urban air pollutants. After being emitted from the motor vehicle, exhaust gas spreads through the air along the road and is gradually deposited in the surrounding area, having an adverse impact on pedestrians and residents. At present, most research on vehicle exhaust directly measures the total emissions from the exhaust pipe or monitors the time variation of air pollutants at the roadside by setting roadside monitoring stations. The spatial resolution of these two methods is very low, however, and it is impossible to describe accurately the diffusion patterns of exhaust gas in the atmosphere after discharge. Some scholars have conducted research on the quality of roadside air by hand-held portable devices, but these are limited by the speed of travel, and the spatial and temporal resolution of the acquired data is also very low. By using multi-rotor unmanned aerial vehicles (UAVs) and portable equipment, this study demonstrates an atmospheric environment monitoring system based on multi-rotor UAV by designing corresponding hardware circuits and software programs. With flexible requirements for takeoff or landing sites and high maneuverability of multi-rotor UAVs, the system increases the capability for high resolution spatial and temporal monitoring of the diffusion of traffic-emitted pollutants. The system can conduct fixed-point measurement by hovering, and can also measure air pollutants in complex urban terrain, providing an innovation in the study of vehicle exhaust gas diffusion.