Urban Particulate Matter Research Articles

Development and Characterization of a Time-Sequenced Cascade Impactor: Application to Transient PM2.5 Pollution Events in Urbanized and Industrialized Environments

To set up a sampling and analysis strategy for particulate matter (PM) based on the time periods used in international standards is often inadequate for assessing the impact of day/night cycles or episodic emissions on urban air quality. To obtain a detailed physico–chemical characterization of urban PM when concentrations exceed the regulatory thresholds, a new rotary cascade impactor named the Time-Resolved Atmospheric Particle Sampler (TRAPS) was designed and tested for coarse and fine particle sampling. The TRAPS implementation, coupled with Optical Particle Counter measurements, provides time-resolved samples that can be analyzed by a wide range of single-particle analysis techniques. The TRAPS theoretical design was verified experimentally. Experimental cut-off diameters of 1.32 and 0.13 µm, respectively, for coarse and fine stages, were found in good agreement with theoretical values. Additionally, good trace separation, preventing inter-sample contamination, was evidenced by Scanning Electron Microscopy (SEM). The homogeneous distribution of particles of different types over a trace was also verified. As a case study, automated SEM-EDX analysis of 2500 particles, collected during two pollution peaks of a transient PM2.5 pollution event, revealed that individual particles’ chemical composition was influenced by local sources during the first pollution peak, and mainly transported during the second peak.

Inhalable antibiotic resistomes emitted from hospitals: metagenomic insights into bacterial hosts, clinical relevance, and environmental risks

BackgroundThreats of antimicrobial resistance (AMR) to human health are on the rise worldwide. Airborne fine particulate matter (PM2.5), especially those emitted from hospitals, could serve as a substantial yet lesser-known environmental medium of inhalable antibiotic resistomes. A genome-centric understanding of the hosting bacterial taxa, mobility potential, and consequent risks of the resistomes is needed to reveal the health relevance of PM2.5-associated AMR from clinical settings.ResultsCompared to urban ambient air PM2.5, the hospital samples harbored nearly twice the abundance of antibiotic resistantance genes (ARGs, ~ 0.2 log10(ARGs/16S rRNA gene)) in the summer and winter sampled. The profiled resistome was closely correlated with the human-source-influenced (~ 30% of the contribution) bacterial community (Procrustes test, P < 0.001), reflecting the potential antibiotic-resistant bacteria (PARB), such as the human commensals Staphylococcus spp. and Corynebacterium spp. Despite the reduced abundance and diversity of the assembled metagenomes from summer to winter, the high horizontal transfer potential of ARGs, such as the clinically relevant blaOXA and bacA, in the human virulent PARB remained unaffected in the hospital air PM samples. The occurring patterns of β-lactam resistance genes and their hosting genomes in the studied hospital-emitting PM2.5 were closely related to the in-ward β-lactam-resistant infections (SEM, std = 0.62, P < 0.01). Featured with more abundant potentially virulent PARB (2.89 genome copies/m3-air), the hospital samples had significantly higher resistome risk index scores than the urban ambient air samples, indicating that daily human exposure to virulent PARB via the inhalation of PM2.5 was ten times greater than from the ingestion of drinking water.ConclusionsThe significance of AMR in the studied hospital-emitting PM2.5 was highlighted by the greater abundance of ARGs, the prevalence of potentially virulent PARB, and the close association with hospital in-ward β-lactam infections. A larger-scale multi-source comparison of genome-resolved antibiotic resistomes is needed to provide a more holistic understanding to evaluate the importance of airborne AMR from the “One-Health” perspective.39Xa41gPReog5Lijw58oAnVideo

A study on the dynamic spatial spillover effect of urban form on PM2.5 concentration at county scale in China

Urban development has brought serious air pollution around the world. Understanding the relationship between urban form and the concentration of fine particulate matter (PM2.5) is very important for urban sustainable development in China. Based on the panel data of 2745 counties in China during 2001–2018, the dynamic spatial Durbin model, combining with meteorological factors, was used to analyze and compare the dynamic impact of urban form on PM2.5 concentration in the whole country and urban agglomerations. The results showed that urban form and meteorological factors were closely related to the concentration of PM2.5. From a national point of view, the decentralized, multi-center urban development model has a lower concentration of PM2.5. There are obvious differences in the relationship between urban form and PM2.5 concentration in different urban agglomerations. The urban form of the Pearl River Delta (PRD) is more conducive to the reduction of PM2.5 concentration than that of Beijing-Tianjin-Hebei (BTH) and Yangtze River Delta (YRD). Therefore, the formulation of different urban development strategies for different regions is an important way to solve PM2.5 pollution. In addition, Spatial autocorrelation and time lag effect significantly worsen PM2.5 pollution in China, while time lag effect can alleviate this effect to some extent. Therefore, regional joint treatment and long-term control should be strengthened to control haze pollution.

Inhalable Antibiotic Resistome from Wastewater Treatment Plants to Urban Areas: Bacterial Hosts, Dissemination Risks, and Source Contributions.

Antibiotic resistance genes (ARGs) are commonly detected in the atmosphere, but questions remain regarding their sources and relative contributions, bacterial hosts, and corresponding human health risks. Here, we conducted a qPCR- and metagenomics-based investigation of inhalable fine particulate matter (PM2.5) at a large wastewater treatment plant (WWTP) and in the ambient air of Hong Kong, together with an in-depth analysis of published data of other potential sources in the area. PM2.5 was observed with increasing enrichment of total ARGs along the coastal-urban-WWTP gradient and clinically relevant ARGs commonly identified in urban and WWTP sites, illustrating anthropogenic impacts on the atmospheric accumulation of ARGs. With certain kinds of putative antibiotic-resistant pathogens detected in urban and WWTP PM2.5, a comparable proportion of ARGs that co-occurred with MGEs was found between the atmosphere and WWTP matrices. Despite similar emission rates of bacteria and ARGs within each WWTP matrix, about 11-13% of the bacteria and >57% of the relevant ARGs in urban and WWTP PM2.5 were attributable to WWTPs. Our study highlights the importance of WWTPs in disseminating bacteria and ARGs to the ambient air from a quantitative perspective and, thus, the need to control potential sources of inhalation exposure to protect the health of urban populations.

Occurrence and in vitro toxicity of organic compounds in urban background PM2.5

This study describes the chemical composition and in vitro toxicity of the organic fraction of fine particulate matter (PM2.5) at an urban background site, which receives emissions either from Frankfurt international airport or the city centre, respectively. We analysed the chemical composition of filter extracts (PM2.5) using ultrahigh-performance liquid chromatography coupled to a high-resolution mass spectrometer, followed by a non-target analysis. In parallel, we applied the bulk of the filter extracts to a Microtox and acetylcholinesterase-inhibition assay for in vitro toxicity testing. We find that both the chemical composition and toxicity depend on the prevailing wind directions, and the airport operating condition, respectively. The occurrence of the airport marker compounds tricresyl phosphate and pentaerythritol esters depends on the time of the day, reflecting the night flight ban as well as an airport strike event during November 2019. We compared the organic aerosol composition and toxicity from the airport wind-sector against the city centre wind-sector. We find that urban background aerosol shows a higher baseline toxicity and acetylcholinesterase inhibition compared to rural PM2.5 that is advected over the airport. Our results indicate that the concentration and individual composition of PM2.5 influence the toxicity. Suspected drivers of the acetylcholinesterase inhibition are i.e. organophosphorus esters like triphenyl phosphate and cresyldiphenyl phosphate, and the non-ionic surfactant 4-tert-octylphenol ethoxylate. However, further research is necessary to unambiguously identify harmful organic air pollutants and their sources and quantify concentration levels at which adverse effects in humans and the environment can occur.

Analysis of the impact of multiscale green landscape on urban PM2.5

Analysis of the impact of multiscale green landscape on urban PM2.5

Chemical characterization and sources of submicron aerosols in Lhasa on the Qinghai–Tibet Plateau: Insights from high-resolution mass spectrometry

In recent years, a great number of studies has been carried out in urban cities regarding urban particulate matter (PM) pollution in China, especially in eastern China. Lhasa, the capital of the Tibet Autonomous Region in western China, is the highest (3650 m a.s.l.) city in China and has notably different lifestyles and PM sources comparing with those in eastern China. However, there is currently a lack of studies on PM pollution in this city. In this study, an Aerodyne high-resolution time-of-flight aerosol mass spectrometer was deployed along with other co-located instruments to explore the chemical characterization of ambient submicron PM (PM1) in Lhasa from 31 August 2019 to 26 September 2019. The mean ambient PM1 mass loading through this study was 4.72 μg m−3. Organic aerosols (OAs) played a dominant role with an average contribution of 82.6% to PM1, followed by 5.4% nitrate, 4.7% ammonium, 3.4% sulfate, 3.1% BC, and 0.7% chloride. The relatively lower contribution from secondary inorganic aerosols (nitrate and sulfate) in this study was distinctly different from that in eastern China, indicating lower fossil fuel usage in this city. Via positive matrix factorization (PMF), organic aerosols were decomposed into four components containing a traffic-related hydrocarbon-like OA (HOA), a cooking-related OA (COA), a biomass burning-related OA (BBOA), as well as an oxygenated OA (OOA). The OOA and COA had higher contributions (34% and 35%, respectively) to total OAs, while the rest accounted for 17% for HOA and 14% for BBOA. However, an increased mass fraction of BBOA (up to 36%) was found during the Sho Dun Festival, suggesting the importance of biomass burning emissions during the religious activities in this city. Frequent new particle formation events were observed during this study and the contribution of chemical species for the particle growth was also explored.

Global urban temporal trends in fine particulate matter (PM2·5) and attributable health burdens: estimates from global datasets

SummaryBackgroundWith much of the world's population residing in urban areas, an understanding of air pollution exposures at the city level can inform mitigation approaches. Previous studies of global urban air pollution have not considered trends in air pollutant concentrations nor corresponding attributable mortality burdens. We aimed to estimate trends in fine particulate matter (PM2·5) concentrations and associated mortality for cities globally.MethodsWe use high-resolution annual average PM2·5 concentrations, epidemiologically derived concentration response functions, and country-level baseline disease rates to estimate population-weighted PM2·5 concentrations and attributable cause-specific mortality in 13 160 urban centres between the years 2000 and 2019.FindingsAlthough regional averages of urban PM2·5 concentrations decreased between the years 2000 and 2019, we found considerable heterogeneity in trends of PM2·5 concentrations between urban areas. Approximately 86% (2·5 billion inhabitants) of urban inhabitants lived in urban areas that exceeded WHO's 2005 guideline annual average PM2·5 (10 μg/m3), resulting in an excess of 1·8 million (95% CI 1·34 million–2·3 million) deaths in 2019. Regional averages of PM2·5-attributable deaths increased in all regions except for Europe and the Americas, driven by changes in population numbers, age structures, and disease rates. In some cities, PM2·5-attributable mortality increased despite decreases in PM2·5 concentrations, resulting from shifting age distributions and rates of non-communicable disease.InterpretationOur study showed that, between the years 2000 and 2019, most of the world's urban population lived in areas with unhealthy levels of PM2·5, leading to substantial contributions to non-communicable disease burdens. Our results highlight that avoiding the large public health burden from urban PM2·5 will require strategies that reduce exposure through emissions mitigation, as well as strategies that reduce vulnerability to PM2·5 by improving overall public health.FundingNASA, Wellcome Trust.

Measurement report: Vehicle-based multi-lidar observational study of the effect of meteorological elements on the three-dimensional distribution of particles in the western Guangdong–Hong Kong–Macao Greater Bay Area

Abstract. The distribution of meteorological elements has always been an important factor in determining the horizontal and vertical distribution of particles in the atmosphere. To study the effect of meteorological elements on the three-dimensional distribution structure of particles, mobile vehicle lidar and fixed-location observations were collected in the western Guangdong–Hong Kong–Macao Greater Bay Area of China during September and October in 2019 and 2020. Vertical aerosol extinction coefficient, depolarization ratio, and wind and temperature profiles were measured using a micro pulse lidar, a Raman scattering lidar, and a Doppler wind profile lidar installed on a mobile monitoring vehicle. The mechanism of how wind and temperature in the boundary layer affects the horizontal and vertical distribution of particles was analysed. The results show that particles were mostly distributed in downstream areas on days with moderate wind speed in the boundary layer, whereas they were distributed homogeneously on days with weaker wind. There are three typical types of vertical distribution of particles in the western Guangdong–Hong Kong–Macao Greater Bay Area (GBA): surface single layer, elevated single layer, and double layer. Analysis of wind profiles and Hybrid Single-Particle Lagrangian Integrated Trajectory Model (HYSPLIT) backward trajectory reveals different sources of particles for the three types. Particles concentrating near the temperature inversion and multiple inversions could cause more than one peak in the extinction coefficient profile. There were two mechanisms affecting the distribution of particulate matter in the upper and lower boundary layers. Based on this observational study, a general model of meteorological elements affecting the vertical distribution of urban particulate matter is proposed.

Precipitation of aqueous transition metals in particulate matter during the dithiothreitol (DTT) oxidative potential assay.

Transition metals in particulate matter (PM) are hypothesized to have enhanced toxicity based on their oxidative potential (OP). The acellular dithiothreitol (DTT) assay is widely used to measure the OP of PM and its chemical components. In our prior study, we showed that the DTT assay (pH 7.4, 0.1 M phosphate buffer, 37 °C) provides favorable thermodynamic conditions for precipitation of multiple metals present in PM. This study utilizes multiple techniques to characterize the precipitation of aqueous metals present at low concentrations in the DTT assay. Metal precipitation was identified using laser particle light scattering analysis, direct chemical measurement of aqueous metal removal, and microscopic imaging. Experiments were run with aqueous metals from individual metal salts and a well-characterized urban PM standard (NIST SRM-1648a, Urban Particulate Matter). Our results demonstrated rapid precipitation of metals in the DTT assay. Metal precipitation was independent of DTT but dependent on metal concentration. Metal removal in the chemically complex urban PM samples exceeded the thermodynamic predictions and removal seen in single metal salt experiments, suggesting co-precipitation and/or adsorption may have occurred. These results have broad implications for other acellular assays that study PM metals using phosphate buffer, and subsequently, the PM toxicity inferred from these assays.

A Study of the Correlation between the Concentration of Particulate Matter and Green Area Ratio Measured through a Portable Monitoring System: With Particular Focus on the Case of Dalseo-Gu, Daegu Metropolitan City

This study analyzed the relationship between the measured concentration of particulate matter (PM) and green area, which is an important spatial factor affecting urban PM concentration and even more carbon neutral in cities. In order to investigate the effects of green area, the green area ratio (GAR) is used and correlated with particulate matter. As a result of analyzing the correlation between GAR and PM concentration using the measured PM data, it was found that there was a positive correlation between the two variables. Hence, the higher the GAR, the lower the PM concentration. It can be said that the introduction of spatial elements with high GAR scores, such as parks and forests in cities, is effective in reducing PM concentration. In this study, a portable PM monitoring system using a vehicle for PM measurement was also established and operated. As a result, it was found that a PM monitoring system using a light-scattering sensor is an effective PM measurement method that can be used at the local government level. It was also found that a follow-up study is needed in the future to identify the PM mitigation functions of urban green areas according to the detailed characteristics of green areas as well as various environmental factors. This study can be used in air quality improvement activities and efforts as reference data by policy decision makers and in the field of environmental planning associated with the removal of airborne particulate matter pollution in urban areas.

Development of In Vitro Co-Culture Model to Mimic the Cell to Cell Communication in Response to Urban PM2.5.

BackgroundAirborne particulate matter (PM), a widespread air contaminant, is a complex mixture of solids and aerosols composed of particles suspended in the air. PM is associated with inflammatory responses and may worsen inflammatory skin diseases. However, the mechanisms through which PM affects atopic dermatitis (AD) remain unclear.ObjectiveTo establish an in vitro model that more accurately mimics AD using human keratinocyte (HaCaT), dermal fibroblast (HDF), and mast cell (HMC-1) and using this model to investigate the mechanism through which PMs affect AD.MethodsAn AD-like in vitro model was established by seeding HaCaT, HDF, and HMC-1 cells with recombinant human interleukin (IL)-1α and polyinosinic:polycytidylic acid. We confirmed the effect of PM on the inflammatory cytokine expression of a triple-cell culture model. SRM 1649b Urban Dust, which is mainly composed of polycyclic aromatic hydrocarbons, was used as the reference PM. The effects of PM on the expression levels of proinflammatory cytokines and skin barrier markers were assessed using quantitative real-time polymerase chain reaction and western blotting. Inflammatory cytokine levels were measured using an enzyme-linked immunosorbent assay.ResultsInteractions between various skin cell types were evaluated using a co-culture system. PM treatment increased mRNA and protein levels of the inflammatory cytokines IL-6, IL-1α, tumor necrosis factor-α, IL-4, and IL-1β and decreased the expression of the skin barrier markers filaggrin and loricrin.ConclusionOur results suggest that an in vitro triple-cell culture model using HaCaT, HDF, and HMC-1 cells may be reliable for obtaining more physiological, functional, and reproducible data on AD and skin barriers.

Impact of Commercial Cooking on Urban PM2.5 and O3 with Realtime Data-Assisted Emission Inventory

Impact of Commercial Cooking on Urban PM2.5 and O3 with Realtime Data-Assisted Emission Inventory

大气污染规制对城市空气污染的防治成效——基于准实验分析

PDF HTML阅读 XML下载 导出引用 引用提醒 大气污染规制对城市空气污染的防治成效——基于准实验分析 DOI: 10.5846/stxb202107262020 作者: 作者单位: 作者简介: 通讯作者: 中图分类号: 基金项目: 国家自然科学基金项目（72033005）；中国博士后科学基金项目（2021M701507）；教育部人文社会科学研究项目（20YJC790014）；江西省教育厅科技项目（GJJ200534） The Effect of air pollution regulation on urban air pollution prevention and control: Evidence from a Quasi-Natural Experiment Author: Affiliation: Fund Project: 摘要 | 图/表 | 访问统计 | 参考文献 | 相似文献 | 引证文献 | 资源附件 | 文章评论 摘要:以2003年实施的大气污染防治重点城市政策为准自然实验，运用双重差分模型从区域层面分析了大气污染规制对城市空气污染治理的影响，研究发现：（1）大气污染规制在1%的显著性水平下降低了重点城市的工业二氧化硫排放强度，工业二氧化硫排放量以及城市PM2.5年均浓度值。（2）大气污染防治重点城市政策实施后的9年时间内有效减少了12215.8万t城市工业二氧化硫排放量，并且使得城市PM2.5年均浓度改善2.97μg/m3，下降比分别达到了36.2%和8.5%，平均每年减少了3.7%的城市工业二氧化硫排放量并降低0.944%的城市PM2.5浓度值。（3）大气污染防治重点城市政策对于城市空气污染治理主要是通过减少能源消耗量、增加城市污染治理力度、促进规制地区产业结构转型升级和提升生产技术水平等渠道予以实现。 Abstract:Based on the quasi-natural experiment of the key city policy of air pollution control implemented in 2003, this paper analyzes the impact of air pollution regulation on urban air pollution control from the regional level by using Differences-in-Difference model. The results show that:(1) air pollution regulation significantly reduce the intensity of industrial sulfur dioxide emission, industrial sulfur dioxide emission and PM2.5 annual concentration in key cities. (2) In the nine years after the implementation of the policy, 122.158 million tons of urban industrial sulfur dioxide emissions have been effectively reduced, and the average annual concentration of PM2.5 has been improved by 2.97 μg/m3, with the reduction ratio of 36.2% and 8.5% respectively. The average annual sulfur dioxide emission of urban industry has been reduced by 3.7% and the urban PM2.5 concentration has been reduced by 0.944%. (3) The key city policy of air pollution prevention and control for urban air pollution control is mainly realized by reducing energy consumption, increasing the intensity of urban pollution control, promoting the transformation and upgrading of regional industrial structure and improving the level of production technology. 参考文献 相似文献 引证文献

Gravimetric and Number Distributions of Urban PM Residuals from Urban Maintenance Practices

AbstractParticulate matter (PM) recovery from street sweeping (SS), catch basin (CB), and unit operation (UO) is essential for sustainability of these urban hydrologic functional units (HFUs). PM i...

Impacts on Urban Vocs and Pm2.5 During a Wildfire Episode

Impacts on Urban Vocs and Pm2.5 During a Wildfire Episode

Spatial and Temporal Heterogeneity of Urban Land Area and Pm2.5 Concentration in China

Spatial and Temporal Heterogeneity of Urban Land Area and Pm2.5 Concentration in China

Urban Rail Scale and Pm2.5 Air Quality in China

Urban Rail Scale and Pm2.5 Air Quality in China

Relationships between 3D urban form and ground-level fine particulate matter at street block level: Evidence from fifteen metropolises in China

Substantial efforts have been devoted to exploring the effects of urban form on fine particulate matter (PM2.5), but the complexity has been far away from being fully understood. The current remarkable inconsistencies with regards to measurements, ascertainment, and findings make the evidence across continents, regions, or cities be necessary to verify the robustness and generalizability of urban form effects. Besides, existing measurements of urban form are often unsystematic and limit analyses in both horizontal and vertical dimensions. In this paper, fifteen metropolises in China were selected to examine the relationships between three-dimensional (3D) urban form and PM2.5 concentrations at the street block level, using 3D spatial metrics and multivariate linear regression. Satellite-derived surface PM2.5 estimates of fine spatial resolution, building footprint, and multiple geographic open datasets were used. Our results demonstrated that urban form effects hold for the metropolises in China, and street accessibility, length of road segments, topography, urban vegetation, surrounding open and green spaces, and transportation facilities were found to be the influential factors of the concentrations of PM2.5. We also revealed the complicated and place-varying effects of urban form indicators, represented by the largely different or opposite effects of many urban form indicators in different cities. For example, building density, building height, and land use mixture have relatively limited and inconsistent effects in most cities. Results of this work suggest critical reflections on some of the current ideas that have been accepted to be vital for improving PM2.5.

Multi-dimensional Sources Apportionment of PM2.5 in Zhongyuan Urban Agglomeration Based on the CAMx Mode

Based on the comprehensive air quality model with extensions (CAMx), the quantitative simulation was conducted on the transport impact of PM2.5 between Zhongyuan Urban Agglomeration and surrounding cities in 2017, and the contribution of 5 major emission sectors to urban PM2.5 concentrations, namely the sector of power, industry, household, transportation and agriculture. A two-dimensional cross matrix was established for 18 cities and major emission sectors in Zhongyuan Urban Agglomeration (hereafter referred as the Urban Agglomeration). The results showed that: On an annual average scale, among the transport contribution to the 18 cities of the Urban Agglomeration, 37.8%–57.8% was from local sources, 6.2%–26.3% from the transport within the Urban Agglomeration, and 5.9%–17.4% from other cities nearby; In terms of sectors contribution, industrial sources contributed the most to the annual average concentration of PM2.5 (12.7%–33.0%) in the Urban Agglomeration, followed by household, transportation and agriculture sources. Household source emissions contributed the most in winter. PM2.5 concentrations in Shangqiu, Puyang and Zhoukou affected by household sources emissions exceeding 30% in winter.