Weekly variation of atmospheric particle micromorphology and chemistry in Brussels urban environment

The purpose of this study was to measure the impact of urban activities on airborne particle dynamics during weekend periods in Brussels urban area. Differences in the granulometry and micromorphology between particles sampled on working days and weekends were studied. We quantified the area, size, number, and the chemistry parameters of the airborne particles and compared between Saturday, Sunday, and Monday. We report and analyze data on airborne particles up to PM10, measured in the Brussels region from October 2002 to September 2003. Our investigation reveals detailed information regarding chemical composition of the airborne particles over the weekend period in the Brussels urban area. Furthermore, the majority of the airborne particles in the Brussels region may belong to sources geographically outside the (in situ) Brussels area.     

Particulate Matter Over A Seven Year Period in Urban and Rural Areas Within, Proximal and Far from Mining and Power Station Operations in Greece

Lignite mining operations and lignite-fired power stations result in major particulate pollution (fly ash and fugitive dust) problems in the areas surrounding these activities. The problem is more complicated, especially, for urban areas located not far from these activities, due to additional contribution from the urban pollution sources. Knowledge of the distribution of airborne particulate matter into size fraction has become an increasing area of focus when examining the effects of particulate pollution. On the other hand, airborne particle concentration measurements are useful in order to assess the air pollution levels based on national and international air quality standards. These measurements are also necessary for developing air pollutants control strategies or for evaluating the effectiveness of these strategies, especially, for long periods. In this study an attempt is made in order to investigate the particle size distribution of fly ash and fugitive dust in a heavy industrialized (mining and power stations operations) area with complex terrain in the northwestern part of Greece. Parallel total suspended particulates (TSP) and particulate matter with an aerodynamic diameter less than 10 μm (PM10) concentrations are analyzed. These measurements gathered from thirteen monitoring stations located in the greater area of interest. Spatial, temporal variation and trend are analyzed over the last seven years. Furthermore, the geographical variation of PM10 – TSP correlation and PM10/TSP ratio are investigated and compared to those in the literature. The analysis has indicated that a complex system of sources and meteorological conditions modulate the particulate pollution of the examined area.     

Distribution of airborne particles from multi-emission source

The purpose of this work was to study the distribution of airborne particles in the surroundings of an iron and steel factory in southern Finland. Several sources of particulate emissions are lying side by side, causing heavy dust loading to the environment. This complicated multi-pollutant situation was studied mainly by SEM/EDX methodology.Particles accumulated on Scots pine bark were identified andquantitatively measured according to their element content,size and shape. As a result, distribution maps of particulateelements were drawn and the amount of different particle typesalong the study lines was plotted. Particulate emissions fromthe industrial or energy production processes were not themain dust source. Most emissions were produced from theclinker crusher. Numerous stockpiles of the industrial wastesand raw materials also gave rise to particulate emissions as aresult of wind erosion. It was concluded that SEM/EDXmethodology is a useful tool for studying the distribution ofparticulate pollutants.     

Determination of response of real-time SidePak AM510 monitor to secondhand smoke, other common indoor aerosols, and outdoor aerosol

The amount of light scattered by airborne particles inside an aerosol photometer will vary not only with the mass concentration, but also with particle properties such as size, shape, and composition. This study conducted controlled experiments to compare the measurements of a real-time photometer, the SidePak AM510 monitor (SidePak), with gravimetric mass. PM sources tested were outdoor aerosols, and four indoor combustion sources: cigarettes, incense, wood chips, and toasting bread. The calibration factor for rescaling the SidePak measurements to agree with gravimetric mass was similar for the cigarette and incense sources, but different for burning wood chips and toasting bread. The calibration factors for ambient urban aerosols differed substantially from day to day, due to variations in the sources and composition of outdoor PM. A field evaluation inside a casino with active smokers yielded calibration factors consistent with those obtained in the controlled experiments with cigarette smoke.     

Relationship between different size classes of particulate matter and meteorology in three European cities

Evidence on the correlation between particle mass and (ultrafine) particle number concentrations is limited. Winter- and spring-time measurements of urban background air pollution were performed in Amsterdam (The Netherlands), Erfurt (Germany) and Helsinki (Finland), within the framework of the EU funded ULTRA study. Daily average concentrations of ambient particulate matter with a 50% cut off of 2.5 microm (PM2.5), total particle number concentrations and particle number concentrations in different size classes were collected at fixed monitoring sites. The aim of this paper is to assess differences in particle concentrations in several size classes across cities, the correlation between different particle fractions and to assess the differential impact of meteorological factors on their concentrations. The medians of ultrafine particle number concentrations were similar across the three cities (range 15.1 x 10(3)-18.3 x 10(3) counts cm(-3)). Within the ultrafine particle fraction, the sub fraction (10-30 nm) made a higher contribution to particle number concentrations in Erfurt than in Helsinki and Amsterdam. Larger differences across the cities were found for PM2.5(range 11-17 microg m(-3)). PM2.5 and ultrafine particle concentrations were weakly (Amsterdam, Helsinki) to moderately (Erfurt) correlated. The inconsistent correlation for PM2.5 and ultrafine particle concentrations between the three cities was partly explained by the larger impact of more local sources from the city on ultrafine particle concentrations than on PM2.5, suggesting that the upwind or downwind location of the measuring site in regard to potential particle sources has to be considered. Also, relationship with wind direction and meteorological data differed, suggesting that particle number and particle mass are two separate indicators of airborne particulate matter. Both decreased with increasing wind speed, but ultrafine particle number counts consistently decreased with increasing relative humidity, whereas PM2.5 increased with increasing barometric pressure. Within the ultrafine particle mode, nucleation mode (10-30 nm) and Aitken mode (30-100 nm) had distinctly different relationships with accumulation mode particles and weather conditions. Since the composition of these particle fractions also differs, it is of interest to test in future epidemiological studies whether they have different health effects.     

Characterization of airborne trace metal and trace organic species from coal gasification

Fugitive emissions from a slagging fixed-bed coal-gasification pilot plant were analyzed by flameless atomic absorption spectrophotometry, gas chromatography, and mass spectrometry for trace metal and trace organic species. Analysis of the size distributions of airborne particulate matter inside the plant showed an abundance of large metal-containing particles; outdoor distributions in the vicinity of the plant resembled the indoor distributions, suggesting the importance of the gasifier in influencing ambient air quality. This conclusion was further supported by identification of similar organic compounds inside and outside the plant. Trace element enrichment factors based on the earth's crustal composition were greater than those based on the composition of the lignite used in the gasifier, showing the importance of characterizing the proper source material when inverstigating chemical fraction during aerosol formation. Enrichments in the present study were much greater than those found in previous sampling during aborted start-up and cleaning procedures, where normal operating temperatures had not yet been reached. Both studies showed evidence of enrichment factors which decreased with increasing particle size. Although much of the airborne mass was associated with large particles having low respirability, the high concentrations of some metals indoors suggests that further assessment of potential occupational exposures is warranted.     

江苏泰州城市霾天和沙尘天气溶胶中细菌群落结构特征研究

近年来,空气污染已成为长三角地区最关键的环境问题之一,气溶胶颗粒物(PM)是最主要的污染物之一.生物气溶胶作为颗粒物的重要组成部分,可能对空气质量和人体健康产生不利影响.利用高通量测序方法研究了江苏省泰州2019年11月至2020年1月期间发生沙尘和霾污染时生物气溶胶中细菌群落结构组成特征.结果表明:冬季沙尘天和霾天气...     

A holistic approach combining factor analysis, positive matrix factorization, and chemical mass balance applied to receptor modeling

Rapid urbanization and population growth resulted in severe deterioration of air quality in most of the major cities in India. Therefore, it is essential to ascertain the contribution of various sources of air pollution to enable us to determine effective control policies. The present work focuses on the holistic approach of combining factor analysis (FA), positive matrix factorization (PMF), and chemical mass balance (CMB) for receptor modeling in order to identify the sources and their contributions in air quality studies. Insight from the emission inventory was used to remove subjectivity in source identification. Each approach has its own limitations. Factor analysis can identify qualitatively a minimal set of important factors which can account for the variations in the measured data. This step uses information from emission inventory to qualitatively match source profiles with factor loadings. This signifies the identification of dominant sources through factors. PMF gives source profiles and source contributions from the entire receptor data matrix. The data from FA is applied for rank reduction in PMF. Whenever multiple solutions exist, emission inventory identifies source profiles uniquely, so that they have a physical relevance. CMB identifies the source contributions obtained from FA and PMF. The novel approach proposed here overcomes the limitations of the individual methods in a synergistic way. The adopted methodology is found valid for a synthetic data and also the data of field study.     

Temporal variations of airborne particles concentration in the Brussels environment

We report and analyze data on the PM10 fraction of airborne particles measured at five recording stations in the Brussels region from October 2002 till September 2003. These stations are representative of the various activity sectors of the Brussels urban area. The objective was the determination of the origin of the PM10 particles (particles up to 10 μm) that are recorded in that region in order to follow the EU directives concerning tolerance level of airborne particles concentration. In order to evaluate the impacts of local and external factors that inject solid particles in the atmosphere of Brussels we compared concentration data from working and not working (holidays) periods. Moreover, we also compared concentrations from periods of agricultural activity and rest in the Brabant provinces surrounding the Brussels region for various crop types. The results lead to the conclusion that the impact or urban traffic is rather limited while that of the agricultural activities is important. Moreover, there appears a clear-cut distinction between different types of crops.     

The lichen transplant methodology in the source apportionment of metal deposition around a copper smelter in the former mining town of Karabash, Russia

The lichen transplant monitoring methodology has been tested for source apportionment of metal deposition around the Cu smelter and former mining town of Karabash. Transplants of the lichen Hypogymnia physodes (L.) Nyl., collected from a ‘control’ site in July 2001, were set up at 10 stations along a 60 km NE–SW transect centred on Karabash. Samples were collected after 2 and 3 month monitoring periods and analysed using established wet-chemical techniques. The sources of particulate investigated were the smelter blast furnace and converter, floatation tailings, metallurgical slags, local road dusts, top soils and ambient airborne total suspended particulate. From multi-element least-squares modelling the blast furnace was the main source of particulate in transplants close to the smelter (<10 km). Particulate from the converter, with relatively high Pb and Zn, was found to be more widely dispersed, being finer-grained and so having a longer atmospheric residence time. Ambient airborne particulate, sampled in Karabash town using air-pump apparatus, was almost entirely derived from the converter, very different to the lichen transplants from the same area which mainly contained blast furnace particulate. It is proposed that lichens close to the smelter mainly trapped larger blast furnace-derived particulate as they have a low capture efficiency for smaller (converter) particles. The study demonstrates the utility of lichen transplants for monitoring atmospheric deposition and highlights the caution required in their use to assess ambient air quality in human health studies.     

Sequential optimal monitoring network design and iterative spatial estimation of pollutant concentration for identification of unknown groundwater pollution source locations

One of the difficulties in accurate characterization of unknown groundwater pollution sources is the uncertainty regarding the number and the location of such sources. Only when the number of source locations is estimated with some degree of certainty that the characterization of the sources in terms of location, magnitude, and activity duration can be meaningful. A fairly good knowledge of source locations can substantially decrease the degree of nonuniqueness in the set of possible aquifer responses to subjected geochemical stresses. A methodology is developed to use a sequence of dedicated monitoring network design and implementation and to screen and identify the possible source locations. The proposed methodology utilizes a combination of spatial interpolation of concentration measurements and simulated annealing as optimization algorithm for optimal design of the monitoring network. These monitoring networks are to be designed and implemented sequentially. The sequential design is based on iterative pollutant concentration measurement information from the sequentially designed monitoring networks. The optimal monitoring network design utilizes concentration gradient information from the monitoring network at previous iteration to define the objective function. The capability of the feedback information based iterative methodology is shown to be effective in estimating the source locations when no such information is initially available. This unknown pollution source locations identification methodology should be very useful as a screening model for subsequent accurate estimation of the unknown pollution sources in terms of location, magnitude, and activity duration.     

石家庄市春季大气颗粒物的铅污染特征

为了解石家庄市2016年春季大气颗粒物的铅污染特征及来源,利用单颗粒气溶胶质谱仪(SPAMS),分析了大气中含铅颗粒的化学成分。结果表明: 研究期间大气环境中含铅颗粒数浓度共出现11次跳跃式升高,跳跃时间段内石家庄均处于轻度污染过程。从成分分析来看,含铅颗粒分为纯铅颗粒、Pb与K(Pb-K)、OC(Pb-OC)、Cl(Pb-Cl)、混合颗粒等八大类。观测结果表明:Pb-K颗粒最多,占到含铅颗粒的84.4%;其次为纯铅颗粒,占比为13.0%。与石家庄市污染源谱库比对进行来源解析,得到Pb-K颗粒主要来自生活垃圾焚烧源, 纯铅颗粒主要来自工业源。结合石家庄市大气污染源排放清单和后向气流轨迹分析,推测含铅颗粒可能来自市区西南方向某区县的生活垃圾焚烧企业。     

Metal release from stainless steel particles in vitro-influence of particle size

Human inhalation of airborne metallic particles is important for health risk assessment. To study interactions between metallic particles and the human body, metal release measurements of stainless steel powder particles were performed in two synthetic biological media simulating lung-like environments. Particle size and media strongly influence the metal release process. The release rate of Fe is enhanced compared with Cr and Ni. In artificial lysosomal fluid (ALF, pH 4.5), the accumulated amounts of released metal per particle loading increase drastically with decreasing particle size. The release rate of Fe per unit surface area increases with decreasing particle size. Compared with massive sheet metal, fine powder particles (<4 microm) show similar release rates of Cr and Ni, but a higher release rate of Fe. Release rates in Gamble's solution (pH 7.4), for all powders investigated, are significantly lower compared to ALF. No clear trend is seen related to particle size in Gamble's solution.     

Observations of urban airborne particle number concentrations during rush-hour conditions: analysis of the number based size distributions and modal parameters

A summertime study of the number concentration and the size distribution of combustion derived nanometre sized particles (termed nanoparticles) from diesel and spark-ignition (SI) engine emissions were made under rush-hour and free-flow traffic conditions at an urban roadside location in Leeds, UK in July 2003. The measured total particle number concentrations (N(TOTAL)) were of the order 1.8 x 10(4) to 3.4 x 10(4) cm(-3), and tended to follow the diurnal traffic flow patterns. The N(TOTAL) was dominated by particles < or =100 nm in diameter which accounted for between 89-93% of the measured particle number. By use of a log-normal fitting procedure, the modal parameters of the number based particle size distribution of urban airborne particulates were derived from the roadside measurements. Four component modes were identified. Two nucleation modes were found, with a smaller, more minor, mode composed principally of sub-11 nm particles, believed to be derived from particles formed from the nucleation of gaseous species in the atmosphere. A second mode, much larger in terms of number, was composed of particles within the size range of 10-20 nm. This second mode was believed to be principally derived from the condensation of the unburned fuel and lube oil (the solvent organic fraction or SOF) as it cooled on leaving the engine exhaust. Third and fourth modes were noted within the size ranges of 28-65 nm and 100-160 nm, respectively. The third mode was believed to be representative of internally mixed Aitken mode particles composed of a soot/ash core with an adsorbed layer of readily volatilisable material. The fourth mode was believed to be composed of chemically aged, secondary particles. The larger nucleation and Aitken modes accounted for between 80-90% of the measured N(TOTAL), and the particles in these modes were believed to be derived from SI and diesel engine emissions. The overall size distribution, particularly in modes II-IV, was observed to be strongly related to the number of primary particle emissions, with larger count median diameters observed under conditions where low numbers of primary soot based particles were present.     

Characterisation of airborne particles collected within and proximal to an opencast coalmine: South Wales,U.K

Airborne particulate matter has been collected from within,and proximal to, an opencast coal mine in south Wales. Thiswork forms the first part of a three year project to collectand characterise, then determine the possible toxicology ofairborne particles in the south Wales region. High-resolutionField Emission SEM has shown that the coal mine dusts consistlargely of an assemblage of mineral grains and vehicle exhaustparticles. SEM-EDX has shown that the mineralogical make-up ofthe PM10 is complex, heterogeneous, and constantly changing.These findings are supported by analytical TEM-EPXMA.However, patterns can be determined relating the mineralogicalcomposition of the airborne particles to collection locationsand mining activities within the opencast. At our studyopencast, Park Slip West, quartz, which has known healtheffects, never exceeded 30% of the total collection mass, andaverage levels were much less. Vehicle exhaust emissions wasthe largest source in terms of particle numbers. The mass ofairborne particulate matter within the pit averagedapproximately twice that of outside the pit: importantlyhowever, this higher mass was due to relatively large, andnon-respirable, mineral grains. This study demonstrates that the physicochemical andmineralogical characterisation of airborne particles frommining and quarrying is essential to quantify the respirablefraction, and to identify potentially hazardous componentswithin the PM10.     

空气微生物污染的监测及研究进展

空气微生物不但与环境空气质量、空气污染和人体健康密切相关,并且还与自然生态平衡及许多生命现象直接相关,在自然界的物质循环中起着非常重要的作用。文章从空气微生物的污染现状、采样方法、粒度分布、分离鉴定、微生物评价、时空分布等方面对空气微生物的研究现状进行了综述,并对空气微生物在环境监测中的研究和前景进行了展望,建议空气微生物污染监测应常态化,应控制和开展对大气细颗粒或超细颗粒物对人体健康的影响研究。     

Micromorphology and chemistry of airborne particles in Brussels during agriculture working periods in surrounding region

The main objective of our research was to compare the airborne particle micromorphology and chemistry in the Brussels environment during agriculture working periods in the surrounding farming region. We used specific methods and instrumentation that are adapted to the climate peculiarities of the Brussels region, the period of investigations (12 months) and the proposed objectives. For the agricultural works we defined the following six periods: before sowing, sowing, after sowing, before harvest, harvest and after harvest. The results indicate a possible temporal correlation between agricultural work periods and airborne particle concentration, micromorphology and chemistry in the Brabant-Brussels region. For wheat and corn plant-growth periods, the average particle size, defined as the area obtained by a planar projection of the particulate, showed important variations in time. For sugar beet and endive, the average area size variations are less important. The roughness and sphericity parameters for the growth periods of the four different plants also showed significant differences. Many of the larger particulates (> 10 microm) are aggregates of even finer particles coated with many still finer ones. The airborne particle chemistry averages (atomic percentage At%), showed that three constituents (Si, S and Fe) dominate all the samples (except for particles 3-10 microm in size, which contain a relatively large percentage of Al). Applying similar investigation methods to study the correlations between airborne particle dynamics in urban zones and the agriculture working periods in their surrounding regions could be of interest to better understand the complexity of the PM problematic.     

Comprehensive two-dimensional gas chromatography, a valuable technique for screening and semiquantitation of different chemical compounds in ultrafine 30 nm and 50 nm aerosol particles

Comprehensive two dimensional gas chromatography-time-of-flight mass spectrometry (GC×GC-TOF-MS) was used for screening and semiquantitation of semivolatile organic compounds in aerosol particles. As the volatility was a prerequisite parameter for the analysis, some compounds were transformed via derivatization such as silylation into more volatile ones. The identification of the analytes was made by comparing the GC retention indices and the TOF mass spectra with the NIST and the Golm metabolome database reference libraries. The data treatment was simplified by exploiting an additional classification of the identified compounds, namely the main functional group or specific element present in the molecule leading to different groups of compounds. This methodology was applied to identify compounds in 30 ± 4 nm, 50 ± 5 nm and total suspended particles (TSP) collected during spring and autumn of 2009 and summer of 2010 at the Station for Measuring Forest Ecosystem Atmosphere Relations (SMEAR II) at Hyyti?l? (Finland). The number of identified compounds was higher than 400, which were the most relevant compounds present in the samples, in terms of concentrations. The analysis of aerosol particles of different sizes, collected simultaneously, revealed that the number of compounds increased with the particle size whereas the normalized response factor decreased in most of the cases, aldehydes being an exception. This decrease could be associated with the formation or aggregation of new compounds onto the particles when they grow in the atmosphere.     

北京市冬季大气细粒子数浓度的粒径分布特征

考虑到对人体的健康危害,大气颗粒物的数浓度值可能比质量浓度值更重要.通过对北京市交通道路边、生活区和远郊背景点大气细粒子数浓度的监测,对北京市大气细粒子数浓度的主要来源、浓度和粒径分布特征进行研究.文章认为交通源是城市大气细粒子数浓度的主要来源.城市生活区的大气细粒子主要是污染源稀释后扩散而来.远郊区既可能存在气象污染物光化学成核生成的超细颗粒物,也存在外部运移而来的细粒子.与国外其他城市相比,北京市大气细粒子数浓度在道路边处于中等偏下水平,但生活区和背景点处于相当或偏高的水平.     

Pool of Dust Particles over the Asian Continent: Balloon-borne Optical Particle Counter and Ground-based Lidar Measurements at Dunhuang, China

Measurements of aerosols were made in 2001 and 2002 at Dunhuang (40 degrees 00'N, 94 degrees 30'E), China to understand the nature of atmospheric particles over the desert areas in the Asian continent. Balloon-borne measurements with an optical particle counter suggested that particle size and concentration had noticeable peaks in super micron size range not only in the boundary mixing layer but also in the free troposphere. Super-micron particle concentration largely decreased in the mid tropopause (from 5 to 10 km; above sea level, a.s.l.). Lidar measurements made during August 2002 at Dunhuang suggested the possibility that mixing of dust particles occurred from near the ground to about 6 km even under calm weather conditions, and a large depolarization ratio of particulate matter was found in the aerosol layer. The top of the aerosol layer was found at heights of nearly 6 km (a.s.l.). It is strongly suggested that nonspherical dust particles (Kosa particles) frequently diffused in the free atmosphere over the Taklamakan desert through small-scale turbulences and are possible sources of dust particles of weak Kosa events that have been identified in the free troposphere not only in spring but also in summer over Japanese archipelago. Electron microscopic experiments of the particles collected in the free troposphere confirmed that coarse and nonspherical particles observed by the mineral particle were major components of coarse mode (diameter larger than 1 microm) below about 5 km over Dunhuang, China.