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1.
Environ Monit Assess ; 192(2): 82, 2020 Jan 02.
Artigo em Inglês | MEDLINE | ID: mdl-31897757

RESUMO

Bacterial contamination occurs in different occupational exposures. Although the level of colony-forming units in airborne samples reveals bacterial exposure, the bacterial origin is not specified. We applied Fourier transform infrared spectroscopy to investigate bacterial species in airborne samples and validated bacterial evaluation in an occupational exposure. As a pilot study, airborn of nurses station (n=40) was assessed according to National Institute of Occupational Safety and Health 0800 method. Bacterial strain in all samples was evaluated by diagnosis gallery tests. Simultaneously, Fourier transform infrared spectroscopy of sampled bacteria was prepared and then classified by principal component analysis. Spectroscopy method was validated for Staphylococcus aureus quantification. For this aim, spectrum band area in different wavenumbers was evaluated for calibration curve plotting and extraction of validation parameters. The second derivatization of spectroscopy data in 1200 to 1500 cm-1 presented the best determination for gram-type discrimination by principal component analysis modeling. Moreover 900-1200 cm-1 region modeling finely differentiated gram-negative bacteria in airborne samples. Adding spectroscopy area band in 2850 and 2906 cm-1 was validated to assess the level of Staphylococcus aureus contamination. Results showed appropriate correlation between the Staphylococcus aureus level in airborne samples analyzed by commercial counting evaluation and Fourier transform infrared spectroscopy method. Fourier transform infrared spectroscopy is a functional technique for assessment of airborne quality in occupational exposure. This analysis was recommended as an alternative method for quantitative and qualitative analysis of bio-aerosols.


Assuntos
Microbiologia do Ar , Bactérias , Monitoramento Ambiental/métodos , Exposição Ocupacional/análise , Aerossóis/análise , Bactérias Gram-Negativas , Humanos , Exposição Ocupacional/estatística & dados numéricos , Projetos Piloto , Análise de Componente Principal , Espectroscopia de Infravermelho com Transformada de Fourier , Staphylococcus aureus
2.
Environ Pollut ; 256: 113428, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31706780

RESUMO

As the most important gas-phase alkaline species, atmospheric ammonia (NH3) contributes considerably to the formation and development of fine-mode particles (PM2.5), which affect air quality and environmental health. Recent satellite-based observations suggest that the North China Plain is the largest agricultural NH3 emission source in China. However, our isotopic approach shows that the surface NH3 in the intraregional urban environment of Beijing-Tianjin-Shijiazhuang is contributed primarily by combustion-related processes (i.e., coal combustion, NH3 slip, and vehicle exhaust). Specifically, the Batch fractionation model was used to describe the partitioning of gaseous NH3 into particles and to trace the near-ground atmospheric NH3 sources. With the development of haze pollution, the dynamics of δ15N-NH4+ were generally consistent with the fractionation model. The simulated initial δ15N-NH3 values ranged from -22.6‰ to -2.1‰, suggesting the dominance of combustion-related sources for urban NH3. These emission sources contributed significantly (92% on hazy days and 67% on clean days) to the total ambient NH3 in urban cities, as indicated by a Bayesian mixing model. Based on the Batch fractionation model, we concluded the following: 1) δ15N-NH4+ can be used to model the evolution of fine-mode aerosols and 2) combustion-related sources dominate the near-ground atmospheric NH3 in urban cities. These findings highlight the need for regulatory controls on gaseous NH3 emissions transported from local and surrounding industrial sources.


Assuntos
Poluentes Atmosféricos/análise , Amônia/análise , Monitoramento Ambiental , Combustíveis Fósseis , Aerossóis/análise , Poluição do Ar/análise , Teorema de Bayes , Pequim , China , Cidades , Carvão Mineral , Gases , Estações do Ano , Emissões de Veículos
3.
Environ Pollut ; 256: 113395, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31708281

RESUMO

We apply convolutional neural network (CNN) model for estimating daily 24-h averaged ground-level PM2.5 of the conterminous United States in 2011 by incorporating aerosol optical depth (AOD) data, meteorological fields, and land-use data. Unlike some of the recent supervised learning-based approaches, which only utilized the predictors from the location of which PM2.5 value is estimated, we naturally aggregate predictors from nearby locations such that the spatial correlation among the predictors can be exploited. We carefully evaluate the performance of our method via overall, temporally-separated, and spatially-separated cross-validations (CV) and show that our CNN achieves competitive estimation accuracy compared to the recently developed baselines. Furthermore, we develop a novel predictor importance metric for our CNN based on the recent neural network interpretation method, Layerwise Relevance Propagation (LRP), and identify several informative predictors for PM2.5 estimation.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Meteorologia , Estados Unidos
4.
Chemosphere ; 242: 125132, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31669986

RESUMO

The present study was conducted at sub-urban and rural site of Agra. The main aim of this study was to characterize WSII in terms of spatial, seasonal and formation characteristics and identify the major sources responsible for the pollution of WSII in PM2.5 particles using different source apportionment models. Since biomass burning is one of the most important sources of PM2.5 pollution in Agra, a case study was also conducted at rural site to investigate the contribution of biomass burning from cooking activities using different types of fuels. PM2.5 mass concentrations were higher at sub-urban site (91.0 ±â€¯50.8 µg/m3) than at rural site (77.1 ±â€¯48.6 µg/m3). WSII contributed 50.0% and 45.8% of annual average PM2.5 mass at both sites. The aerosols were ammonium rich and were therefore alkaline in nature. Aerosol acidity characteristics studied using AIM-II model showed that the aerosols were slightly less acidic at rural site than at sub-urban site. SO42-, NO3- and NH4+ were the major contributors of WSII and their formation was favoured mainly in winter. Although, WSII showed slight variations in seasonal and spatial characteristics, the major sources of pollution were found to be similar. Four sources were identified as biomass burning (29.1% and 27.4%), secondary aerosols (26.2% and 22.5%), coal combustion (22.3% and 26.9%) and soil dust (22.4% and 23.1%) at sub-urban and rural sites. The results of case study showed that among different types of biomass fuels cow dung cakes showed maximum PM2.5 emissions while LPG showed minimum PM2.5 emissions.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Compostos de Amônio , Animais , Biomassa , Bovinos , Carvão Mineral/análise , Culinária , Poeira/análise , Estações do Ano , Solo , Emissões de Veículos/análise
5.
Chemosphere ; 241: 125033, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31610462

RESUMO

To evaluate light extinction contributions of aerosol chemical constituents and their impacts on atmospheric visibility, the PM2.5 and its chemical components, light scattering (bsp) and absorption (bap) were continuously measured in Wuhan from January to February 2018. The average of PM2.5 concentration, bsp and bap were 96.5 ±â€¯13.7 µg m-3, 564 ±â€¯124 Mm-1 and 44 ±â€¯8 Mm-1 during polluted days, respectively, which was about 2.0, 2.1 and 1.6 times higher than those of clean days, respectively. Compared with the clean days, the increase of the mass concentrations of SNA (SO42-, NO3-, NH4+) during polluted days was higher than those of organic (OC) and elemental (EC) carbon, indicated the increase of SNA was the main cause of air pollution. The PM2.5 concentration threshold was 66 µg m-3, corresponding to the visibility lower than 10 km. The revised Interagency Monitoring of Protected Visual Environments (IMPROVE) algorithm was used to reconstruct the light extinction coefficient (bext) in Wuhan. The sum of light extinction coefficients of (NH4)2SO4, NH4NO3 and organic matter (OM) accounted for 70.5% and 83.9% of bext during clean and polluted days, respectively. The backward trajectory and potential source contribution function (PSCF) analysis revealed that regional transport accounted for 55.6% of the total airflow, which originated from south, northwest and west of Wuhan. The increases of (NH4)2SO4 and NH4NO3 concentrations, emitted from local vehicle exhaust and coal combustion, and their hygroscopic growth in ambient were the major causes of pollution in Wuhan.


Assuntos
Aerossóis/química , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Estações do Ano , Aerossóis/análise , Compostos de Amônio/análise , China , Carvão Mineral/análise , Nitratos/análise , Material Particulado/análise , Sulfatos/análise , Emissões de Veículos/análise
6.
Chemosphere ; 241: 125025, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31604190

RESUMO

Metals in atmospheric aerosols play potentially an important role in human health and ocean primary productivity. However, the lack of knowledge about solubility and speciation of metal ions in the particles or after solubilisation in aqueous media (sea or surface waters, cloud or rain droplets, biological fluids) limits our understanding of the underlying physico-chemical processes. In this work, a wide range of metals, their soluble fractions, and inorganic/organic compounds contained in urban particulate matter (PM) from Padua (Italy) were determined. Metal solubility tests have been performed by dissolving the PM in water and in solutions simulating rain droplet composition. The water-soluble fractions of the metal ions and of the organic compounds having ligand properties have been subjected to a multivariate statistical procedure, in order to elucidate associations among the aqueous concentrations of these PM components in simulated rain droplets. In parallel, a multi-dimensional speciation calculation has been performed to identify the stoichiometry and the amount of metal-ligand complexes theoretically expected in aqueous solutions. Both approaches showed that the solubility and the aqueous speciation of metal ions were differently affected by the presence of inorganic and organic ligands in the PM. The solubility of Al, Cr, and Fe was strongly correlated to the concentrations of oxalic acid, as their oxalate complexes represented the expected dominant species in aqueous solutions. Oxalates of Al represented ∼98% of soluble Al, while oxalates of Cu represented 34-75% of the soluble Cu, and oxalates of Fe represented 76% of soluble Fe. The oxidation state of Fe can strongly impact the speciation picture. If Fe is present as Fe(II) rather than Fe(III), the amount of Cr and Cu complexed with diacids can increase from 75% to 94%, and from 32% to 53%, respectively. For other metals, the solubility depended on the formation of soluble aquo-complexes, hence with a scarce effect of the organic ligands. An iron-oxalate complex was also directly detected in aerosol sample extracts.


Assuntos
Complexos de Coordenação/química , Metais/química , Ácido Oxálico/química , Material Particulado/análise , Aerossóis/análise , Humanos , Itália , Ligantes , Oxirredução , Solubilidade , Reforma Urbana , Água
7.
Chemosphere ; 241: 125026, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31606570

RESUMO

With the principal aim to assess the typical Mediterranean profile of the PM2.5 and PM1 pollution, three intensive monitoring campaigns took place simultaneously within different types of environment across an urban location of the basin. Focusing on the PM components with numerous anthropogenic sources and increased potential health risk, the samples were chemically analyzed for 20 p.m.-bound Polycyclic Aromatic Hydrocarbons (PAHs). Carbonaceous and ionic constituents were quantified as well. In order to uncover the spatiotemporal variation of the PM profile the key sources were identified, the seasonal effects and the role of the prevailing mesoscale atmospheric circulation were evaluated and most importantly the potential health risk was estimated. In general, the pollution status of the basin was the result of a complex interaction between the local and external input with Particulate Organic Matter (POM) and Secondary Inorganic Aerosols (SIA) being the main aerosols' components. PM1 was a better indicator of the anthropogenic emissions while according to the results of factor analysis the co-existence of various combustion sources was determinant. Chemically, the maxima of the ΣPAHs, the differentiation of their structure in accordance with their molecular weight and the distribution of the individual compounds confirmed the significance of the emission sources. Similarly, the estimated carcinogenicity/mutagenicity was emission-dependent with the maximum contribution coming from B[a]P, IndP, B[ghi]Per, B[e]P and B[b]F. Seasonally, the highest potential health risk of the PAHs' mixture was recorded during the cold season while meteorologically, it was mostly associated with the south flow.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Meteorologia , Material Particulado/análise , Hidrocarbonetos Policíclicos Aromáticos , Medição de Risco , Aerossóis/análise , Poluição do Ar/análise , Grécia , Tamanho da Partícula , Hidrocarbonetos Policíclicos Aromáticos/análise , Estações do Ano
8.
J Chromatogr A ; 1609: 460437, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31409488

RESUMO

Thermal papers (e.g. point of sale receipts, adhesive labels, tickets) significantly contribute to contamination of paper material cycles and the environment with substances of (eco-) toxicological concern. In particular, they contain color developers like endocrine disrupting bisphenols in typical concentrations of about 1-2 percent per weight (wt%). Bisphenol A (BPA) was used as the common color developer over the last decades, but it will be restricted for thermal paper application in the European Union to a limit of 0.02 wt% from 2020 onwards. Consequently, a variety of BPA substituents such as bisphenol S (BPS) and its derivatives gain importance in thermal paper application. In this study, a rapid, reliable and cost-effective method for identification and quantification of BPA, alternative color developers and related substances like sensitizers is presented based on HPLC separation coupled with diode array detection (DAD) and Corona charged aerosol detection (CAD). Quantification was performed with regard to the intended use of the substances in thermal papers. Besides traditional UV external calibration using reference standards, alternative quantification approaches, in particular UV chromophore concentration for BPS derivatives and CAD universal response technique for low-volatile color developers, were applied and compared in order to allow quantification without reference substances. A market analysis for intended used color developers and sensitizers was performed on thermal paper samples (n = 211) collected in Germany during 2018 and 2019. Pergafast 201 (in 41.7% of the samples) was the most common color developer with concentrations above 0.02 wt%, followed by BPA (36.0%), BPS (13.3%) and other BPS derivatives known as D8, D-90, BPS-MAE and TGSA, that are mainly present in adhesive labels. Sensitizers were determined in over 90% of the samples.


Assuntos
Aerossóis/análise , Compostos Benzidrílicos/análise , Marketing , Papel , Fenóis/análise , Temperatura Ambiente , Compostos Benzidrílicos/química , Calibragem , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Cor , Disruptores Endócrinos/análise , União Europeia , Alemanha , Limite de Detecção , Modelos Lineares , Fenóis/química , Padrões de Referência , Sulfonas
9.
J Chromatogr A ; 1609: 460441, 2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31439440

RESUMO

A simple, rapid, and sensitive ultra-high performance liquid chromatography with charged aerosol detector (UPLC-CAD) method was developed for firstly simultaneous determination of seven oligosaccharides, including two pairs of linear oligosaccharides isomers (DP3-1, DP3-2 and DP4-1, DP4-2) and 3 high branched oligosaccharides (DP 5, 6 and 7), as well as sucrose in Pseudostellaria heterophylla. The separation was performed on a Waters BEH Amide column (2.1 × 150 mm i.d., 1.7 µm) with gradient elution within 20 min. All calibration curves for the investigated analytes showed good linearity (R2 > 0.9992). Their limits of detection (LOD) and quantification (LOQ) were in the ranges of 0.24-1.35 µg/mL and 0.78-4.96 µg/mL, respectively. Repeatability of all investigated components detected in samples was less than 2.9%. All the recoveries of each analyte ranged from 99.2% to 104.3% were acceptable. An ultra-high performance liquid chromatography-tandem quadrupole time-of-flight mass spectrometer (UPLC-QTOF MS) method was also applied to authenticate the oligosaccharides in different samples by comparing to the isolated standards. Oligosaccharides, especially linear oligosaccharides isomers and high branched oligosaccharides with different degree of polymerization (DP), were firstly identified and determined in P. heterophylla. Their contents in 33 samples of P. heterophylla from different locations was successfully compared, which is helpful to evaluate its quality.


Assuntos
Aerossóis/análise , Caryophyllaceae/química , Cromatografia Líquida de Alta Pressão/métodos , Oligossacarídeos/análise , Sacarose/análise , Espectrometria de Massas em Tandem/métodos , Calibragem , Análise por Conglomerados , Limite de Detecção , Análise de Componente Principal , Padrões de Referência , Análise de Regressão , Reprodutibilidade dos Testes , Solventes/química , Fatores de Tempo
10.
Environ Pollut ; 256: 113401, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31753639

RESUMO

This study reveals the impact of biomass burning (BB) on secondary organic aerosols (SOA) formation in the North China Plain (NCP). Filter samples were analyzed for secondary inorganic aerosols (SIA), oxalic acid (C2) and related aqueous-phase SOA compounds (aqSOA), stable carbon isotope composition of C2 (δ13C(C2)) and aerosol liquid water content (ALWC). Based on the PM2.5 loadings, BB tracer concentrations, wildfire spots and air-mass back trajectories, we distinguished two episodes from the whole campaign, Episode I and Episode II, which were characteristic of regional and local BB, respectively. The abundances of PM2.5 and organic matter in the two events were comparable, but concentrations and fractions of SIA, aqSOA during Episode I were much higher than those during Episode II, along with heavier δ13C(C2), suggesting an enhanced aqSOA formation in the earlier period. We found that the enhancement of aqSOA formation during Episode I was caused by an increased ALWC, which was mainly driven by SIA during the regional BB event. Our work showed that intensive burning of crop residue in East Asia can sharply enhance aqSOA production on a large scale, which may have a significant impact on the regional climate and human health.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Biomassa , Carbono/análise , Isótopos de Carbono/análise , China , Clima , Extremo Oriente , Compostos Orgânicos/análise , Material Particulado/análise , Estações do Ano , Água , Incêndios Florestais
11.
Sci Total Environ ; 698: 134315, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783453

RESUMO

Bioaerosol in the atmosphere plays a very important role in environment and public health. To forecast the bioaerosol concentration, the correlation between bioaerosol concentration and meteorological factors was discussed, and a Back Propagation (BP) neural network with Principal Component Analysis (PCA) method was utilized in this study. The proposed method works in three steps. The first step is to compute the correlation between bioaerosol concentration and meteorological factors, which consists of analyzing correlation and selecting meteorological factors applied to the study of forecast model. The second step is to use PCA analysis to reduce the dimensions of meteorological dataset. The third step is to use BP neural network, setting up, training BP neural network and proving the feasibility of forecast model included. The results of our model in forecasting bioaerosol concentration show 10.55% of average relative error, 2.80 pieces/L (pcs/L) of average absolute error, and 84.01 grade of forecast accuracy, providing a promising model for the forecasting of bioaerosol concentration.


Assuntos
Aerossóis/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental/métodos , Atmosfera , Conceitos Meteorológicos
12.
Chemosphere ; 240: 124923, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726605

RESUMO

The purpose of this study is to deepen the knowledge of the various emission phenomena present in aerated tanks, widely used systems for municipal and industrial wastewater treatment. In order to investigate the emission mechanism, a specific model was developed. The theoretical model proposes to consider three different contributions to the emission of organic compounds from aerated wastewater tanks: the convection due to the sweep air flow rate, the rising bubbles stripping and the aerosol formation and successive evaporation. To compare the modeled results, an experimental campaign was conducted with two different solutes, acetone and butanol. The sampling was carried out with a Wind Tunnel system and the outflow gas samples were analysed with gas chromatographic technique. Moreover, this study investigates the dependence of the concentration in the gaseous phase from the speed of the air on the surface (1-5 cm/s) and from the flow of air diffused inside the liquid body (50-200 L/h). The empirical data were compared with theoretical curves. The results confirm two facts: the gas solute concentration decreases as the air velocity increases and, instead, increases with the air flow diffused through the tank.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Modelos Teóricos , Compostos Orgânicos/análise , Aerossóis/análise , Veículos Automotores , Águas Residuárias/análise
13.
Chemosphere ; 240: 124933, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31726611

RESUMO

The occurrence, air-sea exchange, and gas-particle partitioning of polybrominated diphenyl ethers (PBDEs) were analyzed during a 2015 research expedition from the East China Sea (ECS) to the open Northwest Pacific Ocean (NWP). The sum of 13 PBDEs (Σ13PBDEs) in air and surface seawater varied in the range of 0.54-14.5. pg m-3 and 0.60-13.5 pg L-1, respectively, with the highest concentrations observed in the ECS. The Clausius-Clapeyron approach and air mass origin analysis indicated that continued primary emissions of PBDEs, particularly BDE-209, from East Asian sources governed the spatial variability of air PBDEs over the NWP through long-range atmospheric transport (LRAT). Net air-to-seawater gas deposition of PBDEs was evidenced based on the fugacity calculation with sum fluxes of seven selected PBDEs ranging from -45 to -582 pg m-2 d-1. Following the substantial advection of aerosol phase BDE-209 over the ECS, dry particle deposition dominated the input pathway of PBDEs into the ECS, whereas in the open NWP, relatively free from the influence of the land emissions, fluxes in PBDE absorption and in dry particle deposition were comparable. This suggests an impact of continental outflow on the fate of atmospheric PBDEs over the NWP. Regarding gas-particle partitioning, PBDEs over the NWP were obviously absorbed into continental organic aerosols during atmospheric transport, except for BDE-209, which tended to remain within the steady state.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Éteres Difenil Halogenados/análise , Aerossóis/análise , Ásia , Atmosfera/química , China , Extremo Oriente , Oceano Pacífico , Água do Mar
14.
J Environ Sci (China) ; 87: 361-376, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791509

RESUMO

In recent years, haze has posed a serious threat to the global climate change, ecological balance and human health. In this study, the laboratory experiments and field observations were performed and a possible charging mechanism was proposed to investigate the space charge properties in haze events. The laboratory experiments showed that the charge polarity of primary aerosol is determined by species of combustion fuels while the magnitude is dependent on the combustion completeness. The field observations revealed that the space charge of atmosphere aerosol in haze events differs from that of fair weather and is closely related to PM2.5 concentration when Relative Humidity (RH) < 60%, with 1 to 2 orders of magnitude less than the case when RH ≥ 60%. The analysis of equivalent charge-to-mass ratio (ECTM) suggested that in haze events the space charge is governed by primary aerosol emitted by combustion of fossil fuel in a low relative humidity, whereas it is manipulated by the secondary chemical reaction of atmosphere aerosol in a high relative humidity. And we can identify the main pollutants in haze events according to the polarity of atmosphere aerosol and quickly take measures when RH < 60%. Accordingly, the dust-haze of RH < 80% can be divided into dry-dust-haze when RH < 60% and wet-dust-haze when 60% ≤ RH < 80%. Our study firstly elucidated the space charge properties of atmosphere aerosol in haze events and can provide a new perspective for the prevention and control of air pollution.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Poluição do Ar , Atmosfera/química , China
15.
J Environ Sci (China) ; 87: 49-59, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31791517

RESUMO

To clarify the aerosol hygroscopic growth and optical properties of the Pearl River Delta (PRD) region, integrated observations were conducted in Heshan City of Guangdong Province from October 19 to November 17, 2014. The concentrations and chemical compositions of PM2.5, aerosol optical properties and meteorological parameters were measured. The mean value of PM2.5 increased from less than 35 (excellent) to 35-75 µg/m3 (good) and then to greater than 75 µg/m3 (pollution), corresponding to mean PM2.5 values of 24.9, 51.2, and 93.3 µg/m3, respectively. The aerosol scattering hygroscopic growth factor (f(RH = 80%)) values were 2.0, 2.12, and 2.18 for the excellent, good, and pollution levels, respectively. The atmospheric extinction coefficient (σext) and the absorption coefficient of aerosols (σap) increased, and the single scattering albedo (SSA) decreased from the excellent to the pollution levels. For different air mass sources, under excellent and good levels, the land air mass from northern Heshan had lower f(RH) and σsp values. In addition, the mixed aerosol from the sea and coastal cities had lower f(RH) and showed that the local sources of coastal cities have higher scattering characteristics in pollution periods.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , China , Material Particulado/análise , Molhabilidade
16.
Chemosphere ; 239: 124678, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31494323

RESUMO

In the developing countries such as China, most well-developed areas have suffered severe haze pollution, which was associated with increased premature morbidity and mortality and attracted widespread public concerns. Since ground-based PM2.5 monitoring has limited temporal and spatial coverage, satellite aerosol remote sensing data has been increasingly applied to map large-scale PM2.5 characteristics through advanced spatial statistical models. Although most existing research has taken advantage of the polar orbiting satellite instruments, a major limitation of the polar orbiting platform is its limited sampling frequency (e.g., 1-2 times/day), which is insufficient for capturing the PM2.5 variability during short but intense heavy haze episodes. As the first attempt, we quantitatively investigated the feasibility of using the aerosol optical depth (AOD) data retrieved by the Geostationary Ocean Color Imager (GOCI) to estimate hourly PM2.5 concentrations during winter haze episodes in the Yangtze River Delta (YRD). We developed a three-stage spatial statistical model, using GOCI AOD and fine mode fraction, as well as corresponding monitoring PM2.5 concentrations, meteorological and land use data on a 6-km modeling grid with complete coverage in time and space. The 10-fold cross-validation R2 was 0.72 with a regression slope of 1.01 between observed and predicted hourly PM2.5 concentrations. After gap filling, the R2 value for the three-stage model was 0.68. We further analyzed two representative large regional episodes, i.e., a "multi-process diffusion episode" during December 21-26, 2015 and a "Chinese New Year episode" during February 7-8, 2016. We concluded that AOD retrieved by geostationary satellites could serve as a new valuable data source for analyzing the heavy air pollution episodes.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Tecnologia de Sensoriamento Remoto/métodos , Aerossóis/análise , China , Meteorologia , Modelos Estatísticos , Rios , Estações do Ano , Astronave
17.
Chemosphere ; 238: 124634, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31473525

RESUMO

A cavity attenuated phase shift single scattering albedo monitor was set up on a tethered airship platform to study the vertical profiles of particle light extinction coefficient (bext) in the lower troposphere (<1000 m) in Shanghai during 12-29 December 2015. Clear transition heights (THs) for vertical profiles of bext during the polluted days (PM2.5 > 75 µg m-3) were observed below 1000 m. The vertical differences of bext were highly dynamic as the vertical variation in bext was significant by as much as 605 Mm-1. The TH was observed mostly at about 100-200 m, and 450-650 m during night and daytime, respectively, and was in a wide range of ∼50-900 m during 15:00-22:00 due to the low boundary layer and/or the transport of pollutants. In particular, the TH was consistently below 500 m throughout the day during highly polluted haze episodes, highlighting the important role of a stagnant atmosphere situation for high concentrations of PM2.5. The vertical distribution of bext did not have a constant rule with respect to relative humidity and wind. Sometimes, peak values of bext at ∼350 m and 500 m during daytime were caused by enhanced regional transport. During stagnant and highly polluted situations or well-mixed clean days, bext was usually uniformly distributed below and above the TH, respectively, although bext was much smaller above the TH. For other situations, local emissions, pollutant transport, and the physical and chemical characteristics of aerosols resulted in highly dynamic vertical profiles of bext.


Assuntos
Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Aerossóis/análise , China , Estações do Ano , Vento
18.
Chemosphere ; 239: 124776, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31526988

RESUMO

Modern microscopy studies are capable of revealing ultra-fine particles (UFPs) and nanoparticles (NPs) that are produced in the processes related to traffic vehicular, industrial, metropolitan, and marine aerosol dry deposition in the coastal zones. Especially, secondary aerosol passages complexes categories of NPs and UFPs, which can be accumulated on construction compounds and by dry deposition, encourages multiples monuments deterioration routes. The advanced electron microscopies method is one of the most utilized in environmental studies. Between the different industrial areas in the world, the Caribbean area is the most relevant symbols of air quality due to climatic conditions with strong winds, but this study shows that regionally the most industrialized region does not have an adequate air quality. In the present work, electron microscopy analyses are used to describe of the extent of ultra-fine particle and nanoparticles in walls in contact to weathering. Numerous phases were recognized by advanced mineralogy methods. Thanks to the new analytical procedure it was feasible to understand NPs and UFPs; the occurrence of potential hazardous elements (PHEs), most of them as minerals but also combined in multiple accumulations with Al-Cr-Fe-K-Mg-Pb-Si-Ti-Zn amorphous; and carbonaceous phases.


Assuntos
Poluentes Atmosféricos/análise , Nanopartículas/análise , Material Particulado/análise , Aerossóis/análise , Poluentes Atmosféricos/química , Poluição do Ar/análise , Atmosfera , Região do Caribe , Colômbia , Monitoramento Ambiental/instrumentação , Monitoramento Ambiental/métodos , Desenvolvimento Industrial , Minerais/análise , Veículos Automotores , Material Particulado/química , Vento
19.
Environ Monit Assess ; 192(1): 6, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31797169

RESUMO

The extensive use of fireworks generates large amounts of pollutants, deteriorating air quality and potentially causing adverse health impacts. In Medellín and its metropolitan area, although fireworks are banned during December, their use is widespread during the Christmas season, particularly during the midnight of November 30 (La Alborada) and New Year's Eve (NYE). It is therefore essential to assess the effects of these celebrations on air quality in the region. Air-quality data from the official monitoring network and a low-cost particulate matter (PM) citizen science project, backscattering intensity (BI) retrievals from a ceilometer network, potential temperature from a microwave radiometer, and information from a radar wind profiler provide an excellent platform to study the spatio-temporal distribution of contaminants resulting from the La Alborada and NYE celebrations. Substantial increases in PM2.5 and PM10 mass concentrations due to La Alborada and NYE, ranging in some cases from 50 to 100 µgm-3, are observed in the Aburrá Valley and particularly in the densely populated communes of Medellín, with most concentration changes corresponding to ultrafine and fine particles. The PM increments resulting from fireworks show almost no increase in the net amount of black carbon in the atmosphere. Ceilometer BI profiles show a substantial change immediately after the La Alborada and NYE midnights, confined to the atmospheric boundary layer (ABL). Strong thermal inversions lead to fairly homogeneous increments in BI within the ABL, lasting until the onset of the convective boundary layer. In contrast, weak thermal inversions lead to rapid dispersion of aerosols, allowing them to episodically escape above the ABL.


Assuntos
Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , Aerossóis/análise , Poluição do Ar/análise , Atmosfera/química , Colômbia , Tamanho da Partícula , Estações do Ano , Vento
20.
Environ Sci Pollut Res Int ; 26(35): 35945-35956, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31709484

RESUMO

The aim of the research was to assess the possibility to use deciduous tree bark in the biomonitoring of urban areas. The tree bark taken from various deciduous tree species growing in the Opole Province (south-western Poland) was used for the research. The bark was collected from tree trunks in the period of June 2-26, 2017. Concentrations of the heavy metals were determined in the barks by flame atomic absorption spectrometry (FAAS). On the basis of the research, it was determined that type of tree, distance from pollution source, elevation off the ground and the side of trunk from which bark was sampled all influence the research results. A comparison of the values of coefficient of variation CV demonstrated that the bark Quercus robur and Betula pendula is more heterogeneous, e.g. for Fe CVQuercus robur is 48.0 % and CVBetula pendula = 42.3 %, compared to Fagus sylvatica (CVFe = 22.6%). In order to limit the influence of environmental factors (e.g. air movement caused by vehicles and pedestrians) on the samples pollution level with analytes, it seems that the optimum level for collecting the samples is 1.5-2.0 m. It was demonstrated that deciduous tree bark can be used as bioindicator in assessing the pollution of atmospheric aerosol by heavy metals, due to its occurrence in urban areas. However, it is important to validate all stages of the analysis procedure that uses deciduous tree bark.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental/métodos , Metais Pesados/análise , Casca de Planta/química , Betula , Poluição Ambiental/análise , Poluição Ambiental/estatística & dados numéricos , Polônia , Árvores/química
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