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1.
Chemosphere ; 262: 127771, 2021 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-32799139

RESUMO

The review initiates with current state of information on the atmospheric reaction mechanism of biogenic volatile organic compounds (BVOCs) and its fate in the atmosphere. The plants release BVOCs, i.e., isoprene, monoterpenes, and sesquiterpenes, which form secondary organic aerosols (SOA) upon oxidation. These oxidation reactions are primarily influenced by solar radiations along with other meteorological parameters viz.; temperature and relative humidity, therefore, the chemistry behind SOA formation is different during day than the night time. The review throws light upon the day and nighttime formation mechanism of SOA, recent advancements in the analytical techniques available for the measurements, and its impact on the environment. Studies have revealed that day time SOA formation is dominated by OH and O3, however, NOx initiated SOA production is dominated during night. The formation mechanism addresses that the gaseous products of VOCs are firstly formed and then partitioned over the pre-existing particles. New particle formation and biomass-derived aerosols are found to be responsible for enhanced SOA formation. 2-Dimensional gas chromatography-mass spectrometer (2D-GC/MS) is observed to be best for the analysis of organic aerosols. Radiative forcing (RF) SOA is observed to be a useful parameter to evaluate the environmental impacts of SOA and reviewed studies have shown mean RF in the ranges of -0.27 to +0.20 W m-2.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Atmosfera/química , Butadienos/análise , Hemiterpenos/análise , Monoterpenos/análise , Compostos Orgânicos Voláteis/análise , Aerossóis/química , Poluentes Atmosféricos/química , Butadienos/química , Hemiterpenos/química , Monoterpenos/química , Oxirredução , Temperatura , Compostos Orgânicos Voláteis/química
2.
PLoS One ; 15(10): e0239458, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33002057

RESUMO

Styrene in indoor air can adversely affect human health. In this study, styrene monomer and other chemical emission fluxes for products containing expanded polystyrene beads (pillows, cushions, and soft toys) were measured at various temperatures to simulate typical product use. The contributions of the products to styrene and other chemical concentrations in indoor air and human exposure to these chemicals were estimated, and health risk assessments were performed. The styrene monomer emission fluxes for the samples at 25°C were between 25.3 and 8.73×103 µg/(m2 h). The styrene emission fluxes for the product surfaces increased strongly as the temperature increased, from between 124 and 2.44×104 µg/(m2 h) at 36°C (simulating human body temperature) to between 474 and 4.59×104 µg/(m2 h) at 50°C (simulating inside an automobile in summer). The hexane, heptane, toluene, octane, ethylbenzene, m- and p-xylene, o-xylene, and dodecane emission fluxes at 25°C for the sample that emitted the analytes most readily were high. The maximum estimated styrene and xylene concentrations in indoor air caused by emissions from expanded polystyrene beads at 36°C in a bedroom and automobile were higher than the relevant guidelines. The maximum contribution of a product containing expanded polystyrene beads in a living room, bedroom, or automobile could cause the total volatile organic compound concentration in air to exceed the advisable value (400 µg/m3). The estimated maximum hazard quotients for styrene, toluene, and xylene emitted by a product containing expanded polystyrene beads at 36°C in a bedroom were 0.59, 0.30, and 0.37, respectively. These non-carcinogenic risk values for single products could contribute to the non-carcinogenic risk thresholds being exceeded when multiple products and other sources of chemicals are taken into consideration. The estimated styrene concentrations suggest that products containing expanded polystyrene beads are important sources of styrene to indoor air.


Assuntos
Poluentes Atmosféricos/análise , Microesferas , Poliestirenos/química , Estireno/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental , Estireno/química , Temperatura
3.
PLoS One ; 15(8): e0236708, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32790684

RESUMO

BACKGROUND: Polycyclic aromatic hydrocarbons (PAHs) are a kind of endocrine disruptors, which can enter human body by the inhalation of PAH-containing matter and the ingestion of PAH-containing foodstuffs. Studies showed that PAHs can cross the placental barrier and might cause adverse effects on the fetus. OBJECTIVES: This meta-analysis aimed to estimate the associations between prenatal exposure to PAHs and birth weight. METHODS: Articles published in English until May 8, 2020 and reported the effects of prenatal exposure to PAHs on birth weight were searched in multiple electronic databases including PubMed, the Web of Science, EMBASE and the Cochrane Library. The included studies were divided into three groups in accordance with the measurement of PAHs exposure. Then coefficient was extracted, conversed and synthesized by random-effects meta-analysis. And risk of bias was assessed for each study. RESULTS: A total of 3488 citations were searched and only 11 studies were included finally after double assessment. We found that there were no association between PAH-DNA adducts in cord blood (low/high) (OR: 1.0, 95%CI: 0.97, 1.03), 1-hydroxy pyrene (1-HP) concentration in maternal urine (OR: 1.0, 95%CI: 0.97, 1.03) and prenatal maternal airborne PAHs exposure (OR: 0.97, 95%CI: 0.93, 1.01) and birth weight. However, we observed ethnicity may change the effects of PAHs exposure on birth weight. CONCLUSIONS: There is no significant relationship between prenatal exposure to PAHs and birth weight in our meta-analysis. Further studies are still needed for determining the effects of prenatal PAHs exposure on birth weight.


Assuntos
Peso ao Nascer/efeitos dos fármacos , Disruptores Endócrinos/toxicidade , Exposição Materna , Hidrocarbonetos Policíclicos Aromáticos/toxicidade , Poluentes Atmosféricos/química , Poluentes Atmosféricos/toxicidade , Adutos de DNA/química , Bases de Dados Factuais , Disruptores Endócrinos/química , Feminino , Sangue Fetal/química , Humanos , Razão de Chances , Hidrocarbonetos Policíclicos Aromáticos/química , Gravidez , Pirenos/urina
4.
Proc Natl Acad Sci U S A ; 117(37): 22705-22711, 2020 09 15.
Artigo em Inglês | MEDLINE | ID: mdl-32839319

RESUMO

Black carbon (BC) aerosol plays an important role in the Earth's climate system because it absorbs solar radiation and therefore potentially warms the climate; however, BC can also act as a seed for cloud particles, which may offset much of its warming potential. If BC acts as an ice nucleating particle (INP), BC could affect the lifetime, albedo, and radiative properties of clouds containing both supercooled liquid water droplets and ice particles (mixed-phase clouds). Over 40% of global BC emissions are from biomass burning; however, the ability of biomass burning BC to act as an INP in mixed-phase cloud conditions is almost entirely unconstrained. To provide these observational constraints, we measured the contribution of BC to INP concentrations ([INP]) in real-world prescribed burns and wildfires. We found that BC contributes, at most, 10% to [INP] during these burns. From this, we developed a parameterization for biomass burning BC and combined it with a BC parameterization previously used for fossil fuel emissions. Applying these parameterizations to global model output, we find that the contribution of BC to potential [INP] relevant to mixed-phase clouds is ∼5% on a global average.


Assuntos
Carbono/química , Mudança Climática , Água/química , Incêndios Florestais , Aerossóis , Poluentes Atmosféricos/efeitos adversos , Poluentes Atmosféricos/química , Carbono/efeitos adversos , Gelo/análise , Estações do Ano
5.
Chemosphere ; 261: 127758, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32736246

RESUMO

Cooking emissions are both indoor and outdoor sources for fine particulate matter (PM2.5) but their contributions are often ignored. The PM2.5-bound organic compounds, including alkanols, alkanes, monocarboxylic acids, dicarboxylic acids, and polycyclic aromatic hydrocarbons (PAHs) were determined in the emissions from the most popular types of restaurants in the capital city of northwestern China. The mean concentration of total quantified organic compounds (ΣPM_O) ranged from 1112 to 32,016 ng m-3, with the maximum for the Chinese barbecue restaurants. The ΣPM_O accounted for an average of 11% of PM2.5 mass, demonstrating their significances in the cooking emissions. Hexadecanoic acid (C16) and 1-hexadecanol (C16) were considered as the tracers for stir-frying, steaming, and boiling which are usually applied in the traditional Chinese cuisines; 1-undecanol (C11), 9-fluorenone, and indeno[1,2,3-cd]pyrene were found to be potential markers for grilling and deep-frying which are widely applied in the Western style cooking method. The PAH diagnostic ratios also illustrated their representatives to distinguish the emissions from traditional Chinese cuisines and the Western-style restaurants. The estimated carcinogenic risks for the restaurants that consumed a large amount of oils and employed high temperature cooking methods (e.g., barbecuing and deep-frying) were 2.6-4.2 times exceeded the international safety limit. The organic profiles obtained in this study could be contributed to refine PM2.5 source apportionment in urban areas in northwestern China. The estimations of potential cancer risks urge the establishment of more stringent legislations to protect the health of the catering staffs.


Assuntos
Poluentes Atmosféricos/análise , Culinária , Monitoramento Ambiental/métodos , Neoplasias/epidemiologia , Compostos Orgânicos/análise , Material Particulado/análise , Poluentes Atmosféricos/química , China , Cidades , Culinária/métodos , Humanos , Neoplasias/induzido quimicamente , Compostos Orgânicos/química , Material Particulado/química , Restaurantes , Medição de Risco
6.
PLoS One ; 15(8): e0227469, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32822345

RESUMO

China's rapid industrialization and urbanization have led to poor air quality, and air pollution has caused great concern among the Chinese public. Most analyses of air pollution trends in China are based on model simulations or satellite data. Studies using field observation data and focusing on the latest data from environmental monitoring stations covering the whole country to assess the latest trends of different pollutants in different regions are relatively rare. The State Council of China promulgated the toughest-ever Air Pollution Prevention and Control Action Plan (Action Plan) in 2013. This led to a major improvement in air quality. We use the hourly Air Quality Index (AQI) and mass concentrations of PM2.5, PM10, CO, NO2, O3, and SO2 in 362 cities from 2015 to 2019, obtained from the Ministry of Ecology and Environment, to study their temporal and spatial changes and assess the effectiveness of the policy on the atmospheric environment since its promulgation and implementation. We found that the national and regional air quality in China continues to improve, with PM2.5, PM10, AQI, CO, and SO2 exhibiting negative trends. However, O3 and NO2 pollution is an urgent problem that needs to be solved and the current control strategy for PM2.5 will only partially reduce the PM2.5 pollution in the western region. Although the implementation of "Action Plan" measures has effectively improved air quality, China's air pollution is still serious and far from the WHO standard. Implementing measures for continuous and effective emissions control is still a top priority.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Análise Espaço-Temporal , Poluentes Atmosféricos/química , China
7.
Chemosphere ; 261: 127778, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32739692

RESUMO

Vibration is one of the most prevalent energy sources in natural environment, which can also be harvested and utilized to drive chemical reaction. Herein, mechanical vibration is used for enhancing the catalytic decomposition of formaldehyde at ambient temperature with the assistance of four well-defined morphologies α-MnO2 (nanowire, nanotube, nanorod and nanoflower). In particular, α-MnO2 nanowire exhibits the best catalytic activity, which can completely mineralize formaldehyde into carbon dioxide at ambient temperature by harvesting the vibration energy. To the best of our knowledge, this may be the first report that α-MnO2, as a non-noble metal catalyst, can completely decompose formaldehyde to carbon dioxide at ambient temperature. The characterization results show that α-MnO2 nanowire has a much higher oxygen vacancy concentration than other three catalysts. In addition, thermal effect generated from friction between nanoparticles induced by ultrasonic vibration may enhance its catalytic activity. More importantly, it is the vibration that effectively promotes the activation of O2 adsorbed on the surface oxygen vacancy to produce more , thus increasing the catalytic decomposition performance. The strategy presented herein demonstrates a new approach for efficient use of mechanical vibration to improve catalytic activity of traditional catalysts.


Assuntos
Poluentes Atmosféricos/química , Formaldeído/química , Compostos de Manganês/química , Nanoestruturas/química , Adsorção , Carcinógenos , Catálise , Nanopartículas , Nanotubos/química , Nanofios , Oxirredução , Óxidos/química , Oxigênio/química , Temperatura , Vibração
8.
Chemosphere ; 261: 127750, 2020 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-32712379

RESUMO

This study focused on particulate matter (PM2.5) and carbon species in Seoul, South Korea, to quantitatively evaluate their long-term trends and assess the main correlating factors. Ambient PM2.5 samples were collected over a 24 h period every third or sixth day from March 2003 to December 2017. The mean concentrations of PM2.5, organic carbon (OC), elemental carbon (EC), primary and secondary OC (POC and SOC) in Seoul over 15 years were 32.2 µg/m3 and 7.28 µg/m3, 1.85 µg/m3, 4.29 µg/m3 and 3.54 µg/m3 respectively. The long-term concentration trends in PM2.5, OC, EC, POC, and SOC decreased significantly at rates of -2.09, -3.13, -6.31, -2.86, and -3.88 per year, respectively from 2003 to 2017 (p < 0.001), whereas the long-term trends in OC/EC significantly increased at a rate of 12.9/year (p < 0.001). These long-term decreases in PM2.5 and carbon species concentrations were most pronounced in 2008 but almost disappeared from 2013 onwards. Considering the decrease in wind speed and variations in the concentration of gaseous air pollutants (carbon monoxide, sulfur dioxide, nitrogen dioxide, and volatile organic compounds) without a tendency to increase or decrease since 2013, secondary aerosol formation by atmospheric stagnation alleviated long-term decreases in PM2.5 and carbon species concentrations. The long-term decreases in EC concentration were the most consistent and rapid, strongly suggesting that atmospheric policies related to mobile in South Korea were effective in reducing EC concentration. Future air quality management should focus on the secondary formation of air pollutants based on regional trends in air pollutant concentrations.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Carbono/análise , Monitoramento Ambiental/métodos , Material Particulado/análise , Aerossóis , Poluentes Atmosféricos/química , Carbono/química , Material Particulado/química , República da Coreia , Estações do Ano , Seul , Dióxido de Enxofre , Fatores de Tempo , Vento
9.
Chemosphere ; 259: 127331, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32650175

RESUMO

The atmospheric degradation of polycyclic aromatic hydrocarbons (PAHs) can generate organic pollutants that contribute to the formation of secondary organic aerosols (SOAs) and exacerbate their carcinogenicity. Indene is an example of styrene-like bicyclic hydrocarbons that are not fully aromatic. The OH-initiated atmospheric oxidation of indene in the presence of O2 and NO was investigated using quantum chemical methods at M06-2X/6-311++G(3df,2p)//M06-2X/6-311+G(d,p) level. The oxidation products are oxygenated polycyclic aromatic hydrocarbons (OPAHs) containing hydroxyindene, indenone, dialdehydes and 2-(formylmethyl)benzaldehyde. Calculation results showed that 7-indene radical, which is the precursor of various PAHs, has a high production ratio that is 35.29% in the initial reaction, indicating that the OH-initiated oxidation increase the environmental risks of indene in the atmosphere. The rate constants for the crucial elementary reactions were calculated based on Rice-Ramsperger-Kassel-Marcus (RRKM) theory. The overall rate constant of the initial reaction is calculated to be 1.04 × 10-10 cm3 molecule-1 s-1 and the atmospheric lifetime of indene is determined as 2.74 h. This work provides a comprehensive understanding on the oxidation mechanisms of indene and the findings could help to clarify the fate of indene in the atmosphere.


Assuntos
Poluentes Atmosféricos/química , Atmosfera/química , Radical Hidroxila/química , Indenos/química , Aerossóis , Cinética , Óxidos de Nitrogênio/química , Oxirredução , Oxigênio/química , Hidrocarbonetos Policíclicos Aromáticos
10.
J Vis Exp ; (159)2020 05 22.
Artigo em Inglês | MEDLINE | ID: mdl-32510496

RESUMO

The current particle size threshold of the European Particle Number (PN) emission standards is 23 nm. This threshold could change because future combustion engine vehicle technology may emit large amounts of sub-23 nm particles. The Horizon 2020 funded project DownToTen (DTT) developed a sampling and measurement method to characterize particle emissions in this currently unregulated size range. A PN measurement system was developed based on an extensive review of the literature and laboratory experiments testing a variety of PN measurement and sampling approaches. The measurement system developed is characterized by high particle penetration and versatility, which enables the assessment of primary particles, delayed primary particles, and secondary aerosols, starting from a few nanometers in diameter. This paper provides instruction on how to install and operate this Portable Emission Measurement System (PEMS) for Real Drive Emissions (RDE) measurements and assess particle number emissions below the current legislative limit of 23 nm.


Assuntos
Condução de Veículo , Monitoramento Ambiental/métodos , Nanopartículas/análise , Nanopartículas/química , Tamanho da Partícula , Emissões de Veículos/análise , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental/instrumentação , Laboratórios , Material Particulado/análise , Material Particulado/química
11.
Ecotoxicol Environ Saf ; 201: 110827, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32535366

RESUMO

Numerous experimental and epidemiological studies have demonstrated that exposure to PM2.5 may result in pathogenesis of several major cardiovascular diseases (CVDs), which can be attributed to the combined adverse effects induced by the complicated components of PM2.5. Organic materials, which are major components of PM2.5, contain thousands of chemicals, and most of them are environmental hazards. However, the contamination profile and contribution to overall toxicity of PM2.5-bound organic components (OCs) have not been thoroughly evaluated yet. Herein, we aim to provide an overview of the literature on PM2.5-bound hydrophobic OCs, with an emphasis on the chemical identity and reported impairments on the cardiovascular system, including the potential exposure routes and mechanisms. We first provide an update on the worldwide mass concentration and composition data of PM2.5, and then, review the contamination profile of PM2.5-bound hydrophobic OCs, including constitution, concentration, distribution, formation, source, and identification. In particular, the link between exposure to PM2.5-bound hydrophobic OCs and CVDs and its possible underlying mechanisms are discussed to evaluate the possible risks of PM2.5-bound hydrophobic OCs on the cardiovascular system and to provide suggestions for future studies.


Assuntos
Poluentes Atmosféricos/toxicidade , Doenças Cardiovasculares/induzido quimicamente , Sistema Cardiovascular/efeitos dos fármacos , Monitoramento Ambiental/métodos , Compostos Orgânicos/toxicidade , Material Particulado/toxicidade , Poluentes Atmosféricos/química , Humanos , Interações Hidrofóbicas e Hidrofílicas , Compostos Orgânicos/química , Material Particulado/química
12.
Ecotoxicol Environ Saf ; 201: 110726, 2020 Sep 15.
Artigo em Inglês | MEDLINE | ID: mdl-32480160

RESUMO

BACKGROUND: Impaired in utero fetal growth trajectory may have long term health consequences of the newborns and increase risk of adulthood metabolic diseases. Prenatal exposure to air pollution has been linked to fetal development restriction; however, the impact of exposure to ambient air pollutants on the entire course of intrauterine fetal development has not been comprehensively investigated. METHODS: During 2015-2018, two cohorts of mother-infant dyads (N = 678 and 227) were recruited in Shanghai China, from which three categories of data were systematically collected: (1) daily exposure to six air pollutants during pregnancy, (2) fetal biometry in the 2nd (gestational week 24, [GW24]) and 3rd trimester (GW36), and (3) neonatal outcomes at birth. We investigated the impact of prenatal exposure to air pollutant mixture on the trajectory of fetal development during the course of gestation, adjusting for a broad set of potential confounds. RESULTS: Prenatal exposure to PM2.5, PM10, SO2 and O3 significantly reduced fetal biometry at GW24, where SO2 had the most potent effect. For every 10 µg/m3 increment increase of daily SO2 exposure during the 1st trimester shortened femur length by 2.20 mm (p = 6.7E-21) translating to 5.3% reduction from the average of the study cohort. Prenatal air pollution exposure also decreased fetal biometry at GW36 with attenuated effect size. Comparing to the lowest exposed quartile, fetus in the highest exposed quartile had 6.3% (p = 3.5E-5) and 2.1% (p = 2.4E-3) lower estimated intrauterine weight in GW24 and GW36, respectively; however, no difference in birth weight was observed, indicating a rapid catch-up growth in the 3rd trimester. CONCLUSIONS: To our knowledge, for the first time, we demonstrated the impact of prenatal exposure to ambient air pollutants on the course of intrauterine fetal development. The altered growth trajectory and rapid catch-up growth in associated with high prenatal exposure may lead to long-term predisposition for adulthood metabolic disorders.


Assuntos
Poluentes Atmosféricos/toxicidade , Desenvolvimento Fetal/efeitos dos fármacos , Exposição Materna/efeitos adversos , Material Particulado/toxicidade , Adulto , Poluentes Atmosféricos/química , China/epidemiologia , Estudos de Coortes , Feminino , Idade Gestacional , Humanos , Recém-Nascido , Material Particulado/química , Gravidez
13.
Chemosphere ; 258: 127286, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32544811

RESUMO

Micro-capillary bioreactors (1 mm ID, 10 cm long) were investigated for the biodegradation of toluene vapors as a model volatile organic compound (VOC). The intended application is the removal of VOCs from indoor air, when such microbioreactor is coupled with a microconcentrator that intermittently delivers high concentrations of VOCs to the bioreactor for effective treatment. The effects of key operating conditions were investigated. Specifically, gas film and liquid film mass transfer coefficients were determined for different gas and liquid velocities. Both mass transfer coefficients increased with gas or liquid velocity, respectively, and the overall gas-liquid mass transfer was dominated by the liquid-side resistance. Experiments with the microbioreactors focused on the effects of gas velocity, liquid velocity and mineral medium renewal rate on the treatment of toluene vapors at different inlet concentrations. The best performance in terms of toluene removal and mineralization to CO2 was obtained when the gas and liquid velocity ratio was close to one and achieving Taylor or slug flow pattern. Sustained treatment over extended periods of time with toluene elimination capacities ranging from 4000 to over 9000 g m-3 h-1 were obtained, which is orders of magnitude greater than conventional biofilters and biotrickling filters. Biological limitations generally played a more important role than mass transfer limitation. Continuous mineral medium supply at a high rate (10 h liquid retention time) enabled pH control and provided ample nutrient supply and therefore resulted in better toluene elimination and mineralization. Overall, these studies helped select the most suitable conditions for high performance and sustained operation.


Assuntos
Poluentes Atmosféricos/química , Reatores Biológicos , Tolueno/química , Compostos Orgânicos Voláteis/química , Biodegradação Ambiental , Desenho de Equipamento , Gases , Concentração de Íons de Hidrogênio
14.
Chemosphere ; 251: 126598, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443236

RESUMO

Here we present a long-term, hourly resolution dataset (from January 2014 to April 2015) of secondary inorganic aerosol (SIA) matter, organic matter (OM) and black carbon (BC) as PM2.5 chemical components in China. Seasonally differentiated weekly diurnal profiles of major particulate species were investigated in conjunction with potential source contribution function (PSCF) analysis. The average concentration of PM2.5 was 48.3 ± 35.1 µg m-3, in which OM was the major constituent (29.7 ± 13.9%), followed by sulfate (25.1 ± 8.1%), nitrate (18.5 ± 8.3%), ammonium (13.3 ± 3.8%), and other trace species (6.8 ± 4.0%). Interestingly, unlike other PM species, OM concentrations kept very similar level among different seasons, indicating on-road traffic is a stable source of PM2.5. Besides, a persistently strong particulate OM pollution belt was found along the lower reaches of Yangtze River. Significant enhancement of SIA (mainly nitrate) was coincided with high PM2.5 mass loading. Source apportionment were conducted and found the overwhelming dominance of long-range transport of the pollutants from north China. Using a case study, we further integrate Weather Research and Forecasting (WRF) meteorological modeling and lidar observation to better understand the evolution process of a typical pollution episode. Our assessment of the extremely large datasets derived from Shanghai supersite demonstrated the online instrumentation as a robust and credible alternative to filter-based sampling techniques for long-term PM2.5 monitoring and characterization in heavily polluted areas.


Assuntos
Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Monitoramento Ambiental/métodos , Material Particulado/análise , Material Particulado/química , Aerossóis , China , Cidades , Carvão Mineral/análise , Nitratos/análise , Óxidos de Nitrogênio/análise , Rios/química , Estações do Ano , Sulfatos/análise , Tempo (Meteorologia)
15.
Chemosphere ; 251: 126561, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32443240

RESUMO

In this study, low-temperature catalytic NO oxidation with H2O2 over Na- and H-exchanged Y and ZSM-5 zeolites was investigated at 140 °C which is the average exhaust temperature of coal-fired power plant. Fast catalytic NO oxidation rates were observed over H-zeolites, and catalytic activity was proportional to the amount of Brønsted acid sites. HZSM-5 and HY zeolites show 65% and 95% NO removal efficiency, respectively, but the catalytic stability of HY was lower than HZM-5 due to partial dealumination during the reaction. In-situ DRIFTS analysis showed that NO+ species coordinated at framework sites played a direct role in the catalytic NO oxidation. Moreover, the possible reaction pathway was proposed to elucidate the mechanism of NO oxidation with H2O2 catalyzed over Brønsted acid sites. The effect of reaction temperature, H2O2 concentration, H2O2 flow and SO2 concentration on NO oxidation were investigated over H-zeolites. The experimental results indicated that the NO removal efficiency was increased with the increase of H2O2 concentration, but decreased with the increase of SO2 concentration. The NO removal efficiency first increased and then decreased with the increase of H2O2 flow and reaction temperature.


Assuntos
Poluentes Atmosféricos/análise , Peróxido de Hidrogênio/química , Óxidos de Nitrogênio/análise , Zeolitas/química , Ácidos/química , Poluentes Atmosféricos/química , Catálise , Temperatura Baixa , Modelos Teóricos , Óxidos de Nitrogênio/química , Oxirredução , Centrais Elétricas
16.
Ecotoxicol Environ Saf ; 199: 110686, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32408034

RESUMO

Limited studies have been conducted to evaluate the short-term relationships between exposure to coarse particulate matter (PM2.5-10) and outpatient visits in China. We designed this time-series analysis in a Chinese city Yancheng, to explore the relationship of PM2.5-10 with outpatient visits for cardiopulmonary diseases. The study period was from 2013 to 2015. A typical generalized additive model was used. We explored the lag patterns by building a series of lag of exposure. We also built two-pollutant models to ascertain the independence of PM2.5-10. Stratified analyses were applied to compare the season-specific associations. Finally, we pooled the concentration-response (C-R) curves for PM2.5-10 and outpatient visits. We recorded a daily average of 85 and 43 outpatient visits for cardiovascular and respiratory causes, respectively. PM2.5-10 exposures of lag 05 day yielded the best estimates for both outcomes. Per 10-µg/m3 increase in PM2.5-10, there was a 1.69% (95% confidence interval [CI]: 0.68%-2.72%) increase in outpatient visits for respiratory causes, and a 0.85% (95% CI: 0.13%-1.57%) increase for cardiovascular causes. The association kept robust after adjusting for PM2.5 and O3, and there were larger associations in warm seasons. The C-R curves had a larger slope for respiratory diseases in relatively lower concentrations (<30 µg/m3), and PM2.5-10 was positively associated with cardiovascular diseases in higher concentrations (>30 µg/m3). This study indicated significant associations of PM2.5-10 with cardiopulmonary outpatient visit. Such results may be used for health risk assessment and policy making for particulate air pollution control.


Assuntos
Poluentes Atmosféricos/análise , Assistência Ambulatorial/estatística & dados numéricos , Doenças Cardiovasculares/epidemiologia , Exposição Ambiental/efeitos adversos , Exposição Ambiental/análise , Material Particulado/análise , Poluentes Atmosféricos/química , Poluentes Atmosféricos/toxicidade , China , Cidades , Humanos , Pacientes Ambulatoriais , Material Particulado/química , Material Particulado/toxicidade , Medição de Risco , Estações do Ano
17.
Artigo em Inglês | MEDLINE | ID: mdl-32452236

RESUMO

Given the increasing levels of air pollution, understanding the direct shielding response of the skin to air pollutants as a whole under exclusion of the influence from the inside of body is important. We applied topically the water soluble ambient air pollutants to the mouse skin and observed the histological response using 0.3 mM of H2SO3 as a positive control. Water soluble air pollutants samples, WSAP24h and WSA72h, were collected by pumping the outdoor air into ddH2O for 24 and 72 h respectively during two periods with different air quality index (AQI). Morphological examination showed apparent thickening of the epidermal layer in the H2SO3 skin section and in the sections applied with WSAP24h and WSAP72h without significant difference in the extent of epidermal hyperplasia among three groups. The cell viability assay showed no cytotoxic effect by the treatment of H2SO3 and WSAP24h in human skin fibroblast WS-1 cells. WSAP72h sample revealed a dose-dependent cytotoxicity to skin fibroblasts at 48 hr. The evidences indicated that the barrier function of the skin by epidermis hyperplasia could be activated by the insult of a component of air pollution, and the protection could be hold against a more complex and concentrated ambient air pollutants.


Assuntos
Poluentes Atmosféricos/toxicidade , Monitoramento Ambiental/métodos , Pele/efeitos dos fármacos , Água/química , Poluentes Atmosféricos/análise , Poluentes Atmosféricos/química , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Fibroblastos/efeitos dos fármacos , Humanos , Camundongos , Solubilidade
18.
Chemosphere ; 256: 127107, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32445992

RESUMO

The massive use of petroleum-based polymers and their improper waste treatment has brought on significant global environmental problems due to their non-biodegradable nature. Starch/poly(vinyl alcohol) (PVA) bioplastics are suitable substitutes for conventional polymers, such as polyethylene, due to their full biodegradability and excellent mechanical properties. Knowledge of the pollutant emissions during pyrolysis and combustion of starch/PVA films is important because they can arrive at landfills mixed with conventional polymers and be thermally degraded in uncontrolled fires. On the other hand, controlled thermal treatments could result in thermal valorization of the waste. Pyrolysis and combustion experiments were carried out at 650, 750, 850 and 950 °C in a laboratory furnace. The analysis of carbon oxides, light hydrocarbons, and semivolatile compounds, including polycyclic aromatic hydrocarbons (PAHs), is shown. Experiments showed lower pollutant emissions than those found with conventional polymers, such as polyethylene and polyester, in the same equipment. Nevertheless, the pyrolysis run at 950 °C showed the highest light hydrocarbon yield (123013 mg kg-1), but this is considerably lower than the values found for polyethylene. The main semivolatile compounds (not PAHs) emitted, with maximum yields ranging from 1351 to 4694 mg kg-1, were benzaldehyde, phenol, indene, and acetophenone. Specifically, the total semivolatile compounds emitted after pyrolysis and combustion of starch/PVA samples represent only 38 and 50%, respectively, of those emitted with polyethylene. Further, the main PAHs were naphthalene, acenaphthylene, and phenanthrene with maximum values of 4694, 2704 and 1496 mg kg-1, respectively. The PAH yield was considerably higher in experiments with low oxygen content.


Assuntos
Poluentes Atmosféricos/química , Incineração , Álcool de Polivinil/química , Poluentes Atmosféricos/análise , Carbono/análise , Etanol/análise , Hidrocarbonetos Policíclicos Aromáticos/análise , Cloreto de Polivinila/análise , Pirólise , Amido/análise
19.
Toxicol Lett ; 329: 1-11, 2020 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-32371136

RESUMO

In spring 2016, a study was carried out to characterize currently used pesticide (CUP) exposure among children living in Wallonia (Belgium). Pesticides were measured in both first morning urine voids of 258 children aged from 9 to 12 years and in ambient air collected close to the children's schools. Out of the 46 pesticides measured in the air, 19 were detected with frequencies varying between 11 % and 100 %, and mean levels ranging from <0.04 to 2.37 ng/m³. Only 3 parent pesticides were found in 1-10% of the urine samples, while all the metabolites analyzed were positively detected at least once. The captan metabolite (THPI) was quantified in 23.5 % of the samples, while 3,5,6-trichloro-2-pyridinol (chlopryrifos metabolite) was detected in all urines with levels ranging from 0.36-38.96 µg/l. 3-phenoxybenzoic acid (3-PBA), trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropane carboxylic acid (t-DCCA) and diethylphosphate were the most abundant pyrethroid metabolites and dialkylphosphate measured. The air inhalation was demonstrated to be a minor route of exposure for the selected CUPs. Statistical regressions highlighted predictors of exposure for some pesticides such like consumption of grey bread, presence of carpets at home or indoor use of pesticides, although no clear source was identified for most of them.


Assuntos
Poluentes Atmosféricos/urina , Exposição Ambiental , Praguicidas/urina , Poluentes Atmosféricos/química , Bélgica , Criança , Monitoramento Ambiental , Feminino , Humanos , Masculino , Praguicidas/química
20.
Chemosphere ; 255: 126930, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32402878

RESUMO

Emissions of volatile organic compounds (VOCs) air pollutants could worsen air quality and adversely affect human health, thus developing more efficient low-temperature VOCs removal techniques is desired. A novel continuous system integrating UV-assisted photo-electrochemical catalysis with microbial fuel cell (UV-assisted PEC-MFC) has been established for promoting removal of gaseous ethyl acetate or toluene and generating electricity simultaneously. In this system, CeO2/TiO2/ACF catalytic cathode is prepared and used for combination with bio-anode for accelerating cathodic reaction. This UV-assisted PEC-MFC system exhibits an excellent elimination capacity (EC) of ethyl acetate (∼0.39 g/m3, EC: ∼2.52 g/m3/h) or toluene (∼0.29 g/m3, EC: 1.89 g/m3/h) under close-circuit condition. Furthermore, an outstanding elimination capacity (EC: 28.04 g/m3/h) for high concentration toluene (∼4.10 g/m3) removal is obtained after toluene gas passes sequentially through the catalytic cathode then the bio-anode. This way of PEC degradation and biodegradation, avoids inhibition of exoelectrogens activity from toxicity of high concentration toluene. Simultaneously, the cell voltage of UV-assisted PEC-MFC system is stable at 0.11 V (vs. SCE) and 1.452×10-4 kWh is generated from treatment of toluene gas stream in 6 h duration time. The possible mechanism of VOCs removal in this novel system has been proposed and discussed. This study provides new technical basis for treating gaseous pollutants via integrating photo-electrochemical catalysis with electricity generating microbial fuel cell for energy conversion.


Assuntos
Compostos Orgânicos Voláteis/química , Poluentes Atmosféricos/química , Biodegradação Ambiental , Fontes de Energia Bioelétrica , Catálise , Eletricidade , Eletrodos , Poluentes Ambientais , Gases , Titânio , Tolueno/química , Raios Ultravioleta
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