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1.
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
2.
Sci Total Environ ; 707: 135989, 2020 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-31874395

RESUMO

BACKGROUND: Systemic inflammation is considered one of the key mechanisms in the development of cardiovascular diseases induced by fine particulate matter (PM2.5) air pollution. However, evidence concerning the effects of various PM2.5 constituents on circulating inflammatory biomarkers were limited and inconsistent. OBJECTIVES: To evaluate the associations of short-term exposure to a variety of PM2.5 constituents with circulating inflammatory biomarkers. METHODS: We conducted a panel study from May to October 2016 among 40 healthy adults in Shanghai, China. We monitored the concentrations of 27 constituents of PM2.5. We applied linear mixed-effect models to analyze the associations of PM2.5 and its constituents with 7 inflammatory biomarkers, and further assessed the robustness of the associations by fitting models adjusting for PM2.5 mass and/or their collinearity. Benjamini-Hochberg false discovery rate was used to correct for multiple comparisons. RESULTS: The associations of PM2.5 were strongest at lag 0 d with tumor necrosis factor-α (TNF-α), at lag 1 d with interleukin-6, interleukin-8, and interleukin-17A, at lag 02 d with monocyte chemoattractant protein-1 (MCP-1) and intercellular adhesion molecule-1 (ICAM-1). After correcting for multiple comparisons in all models, Cl-, K+, Si, K, As, and Pb were significantly associated with interleukin-8; SO42- and Se were marginally significantly associated with interleukin-8; SO42-, As, and Se were marginally significantly associated with TNF-α; and Si, K, Zn, As, Se, and Pb were marginally significantly associated with MCP-1. CONCLUSIONS: Our results suggested that some constituents (SO42-, Cl-, K+, and some elements) might be mainly responsible for systemic inflammation triggered by short-term PM2.5 exposure.


Assuntos
Material Particulado/análise , Adulto , Poluentes Atmosféricos , Poluição do Ar , Biomarcadores , China , Exposição Ambiental , Humanos
3.
Huan Jing Ke Xue ; 40(11): 4791-4800, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854544

RESUMO

In this study, long-term continuous monitoring of atmospheric new particle formation was conducted from 2015 to 2017 in the Shanghai suburbs using a scanning mobility particle sizer (SMPS). Combined with meteorological parameters, gaseous pollutants, and PM2.5 chemical composition data, the characterization of new particle formation was analyzed. The results of data analysis showed there were 172 new particle formation (NPF) days in the Shanghai suburbs, accounting for 18.3% of the total effective days (942 d). Typical new particle formation days (Event) and new particle growth-shrinkage (Shrinkage) days were 150 d and 32 d, respectively. The frequency of NPF occurrence was the highest in spring and summer, followed by autumn and winter. Compared with non-new particle formation (Non-NPF) days, Event and Shrinkage days had higher temperature and wind speed, lower humidity, less rainfall, and stronger solar radiation. The ratio of Event days was the highest when the prevailing wind was southerly, southwesterly, or westerly, and when the air masses were mainly from the vegetation cover and agricultural planting areas in the Taihu Lake Basin. The prevailing wind directions for Non-NPF and Shrinkage days were northeasterly and easterly to southeasterly. On the Event days, SO2 and O3 were higher than that on the Non-NPF days, indicating gaseous sulfuric acid and photochemical reactions were key contributors to new particle formation. Higher PM10 concentration was detected on the Event days than on the Non-NPF days, which may be attributed to the photocatalytic reaction. All the pollutant concentrations were the lowest on Shrinkage days, except that of O3. The average concentrations of inorganic components of PM2.5, such as NH4+, SO42-, and NO3- were higher on Event than on Non-NPF days in fall, whereas the opposite results were observed in other seasons. The average concentration of organic carbon on Event days was higher than that on Non-NPF days in each season. The concentrations of PM2.5 components on Shrinkage days were the lowest. However, the ratio of organic carbon on Shrinkage days was higher than that on Non-NPF days in spring, summer, and winter. The higher ratio of organic carbon on the NPF days than on the Non-NPF days suggested an important role of organic matter in the formation and growth of new particles in the suburbs of Shanghai.

4.
Proc Natl Acad Sci U S A ; 116(49): 24463-24469, 2019 Dec 03.
Artigo em Inglês | MEDLINE | ID: mdl-31740599

RESUMO

From 2013 to 2017, with the implementation of the toughest-ever clean air policy in China, significant declines in fine particle (PM2.5) concentrations occurred nationwide. Here we estimate the drivers of the improved PM2.5 air quality and the associated health benefits in China from 2013 to 2017 based on a measure-specific integrated evaluation approach, which combines a bottom-up emission inventory, a chemical transport model, and epidemiological exposure-response functions. The estimated national population-weighted annual mean PM2.5 concentrations decreased from 61.8 (95%CI: 53.3-70.0) to 42.0 µg/m3 (95% CI: 35.7-48.6) in 5 y, with dominant contributions from anthropogenic emission abatements. Although interannual meteorological variations could significantly alter PM2.5 concentrations, the corresponding effects on the 5-y trends were relatively small. The measure-by-measure evaluation indicated that strengthening industrial emission standards (power plants and emission-intensive industrial sectors), upgrades on industrial boilers, phasing out outdated industrial capacities, and promoting clean fuels in the residential sector were major effective measures in reducing PM2.5 pollution and health burdens. These measures were estimated to contribute to 6.6- (95% CI: 5.9-7.1), 4.4- (95% CI: 3.8-4.9), 2.8- (95% CI: 2.5-3.0), and 2.2- (95% CI: 2.0-2.5) µg/m3 declines in the national PM2.5 concentration in 2017, respectively, and further reduced PM2.5-attributable excess deaths by 0.37 million (95% CI: 0.35-0.39), or 92% of the total avoided deaths. Our study confirms the effectiveness of China's recent clean air actions, and the measure-by-measure evaluation provides insights into future clean air policy making in China and in other developing and polluting countries.

5.
Sci Total Environ ; 695: 133780, 2019 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-31416039

RESUMO

BACKGROUND: The identification of constituents of fine particulate matter (PM2.5) air pollution that had key impacts of ischemic stroke (the predominant subtype of stroke) is important to understand the underlying biological mechanisms and develop air pollution control policies. OBJECTIVES: To explore the associations between PM2.5 constituents and hospitalization for ischemic stroke in Shanghai, China. METHODS: We conducted a time-series study to explore the associations between 27 constituents of PM2.5 and hospitalization for ischemic stroke in Shanghai, China from 2014 to 2016. The over-dispersed generalized additive models with adjustment for time, day of week, holidays, and weather conditions were used to estimate the associations. We also evaluated the robustness of the effect estimates for each constituent after adjusting for the confounding effects of PM2.5 total mass and gaseous pollutants and the collinearity (the residual) between this constituent and PM2.5 total mass. We also compared the associations between seasons. RESULTS: In total, we identified 4186 ischemic stroke hospitalizations during the study period. The associations of ischemic stroke were consistently significant with elemental carbon and several elemental constituents (Chromium, Iron, Copper, Zinc, Arsenic, Selenium, and Lead) at lag 1 day in single-constituent models, models adjusting for PM2.5 total mass or gaseous pollutants and models adjusting for collinearity. The associations were much stronger in cool season than in warm season. CONCLUSIONS: The current study provides suggestive evidence that elemental carbon and some metallic elements may be mainly responsible for the risks of ischemic stroke hospitalization induced by short-term PM2.5 exposure.


Assuntos
Poluição do Ar/estatística & dados numéricos , Exposição Ambiental/estatística & dados numéricos , Material Particulado/análise , Acidente Vascular Cerebral/epidemiologia , Poluentes Atmosféricos , China/epidemiologia , Hospitalização/estatística & dados numéricos
6.
Environ Int ; 131: 105019, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31330363

RESUMO

BACKGROUND: Fine particulate matter (PM2.5) has been widely associated with airway inflammation represented by increased fractional concentration of exhaled nitric oxide (FeNO). However, it remains unclear whether various PM2.5 constituents have different impacts on FeNO and its production process from the arginase (ARG)-nitric oxide synthase (NOS) pathway. OBJECTIVES: To investigate the acute effects of PM2.5 constituents on FeNO and DNA methylation of genes involved. METHODS: We conducted a longitudinal panel study among 43 young adults in Shanghai, China from May to October in 2016. We monitored the concentrations of 25 constituents of PM2.5. We applied the linear mixed-effect model to evaluate the associations of PM2.5 constituents with FeNO and DNA methylation of the ARG2 and NOS2A genes. RESULTS: Following PM2.5 exposure, NOS2A methylation decreased and ARG2 methylation increased only on the concurrent day, whereas FeNO increased most prominently on the second day. Nine constituents (OC, EC, K, Fe, Zn, Ba, Cr, Se, and Pb) showed consistent associations with elevated FeNO and decreased NOS2A methylation or increased ARG2 methylation in single-constituent models and models adjusting for PM2.5 total mass and collinearity. An interquartile range increase of these constituents was associated with respective decrements of 0.27-1.20 in NOS2A methylation (%5mC); increments of 0.48-1.56 in ARG2 methylation (%5mC); and increments of 7.12%-17.54% in FeNO. CONCLUSIONS: Our results suggested that OC, EC, and some metallic elements may be mainly responsible for the development and epigenetic regulation of airway inflammatory response induced by short-term PM2.5 exposure.


Assuntos
Arginase/metabolismo , Metilação de DNA/efeitos dos fármacos , Óxido Nítrico Sintase Tipo II/metabolismo , Óxido Nítrico/metabolismo , Material Particulado/farmacologia , Adulto , China , Expiração , Feminino , Humanos , Estudos Longitudinais , Masculino , Material Particulado/análise , Adulto Jovem
7.
Sci Total Environ ; 648: 1121-1129, 2019 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-30340258

RESUMO

To reduce air pollution within a 300 km radius from Hangzhou (the capital city of Zhejiang Province in East China) for the 2016 G20 summit (9/4-9/5), the 14-day (8/24-9/6) stringent pollution control measures were implemented in Shanghai. Changes in atmospheric concentrations during the same 14-day period from 2014 to 2016 were examined at two Supersites, i.e., urban Pudong site (PD) and Dianshan Lake regional site (DSL). Up to 50% reductions were found for PM2.5, with 13.1% and 9.7% reductions for SO2 and NO2, respectively. No apparent improvements were found for 8-h average O3 concentrations. Large reductions were also found for SO42- (51.4%), NO3- (68.8%), and NH4+ (84.4%), on average. Elevated coefficient of divergence values (0.52-0.56) suggested that pollutant sources differed at the two sites. Biomass burning, resuspended dust, combustion, iron and steel industry, sea salt, secondary aerosol, and vehicle exhaust were identified at the DSL site by Positive Matrix Factorization (PMF). Secondary aerosol and vehicle exhaust accounted for 45.7% of PM2.5 mass, followed 11.2%-13.7% each by industry, resuspended dust, and coal and oil combustion.

8.
Environ Int ; 119: 186-192, 2018 10.
Artigo em Inglês | MEDLINE | ID: mdl-29960262

RESUMO

Fine particulate matter (PM2.5) has recently been associated with the activation of the hypothalamus-pituitary-adrenal (HPA) axis, increasing cardiometabolic risks. However, it is unknown which constituents of PM2.5 were mainly responsible for these associations. In a longitudinal panel study with 4 repeated measurements among 43 college students in Shanghai, China, we measured serum levels of corticotropin releasing hormone (CRH), adrenocorticotropic hormone (ACTH) and cortisol, as indicators of HPA axis activation. Then, we evaluated the associations of 22 constituents of PM2.5 with these stress hormones using linear mixed-effect models. During the study period, the average daily concentration of PM2.5 was 41.1 µg/m3. We found that short-term exposure to PM2.5 was associated with elevated levels of the 3 stress hormones. We observed that water-soluble inorganic ions, especially nitrate (NO3-) and ammonium, had stronger influences on 3 hormones. Six metallic elements, including Zn, Mn, Cu, Fe, Br, and Cr, had positive but generally instable associations with 3 hormones. The effects of organic carbon and elemental carbon on hormones were generally weak. When correcting for multiple comparisons using false discovery rate, NO3- was still significantly associated with CRH, but other important associations turned to be insignificant. An interquartile range increase in NO3- on the previous day were associated with 12.13% increase (95% confidence interval: 4.45%, 20.37%) in CRH. Our findings suggested that water-soluble inorganic constituents of PM2.5 (especially, NO3-) might have stronger influences on the activation of HPA axis than carbonaceous and elemental components.


Assuntos
Poluentes Atmosféricos/análise , Hormônio Liberador da Corticotropina/sangue , Sistema Hipotálamo-Hipofisário/fisiologia , Material Particulado/análise , Sistema Hipófise-Suprarrenal/fisiologia , Hormônio Adrenocorticotrópico/sangue , China , Humanos , Hidrocortisona/sangue , Estudos Longitudinais , Estudantes/estatística & dados numéricos , Universidades
9.
Sci Rep ; 4: 6233, 2014 Aug 29.
Artigo em Inglês | MEDLINE | ID: mdl-25167887

RESUMO

Fe-based bulk metallic glasses (BMGs) have attracted great attention due to their unique magnetic and mechanical properties, but few applications have been materialized because of their brittleness at room temperature. Here we report a new Fe(50)Ni(30)P(13)C(7) BMG which exhibits unprecedented compressive plasticity (>20%) at room temperature without final fracture. The mechanism of unprecedented plasticity for this new Fe-based BMG was also investigated. It was discovered that the ductile Fe(50)Ni(30)P(13)C(7) BMG is composed of unique clusters mainly linked by less directional metal-metal bonds which are inclined to accommodate shear strain and absorbed energy in the front of crack tip. This conclusion was further verified by the X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy experiments of Fe(80-x)Ni(x)P(13)C(7) (x = 0, 10, 20, 30) and Fe(72-x)Ni(x)B(20)Si(4)Nb(4) (x = 0, 7.2, 14.4, 21.6, 28.8) glassy systems. The results also indicate a strong correlation between the p-d hybridization and plasticity, verifying that the transition from brittle to ductile induced by Ni addition is due to the change of bonding characteristics in atomic configurations. Thus, we can design the plasticity of Fe-based BMGs and open up a new possible pathway for manufacturing BMGs with high strength and plasticity.

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