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1.
Huan Jing Ke Xue ; 44(1): 11-19, 2023 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-36635790

RESUMO

In recent years, the Beijing-Tianjin-Hebei region and its surrounding areas have experienced multiple haze pollution processes. Owing to the limitation of observational instruments, there has not been a comparative study of haze pollution between urban and rural areas in northern Henan province. A series of high-time-resolution instruments were used during a regional heavy pollution process (January 12-25, 2018) at two urban sites and three rural sites. The results showed that SO42-, NO-3, and NH+4 (SNA) were the components with the highest proportion in PM2.5 at the five sites during the haze event with a range of 53%-63%, of which nitrate was the most important, accounting for 24%-32%, followed by sulfate, ranging from 13%-17%. Compared with urban sites, rural sites were more affected by organic matter, especially at night. With the aggravation of pollution, the proportion of SNA increased, reaching 67% during periods of heavy pollution. When the area was affected by the air mass transported from the south, the proportion of NO-3 in PM2.5 increased, and when the area was affected by the air transport in the north, the proportions of SO42- and organic matter increased. Ammonium nitrate was the most important component that led to the decrease in atmospheric visibility during the haze process. Moreover, the contributions of ammonium nitrate and ammonium sulfate at the urban sites were higher than those at the rural sites. To summarize, there were significant differences in PM2.5 components between the urban and rural sites. Urban areas need to continue to strengthen the reduction in gaseous precursors, and rural areas need to pay attention to the sources of carbonaceous aerosol.


Assuntos
Poluentes Atmosféricos , Poluição do Ar , Poluentes Atmosféricos/análise , Poluição do Ar/análise , Material Particulado/análise , Estações do Ano , Monitoramento Ambiental/métodos , Aerossóis/análise , China
2.
Chemosphere ; 307(Pt 3): 136028, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-35973498

RESUMO

Carbonaceous fractions throughout the normal period and lockdown period (LP) before and during COVID-19 outbreak were analyzed in a polluted city, Zhengzhou, China. During LP, fine particulate matters, elemental carbon (EC), and secondary organic aerosol (SOC) concentrations fell significantly (29%, 32% and 21%), whereas organic carbon (OC) only decreased by 4%. Furthermore, the mean OC/EC ratio increased (from 3.8 to 5.4) and the EC fractions declined dramatically, indicating a reduction in vehicle emission contribution. The fact that OC1-3, EC, and EC1 had good correlations suggested that OC1-3 emanated from primary emissions. OC4 was partly from secondary generation, and increased correlations of OC4 with OC1-3 during LP indicated a decrease in the share of SOC. SOC was more impacted by NO2 throughout the research phase, thereby the concentrations were lower during LP when NO2 levels were lower. SOC and relative humidity (RH) were found to be positively associated only when RH was below 80% and 60% during the normal period (NP) and LP, respectively. SOC, Coal combustion, gasoline vehicles, biomass burning, diesel vehicles were identified as major sources by the Positive Matrix Factorization (PMF) model. Contribution of SOC apportioned by PMF was 3.4 and 3.0 µg/m3, comparable to the calculated findings (3.8 and 3.0 µg/m3) during the two periods. During LP, contributions from gasoline vehicles dropped the most, from 47% to 37% and from 7.1 to 4.3 µg/m3, contribution of biomass burning and diesel vehicles fell by 3% (0.6 µg/m3) and 1% (0.4 µg/m3), and coal combustion concentrations remained nearly constant. The findings of this study highlight the immense importance of anthropogenic source reduction in carbonaceous component variations and SOC generation, and provide significant insight into the temporal variations and sources of carbonaceous fractions in polluted cities.


Assuntos
Poluentes Atmosféricos , COVID-19 , Poluentes Atmosféricos/análise , COVID-19/epidemiologia , Carbono/análise , China , Cidades , Carvão Mineral , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Gasolina , Humanos , Dióxido de Nitrogênio , Material Particulado/análise , Aerossóis e Gotículas Respiratórios , Estações do Ano , Emissões de Veículos
3.
Sci Total Environ ; 840: 156404, 2022 Sep 20.
Artigo em Inglês | MEDLINE | ID: mdl-35662601

RESUMO

Secondary inorganic aerosol, including sulfate, nitrate, and ammonium (SNA), is a significant source of PM2.5 during haze episodes in Northern China. A series of high-time-resolution instruments were used in collecting PM2.5 chemical components and gaseous pollutants during a regional heavy pollution process from January 12-25, 2018, at urban and rural sites. SNA, accounting for >50% of PM2.5 at both sites, had greater importance on haze formation. Gas-phase and N2O5 hydrolysis reactions were the main formation pathways of nitrate during the daytime and nighttime, respectively. The OH radical was the primary factor for gas-phase reactions. HONO photolysis played a more critical role in OH radical formation when O3 concentration decreased during the haze episode. N2O5 hydrolysis reaction was mainly affected by O3 and aerosol water content. High relative humidity, aerosol water content, and N2O5 concentrations at the urban site enhanced the hydrolysis reactions more than those at the rural site. The aqueous-phase reactions dominated the sulfate formation with the highest rate of transition metal ion catalytic and H2O2 oxidation reactions at the urban and rural sites, respectively. Elevated relative humidity and particle acidity at the urban site resulted in a higher formation rate of aqueous-phase sulfate than at the rural site. The gas-particle partition coefficient of NH3 had a negative correlation with the particle pH, and the presence of NH3 could promote the increase of SNA concentration. Thus, more attention should be paid to the differences in SNA formation between urban and rural regions when formulating air quality policies.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental/métodos , Gases/análise , Peróxido de Hidrogênio , Nitratos/análise , Óxidos de Nitrogênio/análise , Material Particulado/análise , Estações do Ano , Sulfatos/análise , Óxidos de Enxofre , Água/química
4.
Huan Jing Ke Xue ; 43(6): 2840-2850, 2022 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-35686753

RESUMO

The COVID-19 lockdown was a typical occurrence of extreme emission reduction, which presented an opportunity to study the influence of control measures on particulate matter. Observations were conducted from January 16 to 31, 2020 using online observation instruments to investigate the characteristics of PM2.5 concentration, particle size distribution, chemical composition, source, and transport before (January 16-23, 2020) and during (January 24-31, 2020) the COVID-19 lockdown in Zhengzhou. The results showed that the atmospheric PM2.5 concentration decreased by 4.8% during the control period compared with that before the control in Zhengzhou. The particle size distribution characteristics indicated that there was a significant decrease in the mass concentration and number concentration of particles in the size range of 0.06 to 1.6 µm during the control period. The chemical composition characteristics of PM2.5 showed that secondary inorganic ions (sulfate, nitrate, and ammonium) were the dominant component of PM2.5, and the significant increase in PM2.5 was mainly owing to the decrease in NO3- concentration during the control period. The main sources of PM2.5 identified by the positive matrix factorization (PMF) model were secondary sources, combustion sources, vehicle sources, industrial sources, and dust sources. The emissions from vehicle sources, industrial sources, and dust sources decreased significantly during the control period. The results of analyses using the backward trajectory method and potential source contribution factor method indicated that the effects of transport from surrounding areas on PM2.5 concentration decreased during the control period. In summary, vehicle and industrial sources should be continuously controlled, and regional combined prevention and control should be strengthened in the future in Zhengzhou.


Assuntos
Poluentes Atmosféricos , COVID-19 , Poluentes Atmosféricos/análise , COVID-19/epidemiologia , COVID-19/prevenção & controle , China , Controle de Doenças Transmissíveis , Poeira/análise , Monitoramento Ambiental/métodos , Humanos , Tamanho da Partícula , Material Particulado/análise , Emissões de Veículos/análise
5.
Huan Jing Ke Xue ; 43(4): 1706-1715, 2022 Apr 08.
Artigo em Chinês | MEDLINE | ID: mdl-35393794

RESUMO

In order to study the pollution characteristics and sources of heavy metals in urban atmospheric PM2.5, 21 elements in atmospheric PM2.5 in Zhengzhou City were detected using an online metal analyzer during July and October 2017 and January and April 2018, and the changes in heavy metal concentrations were analyzed. Heavy metals were traced by enrichment factors, principal component analysis, and potential source function. The US EPA risk assessment model was used to assess their health risks. The results showed that:the concentrations of K, Zn, Mn, Pb, Cu, As, Cr, and Se increased with the increase in pollution level. The results of enrichment factors and principal component analysis showed that the main sources of heavy metals were crust, mixed combustion, industry, and motor vehicles. The characteristic radar charts showed that the pollution dominated by crustal sources mainly occurred in spring and winter, whereas the pollution dominated by mixed combustion sources mainly occurred in winter. Pb, As, and Ni were greatly affected by the transport of a fen nutrient-laden plain, Beijing-Tianjin-Hebei, and southern Henan, whereas Cd was greatly affected by the northwest region of the sampling site. As presented a significant carcinogenic risk in both adults and children, whereas Pb and Sb presented a significant non-carcinogenic risk in children.


Assuntos
Monitoramento Ambiental , Metais Pesados , Adulto , Criança , China , Poluição Ambiental/análise , Humanos , Chumbo/análise , Metais Pesados/análise , Material Particulado/análise , Medição de Risco
6.
Huan Jing Ke Xue ; 43(3): 1180-1189, 2022 Mar 08.
Artigo em Chinês | MEDLINE | ID: mdl-35258182

RESUMO

Heavy metal elements in particulate matter can cause adverse effects on human health, and the smaller the particle size, the greater the harm. A total of 16 heavy metal elements (Al, Si, K, Ca, V, Cr, Mn, Fe, Ni, Cu, Zn, As, Se, Ba, Pb, and Cd) in PM1 were continuously determined by an online heavy metal observation instrument in Zhengzhou city from January 7 to 25, 2021. The results showed that ρ(K) concentration was the highest during the observation period (0.62 µg·m-3). According to pollutant concentration and meteorological characteristics, the observation period was divided into clean days, dust days, and haze days. The contribution of heavy metal pollution characteristics and health risk assessment in atmospheric PM1 was different under different pollution processes. The US EPA health risk assessment method was used to assess the health risks of heavy metals, and the enrichment factor method and positive matrix factorization (PMF) were used to analyze the sources of heavy metals. The influence of the transmission was evaluated by using the concentration-weighted trajectory (CWT) method and the backward trajectory method. The results show that the enrichment factors of Zn, As, Se, Pb, and Cd were more than 100 under different pollution processes, which were greatly affected by human activities. During the sampling period, the main sources of heavy metals were industrial sources, coal/biomass sources, motor vehicle sources, and dust sources. The results of the health risk assessment were substituted into PMF analysis, and it was found that industrial sources were the main contributing sources of carcinogenic and non-carcinogenic health risks during cleaning days, dust days, and haze days, and the carcinogenic risk of heavy metal elements in PM1 in this region for adults exceeded that for children. CWT and backward trajectory methods revealed that regional transmission was one of the main factors affecting local health risks.


Assuntos
Monitoramento Ambiental , Metais Pesados , Adulto , Criança , China , Poeira/análise , Poluição Ambiental/análise , Humanos , Metais Pesados/análise , Medição de Risco
7.
Environ Pollut ; 296: 118716, 2022 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-34933059

RESUMO

The significant reduction in PM2.5 mass concentration after the outbreak of COVID-19 provided a unique opportunity further to study the formation mechanism of secondary inorganic aerosols. Hourly data of chemical components in PM2.5, gaseous pollutants, and meteorological data were obtained from January 1 to 23, 2020 (pre-lockdown) and January 24 to February 17, 2020 (COVID-lockdown) in Zhengzhou, China. Sulfate, nitrate, and ammonium were the main components of PM2.5 during both the pre-lockdown and COVID-lockdown periods. Compared with the pre-lockdown period, even though the concentration and proportion of nitrate decreased, nitrate was the dominant component in PM2.5 during the COVID-lockdown period. Moreover, nitrate production was enhanced by the elevated O3 concentration, which was favorable for the homogeneous and hydrolysis nitrate formation despite the drastic decrease of NO2. The proportion of sulfate during the COVID-lockdown period was higher than that before. Aqueous-phase reactions of H2O2 and transition metal (TMI) catalyzed oxidations were the major pathways for sulfate formation. During the COVID-lockdown period, TMI-catalyzed oxidation became the dominant pathway for aqueous-phase sulfate formation because the elevated acidity favored the dissolution of TMI. Therefore, the enhanced TMI-catalyzed oxidation affected by the elevated particle acidity dominated the sulfate formation, resulting in the slight increase of sulfate concentration during the COVID-lockdown period in Zhengzhou.


Assuntos
Poluentes Atmosféricos , COVID-19 , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Controle de Doenças Transmissíveis , Monitoramento Ambiental , Humanos , Peróxido de Hidrogênio , Pandemias , Material Particulado/análise , SARS-CoV-2 , Sulfatos
8.
Huan Jing Ke Xue ; 42(8): 3633-3643, 2021 Aug 08.
Artigo em Chinês | MEDLINE | ID: mdl-34309250

RESUMO

To explore the main sources of PM2.5 and the characteristics of seasonal differences in Zhengzhou, PM2.5 sampling was conducted in 2019 and the concentrations of inorganic water-soluble ions, carbon components, and various elements were analyzed. Results showed that the average mass concentration of PM2.5 in 2019 was (67.0±37.2) µg ·m-3 with the highest concentration in winter and the lowest in summer. The main components of PM2.5 were nitrate, ammonium, sulfate, organic matter, crustal matter, and elemental carbon. In spring and autumn, PM2.5 was greatly affected by crustal matter and elemental carbon, and In summer, concentrations were mainly affected by sulfate. In winter, the concentrations of organic matter and nitrate increased significantly, produced by photochemical reactions in summer and aqueous-phase reactions under high humidity in winter. Carbonaceous aerosols were greatly influenced by automobile exhaust emission, coal combustion, and biomass combustion. Source apportionment showed that secondary sources were the greatest contributors in all four seasons, particularly in in winter (56.5%). Among the primary sources, the proportion of dust in spring (15.2%) and autumn (11.4%) was slightly higher, and the contribution of motor vehicle pollution was the largest (12.3%) in summer. In winter, PM2.5was greatly affected by coal combustion (13.2%). From 2014 to 2019, PM2.5 in Zhengzhou increased annually under the influence of secondary sources. The contribution of industrial sources, biomass combustion sources, and coal combustion sources exhibited a downward trend over this period.


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Nitratos , Material Particulado/análise , Estações do Ano , Emissões de Veículos/análise
9.
J Colloid Interface Sci ; 581(Pt A): 148-158, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32771726

RESUMO

Heterojunction formation and morphology control have always been regarded as effective ways to improve the performance of visible-light-driven photocatalysts. In this study, a new facile strategy was applied to synthesize the Z-scheme GO/AgI/Bi2O3 heterojunction, where polyvinyl pyrrolidone (PVP) and γ-methacryloxypropyl trimethoxy silane (KH-570) were used to modulate the morphologies. Methyl orange and tetracycline hydrochloride were chosen as target contaminants to evaluate the photocatalytic properties of samples and the results revealed that 2% GO/AgI/Bi2O3 exhibited the best photocatalytic performance under visible-light irradiation. The enhanced photocatalytic activity can mainly attribute to Z-scheme heterojunction formed by the deposing of AgI and GO as well as the sufficient heterogeneous interfaces resulted from the improved morphology, which have effectively promoted the separation and transfer of electron-hole pairs. To deeply realize the enhanced performance of GO/AgI/Bi2O3 photocatalysts, the reaction kinetics, trapping experiments and photocatalytic mechanism were deduced.

10.
Chemosphere ; 269: 128744, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33131735

RESUMO

The size distribution and formation of secondary inorganic aerosol play a key role in the increasing PM2.5 concentration. Size-segregated data including mass, number, and chemical component concentrations were obtained during a haze episode from January 12 to 23 in Zhengzhou to gain insight into the dominant factors for the growth of PM2.5. PM2.5 levels during two local processes (LP1 and LP2) were mainly affected by the accumulation and secondary formation of local pollutants. The transport process (TP) was affected by the air mass transported from the northern area of Zhengzhou. Results show that the growth of particle mass concentration in LP1 mainly occurred in the size range of 400-640 nm and 640-1000 nm. With the aggravated particles increases (LP2), 640-1000 nm and 1-1.6 µm particles dominated the increasing PM2.5 concentration. The particles carried by northern air mass (TP) were concentrated in the size range of 1-1.6 µm. Variation trends of hourly PM2.5 chemical components and size distribution of water-soluble inorganic ions suggested that the formation and growth of droplet-mode nitrate, sulfate, and ammonium dominated the increase of PM2.5, and the particle sizes of these components increased with the increasing PM2.5. High concentrations of aerosol water content and large surface area in droplet-mode were beneficial for the heterogeneous reactions for droplet-mode nitrate formation. Moreover, large particle surface area in droplet-mode particles also provided adequate carriers for the adsorption and condensation of gaseous HNO3 onto these particles. Elevated aerosol water, surface area, and particle acidity enhanced the H2O2 and transition metal (TMI) oxidation for aqueous-phase droplet-mode sulfate formation. The contribution of TMI-catalyzed oxidation significantly increased in LP2 because of the high TMI concentration and particle acidity. Relatively low aqueous-phase sulfate production rates in TP suggest that the observed high concentration of droplet-mode sulfate was mainly originated from the completely transformed SO42- carried by air masses. Moreover, droplet-mode particles exhibited moderate acidity, which enhanced the gas-particle partitioning of NH3(g)/NH4+(a).


Assuntos
Poluentes Atmosféricos , Material Particulado , Aerossóis/análise , Poluentes Atmosféricos/análise , China , Monitoramento Ambiental , Peróxido de Hidrogênio , Tamanho da Partícula , Material Particulado/análise , Estações do Ano
11.
Huan Jing Ke Xue ; 41(7): 3004-3011, 2020 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-32608872

RESUMO

To evaluate the effect of the implementation of emission reduction measures and the improvement in air quality during the National Traditional Games of Ethnic Minorities in Zhengzhou, a series of online instruments were used to continuously observe air pollutants and components of PM2.5 from August 5 to September 30, 2019. Three cases, including before emission reduction (August 5-24), during emission reduction (August 25 to September 18), and after emission reduction (September 19-30), were classified by the implementation of control measures. The results show that the growing concentration of PM2.5 after the cancellation of emission abatement measures (11.7 µg·m-3) was greater than that during the emission reduction (2.3 µg·m-3) compared to the PM2.5 concentration before emission reduction. This thus indicates that the control measures have a significant effect on reducing particulate matter. The main components of PM2.5 were organic matter, nitrate, ammonium, sulfate, and crustal elements. Compared to the proportion of components in PM2.5 before and during the control periods, organic matter and nitrate increased by 3.9% and 0.9%, respectively, while sulfate, ammonium, and crustal elements decreased by 1.1%, 1.9%, and 2.2%, respectively. The results of source appointment by positive matrix factorization show that secondary sulfate, secondary nitrate, secondary organic aerosols, vehicular emissions, industrial emissions, dust, and coal combustion are the main sources of PM2.5. Emission abatement measures reduced the contributions of primary sources such as dust, coal combustion, and industry by 8.3%, 8.2%, and 8.1%, respectively. In contrast, the contributions of secondary organic and nitrate aerosols increased during the control periods, which suggested that the control measures implemented in Zhengzhou had a weaker emission reduction effect on nitrogen oxide and volatile organic compounds than on primary sources of PM2.5.

12.
Huan Jing Ke Xue ; 41(1): 75-81, 2020 Jan 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854906

RESUMO

We explore the characteristics and sources of water-soluble ions in aerosol fine particulate matter (PM2.5) samples collected from Anyang, China, during typical seasonal months from 2018 to 2019. Nine water-soluble ions (Na+, NH4+, K+, Mg2+, Ca2+, F-, Cl-, NO3-, and SO42-) were analyzed. The analysis of PM2.5, water-soluble ion concentration levels, anion-cation balance, nitrogen oxidation rate (NOR), sulfur oxidation rate (SOR), and ion correlation showed that the annual average concentrations of PM2.5 and water-soluble ions in Anyang were (85.81±45.43) µg·m-3 and (48.21±30.04) µg·m-3, respectively. Concentrations of ions were ranked as:NO3- > SO42- > NH4+ > Cl- > K+ > Ca2+ > Na+ > Mg2+ > F-. The annual average concentration of the sum of NH4+, NO3-, and SO42- was (42.72±27.87) µg·m-3, which accounted for 87.14% of total water-soluble ions. Moreover, NH4+ was highly related to SO42- and NO3-. The mean values of the nitrogen oxidation rate (NOR) and sulfur oxidation rate (SOR) were 0.25 and 0.37, respectively. These results suggest that these ions were the result of secondary formation. The anion-cation charge equivalent value was 0.75-0.94, which indicates that the sampled aerosols were alkaline. NH4+ mainly existed in the form of (NH4)2SO4 and NH4NO3 in spring, summer, and autumn, whereas in winter it mainly existed in the form of NH4Cl. The results of principal component analysis indicated that secondary aerosols, coal combustion, biomass burning, and dust were the main sources of the water-soluble ions in Anyang during the sampled periods.

13.
J Environ Sci (China) ; 88: 316-325, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31862073

RESUMO

Mineral dust particles play an important role in the formation of secondary inorganic aerosols, which largely contribute to haze pollution in China. During this study, a haze episode (haze days) and a typical haze process mixed with sandstorm (sandy haze days) were observed in Zhengzhou with a series of high-time-resolution monitoring instruments from November 22 to December 8, 2018. Concentrations of PM10 and crustal elements clearly increased in the sandy haze days. Concentrations of gaseous pollutants, metallic elements emitted from anthropogenic sources, nitrate, and ammonium during sandy haze days were slightly lower than those during the haze days but still obviously higher than those during the non-haze days. The sulfate concentrations, the sulfate fractions in PM2.5, and the sulfur oxidation ratios significantly increased in the sandy haze days. Heterogeneous reactions dominated the conversion of SO2 during the haze and sandy haze days. Enhanced SO2 conversion during the sandy haze days may be attributed to the high concentrations of transition metal ions from the sandstorm when the values of relative humidity (RH) were in 30%-70%, and high O3 at certain time points. Gas-phase NO2 oxidation reactions were the main pathways for nitrate formation. In the sandy haze days, higher nitrogen oxidation ratio (NOR) at daytime may be associated with higher RH and lower temperature than those in the haze days, which facilitate the gas-to-particle partitioning of nitrate; higher NOR values at night may be attributed to the higher O3 concentrations, which promoted the formation of N2O5.


Assuntos
Aerossóis/análise , Poluentes Atmosféricos/análise , Monitoramento Ambiental , Material Particulado/análise , China , Areia , Estações do Ano
14.
Huan Jing Ke Xue ; 40(6): 2565-2571, 2019 Jun 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854647

RESUMO

Based on the annual average concentration values, the health effects and health benefits as well as 95% confidence intervals of PM10 and PM2.5 pollution control from 2014 to 2016 in Zhengzhou were evaluated by applying the Poisson regression relative risk model. Results showed that the health benefits of PM10 pollution control were 18.18 billion RMB (15.04, 21.12), 24.25 billion RMB (20.25, 27.94), and 20.62 billion RMB (17.33, 23.92), which accounted for 2.7%, 3.3%, and 2.5% of the GDP of Zhengzhou, respectively, in 2014-2016. The health benefits of PM2.5 pollution control were 17.88 billion RMB (14.37, 21.16), 21.65 billion RMB (17.46, 25.53), and 17.25 billion RMB (13.78, 20.55), which accounted for 2.6%, 3.0%, and 2.1% of the GDP of Zhengzhou, respectively, in 2014-2016. After the PM10 and PM2.5 pollution was controlled, the number of urban beneficiaries was higher than that of rural areas, and acute bronchitis beneficiaries were higher than the beneficiaries of other health end-points. For chronic bronchitis, adults benefited more than children, while the opposite occurred for asthma. In this study, chronic bronchitis had the highest health benefit, followed by asthma, and outpatient and inpatient setting had the lower health benefits.


Assuntos
Poluentes Atmosféricos/efeitos adversos , Poluição do Ar/prevenção & controle , Material Particulado/efeitos adversos , Adulto , Asma/prevenção & controle , Bronquite Crônica/prevenção & controle , Criança , China , Humanos , Análise de Regressão
15.
Huan Jing Ke Xue ; 40(7): 2977-2984, 2019 Jul 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854694

RESUMO

In order to explore the pollution characteristics of water-soluble ions in PM2.5 in Zhengzhou, high time resolution and continuous observation of water-soluble inorganic ions in PM2.5 was conducted from December 1, 2017, to November 30, 2018, in Zhengzhou. The results showed that during the observation period, the average concentration of total water-soluble ions in Zhengzhou was 42.7 µg·m-3. The order of mass concentration of each ion, from large to small, was as follows:NO3-(17.7 µg·m-3), SO42-(10.2 µg·m-3), NH4+(9.0 µg·m-3), Cl-(2.3 µg·m-3), K+(1.3 µg·m-3), Na+(1.3 µg·m-3), Ca2+(0.8 µg·m-3), and Mg2+(0.1 µg·m-3). The mass concentration of total water-soluble ions was the highest in winter, slightly higher in autumn than in spring, and lowest in summer. The diurnal variation in single peak distribution was observed across the whole year in spring, summer, and autumn, while there was no significant diurnal variation in winter. The mass concentration of secondary inorganic ions (SO42-, NO3-, and NH4+) accounted for 43.8% of PM2.5, mainly in the form of (NH4)2SO4 and NH4NO3. There was a large degree of secondary transformation throughout the observation period; relative humidity had a significant influence on the sulfur oxidation rate, and temperature had a significant influence on the nitrogen oxidation rate. During the observation period, there was a good correlation between secondary ions, and K+ showed a good correlation with Mg2+ and Cl-. The main source of the secondary ions was the secondary conversion of gaseous pollutants. Mg2+ and Ca2+ were derived from soil dust and construction dust. K+ was one of the main biomarkers of biomass combustion. Na+ was mainly derived from sea salt and soil dust, and Cl- was derived not only from sea salt but also biomass and fossil fuel combustion. The results of principal component analysis showed that the water-soluble ions in PM2.5 in Zhengzhou were mainly affected by secondary transformation, combustion sources, and dust emission from soil or building construction.

16.
Huan Jing Ke Xue ; 40(9): 3856-3867, 2019 Sep 08.
Artigo em Chinês | MEDLINE | ID: mdl-31854847

RESUMO

Online monitoring data of atmospheric pollutants and meteorological parameters in Zhengzhou from 2014 to 2017 were collected to analyze the concentration levels, seasonal variations, and the ratio characteristics of atmospheric pollutants, as well as the effects of meteorological conditions on these pollutants. Results show that the annual average concentrations of PM2.5 and PM10 in the four years were (88±49.8), (95.8±60.2), (78.6±70.3), and (72.0±53.5) µg·m-3, and (158.5±65.3), (167.7±82.6), (144.5±91.5), and (132.7±70.3) µg·m-3, respectively, and were approximately two times higher than the grade Ⅱ annual limits set by China. Fuel combustion and the formation of secondary pollutants were the main sources of PM2.5 in Zhengzhou. Moreover, the contribution of coal combustion was found to be decreased, while that of traffic sources increased year by year. Low wind speed, high humidity, and reduced precipitation are important meteorological factors that contribute to serious air pollution. In addition, the Potential Source Contribution Function and the Concentration-Weighted Trajectory were used to analyze the potential sources, and the contribution of these sources to the distribution of PM2.5. The potential source areas of PM2.5 were mainly distributed in neighboring cities and provinces, such as Shanxi, Shaanxi, Hubei, Shandong, and Hebei. The short-distance transmission was found to contribute significantly to the mass concentration of PM2.5.

17.
J Hazard Mater ; 371: 304-315, 2019 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-30856441

RESUMO

The series Ag-AgI/BiOI-Bi2O3 visible-light-driven photocataslyts were successfully synthesized by solvothermal method. The as-synthesized samples were systematically characterized by XRD, SEM, TEM, EDS, BET, XPS, FR-IR, UV-vis DRS, photoelectrochemical measurements and EPR. The formation mechanism of the new composite photocataslyts was investigated and the simulate formation process had been illustrated. The photocatalytic properties of the samples were evaluated by degradation of methyl orange under visible-light irradiation. The results shown that the 30% Ag-AgI/BiOI-Bi2O3 photocataslyts possessed the best photocatalytic activity and the kinetics reaction models were followed pseudo-first-order kinetics. The enhanced photocatalytic performance could be attributed to the effective separation and transfer of electron-hole pairs resulting by the deposing of Ag-AgI nanoparticles and Bi2O3. The photocatalytic mechanism was deduced by trapping experiments and EPR, and the results demonstrated that h+, OH, O2- radicals played different roles in the degradation. Furthermore, a new Z-scheme multi-heterojunction mechanism was proposed basing on the results of trapping experiments and EPR.

18.
Environ Pollut ; 247: 515-523, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-30708313

RESUMO

Size-resolved samples were collected using a 14-stage impactor during four seasons in Zhengzhou and analyzed for 26 elements to calculate the health risks from atmospheric particle-bound metals. High concentrations of heavy metals were observed in ultrafine (10.2 (Ni)-66.9 (Cd) ng m-3) or submicrometer (11.4 (Ni)-134 (Pb) ng m-3) mode in winter. Two size-dependent models were used to estimate the deposition of inhaled toxic metals in various regions of the human respiratory system. Results show that heavy metals deposited in the alveolar region ranged from 7.6 (As)-375 (Al) ng m-3 and were almost concentrated in ultrafine and fine modes. Cd (2.2-8.6) may cause accumulative non-carcinogenic health effects on children, and Cr (1.0 × 10-4-2.2 × 10-4) may lead to carcinogenic health risks for nearby residents around the sampling site. The major sources by principal component analysis that contributed to Cr and Cd in ultrafine and fine particles were coal combustion, vehicular and industrial emissions. The atmospheric dry deposition fluxes of Cr and Cd were between 0.7 and 1.9 µg m-2 day-1 calculated by a multi-step method. From the environmental and public health perspective, environmental agencies must control the emission of heavy metals in the atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/estatística & dados numéricos , Monitoramento Ambiental , Exposição por Inalação/estatística & dados numéricos , Material Particulado/análise , Atmosfera/análise , Atmosfera/química , Criança , China , Cidades , Carvão Mineral/análise , Poeira/análise , Humanos , Indústrias , Metais Pesados/análise , Estações do Ano
19.
Sci Total Environ ; 660: 47-56, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30639718

RESUMO

Episodic haze is frequently observed in Zhengzhou, China. Such haze typically contains secondary inorganic aerosols. In this paper, we explore the formation mechanisms of sulfate, nitrate, and ammonium (SNA) in Zhengzhou from January 3 to 25, 2018 based on the results of a series of online instruments and a size-segregated filter sampler. Our results document the remarkable contributions of SNA to winter haze episodes in Zhengzhou, where they account for about 50% of PM2.5 mass concentration. SNA were mainly concentrated in droplet-mode particles, which increased remarkably with the aggravation of the haze episode. In addition, KNO3 and NaNO3 were formed in droplet-mode particles and coarse-mode particles respectively with increasing PM2.5 concentration. The atmosphere during the observation period was ammonia-rich, and the aerosol was acidic under high PM2.5 concentration. Homogeneous reactions dominated the formation of nitrate. HONO photolysis played a more important role in the origin of OH radicals when O3 decreased during haze episode. Under high relative humidity (RH), nitrate formation was influenced by heterogeneous hydrolysis reactions of N2O5. Sulfates were mainly formed through aqueous-phase reactions, especially when the RH was higher than 60%. Under these conditions, there were amounts of liquid water content existed in aerosols. Finally, we observed enhanced conversion of SO2 and NO2 during snowfall periods. This effect may be attributable to the higher RH and O3 levels despite the unfavorable effects of wet deposition and low concentrations of gaseous precursors.

20.
Huan Jing Ke Xue ; 39(11): 4866-4875, 2018 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-30628207

RESUMO

To study the compositional characteristics of atmospheric particulates with different particle sizes in the central city of Zhengzhou, China, a Tisch graded impact sampler was used to sample atmospheric particulates in summer and autumn. The mass concentrations of water-soluble inorganic ions, including anions (Cl-, F-, NO3-, and SO42-) and cations (Na+, Ca2+, NH4+, K+, and Mg2+) were measured by ion chromatography, and the online ion chromatography-based analyzer MARGA monitored the real-time concentration of particulate nitrate. The results showed that the average concentration of water-soluble ions in Zhengzhou City was (70.9±52.1) µg·m-3 during the sampling period, and the order of water-soluble ion mass concentrations was NO3- > SO42- > NH4+ > Ca2+ > Na+ > Cl- > Mg2+ > K+ > F-; NO3-, SO42-, and NH4+ accounted for 79.9% of total water-soluble ions. The NO3- concentration was mainly concentrated in the 0.65-3.3 µm particle size segment, despite the SO42- concentration being concentrated in the ≤ 1.1 µm particle size segment in autumn or summer. Both NO3- and SO42- had a bimodal distribution in summer and autumn and were mainly distributed as fine particles. NH4+ showed seasonal variation with a bimodal distribution in summer and a unimodal distribution in autumn. Zhengzhou City had serious ozone pollution in summer, and O3 and NO3- showed the "staggered peak" phenomenon, indicating photochemical reactions in the atmosphere. In autumn, water-soluble inorganic ion concentration in particulate matter was high, and the ratio of[NO3-]/[SO42-] was higher than 0.5. The mobile source is an important source of particles. NOR and SOR peaks were on the 1.1-2.1 µm particle size segment in summer, whereas those in the 0.65-1.1 µm particle size segment occurred in autumn. The sulfur gas-to-grain conversion in summer was larger than that of nitrogen, contrary to the result in autumn.

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