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1.
Mar Pollut Bull ; 158: 111422, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32753206

RESUMO

China's seaborne foreign oil supply through the Malacca Strait is facing security challenges due to territorial disputes, pirate attacks, and geopolitics. To overcome these challenges, China plans to import oil through one of the corridors of the Belt and Road Initiative (BRI)-the China-Pakistan Economic Corridor (CPEC). This study estimated and compared ship emissions and their externalities associated with seaborne oil supply from the top five oil suppliers to China through the existing shipping route via the Malacca Strait and proposed route via CEPC. Ship activity-based methodology is applied to estimate the emissions of air pollutants (CO2, NOx, SO2, PM10, and CO) during cruising, maneuvering, and hoteling periods. The results show that the total ship emissions of China's seaborne oil supply can be significantly reduced from 6.2 million tons to 2.1 million tons via the CPEC route. While external cost can be reduced up to 65.9% via the CPEC route.


Assuntos
Poluentes Atmosféricos/análise , Navios , China , Internacionalidade , Paquistão
3.
Artigo em Inglês | MEDLINE | ID: mdl-32635543

RESUMO

Aiming at improving the air quality and protecting public health, policies such as restricting factories, motor vehicles, and fireworks have been widely implemented. However, fine-grained spatiotemporal analysis of these policies' effectiveness is lacking. This paper collected the hourly meteorological and PM2.5 data for three typical emission scenarios in Hubei, Beijing-Tianjin-Hebei (BTH), and Yangtze River Delta (YRD). Then, this study simulated the PM2.5 concentration under the same meteorological conditions and different emission scenarios based on a reliable hourly spatiotemporal random forest model (R2 exceeded 0.84). Finally, we investigated the fine-grained spatiotemporal impact of restricting factories, vehicles, and fireworks on PM2.5 concentrations from the perspective of hours, days, regions, and land uses, excluding meteorological interference. On average, restricting factories and vehicles reduced the PM2.5 concentration at 02:00, 08:00, 14:00, and 20:00 by 18.57, 16.22, 25.00, and 19.07 µg/m3, respectively. Spatially, it had the highest and quickest impact on Hubei, with a 27.05 µg/m3 decrease of PM2.5 concentration and 17 day lag to begin to show significant decline. This was followed by YRD, which experienced a 23.52 µg/m3 decrease on average and a 23 day lag. BTH was the least susceptible; the PM2.5 concentration decreased by only 8.2 µg/m3. In addition, influenced by intensive human activities, the cultivated, urban, and rural lands experienced a larger decrease in PM2.5 concentration. These empirical results revealed that restricting factories, vehicles, and fireworks is effective in alleviating air pollution and the effect showed significant spatiotemporal heterogeneity. The policymakers should further investigate influential factors of hourly PM2.5 concentrations, combining with local geographical and social environment, and implement more effective and targeted policies to improve local air quality, especially for BTH and the air quality at morning and night.


Assuntos
Poluição do Ar , Modelos Teóricos , Material Particulado , Análise Espaço-Temporal , Emissões de Veículos , Poluentes Atmosféricos , Pequim , China , Monitoramento Ambiental , Substâncias Explosivas , Instalações Industriais e de Manufatura/legislação & jurisprudência , Meteorologia , Veículos Automotores/legislação & jurisprudência
4.
J Environ Sci (China) ; 95: 111-120, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653170

RESUMO

Rate coefficients for the reaction of NO3 radicals with 6 unsaturated volatile organic compounds (VOCs) in a 7300 L simulation chamber at ambient temperature and pressure have been determined by the relative rate method. The resulting rate coefficients were determined for isoprene, 2-carene, 3-carene, methyl vinyl ketone (MVK), methacrolein (MACR) and crotonaldehyde (CA), as (6.6 ± 0.8) × 10-13, (1.8 ± 0.6) × 10-11, (8.7 ± 0.5) × 10-12, (1.24 ± 1.04) × 10-16, (3.3 ± 0.9) × 10-15 and (5.7 ± 1.2) × 10-15 cm3/(molecule•sec), respectively. The experiments indicate that NO3 radical reactions with all the studied unsaturated VOCs proceed through addition to the olefinic bond, however, it indicates that the introduction of a carbonyl group into unsaturated VOCs can deactivate the neighboring olefinic bond towards reaction with the NO3 radical, which is to be expected since the presence of these electron-withdrawing substituents will reduce the electron density in the π orbitals of the alkenes, and will therefore reduce the rate coefficient of these electrophilic addition reactions. In addition, we investigated the product formation from the reactions of 2-carene and 3-carene with the NO3 radical. Qualitative identification of an epoxide (C10H16OH+), caronaldehyde (C10H16O2H+) and nitrooxy-ketone (C10H16O4NH+) was achieved using a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) and a reaction mechanism is proposed.


Assuntos
Poluentes Atmosféricos , Compostos Orgânicos Voláteis , Cinética
5.
J Environ Sci (China) ; 95: 121-129, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653171

RESUMO

Volatile organic compounds (VOCs) as precursors of ozone and secondary organic aerosols can cause adverse effects on the environment and human health. However, knowledge of the VOC vertical profile in the lower troposphere of major Chinese cities is poorly understood. In this study, tethered balloon flights were conducted over the juncture of Beijing-Tianjin-Hebei in China during the winter of 2016. Thirty-six vertical air samples were collected on selected heavy and light pollution days at altitudes of 50-1000 meters above ground level. On average, the concentration of total VOCs (TVOCs) at 50-100 m was 4.9 times higher than at 900-1000 m (46.9 ppbV vs. 8.0 ppbV). TVOC concentrations changed rapidly from altitudes of 50-100 to 401-500 m, with an average decrease of 72%. With further altitude increase, the TVOC concentration gradually decreased. The xylene/benzene ratios of 34/36 air samples were lower than 1.1, and the benzene/toluene ratios of 34/36 samples were higher than 0.4, indicating the occurrence of aged air mass during the sampling period. Alkenes contributed most in terms of both OH loss rate (39%-71%) and ozone formation potential (40%-72%), followed by aromatics (6%-38%). Finally, the main factors affecting the vertical distributions of VOCs were local source emission and negative dispersion conditions on polluted days. These data could advance our scientific understanding of VOC vertical distribution.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , Pequim , China , Cidades , Monitoramento Ambiental , Humanos
6.
J Environ Sci (China) ; 95: 14-22, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653173

RESUMO

A new state-of-the-art indoor smog chamber facility (CAPS-ZJU) has been constructed and characterized at Zhejiang University, which is designed for chemical mechanism evaluation under well-controlled conditions. A series of characterization experiments were performed to validate the well-established experimental protocols, including temperature variation pattern, light spectrum and equivalent intensity (JNO2), injection and mixing performance, as well as gases and particle wall loss. In addition, based on some characterization experiments, the auxiliary wall mechanism has been setup and examined. Fifty chamber experiments were performed across a broad range of experimental scenarios, and we demonstrated the ability to utilize these chamber data for evaluating SAPRC chemical mechanism. It was found that the SAPRC-11 can well predict the O3 formation and NO oxidation for almost all propene runs, with 6 hr Δ(O3 - NO) model error of -3% ± 7%, while the final O3 was underestimated by ~20% for isoprene experiments. As for toluene and p-xylene experiments, it was confirmed that SAPRC-11 has significant improvement on aromatic chemistry than earlier version of SAPRC-07, although the aromatic decay rate was still underestimated to some extent. The model sensitivity test has been carried out, and the most sensitive parameters identified are the initial concentrations of reactants and the light intensity as well as HONO offgasing rate and O3 wall loss rate. All of which demonstrated that CAPS-ZJU smog chamber could derive high quality experimental data, and could provide insights on chamber studies and chemical mechanism development.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Oxirredução , Smog/análise , Tolueno
7.
J Environ Sci (China) ; 95: 172-182, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653177

RESUMO

The pollution levels, composition characteristics and sources of atmospheric PM2.5 were investigated based on field measurement at a rural site in the North China Plain (NCP) from pre-heating period to heating period in winter of 2017. The hourly average concentrations of PM2.5 frequently exceeded 150 µg/m3 and even achieved 400 µg/m3, indicating that the PM2.5 pollution was still very serious despite the implementation of stricter control measures in the rural area. Compared with the pre-heating period, the mean concentrations of organic carbon (OC), element carbon (EC) and chlorine ion (Cl-) during the heating period increased by 20.8%, 36.6% and 38.8%, accompanying with increments of their proportions in PM2.5 from 37.5%, 9.8% and 5.5% to 42.9%, 12.7% and 7.2%, respectively. The significant increase of both their concentrations and proportions during the heating period was mainly ascribed to the residential coal combustion. The proportions of sulfate, nitrate and ammonium respectively increased from 9.9%, 10.9% and 9.0% in nighttime to 13.8%, 16.2% and 11.1% in daytime, implying that the daytime photochemical reactions made remarkable contributions to the secondary inorganic aerosols. The simulation results from WRF-Chem revealed that the emission of residential coal combustion in the rural area was underestimated by the current emission inventory. Six sources identified by positive matrix factorization (PMF) based on the measurement were residential coal combustion, secondary formation of inorganic aerosols, biomass burning, vehicle emission and raising dust, contributing to atmospheric PM2.5 of 40.5%, 21.2%, 16.4%, 10.8%, 8.6% and 2.5%, respectively.


Assuntos
Poluentes Atmosféricos/análise , Material Particulado/análise , Aerossóis/análise , China , Carvão Mineral/análise , Monitoramento Ambiental , Estações do Ano , Emissões de Veículos/análise
8.
J Environ Sci (China) ; 95: 183-189, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653178

RESUMO

Coking industry is an important volatile organic compounds (VOCs) emission source in China, however, detailed information on VOCs emissions is lacking. Therefore, we selected a typical mechanized coking plant and collected air samples according to the Emission Standard of Pollutants for Coking Chemical Industry (GB16171-2012). Using gas chromatography-mass spectrometry method, we analyzed the VOCs in the air samples, and applied maximum increment reactivity (MIR) rule to estimate ozone formation potential (OFP) of the VOCs emitted from the coke production. More than 90 VOCs species were detected from the coking plant, including alkanes, alkenes, alkynes, aromatic hydrocarbons, halogenated hydrocarbons and oxygenated VOCs. The concentrations of VOCs (ρ(VOCs)) generated at different stages of the coking process are significantly different. ρ(VOCs) from coke oven chimney had the highest concentration (87.1 mg/m3), followed by coke pushing (4.0 mg/m3), coal charging (3.3 mg/m3) and coke oven tops (1.1 mg/m3). VOCs species emitted from the coke production processes were dominated by alkanes and alkenes, but the composition proportions were different at the different stages. Alkenes were the most abundant emission species in flue gases of the coke oven chimney accounting for up to 66% of the total VOCs, while the VOCs emissions from coke pushing and coal charging were dominated by alkanes (36% and 42%, respectively), and the alkanes and alkenes emitted from coke oven top were similar (31% and 29%, respectively). Based on above results, reduction of VOCs emissions from coke oven chimney flue gases is suggested to be an effective measure, especially for alkenes.


Assuntos
Poluentes Atmosféricos/análise , Coque , Ozônio/análise , Compostos Orgânicos Voláteis/análise , China , Monitoramento Ambiental
9.
J Environ Sci (China) ; 95: 190-200, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653179

RESUMO

Atmospheric volatile organic compounds (VOCs) were observed by an on-line gas chromatography-flame ionization detector monitoring system from November 2016 to August 2017 in Beijing. The average concentrations were winter (40.27 ± 25.25 µg/m3) > autumn (34.25 ± 19.90 µg/m3) > summer (32.53 ± 17.39 µg/m3) > spring (24.72 ± 17.22 µg/m3). Although benzene (15.70%), propane (11.02%), ethane (9.32%) and n-butane (6.77%) were the most abundant species, ethylene (14.07%) and propene (11.20%) were the key reactive species to ozone formation potential (OFP), and benzene, toluene, ethylbenzene, m-xylene + p-xylene and o-xylene (54.13%) were the most reactive species to secondary organic aerosol formation potential (SOAFP). The diurnal and seasonal variations indicated that diesel vehicle emission during early morning, gasoline vehicle emission at the traffic rush hours and coal burning during the heating period might be important sources. Five major sources were further identified by positive matrix factorization (PMF). The vehicle exhaust (gasoline exhaust and diesel exhaust) was found to be contributed most to atmospheric VOCs, with 43.59%, 41.91%, 50.45% and 43.91%, respectively in spring, summer, autumn and winter; while solvent usage contributed least, with 11.10%, 7.13%, 14.00% and 19.87%, respectively. Biogenic emission sources (13.11%) were only identified in summer. However, both vehicle exhaust and solvent usage were identified to be the key sources considering contributions to the OFP and SOAFP. Besides, the contributions of combustion during heating period and gasoline evaporation source during warm seasons to OFP and SOAFP should not be overlooked.


Assuntos
Poluentes Atmosféricos/análise , Compostos Orgânicos Voláteis/análise , Pequim , China , Monitoramento Ambiental , Emissões de Veículos/análise
10.
J Environ Sci (China) ; 95: 2-13, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653180

RESUMO

In December 2015, the Beijing-Tianjin-Hebei (BTH) region experienced several episodes of heavy air pollution. The government immediately issued emergency control measures to reduce the pollution, which provided a good opportunity to explore the impact of emission reduction on aerosol-radiation interaction. In this study, four tests were conducted, including the base1 simulation with emission reduction and aerosol-radiation interaction on, the base2 simulation with emission reduction and aerosol-radiation interaction off, the scenario1 simulation without emission reduction and aerosol-radiation interaction on and the scenario2 simulation without emission reduction and aerosol-radiation interaction off. We find that the aerosol-radiation interaction decreased the downward shortwave radiation and the temperature at 2 m, reduced the planetary boundary layer height (PBLH) in the region, and increased the relative humidity at 2 m, which is favorable for pollution accumulation. Our results revealed that the interaction effect due to emission reductions increased downward shortwave radiation by an average of 0-5 W/m2, leading to increase in surface temperature of 0-0.05°C, increase in the daytime mean PBL high of 0-8 m, and decrease in daytime mean relative humidity at 2 m of 0.5%. We found that if there were aerosol-radiation interaction, it would enhance the effectiveness of emission control measures on air pollution control. The enhance of PM2.5 (particulate matter less than 2.5 µm), PM10 (particulate matter less than 10 µm), and NO2 (nitrogen dioxide) emission reduction effects reached 7.62%, 6.90%, 11.62%, respectively, over this region.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Aerossóis/análise , Pequim , China , Monitoramento Ambiental , Material Particulado/análise
11.
J Environ Sci (China) ; 95: 201-209, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653181

RESUMO

To investigate the cause of fine particulate matter (particles with an aerodynamic diameter less than 2.5 µm, PM2.5) pollution in the heating season in the North China Plain (specifically Beijing, Tianjin, and Langfang), water-soluble ions and carbonaceous components in PM2.5 were simultaneously measured by online instruments with 1-hr resolution, from November 15, 2016 to March 15, 2017. The results showed extreme severity of PM2.5 pollution on a regional scale. Secondary inorganic ions (SNA, i.e., NO3-+SO42+ NH4+) dominated the water-soluble ions, accounting for 30%-40% of PM2.5, while the total carbon (TC, i.e., OC + EC) contributed to 26.5%-30.1% of PM2.5 in the three cities. SNA were mainly responsible for the increasing PM2.5 pollution compared with organic matter (OM). NO3- was the most abundant species among water-soluble ions, but SO42- played a much more important role in driving the elevated PM2.5 concentrations. The relative humidity (RH) and its precursor SO2 were the key factors affecting the formation of sulfate. Homogeneous reactions dominated the formation of nitrate which was mainly limited by HNO3 in ammonia-rich conditions. Secondary formation and regional transport from the heavily polluted region promoted the growth of PM2.5 concentrations in the formation stage of PM2.5 pollution in Beijing and Langfang. Regional transport or local emissions, along with secondary formation, made great contributions to the PM2.5 pollution in the evolution stage of PM2.5 pollution in Beijing and Langfang. The favourable meteorological conditions and regional transport from a relatively clean region both favored the diffusion of pollutants in all three cities.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Aerossóis/análise , Pequim , China , Cidades , Monitoramento Ambiental , Calefação , Material Particulado/análise , Estações do Ano
12.
J Environ Sci (China) ; 95: 217-224, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653183

RESUMO

In order to understand the compositions characteristics of particulate matter with aerodynamic diameter less than 2.5 µm (PM2.5) fraction in road dust (RD2.5) of oasis cities on the edge of Tarim Basin, 30 road dust (RD) samples were collected in Kashi, Cele, and Yutian in the spring, 2018, and RD2.5 was collected using the resuspension approach. Eight water-soluble ions, 39 trace elements and 8 fractions of carbon-containing species in PM2.5 were analyzed. Ca2+ and Ca were the most abundant ions and elements in RD2.5 (7.1% and 9.5%). Cl- in RD2.5 was affected not only by attributed to saline-alkali soils in oasis cities of the Tarim Basin and dust from Taklimakan Desert but also by human activities. Moreover, the organic carbon/elemental carbon (OC/EC) ratio indicated that carbon components in RD2.5 in Cele town mainly come from fossil fuel combustion, while those in Yutian and Kashi mainly come from biomass combustion. It is noteworthy that high Ca in RD2.5 was seriously affected by anthropogenic emissions, and high Na and K contents in RD2.5 could be derived from soil and desert dust. It was estimated that Cd, Tl, Sn and Cr were emitted from anthropogenic emissions using the enrichment factor. The coefficients of divergence (COD) result indicated that the influence of local emission on road dust emission is greater than that of long-distance transmission. This study is the first time to comprehensively analyze the chemical characteristics of road dust in oasis cities, and the results provides the sources of road dust at the margin of Tarim Basin.


Assuntos
Poluentes Atmosféricos/análise , Poeira/análise , China , Cidades , Monitoramento Ambiental , Humanos , Tamanho da Partícula , Material Particulado/análise , Emissões de Veículos/análise
13.
J Environ Sci (China) ; 95: 225-239, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653184

RESUMO

Benzene homologues are important chemical precursors to the formation of ground-level ozone and secondary organic aerosol (SOA) in the atmosphere, in addition, some toxic species are harmful to human health. Strict countermeasures have been taken to fight air pollution since 2013, and total amount control of volatile organic compounds is being promoted in China at present. Therefore, it is important to understand the pollution situation and the control status of ambient benzene homologues in China. This paper reviews research progress from published papers on pollution characteristics, atmospheric photochemical reactivity, health risk assessment and source identification of ambient benzene homologues in recent years in China, and also summarizes policies and countermeasures for the control of ambient benzene homologues and the relevant achievements. The total ambient levels of benzene, toluene, ethylbenzene and xylenes (BTEX) shows a declining tendency from 2001 to 2016 in China. The mass concentrations of BTEX are generally higher in southern regions than in northern regions, and they present vertical decreasing variation characteristics with increasing altitude within the height range of about 5500 m. Toluene has the highest ozone formation potential and SOA formation potential both in urban areas and background areas, while benzene poses an obvious carcinogenic risk to the exposed adult populations in urban areas. Source identification of ambient benzene homologues suggested that local governments should adopt differentiated control strategies for ambient benzene homologues. Several recommendations are put forward for future research and policy-making on the control of ambient benzene homologues in China.


Assuntos
Poluentes Atmosféricos/análise , Benzeno , Adulto , Derivados de Benzeno/análise , China , Monitoramento Ambiental , Humanos , Medição de Risco , Tolueno/análise , Xilenos
14.
J Environ Sci (China) ; 95: 256-265, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653188

RESUMO

Atmospheric carbonyls were measured at a typical rural area of the North China Plain (NCP) from November 13 to December 24, 2017 to investigate the pollution characteristics, sources and environmental implications. Fifteen carbonyls were detected, and formaldehyde, acetaldehyde and acetone accounted for about 81% at most. The concentration of the total carbonyls in heavily polluted days was twice more than that in clean days. In contrast to other carbonyls, m-tolualdehyde exhibited relatively high concentrations in the clean days in comparison with the polluted days. The ratios of three principal carbonyls to CO showed similar daily variations at different pollution levels with significant daytime peaks. Multiple linear regression analysis revealed that the contributions of background, primary and secondary sources to three principal carbonyls showed similar variation trends from the clean level to the heavily polluted level. The OH formation rate of formaldehyde showed a similar variation trend to its photodegradation rate, reaching the peak value at noon, which is important to maintain relatively high OH levels to initiate the oxidation of various gas-phase pollutants for secondary pollutant formation at the rural site. OH radical consumption rate and ozone formation potential (OFP) calculations showed that formaldehyde and acetaldehyde were the dominant oxidative species among measured carbonyls. As for OH radical consumption, n-butyraldehyde and m-tolualdehyde were important contributors, while for ozone formation potential, n-butyraldehyde and propionaldehyde made significant contributions. In addition, the contribution of carbonyl compounds to secondary organic aerosol (SOA) formation was also important and needs further investigation.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , China , Monitoramento Ambiental , Estações do Ano
15.
J Environ Sci (China) ; 95: 266-277, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653189

RESUMO

Biogenic volatile organic compounds (BVOCs) in the atmosphere play important roles in the formation of ground-level ozone and secondary organic aerosol (SOA) in global scale and also in regional scale under some condition due to their large amount and relatively higher reactivity. In places with high plant cover in the tropics and in China where air pollution is serious, the effect of BVOCs on ozone and secondary organic aerosols is strong. The present research aims to provide a comprehensive review about the emission rate, emission inventory, research methods, the influencing factors of BVOCs emissions, as well as their impacts on atmospheric environment quality and human health in recent years in Asia based on the summary and analysis of literatures. It is suggested to use field direct measurement method to obtain the emission rate and model method to calculate the emission amount. Several recommendations are given for future investigation and policy development on BVOCs emission.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Compostos Orgânicos Voláteis/análise , Ásia , China , Humanos
16.
J Environ Sci (China) ; 95: 33-42, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653190

RESUMO

Vertical profiles of isoprene and monoterpenes were measured by a proton transfer reaction-time of flight-mass spectrometry (PTR-ToF-MS) at heights of 3, 15, 32, 64, and 102 m above the ground on the Institute of Atmospheric Physics (IAP) tower in central Beijing during the winter of 2016 and the summer of 2017. Isoprene mixing ratios were larger in summer due to much stronger local emissions whereas monoterpenes were lower in summer due largely to their consumption by much higher levels of ozone. Isoprene mixing ratios were the highest at the 32 m in summer (1.64 ± 0.66 ppbV) and at 15 m in winter (1.41 ± 0.64 ppbV) with decreasing concentrations to the ground and to the 102 m, indicating emission from the tree canopy of the surrounding parks. Monoterpene mixing ratios were the highest at the 3 m height in both the winter (0.71 ± 0.42 ppbV) and summer (0.16 ± 0.10 ppbV) with a gradual decreasing trend to 102 m, indicting an emission from near the ground level. The lowest isoprene and monoterpene mixing ratios all occurred at 102 m, which were 0.71 ± 0.42 ppbV (winter) and 1.35 ± 0.51 ppbV (summer) for isoprene, and 0.42 ± 0.22 ppbV (winter) and 0.07 ± 0.06 ppbV (summer) for monoterpenes. Isoprene in the summer and monoterpenes in the winter, as observed at the five heights, showed significant mutual correlations. In the winter monoterpenes were positively correlated with combustion tracers CO and acetonitrile at 3 m, suggesting possible anthropogenic sources.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Compostos Orgânicos Voláteis/análise , Pequim , Monitoramento Ambiental , Monoterpenos/análise
17.
J Environ Sci (China) ; 95: 43-48, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653191

RESUMO

Pollen pollution and allergy are becoming prominent issues in China. However, few studies on pollinosis have been reported. As an allergen in the atmosphere, allergenic Humulus scandens pollen was collected from four districts of Shanghai, including Wusong (WS), Jiading (JD), Xujiahui (XJH) and Songjiang (SJ). The mass concentrations of SO2, NO2, O3, PM10, and PM2.5 (particulate matter with air dynamic diameter less than 10 and 2.5 µm, respectively) near the four sampling sites were also recorded during Humulus scandens pollen season. The allergenicity of the Humulus scandens pollen was assessed by using of a rat model and enzyme linked immunosorbent assay (ELISA). Relationships between the allergenicity and air pollutants were correlated. Our results demonstrated that the biological viability of the pollens collected from the four districts exhibited no significant differences. ELISA and dot blotting results further demonstrated that the serum of sensitized rats exhibited much higher immune-reactive response than that of control groups. Western blotting showed that the 15 KD (1KD = 1000 dalton) proteins of Humulus pollen led to the allergic response. The allergenic intensity of Humulus pollen protein from different samples followed the pattern: WS > JD > XJ > SJ. There was a negative relationship between the allergenicity of Humulus pollens and PM10 (R = -0.99) / PM2.5 (R = -0.73), and a positive relationship with O3 (R = 0.92). These data clearly showed that PM10 and PM2.5 could enhance Humulus pollen protein release, and O3 could aggravate the allergenicity of the Humulus pollen.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Humulus/imunologia , Alérgenos/análise , Animais , China , Material Particulado/análise , Pólen/química , Pólen/imunologia , Ratos
18.
J Environ Sci (China) ; 95: 49-57, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653192

RESUMO

Mass level of fine particles (PM2.5) in main cities in China has decreased significantly in recent years due to implementation of Chinese Clean Air Action Plan since 2013, however, O3 pollution is getting worse than before, especially in megacities such as in Shanghai. In this work, O3 and PM2.5 were continuously monitored from May 27, 2018 to March 31, 2019. Our data showed that the annual average concentration of PM2.5 and O3 (O3-8 hr, maximum 8-hour moving average of ozone days) was 39.35 ± 35.74 and 86.49 ± 41.65 µg/m3, respectively. The concentrations of PM2.5 showed clear seasonal trends, with higher concentrations in winter (83.36 ± 18.66 µg/m3) and lower concentrations in summer (19.85 ± 7.23 µg/m3), however, the seasonal trends of O3 were different with 103.75 ± 41.77 µg/m3 in summer and 58.59 ± 21.40 µg/m3 in winter. Air mass backward trajectory, analyzing results of potential source contribution function model and concentration weighted trajectory model implied that pollutants from northwestern China contributed significantly to the mass concentration of Shanghai PM2.5, while pollutants from areas of eastern coastal provinces and South China Sea contributed significantly to the mass level of ozone in Shanghai atmosphere. Mass concentration of twenty-one elements in the PM2.5 were investigated, and their relationships with O3 were analyzed. Mass level of ozone had good correlation with that of Ba (r = 0.64, p < 0.05) and V (r = 0.30, p > 0.05), suggesting vehicle emission pollutants contribute to the increasing concentration of ozone in Shanghai atmosphere.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar , Ozônio/análise , Atmosfera , China , Cidades , Monitoramento Ambiental , Material Particulado/análise , Estações do Ano
19.
J Environ Sci (China) ; 95: 58-64, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653193

RESUMO

Hydroxyl free radicals (OH radicals) play the main role in atmospheric chemistry and their involving reactions are the dominant rate determining step in the formation of secondary fine particulate matter and in the removal of air pollutants from the atmosphere. In this paper, we studied the seasonal variation characteristics of OH radicals during the daytime in Lanzhou and explored the potential formation mechanism of high concentration OH radicals. We found that the OH radicals in four seasons was 2.7 × 106, 2.6 × 106, 3.1 × 106, and 2.2 × 106 cm-3, respectively. Since the rainfall was concentrated in summer, the wet deposition had a significant effect on removing OH radicals. Among the four pollutants (including ozone (O3), volatile organic compounds (VOCs), nitrogen dioxide (NO2) and fine particulate matter (PM2.5)), the variation of OH radicals were closely related to ozone concentration especially in spring and summer. In autumn, the correlation between PM2.5 and OH radicals were the closest among the observing pollutants and its formation mechanism was different conventional regeneration pathway. In Event 1, high concentration of ozone was the main source of OH radicals; under the high humidity condition, except for ozone, the multiple factors including VOCs, NO2 and PM2.5 interplayed and leaded to the Event 2.


Assuntos
Poluentes Atmosféricos/análise , Ozônio/análise , Atmosfera , Monitoramento Ambiental , Radical Hidroxila/análise , Material Particulado/análise , Estações do Ano
20.
J Environ Sci (China) ; 95: 65-72, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32653194

RESUMO

Mineral dust, soil, and sea salt aerosols are among the most abundant primary inorganic aerosols in the atmosphere, and their hygroscopicity affects the hydrological cycle and global climate. We investigated the hygroscopic behaviors of six Na- and K-containing salts commonly found in those primary organic aerosols. Their hygroscopic growths as a function of relative humidity (RH) agree well with thermodynamic model prediction. Temperature dependence of deliquescence RH (DRH) values for five of those salts was also investigated, which are comparable to those in literature within 1%-2% RH, most showing negative dependence on temperature. Hygroscopic growth curves of real-world soil and sea salt samples were also measured. The hygroscopic growths of two more-hydroscopic saline soil samples and of sea salt can be predicted by the thermodynamic model based on the measured water-soluble ionic composition. The substantial amounts of water-soluble ions, including Na+ and K+, in saline soil samples imply that even nascent saline soil samples are quite hygroscopic at high-RH (>80%) conditions. For three less-hygroscopic dust samples, however, measurements showed higher water uptake ability than that predicted by the thermodynamic model. The small amount of water taken up by less-hygroscopic dust samples suggests that dust particles might contain thin layers of water even to very low RH. The results of this study provide a comprehensive characterization of the hygroscopicity of Na- and K-containing salts as related to their roles in the hygroscopic behaviors of saline mineral dusts and sea salt aerosols.


Assuntos
Poluentes Atmosféricos/análise , Poeira , Aerossóis/análise , Minerais , Potássio , Sais , Sódio , Molhabilidade
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