ANALYTICAL CHEMISTRY
·
2022
·
IF 8.008
Han Lun Lu,Zhan Min Su,Lei Li,Xuan Li
Detection methods for microbiological aerosols based on single particle mass spectrometry (SPAMS) and a fluorescent aerosol particle sizer (FLAPS) have been developed progressively. However, they encounter interference and inefficiency issues. By merging FLAPS and SPAMS technologies, the majority of inorganic ambient aerosols may be eliminated by the FLAPS, thus resolving SPAMS’ large data volume. SPAMS, on the other hand, may eliminate the secondary fluorescence interference that plagues the FLAPS. With the addition of the enhanced machine learning classifier, it is possible to extract microbial aerosol signals more precisely. In this work, a FLAPS–SPAMS instrument and a Random Forest classifier based on Kendall’s correlation expansion training set approach were built. In addition to analyzing the outdoor microbial proportions, the interference components of non-microbial fluorescent particles were also examined. Results indicate that the fraction of outdoor microbial aerosols in fluorescent particles is 25.72% or roughly 2.57% of total particles. Traditional ART-2A algorithm and semi-empirical feature clustering approaches were used to identify the interference categories of abiotic fluorescent particles, which were mostly constituted of EC/OC, LPG/LNG exhaust, heavy metal organics, nicotine, vinylpyridine, polycyclic aromatic hydrocarbons (PAHs), and polymers, accounting for 68.51% of fluorescent particles.
研究领域:
环境科学
·
生物技术
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分析化学
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DOI
PubMed
高影响因子
Analytical Methods
·
2022
·Vol. 14
·期 25
·2531-2540
·
IF 3.532
Wenjing Li,Maoyu Cao,Pengxiang Ge,Xiaoyu Fu,Jiajie Tang,Mindong Chen
Organosulfates (OSs) derived from the oxidation of biogenic volatile organic compounds (BVOCs) in the presence of anthropogenic sulfate aerosols are the important tracers of secondary organic aerosols (SOAs). In order to better understand the concentration of pinene-nitrooxy organosulfates (pNOSs) in Nanjing, a sensitive high-performance liquid chromatography-electron spray ionization spectrum/mass spectrum (HPLC-ESI-MS/MS) to determine pNOSs in PM2.5 has been developed and validated in this study. Firstly, Hypersil Gold C18 (Thermo Scientific, San Jose, USA) was selected to separate pinene-derived nitrooxy organosulfates (pNOSs) based on their polarity. Three kinds of pNOSs were detected in the full scan mode (MS) with an ESI source under the negative mode. Secondly, three isomers of pNOSs with fragment ions m/z 220, 151, and 142 were identified based on the MS/MS maps. At least two pairs of transfer ions should be selected as identification and quantification ions according to the optimization results of target compounds. For example, to determine pNOSs, these transfer ions of m/z 294 → 247, m/z 294 → 231, m/z 294 → 220, m/z 294 → 142, m/z 294 → 151, m/z 294 → 96, m/z 294 → 80 were selected as quantification and identification ions. Finally, the influence of scan mode on pNOS detection was evaluated, and the results showed that pNOSs were most sensitive in the SRM (selected reaction monitor) scan mode. Therefore, the SRM scan mode was chosen to detect pNOSs. We applied this method to analyze year-round PM2.5 (PM2.5 is fine particulate matter, which refers to particulate matter in ambient air with an aerodynamic equivalent diameter of less than or equal to 2.5 microns) samples in Nanjing. The average concentration of all the three kinds of pNOSs was 69.95 ng m−3. The results showed that the average concentration of pNOSs was high in spring (92.94 ng m−3) and summer (90.57 ng m−3), and lowest in winter (30.03 ng m−3).
研究领域:
大气化学
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环境科学
·
分析化学
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产品关联
DOI
PubMed
高影响因子
SCIENCE OF THE TOTAL ENVIRONMENT
·
2022
·
IF 10.753
Huihui Kang,Xiaona Shang,Munira Abdumutallip,Yunqian Chen,Ling Li,Xiaofei Wang,Chunlin Li,Huiling Ouyang,Xu Tang,Lin Wang,Yinon Rudich,Jianmin Chen
Carbonaceous aerosols (CAs) are major components of fine particulate matter (PM 2.5 ) that dramatically influence the energy budget of Earth. However, accurate assessment of the climatic impacts of CAs is still challenging due to the large uncertainties remaining in the measurement of their optical properties . In this respect, a modified versatile aerosol concentration enrichment system integrated into optical instruments (VACES-OPTS) was set up to increase particle concentration and amplify signal-noise ratio during optical measurement . Based on the novel technique, this study was able to lower the detection limit of CAs by an order of magnitude under high temporal resolution (2 h) and small sampling flow (6 L min −1 ). Besides, stable and reliable optical data were obtained for absorption apportionment and source identification of black carbon (BC) and brown carbon (BrC). In the field application of the new system, high absorption coefficient of CAs in Shanghai, China was witnessed. Further analysis of the contribution of black carbon BC and BrC to light absorption revealed that BrC could account for over 15% of the total absorption at 370 nm. According to the potential source contribution function model (PSCF) classification, CAs with strong light absorption in urban Shanghai originated not only from highly polluted inland China but also from active marine ship emissions.
研究领域:
环境科学
·
大气科学
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DOI
PubMed
高影响因子
ANALYTICAL CHEMISTRY
·
2023
·
IF 7.4
Yao-Yu Pan,Bai-Chuan Zhao,Xin Zhang,Wei Zhu,Ai-Guo Shen
While the global COVID-19 pandemic has subsided, microbial aerosol detection has become of high concern. Timely, accurate, and highly sensitive monitoring of microbial aerosols in indoor air is the basis for effective prevention and control of infectious diseases. At present, no commercial equipment or reliable technology can simultaneously control the detection time and limit at 6 h and 102 CFU/mL, respectively. Based on the “safety size range” of particulate matter in the air, we propose a new method of microbial dilation detection, which enables the pathogen to grow rapidly and dramatically into a polymeric microsphere, larger in size than the coexisting aerosol particles. “Like a crane standing among chickens”, the microorganism can be easily visualized and counted. Different from routine chemical and biological sensing technologies, this method can achieve absolute counting of microbial particles, and the simple principles can be developed into devices for different life scenarios.
研究领域:
环境科学
·
生物技术
·
公共卫生
·
气溶胶科学
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产品关联
DOI
PubMed
高影响因子
Atmospheric Pollution Research
·
2021
·
IF 4.352
Ranran Zhao,Qixing Zhang,Xuezhe Xu,Weixiong Zhao,Hui Yu,Wenjia Wang,Yongming Zhang,Weijun Zhang
As global air pollution aggravates, it urges us to investigate the evolution of atmospheric related emissions. Recently oxidation flow reactor (OFR) has been widely used to simulate the aging of atmospheric related emissions as its excellent performance. In this work, we systematically characterized the SOA formation from α-pinene using a custom-built OFR under different conditions. The particle loss of the OFR was evaluated by particle transmission efficiency, then the effect of O 3 concentration, relative humidity (RH), precursor amounts, OH exposure level, and acidic seed aerosol on SOA formation was investigated. The particle losses of our OFR for particles above 50 nm were very small, which was comparable to or even better than those of previous traditional flow reactors. The formation of SOA particles nearly achieved stability after UV radiation for 15 min. When OH exposure concentration at approximately 0.6 × 10 12 molec cm −3 s, the SOA yield reached the maximum yield of 0.51 and 0.39 in the presence and absence of acidic seed aerosol respectively. The addition of acidic seed aerosol increased both particle number concentration and particle size, resulting in an increase of SOA yield of 1.2–1.5 times at OH exposure concentration ranged from 0.1 × 10 12 to 1.8 × 10 12 molec cm −3 s. The results provided significant guidance for studying the aging of atmospheric related emission under different working conditions by using an OFR.
研究领域:
大气科学
·
环境科学
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DOI
高影响因子
Journal of Environmental Sciences
·
2023
·
IF 6.9
Yue Liu,Junjie Liu,Ji Xiao,Jing Ye,Lixu Guo,Caiqing Yan
Carbonaceous aerosol, including organic carbon (OC) and elemental carbon (EC), has significant influence on human health, air quality and climate change. Accurate measurement of carbonaceous aerosol is essential to reduce the uncertainty of radiative forcing estimation and source apportionment. The accurate separation of OC and EC is controversial due to the charring of OC. Therefore, the development of reference materials (RM) for the validation of OC/EC separation is an important basis for further study. Previous RMs were mainly based on ambient air sampling, which could not provide traceability of OC and EC concentration. To develop traceable RMs with known OC/EC contents, our study applied an improved aerosol generation and mixing technique, providing uniform deposition of particles on quartz filters. To generate OC aerosol with similar pyrolytic property of ambient aerosol, both water soluble organic carbon (WSOC) and water insoluble organic carbon (WIOC) were used, and amorphous carbon was selected for EC surrogate. The RMs were analyzed using different protocols. The homogeneity within the filter was validated, reaching below 2 %. The long-term stability of RMs has been validated with RSD ranged from 1.7–3.2 %. Good correlation was observed between nominal concentration of RMs with measured concentration by two protocols, while the difference of EC concentration was within 20 %. The results indicated that the newly developed RMs were acceptable for the calibration of OC and EC, which could improve the accuracy of carbonaceous aerosol measurement. Moreover, the laboratory-generated EC-RMs could be suitable for the calibration of equivalent BC concentration by Aethalometers.
研究领域:
环境科学
·
大气化学
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分析化学
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产品关联
DOI
高影响因子
Environmental Science & Technology Letters
·
2023
·
IF 10.9
Lin Du,Li Xu,Kun Li,Christian George,Maofa Ge
Anthropogenic air pollutants can be involved in biogenic secondary organic aerosol (SOA) formation. However, such interactions are currently one of the least understood aspects of atmospheric chemistry. Herein, SOA formation via chemical interactions between anthropogenic SO2, NH3, and O3 and biogenic β-caryophyllene was investigated. It is shown that although SO2 considerably enhanced SOA formation, this enhancing effect was weakened by NH3 when SO2 and NH3 coexisted. NH3-induced neutralization of particle acidity generated by SO2 oxidation may be the primary driving factor of this weakening effect. Molecular-level characterization using high-resolution quadrupole time-of-flight mass spectrometry revealed additional connections between NH3-induced changes in SOA composition and aerosol acidity. Specifically, the lower relative abundances of several main products generated in the presence of SO2 and NH3 than those formed in the presence of only SO2 were consistent with their suppressed formation by lower seed acidity. The suppression of oligomer formation by NH3 provided more evidence for the weakening of acid-catalyzed processes caused by acidity neutralization. Accordingly, the current study demonstrates that NH3 as a less effectively regulated alkaline gas resulting from an unbalanced reduction of different pollutants must be considered with caution when evaluating effects of SO2 on SOA formation via anthropogenic–biogenic interactions.
研究领域:
大气化学
·
环境科学
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DOI
高影响因子
Journal of Environmental Sciences
·
2024
·
IF 5.9
Yingqi Zhao,Zhaoyan Zhang,Ya Zhao,Chong Wang,Hua Xie,Jiayue Yang,Weiqing Zhang,Guorong Wu,Gang Li,Ling Jiang,Xueming Yang
It is highly challenging to precisely compare the impacts of anthropogenic pollutants on the photooxidation of isomeric volatile organic compounds with respect to molecular compositions and particle number/mass concentrations of secondary organic aerosols (SOAs). In this study, we conducted a series of well-defined indoor chamber experiments to compare the effects of NO x (NO and NO 2 ) on the photooxidation of isomeric monoterpenes of β -pinene and limonene. For the photooxidation of β -pinene with NO x , the increase of the initial concentrations of NO ([NO] 0 ) shows a monotonous suppression of the particle mass concentration, whereas the increase of [NO 2 ] 0 shows a monotonous enhancement of the particle mass concentration. For the photooxidation of limonene with NO x , the increase of [NO] 0 exhibits a monotonous suppression of the particle mass concentration, whereas the increase of [NO 2 ] 0 shows a parabolic trend of the particle mass concentration. Utilizing a newly developed vacuum ultraviolet free electron laser (VUV-FEL), the online threshold photoionization mass spectrometry reveals a series of novel compounds at molecular weight (MW) = 232 and 306 for the β -pinene + NO x system and MW = 187, 261, 280, and 306 for the limonene + NO x system. The molecular structures and formation pathways of these species were inferred, which led to the prediction of the diversity and difference of SOA products (i.e., ester and peroxide accretion products) formed from different monoterpene precursors. To improve the predictions of future air quality, it is recommended that climate models should incorporate the NO x -driven diurnal photooxidation of monoterpenes for SOA formation mechanisms.
研究领域:
大气化学
·
环境科学
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DOI
高影响因子
RSC Advances
·
2016
·Vol. 6
·期 103
·101365-101371
·
IF 3.289
Guang Xiong,Jinpeng Yin,Jiaxu Liu,Xiyan Liu,Zhendong Guo,Liping Liu
Nano-sized ZSM-5 aggregates with interparticle mesopores was synthesized by an aerosol-assisted method. The amorphous aluminosilicate powder was used as a precursor, which was obtained by an aerosol process from an aqueous solution of the silicon and aluminium sources. The amorphous powder was crystallized in an autoclave with the structure-directing agent tetrapropylammonium hydroxide. No extra water was added in this step. The synthesis was performed in an extremely dense system, hence the amount of both template and waste water can be significantly reduced. The formation of the nanocrystalline MFI zeolite is mainly based on the liquid phase transformation in a supersaturation system. The nano-sized ZSM-5 aggregates were composed of nanocrystals with a size of 50–100 nm. Compared with the ZSM-5 zeolite synthesized by a conventional hydrothermal method, the nano-sized ZSM-5 aggregates exhibits a higher BET surface area, external surface area, and total pore volume and better Al species distribution. This nanocrystalline ZSM-5 zeolite shows a higher catalytic activity and stability in catalytic cracking of 1,3,5-triisopropylbenzene.
研究领域:
材料科学
·
催化化学
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产品关联
DOI
高影响因子
Polymers
·
2021
·Vol. 13
·期 12
·1998
·
IF 4.329
Ebuka A. Ogbuoji,Amr M. Zaky,Isabel C. Escobar
The outbreak of the COVID-19 pandemic, in 2020, has accelerated the need for personal protective equipment (PPE) masks as one of the methods to reduce and/or eliminate transmission of the coronavirus across communities. Despite the availability of different coronavirus vaccines, it is still recommended by the Center of Disease Control and Prevention (CDC), World Health Organization (WHO), and local authorities to apply public safety measures including maintaining social distancing and wearing face masks. This includes individuals who have been fully vaccinated. Remarkable increase in scientific studies, along with manufacturing-related research and development investigations, have been performed in an attempt to provide better PPE solutions during the pandemic. Recent literature has estimated the filtration efficiency (FE) of face masks and respirators shedding the light on specific targeted parameters that investigators can measure, detect, evaluate, and provide reliable data with consistent results. This review showed the variability in testing protocols and FE evaluation methods of different face mask materials and/or brands. In addition to the safety requirements needed to perform aerosol viral filtration tests, one of the main challenges researchers currently face is the inability to simulate or mimic true aerosol filtration scenarios via laboratory experiments, field tests, and in vitro/in vivo investigations. Moreover, the FE through the mask can be influenced by different filtration mechanisms, environmental parameters, filtration material properties, number of layers used, packing density, fiber charge density, fiber diameter, aerosol type and particle size, aerosol face velocity and concentration loadings, and infectious concentrations generated due to different human activities. These parameters are not fully understood and constrain the design, production, efficacy, and efficiency of face masks.Keywords:coronavirus;SARS-CoV-2;personal protection equipment;aerosol;filtration
研究领域:
公共卫生
·
医学工程
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产品关联
DOI
PubMed
高影响因子
ATMOSPHERIC ENVIRONMENT
·
2021
·
IF 4.798
Lihui Han,Xinhang Liu,Yuanyuan Chen,Xin Xiang,Shuiyuan Cheng,Haiyan Wang
A significant technique of combining simulation experiments with a long-term real-time field measurement was first deployed to explore impacts of various environmental factors on formations of sulfate aerosol on the surface of mineral aerosols as MgO in the different reaction systems, and synergistic impacts of these environmental factors on the formation of sulfate aerosols in the different seasonal systems, especially in haze days. Meanwhile, a new correction technique was developed to estimate the effective reaction area and initial uptake coefficient of SO 2 on the MgO aerosol surfaces. The significant results showed that the reactions of SO 2 on the MgO aerosol surfaces in the system of SO 2 -MgO-dark could produce a small amount of sulfate and a large amount of sulfite and bisulfite, while in the systems of SO 2 -MgO- hν and SO 2 -MgO-O 3 produce a large amount of sulfate and a small amount of sulfite and bisulfite. The impacts of temperature T and relative humidity RH on the sulfate formation on MgO aerosol surfaces showed a single-peak mode under the UV light condition, respectively. The sensitivities of these environmental factors to the sulfate aerosol formation were found to follow the order of RH > UV >T > O 3 > SO 2 . The revised initial uptake coefficient γ 0 . REV of SO 2 on the MgO aerosols was always between γ 0.BET and γ 0 . GEO , and much closer to actual value. The heterogeneous reaction mechanisms of SO 2 on the MgO aerosol surfaces in the different reaction systems were obviously different. In the presence of water, light irradiation and O 3 exerted crucially significant roles in promoting sulfate heterogeneous formation. The various environmental factors in the different seasonal systems, especially in haze days, showed different synergistic effects on sulfate aerosol formations. The sulfate aerosol formations in haze days were mostly impacted by RH, T, O 3 , and SO 2 in spring, RH in summer, RH, T, and SO 2 in autumn, and RH and SO 2 in winter. The study will provide significant scientific bases for understanding and controlling haze pollution formation.
研究领域:
大气化学
·
环境科学
·
气溶胶科学
·
空气污染
✓ 已验证
产品关联
DOI
高影响因子
ENVIRONMENTAL POLLUTION
·
2025
·
IF 7.3
Xinyue Zhao,Siyu Liu,Lina Wang,Li Yang,Jun He,Chengjun Wang
A gas chromatography-flame ionization detection method was developed to investigate the occurrence and transformations of phthalate esters (PAEs) in atmospheric aqueous aerosol in Wuhan City. Six of PAEs were detected in collected aerosol samples and their concentrations in atmosphere were followed the order of diallyl phthalate (0.244 μg m −3 ) > diethyl phthalate (0.235 μg m −3 ) > di(2-ethylhexyl) phthalate (0.176 μg m −3 ) > dimethyl phthalate (0.110 μg m −3 ) > di-n-octyl phthalate (0.081 μg m −3 ) > dipropyl phthalate (0.024 μg m −3 ). The Redundancy analysis results indicated that, compared to humidity and wind speed, temperature had the most important influence on the occurrence of PAEs in aqueous aerosol. The hydrolysis of selected PAEs in aqueous extracts of aerosol samples was examined under different conditions, determining that hydrolysis of PAEs is most susceptible to the ambient temperature at typical atmospheric aqueous pH of 3–5. In addition, photodegradation results suggested that indirect photodegradation played a key role in photodecomposition of PAEs under sunlight irradiation. The photo-generated reactive species including triplet water-soluble organic matter ( 3 WSOM∗) and reactive oxygen species (ROS) mainly contribute to the degradation of PAEs in atmospheric aqueous aerosol. This study provides an important reference for better understanding the occurrence and transformations of PAEs in ambient urban atmospheric aqueous aerosol.
研究领域:
环境科学
·
化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）