显示样式:     当前期刊: Atmospheric Environment    加入关注       排序: 导出
我的关注
我的收藏
您暂时未登录!
登录
  • Excess deaths associated with fine particulate matter in Brazilian cities
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-18
    Willian L. Andreão, Taciana T.A. Albuquerque, Prashant Kumar
    更新日期:2018-09-19
  • Optical properties and oxidative potential of water- and alkaline-soluble brown carbon in smoke particles emitted from laboratory simulated biomass burning
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-17
    Xingjun Fan, Meiju Li, Tao Cao, Chongchong Cheng, Feiyue Li, Yue Xie, Siye Wei, Jianzhong Song, Ping'an Peng

    Biomass burning (BB) is an important source of brown carbon (BrC) in atmospheric aerosols. The aim of this study is to investigate the light absorbing ability and oxidative potential of BB-derived BrC fractions (including not only the water soluble fraction but the water-insoluble ones). For this purpose, BrC fractions in the smoke particles (PM2.5) generated from burning of crop residues (rice straw, wheat straw, and corn straw) and wood stems (pine wood and Chinese fir) were sequentially extracted and fractionated into water- and alkaline-soluble extracts, and water- and alkaline-soluble humic-like substances (HULISWS and HULISAS). Their organic carbon (OC) contents, light absorption, and oxidative potential were comparably investigated. The results showed that the OC within water extracts (WSOC) and alkaline extracts (ASOC), and HULISWS and HULISAS accounted for 24.8%–28.5%, 10.7%–15.3%, 12.4%–16.6%, and 2.2%–5.6% of the BB smoke PM2.5 mass, respectively, thereby indicating that BB potentially influenced the atmospheric water-soluble and alkaline-soluble BrC levels. The BrC fractions had similar absorption patterns, but they also exhibited distinct features. BrC SUVA254 decreased in the order of: HULISAS (3.68–4.58 m2/gC) > HULISWS (2.99–3.72 m2/gC) > WSOC (2.54–2.80 m2/gC) > ASOC (1.30–2.06 m2/gC). BrC MAE365 was in the order of: HULISAS (1.95–2.40 m2/gC) > HULISWS (1.12–1.60 m2/gC) > WSOC (0.86–1.23 m2/gC) and ASOC (0.54–0.95 m2/gC). These results suggest that the HULIS fractions exhibited high aromaticity and strong light absorption. Moreover, BB extractable fractions exhibited a strong oxidative potential to generate reactive oxygen species, and the dithiothreitol activity followed the order of: water extracts (12.5–20.6 pmol/min/μg) > alkaline extracts (9.3–16.2 pmol/min/μg) > HULISWS (6.6–10.7 pmol/min/μg) > HULISAS (3.7–7.1 pmol/min/μg). The chemical characteristics of the BB BrC fractions also varied among the biomass types, where the crop residue smoke PM2.5 contained more BrC than wood smoke PM2.5, but the water-soluble BrC in the former generally exhibited weaker light absorption than the latter.

    更新日期:2018-09-18
  • Straw removal reduces the mulch physical barrier and ammonia volatilization after urea application in sugarcane
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-18
    Patrick Leal Pinheiro, Sylvie Recous, Guilherme Dietrich, Douglas Adams Weiler, Roberta Lago Giovelli, Ana Paula Mezzalira, Sandro José Giacomini

    Crop residues left as mulch on the soil surface generally increase the risk of ammonia (NH3) volatilization from fertilizer-N, but the roles of mulch as a physical barrier and as a biological support of N transformation are not well known, particularly in response to straw removal. Thus, our goal was to assess how NH3 volatilization from urea-N was affected by different amounts of residues left on the soil surface after harvest in the sugarcane crop by mimicking different rates of straw removal. We ran a replicated field experiment during two consecutive years in the first ratoon sugarcane with 4 amounts of straw (0, 4, 8 and 12 Mg dry matter ha−1) and with 0 or 100 kg urea-N ha−1. Over approximately 2 weeks, we measured the NH3 emissions, levels of inorganic N in soil and water-soluble total N and NH4+ of straw. The dynamics of N in the soil and in straw supported the hypothesis that mulch acts as a physical barrier to the incorporation of urea in soil but also that NH3 emissions occurred directly from the mulch. The NH3 losses were different according to rain pattern of each year, but we showed that the emissions of NH3 were higher with higher amounts of straw (12 > 8 > 4 > 0) for both years (9.2–27.6% in 2016 and 30.7–60.8% in 2017). These results suggest that straw removal contributes to a reduction in NH3-N losses, but since total straw removal is not a recommended practice, N fertilization strategies should be implemented in systems with residue mulches on the soil surface to prevent N loss and to improve the environmental footprint of these cropping systems.

    更新日期:2018-09-18
  • Comparative study of the airborne microbial communities and their functional composition in fine particulate matter (PM2.5) under non-extreme and extreme PM2.5 conditions
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-18
    Azilah Abd Aziz, Kwangyul Lee, Byeonghyeok Park, Hongjae Park, Kihong Park, In-Geol Choi, In Seop Chang
    更新日期:2018-09-18
  • Use of networks of low cost air quality sensors to quantify air quality in urban settings
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-18
    Olalekan Popoola, David Carruthers, Chetan Lad, Vivien Bright, Iqbal Mead, Marc Stettler, John Saffell, Roderic Jones

    Low cost sensors are becoming increasingly available for studying urban air quality. Here we show how such sensors, deployed as a network, provide unprecedented insights into the patterns of pollutant emissions, in this case at London Heathrow Airport (LHR). Measurements from the sensor network were used to unequivocally distinguish airport emissions from long range transport, and then to infer emission indices from the various airport activities. These were used to constrain an air quality model (ADMS-Airport), creating a powerful predictive tool for modelling pollutant concentrations. For nitrogen dioxide (NO2), the results show that the non-airport component is the dominant fraction (∼75%) of annual NO2 around the airport and that despite a predicted increase in airport related NO2 with an additional runway, improvements in road traffic fleet emissions are likely to more than offset this increase. This work focusses on London Heathrow Airport, but the sensor network approach we demonstrate has general applicability for a wide range of environmental monitoring studies and air pollution interventions.

    更新日期:2018-09-18
  • Impacts of O3 on premature mortality and crop yield loss across China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-15
    Yuanye Lin, Fei Jiang, Jing Zhao, Ge Zhu, Xiaojing He, Xiaolin Ma, Shan Li, Clive E. Sabel, Haikun Wang

    Exposure to ambient ozone (O3) is a risk factor for public health and causes damage to vegetation, including agricultural crops. In this study, we performed a comprehensive estimate of the spatial distribution of premature deaths and main crop yield losses attributed to ambient O3, across China in 2014, by applying the Global Burden of Diseases approach and AOT40 metric (i.e., above a threshold of O3 concentration of 40 ppb). Our results show that China's total premature deaths in 2014 due to COPD attributed to O3 exposure were 89,391 (CI95: 32,225–141,649) with spatial variation across provinces. O3 induced production losses from all crops were 78.4 million metric tons, and the relative yield losses ranged from 8.5 to 14.0% for winter wheat, 3.9–15.0% for rice, and 2.2–5.5% for maize. The top four Chinese provinces (Sichuan, Shandong, Henan and Hunan) for premature deaths attributed to O3 pollution also suffered severe losses in yields of winter wheat and rice. Our results provide quantitative evidence of O3 induced impacts on both the public health and crop yields across Chinese provinces, which have important policy implications for the government to alleviate O3 pollution in addition to PM2.5 pollution that is currently being addressed.

    更新日期:2018-09-17
  • Quantifying impacts of crop residue burning in the North China Plain on summertime tropospheric ozone over East Asia
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-15
    Mingliang Ma, Kaixu Bai, Fengxue Qiao, Runhe Shi, Wei Gao

    Crop residue burning has been proved to have negative impacts on regional atmospheric environment. In this study, an evidence-based statistical modeling framework was established to quantify potential impacts of crop residue burning in the North China Plain (NCP) on summertime tropospheric ozone increase over East Asia during 2004–2016. To assess the intensity of crop residue burning, fire occurrence counts derived from the MODerate-resolution Imaging Spectroradiometer onboard the Terra and Aqua satellites were used as a proxy. Additionally, another six factors were employed as potent explanatory variables. Maximum covariance analysis was first applied to decouple spatiotemporal interactions between tropospheric ozone and each explanatory variable. Based on the decoupled modes, multivariate linear regression (MLR) and artificial neural network (ANN) were used to establish statistical relationships between tropospheric ozone and contributing factors, respectively. The results indicate that the ANN-based modeling scheme enables to approximate the observed tropospheric ozone variations better than MLR. Further investigations reveal that the summertime crop residue burning in the NCP is the predominant factor contributing to the observed additive tropospheric ozone increases over East Asia, yielding extra 8% tropospheric ozone elevation on average in June. Moreover, UV radiation and wind also played critical roles in modulating the observed tropospheric ozone variations therein. In general, the critical role of crop residue burning over the NCP in modulating summertime tropospheric ozone increase over East Asia have been well demonstrated based on the proposed evidenced-based modeling framework.

    更新日期:2018-09-17
  • Isotopic signature of atmospheric phosphate in airborne tree pollen
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-14
    Laura Bigio, Alon Angert

    In non-desert areas primary biological aerosol particles, including pollen, are an important source of phosphorus (P). During the flowering season large quantities of pollen from wind pollinated trees, are observed in boreal and temperate lakes and forest, which contain high P concentrations. However, there are different estimations for the contribution of pollen to the atmospheric P cycle, and there is no accepted method for the identification of phosphate from pollen origin. In this study we measured the P concentrations in pollen from various locations. In addition, the oxygen stable isotopes ratio in phosphate (δ18OP) was measured for the first time for both the bioavailable pool (P extractable by anion-exchange resin), and for the HCl-extractable pool. The resin and HCl-extractable δ18OP values were on average (±SE) 25.6 ± 3.4‰, and 25.8 ± 2.9‰, which are distinctively higher than mineral dust δ18OP values (average 22.1 ± 0.7‰). Pollen unique isotopic signature in phosphate can be used as a tool to identify P in aerosols from pollen origin, and hence to better understand the atmospheric P cycle. The high P concentrations found in this study (average (±SE) resin-P and HCl-P values were 0.67 ± 0.10 and 0.75 ± 0.9 mg P g−1), confirm that pollen is important to the atmospheric P budget, and can help to solve the uncertainties regarding its role in the global P cycle.

    更新日期:2018-09-15
  • Investigation of high ozone events due to wildfire smoke in an urban area
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-14
    Crystal D. McClure, Daniel A. Jaffe
    更新日期:2018-09-14
  • On particle-bound polycyclic aromatic hydrocarbons (PPAH) and links to gaseous emissions in Mexico city
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-14
    Luis A. Ladino, Graciela B. Raga, Darrel Baumgardner
    更新日期:2018-09-14
  • Optical property variations from a precursor (isoprene) to its atmospheric oxidation products
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-12
    Yaling Zeng, Zhenxing Shen, Tian Zhang, Di Lu, Guohui Li, Yali Lei, Tian Feng, Xin Wang, Yu Huang, Qian Zhang, Hongmei Xu, Qiyuan Wang, Junji Cao
    更新日期:2018-09-13
  • Factors affecting relative humidity and its relationship with the long-term variation of fog-haze events in the Yangtze River Delta
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-12
    Weijia Liu, Yongxiang Han, Jiaxin Li, Xinru Tian, Yangang Liu

    Relative humidity (RH) is one of the most important parameters in the study of fog-haze. This paper first estimates the contributions of the key quantities (temperature, water vapor, air pollutant) and their combinations to the relative change of RH, and then investigates the relationships of RH with the long-term variation of haze and fog days based on the meteorological data in the Yangtze River Delta over the period 1970–2010. The main conclusions are as follows. (1) Temperature is the foremost factor influencing RH, with the effect of specific humidity and direct contribution of air pollutant being second and third. (2) RH shows a prominent descending trend in the Yangtze River Delta, due to global warming and the ‘analogous heat island effect’ (AHIE). (3) Decreasing RH was responsible for the reduction of fog days. The AHIE can explain the phenomenon in which fog days in metropolises are less than in small cities. (4) Granger causality analysis of inter-annual variation further shows that increasing aerosol loading Ganger-causes the increasing haze days, rather than meteorological parameters such as RH. High RH would enhance hygroscopic growth of particle and then suppress the planet boundary layer height (PBLH) and lead to more haze days, lower PBLH further increases aerosols and RH, this positive feedback mechanism can be established under the condition of aerosol loading being relatively stable and beyond the threshold for haze formation. (5) If aerosol emissions maintain the status quo, climate cooling would result in serious fog-haze events occurring more frequently in Yangtze River Delta. The research provide a scientific basis for understanding the influence of meteorological factors on RH and the connection between the variation of long term fog-haze days and RH under the background of climate change.

    更新日期:2018-09-13
  • Analysis of atmospheric visibility degradation in early haze based on the nucleation clustering model
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-13
    Quan Xue, Zhong Lan, Shijun Lian, Yansong Chen, Kejian Cao, Zongchang Zhao, Xuehu Ma

    The initial nucleation of ultrafine particle recently attracts more attention as a key factor in visibility degradation during early haze. In this study, we have performed Density Functional Theory (DFT) calculation to investigate the particle-induced initial nucleation process during early haze. Our calculation results show that the water molecules aggregate surrounding nuclei to form heterogeneous cluster under a certain RH, the synergistic effect of multiple-bonding interactions makes heterogeneous cluster incline to form and stably exist with lower total energy as well as approximately 3–10 times expansionary volume, the hygroscopic growth of aerosol particles would play an important role in affecting the atmospheric visibility. The electron cloud density transferring from the exterior H2O molecule to the interior nuclei in the cluster is characterized by migration effect or nonuniform distribution. The decreasing energy gap between the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) in the heterogeneous cluster would lead to a red-shifted absorption wavelength λmax. It exerts the blue, indigo and violet visible-light absorption of corresponding wavelength for NO, NO2, NO3− and O3 heterogeneous clusters to enhance light extinction, thus contributing to visibility degradation, during early haze periods. It helps to intensify the color-enhancing effect of visible light with longer wavelength, such as red, orange as well as yellow light, to promote the evolution of early haze in clean weather period. This study shows that one of the important mechanisms of atmospheric visibility degradation in haze event is the heterogeneous cluster formation in the size range of about 2–4 nm during initial nucleation stage. Our results highlight that prevention of gas-phase chemical species (NO, NO2 and SO2) emission, and also regulatory controls of the concentrations of NO3−, O3 in atmosphere are necessary to prevent deterioration of the air quality in future.

    更新日期:2018-09-13
  • 更新日期:2018-09-13
  • Aeolian dust chemistry and bacterial communities in snow are unique to airshed locations across northern Utah, USA
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-13
    D.B. Dastrup, G.T. Carling, S.A. Collins, S.T. Nelson, D.P. Fernandez, D.G. Tingey, M. Hahnenberger, Z.T. Aanderud

    Wind-blown dust is an important source of trace metals, nutrients, and biological material to montane ecosystems. Mountain ranges in northern Utah are located downwind of multiple dust sources including the Great Basin Desert and the Wasatch Front urban area, providing an opportunity to investigate regional-scale differences in dust deposition chemistry and bacterial composition. We sampled discrete dust layers from snowpack across multiple locations in the Wasatch and Uinta Mountains (Utah) and the Snake Range (Nevada) during spring 2014 and 2015. Dust chemistry was unique in each airshed, suggesting that spatial variability and local sources were more important than temporal variability for the sampling period. The central Wasatch dust contained the highest concentrations of playa-associated elements (U, Mg, Li, Ca, Sr, As) and anthropogenic elements (Sb, Cu, Pb, Se) compared with lowest concentrations of these elements in the northern Wasatch, which is further from playa and anthropogenic sources. Sequential extractions indicate that the majority of Ca, Sr, and Cd is potentially available for transport during snowmelt while other elements are relatively immobile. Central Wasatch dust was more reactive to acetic acid than northern Wasatch dust for most elements, including REE + Y. Sr isotopes (87Sr/86Sr ratios) were also unique to each sampling area, with the most radiogenic values in the central Wasatch. Similar to dust chemistry, bacterial communities in dusty snow reflected geographically localized dust events. In the central Wasatch, 69% of bacterial species were unique, suggesting that the airshed received the most diverse dust inputs from a combination of playa and anthropogenic sources. Gram-positive Actinobacteria and Firmicutes were common in snow but specific bacterial families distinguished airsheds (e.g., Bacillaceae, Geodermatophilaceae, Nakamurellaceae). Our results demonstrate that evaluating dust chemistry and bacteria in snow on a regional scale may more clearly link dust sources to the entrainment of pollutants and seeding of bacteria species to montane systems.

    更新日期:2018-09-13
  • Nitrate photolysis in ice and snow: A critical review of its multiphase chemistry
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-12
    Christopher S. Blaszczak-Boxe, Alfonso Saiz-Lopez

    Nitrate, a member of the oxidized nitrogen family (NOy), is one of the primary species involved in the nitrogen cycle and thus plays a key role in ecosystem processes, globally. It exists as nitrate salts and as nitric acid (HNO3) in both aerosols and the gas phase. It is formed from the NO3 radical/N2O5 or directly from the oxidation of NO2 and is lost by photolysis, OH oxidation, and deposition. In regions covered with snow/ice it has a significant impact on air quality, atmospheric oxidizing capacity, greenhouse gas concentrations, and paleoclimate/isotopic data. Snow/ice environments can, at seasonal maximum, comprise ∼30% of Earth's surface area while 10% is covered with ice/snow found at the polar cryosphere. Nitrate makes up 75–100% of the nitrogen budget deposited from the atmosphere and measured at the Arctic and Antarctica. Its concentrations in Greenland ice have risen by a factor of 2–3, reflecting the long-ranged transport of increased anthropogenic NOx (NO + NO2) emissions.The polar cryosphere is an active medium for the movement of traces gases, such as nitrate, between the snowpack/sea-ice and overlying atmosphere. Field, laboratory, and modeling efforts have quantitatively shown that the exchange of trace species between the snowpack and the air above is governed by photochemistry in combination with air moving gases between these two matrices. Polar tropospheric chemistry and dynamics immensely impact processes governing chemical composition, isotopic signatures, oxidizing capacity, and thus regional climate. This study presents a comprehensive review of laboratory and modeling efforts – contextualized by field measurements – that have elucidated physicochemical processes governing nitrate photochemistry and its impact on the polar snowpack. Specifically, after an Introduction to nitrate photochemistry in ice, we discuss the: 1) initial Arctic field measurements that sparked interest in ice photolysis in the polar regions; 2) suite of follow-up field studies that catalyzed laboratory and snow-chamber investigations that gave deeper understanding of the effects of snow/ice – air trace gas exchange due to nitrate photochemistry; 3) complementary laboratory, snow-chamber investigations; and 4) a detailed review of recent nitrate ice photolysis laboratory experiments and the potential impact of utilizing laboratory and computational models to study the role of nitrate in the nitrogen cycle.

    更新日期:2018-09-12
  • Is oil temperature a key factor influencing air pollutant emissions from Chinese cooking?
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-11
    Yuejing Zhao, Chen Chen, Bin Zhao

    Cooking is an important source of air pollutants in Chinese residences. Cooking emissions are influenced by many factors, among which oil temperature is one of the most influential. In this study, 15 typical Chinese dishes, prepared using oil-based cooking methods (stir-, pan- and deep-frying), were chosen. The experiment was repeated three times with each dish—freshly prepared for each subsequent analysis—considering five key factors, to determine the emission rates of fine particulate matter (PM2.5), ultra-fine particles (UFPs), formaldehyde, and total volatile organic compounds (TVOC). The oil temperature and oil consumption were measured. A partial correlation analysis was performed to identify the influence of oil temperature on air pollutant emission rates during Chinese residential cooking. The zero-order correlation coefficients for all air pollutants, excluding UFPs, and partial correlation coefficients for all air pollutants, were not significant, implying that the influence of oil temperature on air pollutant emission rates was not significant, because practical peak oil temperatures (112–177 °C) were mostly below the oil smoke point (107–234 °C).

    更新日期:2018-09-11
  • Development of a fetch dependent sea-spray source function using aerosol concentration measurements in the North-Western Mediterranean
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-11
    S. Laussac, J. Piazzola, G. Tedeschi, C. Yohia, E. Canepa, U. Rizza, A.M.J. Van Eijk

    The aim of this paper is to determine an accurate formulation for the sea-spray source function characteristic for the North-Western Mediterranean. To this end, the MACMod aerosol transport model was implemented in the study area using different sea-state dependent flux formulations. The simulations were compared to a large data set of aerosol size distributions acquired over the last ten years in the study area, yielding the evolution of the sea-spray concentrations with increasing fetch and hence, with the development of the wave field. This allowed for an improvement of the Demoisson et al. (2013) sea-spray source function (S3F) for the Mediterranean. The new formulation extends its validity to shorter fetch and larger radii and turned out to be most suitable for predicting the atmospheric concentrations of sea-spray aerosols in this region.

    更新日期:2018-09-11
  • Sugarcane burning emissions: Characterization and emission factors
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-11
    Violeta Mugica-Álvarez, Francisco Hernández-Rosas, Miguel Magaña-Reyes, Jorge Herrera-Murillo, Naxieli Santiago-De La Rosa, Mirella Gutiérrez-Arzaluz, José de Jesús Figueroa-Lara, Griselda González-Cardoso
    更新日期:2018-09-11
  • Characterization of PM2.5 and gaseous emissions during combustion of ultra-clean biomass via dual-stage treatment
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-10
    Young-Joo Lee, Ju-Hyoung Park, Gyu-Seob Song, Hueon Namkung, Se-Joon Park, Joeng-Geun Kim, Young-Chan Choi, Chung-Hwan Jeon, Jong Won Choi
    更新日期:2018-09-11
  • Source impact modeling of spatiotemporal trends in PM2.5 oxidative potential across the eastern United States
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-07
    Josephine T. Bates, Rodney J. Weber, Vishal Verma, Ting Fang, Cesunica Ivey, Cong Liu, Stefanie E. Sarnat, Howard H. Chang, James A. Mulholland, Armistead Russell

    Oxidative potential (OP) of particulate matter measures the ability of particles to catalytically generate reactive oxygen species while simultaneously depleting antioxidants, leading to oxidative stress and, in turn, inflammation in the respiratory tract and cardiovascular system. OP measurements have been linked with adverse cardiorespiratory endpoints, such as asthma/wheezing, lung cancer, and ischemic heart disease. However, measurements of OP are limited, restricting the area over which epidemiologic analyses can be performed. In this work, a modeling approach is developed and evaluated that uses limited measurements of water-soluble OP and PM2.5 source impact analysis to estimate OP over a large spatial domain (eastern United States). The dithiothreitol (DTT) assay was used to measure daily OP of water-soluble PM2.5 from June 2012 to July 2013 across four sites in the southeastern United States. Daily PM2.5 source impacts were estimated using CMAQ-DDM during the same time period and related to OPDTT measurements via multivariate linear regression. This regression was then applied to spatial fields of daily CMAQ-DDM source impacts across the eastern United States to provide daily spatially-varying OPDTT estimates. Backward selection during regression development showed vehicle and biomass burning emissions to be significantly predictive of OPDTT, as observed in previous studies. The fire source impact was the largest contributor to OPDTT (29%) across the study domain during the study time period, and both spatial and seasonal variations were largely driven by fires. Vehicular impacts, especially diesel impacts, were more significant in urban areas. This CMAQ-DDM modeling approach provides a powerful tool for integrating OP measurements from multiple locations and times into a model that can provide spatio-temporal exposure fields of OPDTT across a wide spatial domain for use in health analyses, and the results offer insight into the large-scale spatial distribution of OPDTT driven by emission source impacts.

    更新日期:2018-09-09
  • Particulate matter in air at indoor go-kart facilities in Bavaria, Germany
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-07
    Marina Sysoltseva, Richard Winterhalter, Janine Wolf, Knut Berlin, Saskia Eckert, Ludwig Fembacher, Wolfang Matzen, Lutz Nitschke, Christina Scheu, Hermann Fromme
    更新日期:2018-09-09
  • Responses of secondary aerosols to relative humidity and photochemical activities in an industrialized environment during late winter
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-06
    Yangzhou Wu, Xinlei Ge, Junfeng Wang, Yafei Shen, Zhaolian Ye, Shun Ge, Yun Wu, Huan Yu, Mindong Chen

    Secondary aerosols often dominate fine aerosol mass, elucidation of their chemical characteristics is thus important. In this work, we measured submicron aerosols (PM1) by using an Aerodyne high resolution soot-particle aerosol mass spectrometer during late winter (February–March 2015), in a suburban site of Nanjing, China surrounded by industry plants. We found that under such environment, PM1 was predominantly comprised of secondary species (on average 80.6%). Investigations on the relationships of nitrate/sulfate and relative humidity (RH) suggest that moisture can play a significant role to enhance their formations. The organic aerosol (OA) occupied ∼1/4 of total PM1 mass, and primary OA (POA) and secondary OA (SOA) contributed almost equally. The most abundant OA factor, which was the one with highest oxidation degree, responded positively to RH but not to photochemical activities, indicating it was driven by aqueous-phase processing; while the other two less oxygenated SOA factors behaved oppositely, probably were governed by photochemical processing. Peak sizes of sulfate, nitrate and OA all shifted towards larger sizes with the increases of RH, again reflecting the effects of aqueous-phase processing. Overall, aqueous-phase driven secondary aerosols appeared to be very important in enhancing PM1 pollution, while photochemical processed SOA was important to OA pollution, leading to a fresher OA at higher OA concentrations. We further demonstrated the influences of aqueous-phase and photochemical processes on secondary aerosol characteristics by using two cases, respectively. This work points out the importance of aqueous-phase chemistry on sulfate and nitrate formations, and different portions of SOA can be dominated by different mechanisms in an industrialized environment.

    更新日期:2018-09-07
  • Atmospheric SO2 oxidation by NO2 plays no role in the mass independent sulfur isotope fractionation of urban aerosols
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-06
    D. Au Yang, G. Bardoux, N. Assayag, C. Laskar, D. Widory, P. Cartigny
    更新日期:2018-09-06
  • Stable carbon and nitrogen isotope compositions of bulk aerosol samples over the South China Sea
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-05
    Hong-Wei Xiao, Hua-Yun Xiao, Li Luo, Zhong-Yi Zhang, Qi-Wei Huang, Qi-Bin Sun, Zi-qi Zeng

    The marine aerosols is mainly produced primary sea salt and secondary form of non-sea salt (nss) sulfate and organic species from marine emission, but get modified significantly by the anthropogenic and terrestrial materials, such as total carbon (TC) and total nitrogen (TN), which transported by the atmospheric circulation from land to the ocean. Rarely studies focus on the total carbon (TC) and total nitrogen (TN) in marine aerosol in the open ocean due to the sampling difficulty, let alone the annual observation. Concentrations of TC and TN, and their isotope compositions (δ13C-TC and δ15N-TN) were measured in total suspended particulate (TSP) which sampled at Yongxing Island over the South China Sea from March 2014 to February 2015, and coastal mega-city Guangzhou in April/May and October/November 2014. The annual average concentrations of TC and TN at Yongxing Island were 4.20 ± 2.38 μg m−3 and 0.77 ± 0.47 μg m−3, respectively. Much higher concentration of TC and TN were observed at Guangzhou. Contributions of NO3− and NH4+ (inorganic nitrogen, IN) to TN at Yongxing Island averaged 55.7% and 6.8%, respectively, while they averaged 27.4% and 12.2% at Guangzhou, respectively. The average values of δ15N in TN were +0.7 ± 3.3‰, +6.8 ± 6.3‰ and −0.7 ± 2.7‰ during winter, transitional and warm seasons, respectively, with an annual average value of +1.1 ± 4.3‰. The δ13C of TC varied from −16.2 to −26.8‰, with an annual average value of −22.7‰. The average of values of δ13C were −22.9 ± 1.7‰, −22.9 ± 1.4‰, and −22.4 ± 2.6‰ during winter, transitional and warm seasons, respectively. The average values of δ15N in TN and δ13C of TC were +13.2 ± 0.9‰ and −25.8 ± 0.4‰ in winter season, +13.6 ± 0.8‰ and - 26.5 ± 0.3‰ in warm season at Guangzhou, respectively. Based on aerosol δ15N and δ13C values, the marine realm may be an important source of aerosol TN, while aerosol TC may dominantly contributed by the combustion of fossil fuels and biomass burning from continental mass over the South China Sea. The secondary aerosol formation and long-range transport on aerosol chemistry also varied the concentrations and isotopic composition of TN and TC at Yongxing Island.

    更新日期:2018-09-05
  • Temporal variations, sources and tracer significance of Polonium-210 in the metropolitan atmosphere of Beijing, China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-05
    Jie Ouyang, Li-Juan Song, Ling-Ling Ma, Min Luo, Yang Shao, Xiong-Xin Dai, Guo-Sheng Yang, Yong-Gang Yang, Mao-Yi Luo, Dian-Dou Xu
    更新日期:2018-09-05
  • Appraising the effects of atmospheric aerosols and ground particulates concentrations on GPS-derived PWV estimates
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-05
    Yahaya A. Aliyu, Joel O. Botai

    In 2016, three Nigerian cities were listed amongst the World's most polluted in terms of particulate matter (PM). Acknowledging Nigeria's limited resources for outdoor air pollution monitoring, this study attempts to investigate the effects on atmospheric aerosol optical depth and ground PM on GPS derived-precipitable water vapour estimates. The study utilized available GPS-derived precipitable water vapour (GPSPWV), the moderate resolution imaging spectroradiometer aerosol optical depth (MODISAOD) and the ground level particulate matter of less than 10 μm (GPM) datasets for December 2015–November 2016. All the datasets were tested for normality. To evaluate the atmospheric aerosol properties, the MODISPWV estimates were pre-validated using the GPSPWV measurements. The results revealed GPSPWV-MODISPWV agreement (R = 0.964; RMSE = 3.810 mm). The GPSPWV-MODISAOD analysis showed relationship (R ≤ −0.636; RMSE ≤ 0.563) for the atmospheric aerosol experiment, while the collocating GPSPWV-GPM seasonal analysis also revealed significant correlation (R < −0.660). The correlation of combined seasonal datasets for the GPSPWV-MODISAOD and GPSPWV-GPM relationships showed high negative correlation values of 0.79 and 0.68 respectively. The findings of this study is in agreement with similar related studies, as well as serve as future position accuracy for similar related studies.

    更新日期:2018-09-05
  • Springtime Beryllium-7, meteorology, and ozone variability in the southeastern United States
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-04
    G.M. Hidy, C.L. Blanchard, E. Edgerton

    Ground level 24 h average observations of 7Be activity, combined with continuous ozone (O3), carbon monoxide (CO) and minimum relative humidity (minRH) measurements, were conducted at two non-urban sites in the Deep South of the United States. One site is inland at Yorkville, Georgia, YRK (33°55′27″N; 84°59′44″W); the other is near the coast of the Gulf of Mexico outside Pensacola, Florida, OLF (30°25′N:87°13′W). The objective of the measurements was to explore the potential for estimating a contribution to surface O3 from stratospheric and upper tropospheric air for during the springtime months from April 2 to June 13, 2015 using 7Be as a tracer. The observed 24 h average 7Be activities were 1.88 ± 0.66 mBq/m3 at YRK and 1.99 ± 0.68 mBq/m3 at OLF. Corresponding means of 24 h average O3 mixing ratios were 38.3 ± 10.1 ppbv for YRK and 28.7 ± 8.9 ppbv at OLF. A weak statistically significant O37Be regression based estimate of O3 from the stratosphere and upper troposphere was constrained to a conservative upper bound of 14 ± 4 (1σ) ppbv. From daily inspection of meteorological features, a lower bound of 3–7 ppbv was estimated. A multiple regression of O3 versus 7Be and daily minimum relative humidity (minRH) improved the statistical fit and indicated stratosphere-upper troposphere contributions of 8.6 ± 4.0 ppbv for YRK and 6.6 ± 3.3 ppbv for OLF. Daily variability of 7Be and O3 was explored with respect to meteorological variability. 7BeO3 relationships in this experiment were examined using (a) ozonesonde and vertical dew point temperature profiles, inferring very dry air as an upper atmosphere tracer descending into the boundary layer, (b) backward air trajectories, identifying 7Be spatial and temporal variation, and (c) precipitation, indicating 7Be scavenging and lowered O3 with suppression of photochemistry. The average 7Be measurements at the ground during the study are useful for helping estimate the long-term O3 contributions from the upper atmosphere. However, the day-to-day 7Be observations had limited value for determining the contributions of upper air O3 to daily O3 mixing ratios. Conventional surface and upper-air meteorological data could be used effectively as an alternative.

    更新日期:2018-09-04
  • Human exposure to airborne particles during wood processing
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-01
    Jianwei Gu, Ina Kirsch, Tobias Schripp, Frank Froning-Ponndorf, Dirk Berthold, Tunga Salthammer

    Wood processing has been known to emit a large amount of inhalable wood dust, but the emissions of particles with diameters smaller than 10 μm and ultrafine particles (UFP, particles with diameters smaller than 100 nm), as well as their exposure levels, remain unclear. The present study measured the particle profiles from 5.6 nm to 10 μm from wood processing in a pilot plant and in the wood industry, respectively. Large increase of particle number concentrations (PNC) was observed during pilot scale refinery, flaking, cross hammer mill, chipping and sawing, but not during sieving, drying, gluing and pressing, when comparing with background PNC. In the wood industry (one sawmill and one wood-based panel factory), we observed high PNCs, and in some production sites (chipping, MDF form station, MDF press station) high particle mass concentrations (PMCs). Human respiratory tract deposition modelling showed that the deposition of the particle surface area in the size range of 0.3–10 μm was mainly in the extrathoracic region, and the particle surface area in the size range of 5.6–560 nm was mainly deposited in the alveolar interstitial. Exposure of a few minutes when processing wood in the pilot plant can lead to a high particle dose. The particle dose for an 8-h exposure in the wood industry was much higher than urban background exposure scenarios, in some workplaces by a factor of about 50–100. This study gives first evidence that wood processing could emit a large number of UPF and particles <10 μm. Our results indicate that the current mass-based occupational exposure limit for wood dust is not able to reveal the high exposure to UFP and particles <10 μm.

    更新日期:2018-09-03
  • High-resolution ammonia emission inventories with comprehensive analysis and evaluation in Henan, China, 2006–2016
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-01
    Chen Wang, Shasha Yin, Ling Bai, Xichao Zhang, Xingke Gu, Huan Zhang, Qing Lu, Ruiqin Zhang
    更新日期:2018-09-03
  • Emissions of Volatile Organic Compounds from road marking paints
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-03
    Tomasz E. Burghardt, Anton Pashkevich
    更新日期:2018-09-03
  • Aerosol vertical profile retrieved from ground-based MAX-DOAS observation and characteristic distribution during wintertime in Shanghai, China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-31
    Jiawei Zhang, Shanshan Wang, Yanlin Guo, Ruifeng Zhang, Xiaofei Qin, Kan Huang, Dongfang Wang, Qingyan Fu, Jie Wang, Bin Zhou

    Multi-AXis-Differential Optical Absorption Spectroscopy (MAX-DOAS) measurements were performed to remote sensing the aerosol vertical profiles in suburb area of Shanghai, China from April to December 2017. The retrieval of aerosol extinction was based on the optimal estimation method combing the measured oxygen dimer O4 absorption with simulation of forward radiative transfer model. It suggests that the employment of O4 correction factor (CFO4) for daily aerosol retrieval should be adjusted, which includes three typical cases that a fixed CFO4, no usage of CFO4 and different CFO4 in the morning and afternoon. In cases of using CFO4, elevation angle dependent CFO4(α) were further proposed. Moreover, the retrieval results can be improved if the local sounding data of atmospheric temperature and pressure profiles were introduced into the forward radiative transfer model without utilizing additional CFO4. Afterwards, the retrieved Aerosol Optical Depth (AOD) and the surface Aerosol Extinction Coefficient (AEC) was in a good agreement with the AOD obtained from sun photometer observations and in-suit PM2.5 concentrations, with a correlation coefficient R of 0.866 and 0.833, respectively. Besides, the vertical AEC profiles retrieved by MAX-DOAS were also validated well by the co-located lidar measurement. It can be found that the particles were mainly distributed below 1 km, and the maximum AEC usually appeared in the lowest 300 m and decreased with the altitudes. The averaged AEC within 1 km varied from 0.20 to 0.75 km−1, 0.25 to 1.08 km−1, 0.55 to 2.45 km−1 and 0.70 to 2.75 km−1 under different air quality of Grade II,III, IV and V. The sounding meteorological parameters and backward trajectories of air masses were integrated to diagnose the influencing factor of AEC at different altitudes, which illustrated that the AEC levels at lowest layer were impacted by the long distance transportation of air pollutants from north-northwest and regional local air pollution nearby during the winter time. The study shows that ground-based MAX-DOAS observation is powerful remote sensing technique to provide better understanding of aerosol properties at both ground surface and higher altitudes.

    更新日期:2018-09-01
  • Characteristics of visibility-impairing aerosol observed during the routine monitoring periods in Gwangju, Korea
    Atmos. Environ. (IF 3.708) Pub Date : 2018-09-01
    Kyung Won Kim, Young J. Kim

    Aerosol chemistry measurements were performed during the routine monitoring periods in the urban atmosphere of Gwangju, Korea. Routine aerosol monitoring was carried out every sixth day in order to investigate the dependence of domestic sources and air mass transport characteristics on physicochemical and optical properties of atmospheric aerosol. Aerosol optical properties; atmospheric extinction and scattering coefficients were also measured continuously with a transmissometer and a nephelometer, respectively in order to investigate the causes of visibility impairment. Prevailing atmospheric condition was classified into four categories; one affected by stagnant condition (D), one affected by continental and domestic aerosols (CD), one affected by marine and domestic aerosols (MD), and one affected by continental, marine and domestic aerosols (CMD). Atmospheric condition type was further classified into thirteen sub-categories with the occurrences of episodic events such as Asian dust storm, biomass burning, and airborne pollen. The air mass types of D, CD, MD, and CMD were observed to be 11, 18, 43, and 78 events out of total 150 events, respectively. The fine mass concentration increased under continental air mass types. The average fine mass concentration of 23.0 ± 8.6 μg m−3 for CD type was slightly larger than that of 20.7 ± 5.2 μg m−3 for CMD type. Both of them were higher than that for D (18.9 ± 4.5 μg m−3) type. Increments of the fine mass concentrations for Asian dust storm (A) and Biomass-burning (B) events ranged from 141 to 151% and from 152 to 160% compared to those for D and CD types, respectively. The increments in the mass concentrations of nitrate, OC, EC, and BC for CD and CMD types in comparison with D air mass type were calculated to be approximately 17, 6, 8, and 22%, respectively. The mean mass extinction efficiency of PM10 was relatively higher in D (3.6 ± 1.6 m2 g−1) type and B events (4.1 ± 1.5 m2 g−1), but it was the lowest in MD air mass type. The aerosols observed in Gwangju were found to be influenced by the continental aerosol during the A events. Aerosol of CMD air mass type caused mainly poor visibility. The visibility reduction of Gwangju was influenced by the increase of carbonaceous particles under both domestically stagnant condition and air mass pathway from the continent. And ammonium sulfates and ammonium nitrates contributed the largest in CMD air mass type.

    更新日期:2018-09-01
  • Sources of atmospheric lead in and around an Indian megacity
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-30
    Reshmi Das, Ahmad Taufiq Bin Mohamed Mohtar, Dibyendu Rakshit, Debasish Shome, Xianfeng Wang

    Lead (Pb) is a toxic metal whose global anthropogenic fluxes are an order of magnitude higher than natural fluxes. Among all the environmental compartments, the atmosphere is the major initial recipient of Pb. To minimize the exposure to this toxic metal, it is important to determine the potential sources of atmospheric Pb. This study uses a multiproxy approach, Pb isotopes in conjunction with metal composition of aerosols to determine the possible sources of anthropogenic Pb in the atmosphere, in and around an Indian megacity, Kolkata. In Asia, India is the second largest atmospheric Pb emitter, after China through coal combustion. Indian automobile and high temperature metallurgy industries are growing rapidly and Pb emissions from India can be traced as far south as in Chagos Island in the Indian Ocean. This study investigates the anthropogenic sources of atmospheric Pb in eastern India at three locations along a 150 Km N-S stretch. The locations have very different environmental settings; a pristine river island, a megacity, and an industrial town. Pb isotope and metal compositions indicate different sources of atmospheric Pb for the three locations: gasoline exhaust from road and riverine traffic in the island, emissions from the high temperature metallurgy industry in the industrial town and long-range transport of coal combustion and industrial emissions for the megacity. The Pb isotope ratios (206Pb/207Pb = 1.1155–1.1681 and 208Pb/207Pb = 2.3905–2.4494) measured in this study have a wider range and are mostly higher than previously measured in Indian aerosols. Pb isotope compositions of two end members, Indian coal and road dust are also measured. This study shows that post leaded gasoline phase-out, the atmospheric Pb emissions in India are dominated by Indian coal combustion and ore processing.

    更新日期:2018-08-31
  • Spatial and temporal distribution of current-use pesticides in ambient air of Provence-Alpes-Côte-d’Azur Region and Corsica, France
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-31
    Marine Désert, Sylvain Ravier, Grégory Gille, Angélina Quinapallo, Alexandre Armengaud, Gabrielle Pochet, Jean-Luc Savelli, Henri Wortham, Etienne Quivet

    A total of 59 current-use pesticides were monitored in ambient air samples collected from February 2012 to December 2017, at two rural and six urban sites in Provence-Alpes-Côte-d’Azur Region and Corsica, France. 45 of searched active substances were detected at least in one sample, at frequencies ranging from 0.1 to 98.6%. Among the most frequently detected pesticides, we found the herbicide Pendimethalin (64.6%), the fungicide Tebuconazole (65.9%), and the insecticides Chlorpyrifos (71.5%) and Lindane (98.6%). A wide range of atmospheric concentrations was measured from few pg m−3 to several hundreds of ng m−3, with a maximum concentration of 407.79 ng m−3 for Chlorpyrifos (Cavaillon, May 2012). 17 active substances exceeded an atmospheric concentration of 1 ng m−3 for at least one sample, including Folpet (147 times/162 detections), Chlorpyrifos (56/520), and Pendimethalin (29/464). The spatial distribution shows that pesticides were detected both in the eight rural and urban sampling sites, suggesting an atmospheric transport from agricultural areas to cities. Classifying the 8 sampling sites according to samples composition, two types of site were observed, those (Aléria, Arles, Avignon, Port-de-Bouc, and Toulon) where a majority of fungicides are found and those (Cannes, Cavaillon, and Nice) where insecticides are dominant. Long-term (6 years) monitoring shows a seasonally trend for each pesticide, depending on pest pressure. Inter-annual variation suggests a downward trend which is consistent with the regional sales data.

    更新日期:2018-08-31
  • Evaluation of isoprene emission rates of tropical trees by an iterative optimization procedure for G-93 parameters
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-31
    Takuya Higa, Shahanaz Parveen, Ishmael Mutanda, Md Asif Iqbal, Masashi Inafuku, Fumio Hashimoto, Hirosuke Oku

    Isoprene emissions from six tropical trees were evaluated by “Ping-Pong” method that iteratively optimized the temperature (CT) and light (CL) parameters of the Guenther model, G-93. Six tropical trees; Bauhinia variegate (camel's foot tree), Calophyllum inophyllum (ball tree), Garcinia subelliptica (fukugi tree), Syzygium cumini (black plum), Syzygium samarangense (wax jambu), and Mangifera indica (mango; red and yellow fruit) were exposed to LED light in a phytotron. Saplings of Populus nigra were similarly treated under the same experimental conditions for reference. The irradiance protocol consisted of 26 steps and two cycles of increase and decrease in light intensity. Plants were exposed to a wide variation in light intensity (200–1500 μmol/m2/s), which resulted in leaf temperature variation of 29–40 °C. Predictions of isoprene emission by the optimized G-93 well captured the light and temperature dependent increase and decrease of isoprene emission rate in all tropical trees assessed. Comparatively, G-93 with default parameters showed lower efficacy in predicting emission rates during the ascending phase in the initial round, and at the peak phase in the second round of the irradiation scheme. G-93 with default parameters overestimated emissions at the initial ascending phase and underestimated at the second peak phase. Calculated Q10 values for isoprene emission from tropical trees were much higher than that of the temperate plant Populus nigra under same observational conditions. These results strongly imply that isoprene emission behavior of tropical plant deviates from that of temperate plant.

    更新日期:2018-08-31
  • Analyses of winter circulation types and their impacts on haze pollution in Beijing
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-30
    He Jianjun, Gong Sunling, Zhou Chunhong, Lu Shuhua, Wu Lin, Chen Ying, Yu Ye, Zhao Suping, Yu Lijuan, Yin Chengmei
    更新日期:2018-08-30
  • Distribution and dry deposition of alternative and legacy perfluoroalkyl and polyfluoroalkyl substances in the air above the Bohai and Yellow Seas, China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-30
    Xiangguang Fang, Qi Wang, Zhen Zhao, Jianhui Tang, Chongguo Tian, Yiming Yao, Junchao Yu, Hongwen Sun
    更新日期:2018-08-30
  • Assessing air-quality in Beijing-Tianjin-Hebei region: The method and mixed tales of PM2.5 and O3
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-30
    Lei Chen, Bin Guo, Jiasheng Huang, Jing He, Hengfang Wang, Shuyi Zhang, Song Xi Chen

    Motivated by a need to evaluate the effectiveness of a campaign to alleviate the notorious air pollution in China's Beijing-Tianjin-Hebei (BTH) region, we outline a temporal statistical adjustment method which is demonstrated from several aspects on its ability to remove the meteorological confounding existed in the air quality data. The adjustment makes the adjusted average concentration temporally comparable, and hence can be used to evaluate the effectiveness of the emission reduction strategies over time. By applying the method on four major pollutants from 73 air quality monitoring sites along with meteorological data, the adjusted averages indicate a substantial regional reduction from 2013 to 2016 in PM2.5 by 27% and SO2 by 51% benefited from the elimination of high energy consumption and high polluting equipments and a 20.7% decline of the coal consumption, while average NO2 levels had been static with a mere 4.5% decline. Our study also reveals a significant increase in the ground O3 by 11.3%. These suggests that future air quality management plans in BTH have to be based on dual targets of PM2.5 and O3.

    更新日期:2018-08-30
  • Day-of-week and seasonal patterns of PM2.5 concentrations over the United States: Time-series analyses using the Prophet procedure
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-29
    Naizhuo Zhao, Ying Liu, Jennifer K. Vanos, Guofeng Cao

    Fluctuations of ambient fine particulate matter (PM2.5) concentrations show clear yearly and weekly patterns, which has been revealed by previous studies. However, reliability of those studies may be affected by their small research areas, short observation periods, and/or the lack of using specialized statistical approaches for time series. The current study applies a recently developed time-series analysis procedure, Prophet, to investigate seasonality of daily PM2.5 concentrations over nine years (2007–2015) measured at 220 monitoring stations across the United States. Prophet is a new tool for producing high quality forecasts from time series data that have characteristics of multiple temporal patterns with either linear or non-linear growth/decline. Through decomposing each PM2.5 time series into three major components (i.e., trend, seasonality, and holidays), we observed periodically changing patterns of PM2.5 concentrations weekly and yearly consistent with previous findings. Specifically, relatively high PM2.5 concentrations tend to appear in the month of January and on Fridays, and PM2.5 concentrations on Sunday are generally lower than those on most other days of the week. However, we discovered that high PM2.5 concentrations are also likely to appear in July. Additionally, compared to Fridays in most studies, the highest PM2.5 concentrations are found to more likely occur on Saturdays, while the lowest concentrations are found on Monday as universally as on Sunday. Beyond understanding the seasonality of PM2.5 concentrations, this study revealed the potential use of Prophet, originally designed for business time series, for detecting periodicities of environmental phenomena.

    更新日期:2018-08-30
  • Chemical characterization of PM10 samples collected simultaneously at a rural and an urban site in the Caribbean coast: Local and long-range source apportionment
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-29
    Yasser Morera-Gómez, David Elustondo, Esther Lasheras, Carlos Manuel Alonso-Hernández, Jesús Miguel Santamaría
    更新日期:2018-08-30
  • The impact of urban trees on concentrations of PAHs and other gaseous air pollutants in Yanji, northeast China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-29
    Vesa Yli-Pelkonen, Viljami Viippola, Anna-Lea Rantalainen, JunQiang Zheng, Heikki Setälä

    It is generally conceived that trees can clean polluted air in urban areas sufficiently enough to be considered providers of a vital ecosystem service, although there have not been many field studies showing this in practice in the neighbourhood scale. Using passive sampling methods, we investigated the effect of urban park trees on the concentrations of gaseous polycyclic aromatic hydrocarbons (PAHs), nitrogen dioxide (NO2), ground-level ozone (O3) and sulfur dioxide (SO2) in early summer in the temperate zone city of Yanji, northeast China. Concentrations of total gaseous PAHs and certain PAH constituents were higher and concentrations of O3 lower in tree-covered areas compared to nearby open areas, while tree cover did not affect the concentrations of NO2 and SO2. The higher PAH concentrations under tree canopies may associate with air-soil gas exchange and the trapping of polluted air under canopies. Lower O3 concentrations in tree-covered areas may result from a combination of absorption of O3 by tree canopies, and lower temperatures and solar radiation under tree canopies compared to open areas.

    更新日期:2018-08-30
  • Projecting the impacts of atmospheric conditions under climate change on air quality over Pearl River Delta region
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-29
    Cheuk Hei Marcus Tong, Steve Hung Lam Yim, Daniel Rothenberg, Chien Wang, Chuan-Yao Lin, Yongqin David Chen, Ngar Cheung Lau

    Anthropogenic climate change has been increasingly confirmed by weather observation and scientific literature in recent decades. Atmospheric stability, which has strong effects on vertical mixing of air pollutants and thus air quality, may be affected under climate change. This study aims to statistically assess the impacts of climate change alone on the future air quality in the Pearl River Delta region in the near future (2030–2039) and the far future (2090–2099) under two Representative Concentration Pathways (RCP) scenarios, i.e., RCP 4.5 and RCP 8.5, based on the future surface and upper level meteorological data projected by one regional climate model (RCM): WRF, and by four general circulation models (GCMs): CanESM2, MIROC, MRI-CGCM3 and MPI-ESM-LR. The arithmetic means of projections reveal an increase in the levels of air pollutants [ozone (O3), respirable suspended particulates (RSP) and sulphur dioxide (SO2)] in various seasons, even though a decrease is projected to occur in June-July-August. These changes in projected mean concentration are more significant in the far future, and under the RCP8.5 scenario. Among difference meteorological variables, surface temperature is most associated with the projected change in the three pollutants, with a range from 56.9% to 65.2% in all seasons and for all pollutants, relative to all contributions in RCP8.5 for example. Other notable associations include positive effects of vertical temperature gradient and the temperature-dew point difference on pollutant concentration. We found an increase in frequency of high pollution levels in December-January-February and March-April-May, as the occurrence proportion of pollutant concentration greater than the recent 95th percentile is 9.5%–9.6% and 6.4% - 9.2%, respectively. We conclude that climate change alone is projected to have significant effect on air quality in the Pearl River Delta region in future, implying the necessity of more stringent air pollutant emission control policies to mitigate air pollution in the future.

    更新日期:2018-08-30
  • The impact of biomass burning on total suspended particulate matter in the southeastern Tibetan Plateau
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-29
    Chong-Shu Zhu, Jun-Ji Cao, Zhi-Sheng Zhang, Sui-Xin Liu, Jia-Mao Zhou, Ping Wang, Jun Tao, Ting Zhang, Xiao-Li Su, Qi-Yuan Wang, Ning-Ning Zhang
    更新日期:2018-08-29
  • Technical notes: Quantification of nitrated-polycyclic aromatic hydrocarbons in atmospheric aerosol samples with in-injection port thermal desorption-gas chromatography/ negative chemical ionization mass spectrometry method
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-28
    Lijuan Li, Steven Sai Hang Ho, Yong Ming Han, Judith C. Chow, John G. Watson, Liqin Wang, Linli Qu, Junji Cao

    In-injection port thermal desorption (TD) was extended in determination of particulate phase nitrated-polycyclic aromatic hydrocarbons (N-PAHs) on filter samples coupled with a gas chromatography/negative ion chemical ionization-mass spectrometry (GC/NCI-MS). The experimental and analytical parameters were optimized with standard testing and ambient samples. Fourteen of the most abundant N-PAHs in ambient airs were included for their quantification. A desorption temperature of 280 °C for 10 min was sufficient to transfer entire target compounds from injection port to the analytical system. Good linearity (R2 >0.995) on the calibrations for each analyte was achieved. The limit of detections (LODs) ranged from 46.5 to 152.3 pg per filter sample, which were 4–66% better than solvent extraction (SE) approach. Method precision, repeatability and reproducibility, determined by replicate analyses of calibration standards and ambient samples, were less than 6% for target compounds. Validation of the method were conducted with two batches of a total of 30 ambient aerosol-loaded filters using our TD and the traditional SE approaches. Reasonably good agreement (R2 = 0.98) by the two methods was demonstrated for most of N-PAHs, except for 9-nitrophenanthrene and 6-nitrobenzo(a)pyrene. The in-injection port TD can improve laboratory efficiency and reduce solvent-based costs for the measurement of N-PAHs.

    更新日期:2018-08-29
  • Impact of river-dust events on air quality of western Taiwan during winter monsoon: Observed evidence and model simulation
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-28
    Chuan-Yao Lin, Yen-Huei Lee, Chung-Yih Kuo, Wan-Chin Chen, Yang Fan Sheng, Chiung-Jui Su
    更新日期:2018-08-29
  • Adjoint sensitivity of inland ozone to its precursors and meteorological and chemical influences
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-27
    Soon-Young Park, Changhyoun Park, Jung-Woo You, Soon-Hwan Lee, Hwa Woon Lee
    更新日期:2018-08-28
  • Analysis of SAPRC16 chemical mechanism for ambient simulations
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-27
    Melissa A. Venecek, Chenxia Cai, Ajith Kaduwela, Jeremy Avise, William P.L. Carter, Michael J. Kleeman

    SAPRC16 is an interim update to the SAPRC series of chemical mechanisms that includes updated rate constants, a revised representation of radical chemistry, and a new speciation lumping scheme to better develop predictions of SOA precursors. In this study, the ability of the SAPRC16 chemical mechanism to simulate regional ozone episodes is tested in seven (7) major cities across the United States. The UCD-CIT 3-dimensional (3D) airshed model was configured with both SAPRC11 (base mechanism) and SAPRC16 (updated mechanism). Concentrations of ozone, hydroxyl radical (OH) and hydroperoxyl (HO2) radical predicted with both mechanisms were compared to measured values. It was generally observed that SAPRC16 predicts slightly lower ozone concentrations than SAPRC11 in NOx rich urban centers. A box model analysis shows that the SAPRC16 mechanism quenches ozone production earlier than SAPRC11 as NOx concentrations increase (yielding decreasing VOC/NOx ratios). This could be caused by more detailed HO2+RO2 reactions and RO2 isomerization reactions in SAPRC16 that compete with the HO2+NO reaction. Predictions from SAPRC11 are in better agreement with the measurements in the western United States, however SAPRC16 outperforms SAPRC11 in some eastern and southern U.S. cities. These results may also be strongly influenced by the accuracy of emissions inventories in each region. Differences in ozone concentrations predicted by SAPRC16 and SAPRC11 increased as emissions decreased suggesting that the two mechanisms will predict different outcomes from future emissions control programs. In general, the SAPRC11 mechanisms slightly over-predicts OH concentration while under-predicting HO2 radical concentration and the SAPRC16 mechanism slightly under predicts OH and largely under predicts HO2, sometimes by large amounts. The reasons for this are unknown at this time. These features will influence the secondary organic aerosol (SOA) predictions from each mechanism since the branching between high NOx and low NOx regimes depends on calculated HO2 concentrations. Further analysis of the HO2+RO2 reactions and RO2 isomerization reactions and the reasons for the lower HO2 predictions in the updated SAPRC16 chemical mechanism should be carried out before widespread adoption of the new mechanism.

    更新日期:2018-08-28
  • A long-term source apportionment of PM2.5 in New York State during 2005–2016
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-26
    Stefania Squizzato, Mauro Masiol, David Q. Rich, Philip K. Hopke

    The development and implementation of effective policies for controlling PM2.5 mass concentrations and protecting human health depend upon the identification and apportionment of its sources. In this study, the PM2.5 sources affecting 6 urban and 2 rural sites across New York State during the period 2005–2016 were determined. The extracted profiles were compared to identify state-wide common profiles. The source contributions provide detailed, long-term quantification of the emission sources across the state during the investigated period (2005–2016). Seven factors were common to all sites: secondary sulfate, secondary nitrate, spark-ignition emissions, diesel emissions, road dust, biomass burning, and pyrolyzed organic (OP) rich. The largest contributors were secondary sulfate, secondary nitrate, spark-ignition (gasoline), diesel, and OP-rich. Secondary sulfate concentrations ranged from 2.3 μg m−3 at Whiteface to 3.2 μg m−3 at Buffalo and Bronx. The highest secondary sulfate fractional contributions were found at the rural sites (∼46% of PM2.5 mass) also showed the highest OP-rich contributions (∼19%). Secondary nitrate showed the highest concentrations at the urban sites representing ∼17% of PM2.5 mass (1.6 ± 0.3 μg m−3 on average). Urban sites also showed the highest average spark-ignition concentrations (1.7 ± 0.2 μg m−3, ∼18%) and diesel emissions (1.0 ± 0.2 μg m−3, ∼10%). During this period, secondary sulfate concentrations declined likely related to the implementation of mitigation strategies for controlling SO2 emissions and the changing economics of electricity generation. Similarly, diesel and secondary nitrate showed decreases in concentrations likely associated with the introduction of emissions controls and improved quality fuels for heavy-duty diesel on-road trucks and buses. Spark-ignition concentrations showed an increase across the state during 2014–2016 associated with the increase of registered vehicles in New York State.

    更新日期:2018-08-26
  • Factors affecting the concentration and distribution of gaseous elemental mercury in the urban atmosphere of downtown Toronto
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-24
    Daniel Prete, Matthew Davis, Julia Lu

    Atmospheric gaseous elemental mercury (GEM) and meteorological parameters were simultaneously monitored at two building rooftops in downtown Toronto, Canada from Oct. 2015 to Oct. 2016. The two buildings are ∼136 m apart, one is an office building (60 m tall) and the other (30 m tall) mainly contains chemistry and biology laboratories, offices and classrooms. The average mercury concentrations were found to be 1.46 ± 0.54 ng/m3 and 1.78 ± 0.89 ng/m3 for the 60 m and 30 m sites, respectively. Analysis of the data reveals that sporadic events of high mercury concentration are related to local sources; that the higher level of GEM at the 30 m site resulted from a combination of local sources and weaker mixing of air at lower height; regional sources contributed to the loading of GEM in urban atmosphere. Comparing the data set with a data set collected in 2004 from the same location revealed that the average atmospheric GEM concentration in downtown Toronto dropped from 4.5 ng/m3 to 1.78 ng/m3 (60% decrease). Decreases in GEM were also observed in the data reported by CAMNet over the same period in rural and remote areas but to a lesser extent (10.5 and 13.9% respectively). The decrease is in line with the key national and provincial policies on mercury use, emission control and management that have been enacted since 2004.

    更新日期:2018-08-24
  • Characteristics, source apportionment and contribution of VOCs to ozone formation in Wuhan, Central China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-24
    Lirong Hui, Xingang Liu, Qinwen Tan, Miao Feng, Junling An, Yu Qu, Yuanhang Zhang, Meiqing Jiang

    Based on the detailed data of volatile organic compounds (VOCs) with 102 components measured continuously from September 2016 to August 2017 in Wuhan, the pollution characteristics, source apportionment, chemical reactivity and contribution to O3 formation were analysed. The results revealed that the annual average concentration of total VOCs (TVOCs) was 34.65 ppbv. Alkanes were the species with the largest concentration, which accounted for 45.88% of TVOCs, and propane, ethane and ethylene were the most abundant components. Diagnostic ratios (toluene/benzene, typical VOC species/acetylene) showed that vehicle exhaust emissions had significant effects on VOCs. Eight major sources were identified by positive matrix factorization (PMF), which included vehicular exhaust (24.42%), industrial sources (16.43%), coal burning (14.18%), solvent usage in painting/coating (13.48%), liquefied petroleum gas (LPG) usage (12.57%), fuel evaporation (11.34%), biomass burning (5.11%) and biogenic sources (2.47%). In addition, industrial sources, vehicle exhaust and LPG usage were the main sources that significantly aggravated VOC pollution in Wuhan. Potential source contribution function (PSCF) results showed that local pollution sources were the main sources influencing VOC pollution in Wuhan. The results of Empirical Kinetic Modelling Approach (EKMA) showed that Wuhan belongs to a VOC limited area. Finally, the results of the OH radical loss rate (LOH) and ozone formation potential (OFP) showed that alkenes were the species with the largest amount of chemical activity, in which the highest OH radical loss rate was 42.56%. Simultaneously, alkenes contributed the most to O3 formation, which accounted for 48.34%. The results can provide references for local governments regarding control strategies of VOCs and O3 pollution.

    更新日期:2018-08-24
  • Validation of a Lagrangian particle dispersion model with wind tunnel and field experiments in urban environment
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-23
    S. Trini Castelli, P. Armand, G. Tinarelli, C. Duchenne, M. Nibart
    更新日期:2018-08-23
  • High temporal resolution of airborne Ambrosia pollen measurements above the source reveals emission characteristics
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-23
    B. Šikoparija, G. Mimić, M. Panić, O. Marko, P. Radišić, T. Pejak-Šikoparija, A. Pauling
    更新日期:2018-08-23
  • Analyzing temporo-spatial changes and the distribution of the CO2 concentration in Australia from 2009 to 2016 by greenhouse gas monitoring satellites
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-23
    Shuai Yin, Xiufeng Wang, Hiroshi Tani, Xirui Zhang, Guosheng Zhong, Zhongyi Sun, Anthony R. Chittenden

    We comprehensively analyzed the temporo-spatial changes in the CO2 concentrations in Australia from June 2009 to December 2016 using greenhouse gas monitoring satellites, Greenhouse Gases Observing Satellite (GOSAT) and Orbiting Carbon Observatory-2 (OCO-2). Regarding the spatial distribution, the CO2 concentration in central Australia was always higher than that of other regions, and the lack of precipitation in this region is thought to be one of the main causes of this increased concentration. By combining the results with the Köppen-Geiger climate classification, a subtle relationship between the spatial distribution of CO2 and various climate types were found. Precipitation, Sea Surface Temperature (SST), phytoplankton around the coastal region, vegetation cover and other factors jointly affected the spatial CO2 concentration in Australia. Moreover, the results indicated that the abnormal SST in the 4 Niño zones would affect the precipitation and vegetation growth in Australia and the total chlorophyll in the equatorial Eastern Central Pacific Ocean, which would in turn influence carbon cycling in Australia. According to the Niño-3 and Niño-3.4 indices, two El Niño-Southern Oscillation (ENSO) events occurred during the study period. The CO2 increase rate decreased during the period of the 2011 La Niña, while the CO2 increase rate increased during the period of the 2015 El Niño. With the global CO2 concentration as the background, the abnormal change of CO2 in Australia was analyzed. Lastly, the results showed that SST around Australia, precipitation, vegetation, ENSO events, oceanic chemical processes and bushfires were assumed to directly or indirectly influence the temporal changes in CO2 in this region.

    更新日期:2018-08-23
  • National scale spatiotemporal land-use regression model for PM2.5, PM10 and NO2 concentration in China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-23
    Zhenyu Zhang, Jianbing Wang, Jaime E. Hart, Francine Laden, Chen Zhao, Tiantian Li, Peiwen Zheng, Die Li, Zhenhua Ye, Kun Chen

    Background Air pollution epidemiological studies increasingly rely on high-resolution exposure prediction models. However, to date, few models of this type exist for use in China. Objectives We produced a national land-use regression model (LUR) to estimate monthly average PM2.5, PM10 and NO2 from 2014 to 2016 in China. Methods We developed a spatiotemporal semi-parametric model using generalized additive mixed models. A variety of predictor variables were included in model: time varying meteorological data, high resolution land cover data from Globaland30, satellite measures of aerosol optical depth, and Geographic Information System (GIS)-derived predictors. We assessed model performance with two cross-validation (CV) approaches, including hold-out CV, and 10-fold CV. Results Over 22,000 monthly observations at 1382 monitoring locations were included to estimate the air pollution exposure. The time-varying spatial terms explained 87%, 71%, and 69% of variability with a hold-out cross-validated R2 of 0.85, 0.62, and 0.62 for PM2.5, PM10 and NO2 models, respectively. Models shows that meteorological variables, population density, elevation, distance to road, and land cover types were important predictors for air pollution exposure. Conclusions we have developed a new nationwide model to estimate residence-level air pollution exposures, which can be used in studies of the chronic adverse effects of air pollution.

    更新日期:2018-08-23
  • Estimation and analysis of emissions from on-road vehicles in Mainland China for the period 2011–2015
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-22
    Tao Jia, Qi Li, Wenzhong Shi

    With the enforcement of emissions standards and fuel-economy standards in Mainland China, it is both important and interesting to see how these recent emissions reduction strategies affected the spatiotemporal patterns of emissions over the period 2011–2015, which have rarely been examined in previous studies. This study aimed to fill this gap by estimating and analyzing vehicle emissions patterns to support the development of emissions reduction strategies. We established emissions inventories for Mainland China and individual provinces using statistical data from official yearbooks. The aggregated results showed that emissions of greenhouse gas increased slowly and emissions of pollutants decreased sharply. The individual results showed that there was an imbalance in the distribution of emissions, with high total emissions and emissions per inhabitant in developed provinces and high emissions per unit GDP in developing provinces. Specifically, light passenger cars and heavy-duty trucks contributed more than 50% of emissions, and their emissions were statistically spatially auto-correlated, which might hint that there were inherent spatial clustering patterns among emissions. Thereafter, a self-organizing map was used to cluster individual provinces, and indicated that a few provinces can be clustered together according to the similarity of their emissions patterns. Finally, we found that the influences of socioeconomic factors on emissions varied across space, where emissions in northeastern provinces were more likely to be affected by population and those in southwestern provinces tended to be influenced by GDP. These findings are believed to be useful for the development of emissions reduction strategies for sustainable development.

    更新日期:2018-08-22
  • Light absorption properties of HULIS in primary particulate matter produced by crop straw combustion under different moisture contents and stacking modes
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-21
    Yaoqiang Huo, Min Li, Meihe Jiang, Weiming Qi

    Crop straw combustion is a significant source for humic-like substances (HULIS) in fine particles (PM2.5), which have strong light absorption in the near ultraviolet and visible light region. In this study, the relative abundances, light absorption properties and fluorescence characteristics of HULIS produced by three crop straws (wheat, rice and corn straws) combusted under different moisture contents and stacking modes were comprehensively characterized. The results show that the moisture contents and stacking modes can affect the ratio of carbon content in HULIS to water-soluble organic carbon (HULIS-C/WSOC) and the ratio of HULIS to PM2.5 (HULIS/PM2.5). The absorption Ångström exponent (AAE) and absorptivity ratios between 250 and 365 nm (E2/E3) for HULIS increased either under high moisture or stacking conditions for all three crop straws, while mass absorption efficiencies at 365 nm (MAE365) decreased under high moisture or stacking conditions. Four fluorescent components of HULIS were identified based on the characterization of the excitation-emission matrix combined with a parallel factor analysis model (EEM-PARAFAC): protein-like organic matter (C1 and C4), highly oxygenated humic-like substances (C3) and less-oxygenated humic-like substances (C2). A correlation analysis of the fluorescent components and light absorption indicators showed that the components C4, (C2, C3) and (C1, C2) determined the variations in the light absorption properties of HULIS derived from wheat, rice and corn straw burning, respectively. We also found that the flame burning of crop straw could reduce the contribution of light absorption to HULIS per unit mass of crop straw.

    更新日期:2018-08-21
  • Evaluation of El Niño-Southern Oscillation influence on 30 years of tropospheric ozone concentrations in Houston
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-20
    Rebecca Paulsen Edwards, Oliver Sale, Gary A. Morris

    Surface observations collected over the period 1980–2010 at three Continuous Ambient Monitoring Stations located in Houston, Texas were leveraged to create a long-term composite dataset of tropospheric ozone measurements. This dataset was used to evaluate large-scale influences and their relationship to exceedances of the 70 ppbv National Ambient Air Quality Standard for ozone. A linear regression fit to monthly mean daily peak 8-h concentrations for each month revealed a decreasing trend for the duration of the study period. After removal of this temporal trend, 8-h peak values averaged for each month featured peaks in springtime and late-summer with relative minima in mid-summer and winter. Stratification of the database by El Niño-Southern Oscillation phase using the Oceanic Niño Index revealed a statistically significant (α = 0.05) dependence of peak 8-h concentration on ENSO phase, with an enhancement of 5.8, 4.8, and 7.0 for March, April, and June during warm phase years, while cool phase years had statistically significant enhancements of 5.0, 4.0, and 3.6 ppbv in February, October, and December relative to neutral conditions. Importantly, relative to neutral conditions, “El Nino years” produce 26% more exceedences while “La Nina years” produce 23% fewer. The earlier onset of ozone seasons both in spring and late summer during El Nino years leads to more exposure to direct sunlight and more seasonal photochemical production, while the delayed late summer season during La Nina years leads to decreased sunlight and suppressed seasonal photochemical production relative to neutral years. Evaluation of the number of exceedances per month for each ENSO regime also suggests high tropospheric ozone concentrations in the fall and spring, with 4.4 and 6.8 exceedances per month in June and September, respectively for the warm phase. During cool phase conditions, Houston averaged 5.0 exceedances per month in September. Exceedances for neutral conditions ranged from zero exceedances in December to 2.2 exceedances in May and 5.0 in September. Analysis of exceedance data and mean values in light of parameters of the underlying distribution of daily peak 8-h data suggests that ENSO may influence the shape of those distributions, influencing both background ozone concentrations and the number of exceedances. Fast Fourier analysis indicated a common spectral signature for the ENSO and ozone spectra. This finding has implications for air quality mitigation strategies employed during warm phase and cool phase years.

    更新日期:2018-08-20
  • Temporal variation (2011–2014) of atmospheric OCPs at King George Island, west Antarctica
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-18
    Pu Wang, Wenying Meng, Yingming Li, Qinghua Zhang, Lin Zhang, Jianjie Fu, Ruiqiang Yang, Guibin Jiang

    A three-year sampling campaign (Jan 2011–Jan 2014) was conducted on organochlorine pesticides (OCPs) using high-volume air sampling nearby the Chinese Great Wall Station, west Antarctica. The concentrations of ∑23OCPs ranged between 5.87 and 27.9 pg m−3 (mean 14.3 ± 5.4 pg m−3), and no temporal trend was observed over the entire sampling period. However, the dominant compound, hexachlorobezene (HCB) (71% on average of ∑23OCPs), exhibited a seasonal variation with higher levels in the austral winter. Gas-particle partitioning of OCPs was explored based on KOA absorption model, steady-state model and Junge–Pankow adsorption model. logKP showed significantly negative correlations with logPL0 of OCPs (p < 0.01, the slope is -0.30) and TSP values in the samples (p < 0.01), suggesting absorption by the organic matter as the dominant sorption process and TSP as an important factor influencing gas-particle partitioning of OCPs in this remote environment. The chiral signature indicated a commonly nonracemic residue of α-HCH and o,p’-DDT in the Antarctic air. The deviation from racemic (DFR) of o,p’-DDT showed strongly negative dependence on its concentrations (p < 0.01), properly suggesting more fresh input of o,p’-DDT after 2011. Preferential depletion of (+) α-HCH was observed mainly in gas phase, indicating the influence of re-volatilization of chiral compounds from source areas and/or ocean on their enantiomeric composition in remote air. Source apportionment demonstrated that long range atmospheric transport (LRAT) was the main transport pathway of OCPs, while nonracemic residues of HCHs and DDTs indicated a contribution of secondary source emission, i.e. seawater-air exchange, to their occurrence in west Antarctica.

    更新日期:2018-08-20
  • A high-resolution emission inventory of anthropogenic trace elements in Beijing-Tianjin-Hebei (BTH) region of China
    Atmos. Environ. (IF 3.708) Pub Date : 2018-08-19
    Chuanyong Zhu, Hezhong Tian, Yan Hao, Jiajia Gao, Jiming Hao, Yong Wang, Shenbing Hua, Kun Wang, Huanjia Liu
    更新日期:2018-08-20
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
化学 • 材料 期刊列表