Search

Wastewater treatment plants (WWTPs) are major sources of volatile gaseous compounds, especially in mixed-source systems such as domestic wastewater and landfill leachate. This study aimed to investigate the emission behavior and environmental impact of gaseous substances, such as hydrogen sulfide (H 2 S), ammonia (NH 3 ), carbon sulfide (CS 2 ), and phosphine (PH 3 ), at a WWTP in Northwest China. Odorants were detected in the air surrounding the grid room (XGS), biochemical treatment tank (SHC), secondary sedimentation tank (ECC), and sludge dewatering room (NTS). For comparison, the upwind boundary (O-SF) and downwind boundaries (O-XF) monitoring points were used, with odor concentrations ranging from 3.95 to 725.27 odor units. The concentration ranges of the odorant substances were 5.27-88.69, 5.61-71.96, 5.70-32.63, and 0.12-5.87 mg/m 3 for H 2 S, NH 3 , CS 2 , and PH 3 , respectively. Meteorological factors such as temperature, relative humidity, and wind speed and direction substantially influence odorant emissions. The concentrations of various odorants and volatile organic compounds (VOCs) detected at the O-XF monitoring point were higher than those detected at the O-SF monitoring point, indicating that the wind intensified their diffusion toward the downwind plant boundary. The average odor intensities of odorant substances emitted from wastewater or sludge treatment equipment were 3.37, 5.09, 4.42, 2.00, and 3.82 for total VOCs, H 2 S, NH 3 , CS 2 , and PH 3 , respectively. Among them four, with downwind diffusion, only H 2 S presented olfactory and chronic toxicity risks based on Gaussian plume model calculations. The hazard index ranking across monitoring sites was XGS > NTS > SHC > ECC > O-XF > O-SF. These findings emphasize the urgent need for effective measures to control and mitigate gaseous pollutants emitted by collaborative WWTPS, thereby protecting environmental quality and public health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ammonia (NH 3 ) plays an important role in the formation of atmospheric particulate matter, but the contribution of traffic-related emissions remains unclear, particularly in megacities with a large number of vehicles. Taking the opportunity of the stringent COVID-19 lockdowns implemented in Beijing and Shanghai in 2022, this study aims to estimate the traffic-related NH 3 emissions in these two megacities based on satellite observations. Differences between urban and suburban areas during the lockdown and non-lockdown periods are compared. It was found that despite different dominating sources, the overall NH 3 concentrations in urban and suburban areas were at a similar level, and the lockdown resulted in a more prominent decrease in urban areas, where traffic activities were most heavily affected. The traffic-related contribution to the total emission was estimated to be ∼30% in megacities, and ∼40% in urban areas, which are about 2-10 times higher than that in previous studies. The findings indicate that the traffic-related NH 3 emissions have been significantly underestimated in previous studies and may play a more critical role in the formation of air pollution in megacities, especially in winter, when agricultural emissions are relatively low. This study highlights the importance of traffic-related NH 3 emissions in Chinese megacities and the need to reassess the emissions and their impacts on air quality., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Ammonia (NH 3 ) is the major constituent among all the reactive nitrogen species present in the atmosphere, and the most essential species for secondary inorganic aerosol formation. Recent satellite-based observations have identified the Indo-Gangetic Plain (IGP) as a major hotspot of global NH 3 emission; however, the major sources and atmospheric processes affecting its abundance are poorly understood. The present study aims to understand the wintertime sources of NH 3 over a semi-urban site (Patiala, 30.3°N, 76.4°E, 249 m amsl) located in the IGP using species specific δ 15 N in PM 2.5 . A distinct diurnal variation in the stable isotopic signature of total nitrogen (δ 15 N-TN) and ammonium (δ 15 N-NH 4 + ) were observed; although, average day and night time concentrations of TN and NH 4 + were similar. Mixing model results using δ 15 N-NH 3 reveal the dominance of non-agricultural emissions (NH 3 slip: 47 ± 24%) over agricultural emissions (24 ± 11%), combustion sources (19 ± 14 %), and biomass burning (10 ± 8%) for atmospheric NH 3 . Diurnal variability in source contributions to NH 3 was insignificant. Further, significantly negative correlations of δ 15 N-NH 4 + with ambient relative humidity (RH) and daytime NO 3 - -N concentration were observed, and attributed to the possibility of NH 4 NO 3 volatilization during day-time owing to lower RH and higher temperature, resulting in isotopic enrichment of the remaining NH 4 + in aerosol phase. This study, a first of its type from India, highlights the importance of non-agricultural NH 3 emissions over the agriculture dominated IGP region, and the role of local meteorology on the isotopic fractionation of δ 15 N in aerosol NH 4 + ., Competing Interests: Declaration of competing interest Authors declare that there is no conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The application of numeric modelling for determining the impact of landfills needs for reliable emission source data. In this study, a methodology for the characterization of the emission profiles of the different sources present in landfills for emission factors determination, applying an indirect methodology, is presented. Ambient air concentrations of volatile organic compounds (VOCs), hydrogen sulphide (H 2 S) and ammonia (NH 3 ) were determined in three potentially emission sources in Can Mata landfill (Hostalets de Pierola, Catalonia, Spain): dumping areas, pre-closed zone and leachate reservoir as well as in biogas, for the determination of emission factors. Multi-sorbent bed and Tenax TA tubes were used for a wide range of VOCs sampling, and analysis was conducted through TD-GC/MS. H 2 S and NH 3 were sampled and analysed using Radiello passive samplers. The highest total VOC (TVOC) concentrations were found in dumping areas (0.7-3.5 mg m -3 ), followed by leachate reservoir (0.3-0.6 mg m -3 ) and pre-closed area (77-165 μg m -3 ). On the other hand, the highest H 2 S and NH 3 concentrations were found in leachate reservoir, presenting values of 0.8-1.1 mg m -3 and 1.7-1.8 mg m -3 , respectively. With the application of odour thresholds to the concentrations obtained, the most critical compounds regarding odour annoyances were determined. The highest odour units (O.U.) were found in leachate reservoir due to H 2 S concentrations, whereas VOCs contributed mainly to O.U. in the dumping areas. The obtained ambient air concentrations were used for the indirect determination of the emission factors through numerical modelling using a Eulerian dispersion model. The emission factors obtained for the landfill for TVOC, H 2 S and NH 3 were in the range of 0.44-10.9 g s-1, 0.16-1.02 g s -1 and 0.23-1.82 g s -1 , respectively, depending on the emission source. Reliable emission factors are crucial to obtain landfill impact maps, which are essential for the correct management of these facilities., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Ammonia (NH 3 ) is attracting attention as a carbon-free energy source and a significant precursor to inorganic PM 2.5 (hereafter PM 2.5 ), aside from NO x and SO x . Since the emission of NH 3 has often been overlooked compared to NO x and SO x, this study aims to reveal the role of NH 3 and its emission control on PM 2.5 in Kanto, Japan. With the aid of gas ratio (GR) quantitatively defining the stoichiometry between the three precursors to PM 2.5 , and the aid of atmospheric modeling software ADMER-PRO, coupled with thermodynamics calculations, the spatiotemporal distribution along with PM 2.5 reduction under different NH 3 emission cutoff strategies in Kanto had been revealed for the first time. The cutoff of NH 3 emission could effectively reduce the PM 2.5 concentration, with sources originated from agriculture, human/pet activities, and vehicle sources, overall giving a 93.32% PM 2.5 reduction. Different cutoff strategies lead to distinct reduction efficiencies of the overall and local PM 2.5 concentrations, with GR as a crucial factor. The regions with GR ∼1, are sensitive to the NH 3 concentration for forming PM 2.5 , at which the NH 3 reduction strategies should be applied with high priority. On the other hand, installing a new NH 3 emission source should be avoided in the region with GR < 1, suppressing the so-yielded PM 2.5 pollution. The future PM 2.5 pollution control related to the NH 3 emission control strategies based on GR, which is stoichiometry-based and applicable to regions other than Kanto, has been discussed., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

With the development of industry and economy, ammonia nitrogen pollutions in surface water are of great concern worldwide. This study investigated the historical contents of total ammonia nitrogen (TAN) and unionized ammonia molecules (NH 3 ) in nine fresh lakes in China during 2014-2022. Three different classification methods (flood season, season, and geographical distribution) were used to analyze the concentration variation of TAN and NH 3 . The concentration of TAN first decreased and then increased in the flood season, showing a lower concentration in summer and a higher concentration in winter. The variation trend of NH 3 was in an opposite way with TAN. Correlation analysis between ammonia and 10 water quality parameters and 4 pollution emission and treatment parameters showed that the correlation coefficient between TAN and total phosphorus (total nitrogen) was 0.44 (0.43), respectively. The correlation coefficients between average annual TAN concentration and total emissions (waste water treatment input) were 0.35 (0.53), respectively. Combined with ecotoxicity data from a series of aquatic species, the ecological risks of TAN and NH 3 in lakes were evaluated using hazard quotient and joint probability curve methods. From 2014 to 2022, the probability of 5% species affected in the acute ecological risk of TAN and NH 3 is lower than 0.01, but for the chronic ecological risk of TAN and NH 3 , the probabilities of 5% species affected are 0.003-0.030 and 0.04-0.14, respectively. The chronic ecological risks were higher than the acute ecological risks, and high risks in plateau lakes like Dianchi Lake should be paid more attention to., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

The Pearl River Delta (PRD) region has been identified as a significant hotspot of wet ammonium deposition. However, the absence of long-term monitoring data in the area hinders the comprehension of the historical trends and changes in wet NH 4 + -N deposition in response to emissions, which interferes with the ability to make effective decisions. This study has analyzed the long-term trends of wet NH 4 + -N deposition flux and has quantified the effect of anthropogenic emissions and meteorological factors at a typical urban site and a typical forest site in the PRD region from 2009 to 2020. It revealed a significant decreasing trend in wet NH 4 + -N flux in both the typical urban and forest areas of the PRD region, at -6.2%/year (p < 0.001) and -3.3%/year (p < 0.001), respectively. Anthropogenic emissions are thought to have contributed 47%-57% of the wet NH 4 + -N deposition trend over the past 12 years compared to meteorological factors. Meteorological conditions dominated the inter-annual fluctuations in wet NH 4 + -N deposition with an absolute contribution of 46%-52%, while anthropogenic emissions change alone explained 10%-31%. NH 3 emissions have the greatest impact on the urban area among anthropogenic emission factors, while SO 2 emissions have the greatest impact on the forest area. Additionally, precipitation was identified as the primary meteorological driver for both sites. Our findings also imply that the benefits of NH 3 emissions reductions might not immediately emerge due to interference from weather-related factors., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

This study focuses on the spatiotemporal distribution, urban-rural variations, and driving factors of ammonia Vertical Column Densities (VCDs) in China's Yangtze River Delta region (YRD) from 2008 to 2020. Utilizing data from the Infrared Atmospheric Sounding Interferometer (IASI), Generalized Additive Models (GAM), and the GEOS-Chem chemical transport model, we observed a significant increase of NH 3 VCDs in the YRD between 2014 and 2020. The spatial distribution analysis revealed higher NH 3 concentrations in the northern part of the YRD region, primarily due to lower precipitation, alkaline soil, and intensive agricultural activities. NH 3 VCDs in the YRD region increased significantly (65.18%) from 2008 to 2020. The highest growth rate occurs in the summer, with an annual average growth rate of 7.2% during the period from 2014 to 2020. Agricultural emissions dominated NH 3 VCDs during spring and summer, with high concentrations primarily located in the agricultural areas adjacent to densely populated urban zones. Regions within several large urban areas have been discovered to exhibit relatively stable variations in NH 3 VCDs. The rise in NH 3 VCDs within the YRD region was primarily driven by the reduction of acidic gases like SO 2 , as emphasized by GAM modeling and sensitivity tests using the GEOS-Chem model. The concentration changes of acidic gases contribute to over 80% of the interannual variations in NH 3 VCDs. This emphasizes the crucial role of environmental policies targeting the reduction of these acidic gases. Effective emission control is urgent to mitigate environmental hazards and secondary particulate matter, especially in the northern YRD., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

Environmental process assessment based on the environmental depletion index (EDI) is an important part of the long-term monitoring and early warning mechanism of China's resources and environmental carrying capacity. The EDI aims to realize the unified environmental impact assessment of economic and environmental systems through the ratio relationship between economic growth and pollutant emission growth. However, in terms of pollutant emissions, the EDI ignores the environmental capacity (EC), which means that the effectiveness and objectivity of environmental impact assessment must be verified. In this study, with Xinjiang as an example and based on the EDI, Sulfur dioxide (SO2), Nitrogen oxide (NOx), Chemical oxygen demand (COD) and Ammonia nitrogen (NH3-N) were selected for calculation and assessment both without and with consideration of EC and for discussion of the suitability of the environmental depletion method for resources and environmental carrying capacity. The results indicated that ① the percentages of SO2, NOx, COD, NH3-N and CEDI in counties and cities that tend to be poor and lack EC were 32.98%, 29.79%, 30.85%, 28.72% and 38.30%, respectively, while the percentages in counties and cities with EC were 10.64%, 3.19%, 13.83%, 8.51% and 10.64%, respectively. ② When EC was included, the number of counties and cities where changes in SO2, NOx, COD, NH3-N and CEDI tended to be "poor → good" were 23, 26, 17, 21 and 28, respectively, and the number of counties and cities where such changes tended to be "good → poor" were 2, 1, 1, 2 and 2, respectively. ③ EC inclusion corrected overestimated or underestimated EDI results, making the evaluation results more objective and reasonable. This understanding provides a scientific reference for the coordinated development of the regional economy and environment in Xinjiang and worldwide., Competing Interests: The authors have declared that no competing interests exist.

Ammonia (NH 3 ) emissions, mainly from agricultural sources, generate substantial health damage due to the adverse effects on air quality. NH 3 emission reduction strategies are still far from being effective. In particular, a growing trade network in this era of globalization offers untapped emission mitigation potential that has been overlooked. Here we show that about one-fourth of global agricultural NH 3 emissions in 2012 are trade-related. Globally they induce 61 thousand PM 2.5 -related premature mortalities, with 25 thousand deaths associated with crop cultivation and 36 thousand deaths with livestock production. The trade-related health damage network is regionally integrated and can be characterized by three trading communities. Thus, effective cooperation within trade-dependent communities will achieve considerable NH 3 emission reductions allowed by technological advancements and trade structure adjustments. Identification of regional communities from network analysis offers a new perspective on addressing NH 3 emissions and is also applicable to agricultural greenhouse gas emissions mitigation., (© 2021. The Author(s).)

This study utilized the freshwater amphipod (Hyalella azteca) for the indication of contamination risk levels of sediment-associated contaminants in the Erren (ER1∼ER10) and Sanye Rivers (SY1∼SY5) which were contaminated by metal scrap and smelting industries for decades. Toxicity identification evaluations involving the manipulation of pore water and whole-sediment samples were conducted to identify causative pollutants. Impacts on the aquatic environment were then evaluated in order to explore how industrial development led to contaminant accumulation in sediments and resulted in biological effects. A whole-sediment TIE indicated that the major toxicant at sampling sites ER8 and SY5 was ammonia and that its toxicity was significantly reduced by the addition of zeolite. Toxicity at sampling sites ER4 and ER9 was induced by ammonia and heavy metals (Zn, Cd, Cr, As), whereas Cr was at toxic levels at ER6. ∑PAHs was another major class of contaminants at site ER2. Metals (Zn, Ni, Pb, Cd, Cr, and As) were identified as major toxic contaminants at three sites (ER3, SY1, and SY3). The application of TIEs confirmed that a causative toxicant can be identified and that its measured toxicity correlated with its concentration. In conclusion, a TIE approach was successful in demarcating most effective contaminant groups (ammonia, heavy metals, and non-polar organic compounds) in whole-sediment cores, their porewaters and potential toxicities from a highly polluted river after remediation in southern Taiwan to an invertebrate animal model H. azteca., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Ammonia has been of concern for its high toxicity to aquatic species and frequent detection in waters worldwide. This study calculated the national aquatic life criteria for ammonia in China. The temporal and spatial distributions were investigated and the multi-tier ecological risks were assessed for ammonia and un-ionized ammonia (NH 3 ) during 2014-2018 based on a total of 18989 ammonia monitoring data from 110 monitoring sites in seven river basins. The sensitivity comparison of different species taxa to ammonia showed that Perciformes fish should be listed as a priority protected species in the derivation of ammonia criteria. The participation of introduced aquaculture species have no significant impact on the final criteria values (t-test, p > 0.05). The final criterion maximum concentration (CMC) and criterion continuous concentration (CCC) were 10.24 and 3.31 mg/L for ammonia (pH 7.0 and 20 °C). The interannual variation showed that decreasing trends were observed for ammonia and NH 3 pollutions in the past five years. However, the increasing trends were observed for ammonia in Liao River basin, for NH 3 in Yangtze River and Pearl River basins (2014-2018). The significant seasonal and geographical differences of ammonia and NH 3 pollution were found. Moreover, the pollutions of ammonia and NH 3 in some monitoring points of Huai River, Yellow River and Songhua River basins at the provincial borders were significant. The result of ecological risk assessment showed that the average exceedance probability for 5% affected species by NH 3 in long-term exposure was 28.96% in the past five years., (Copyright © 2020 The Authors. Published by Elsevier Inc. All rights reserved.)

To prevent and control non-point source pollution, many policies have been carried out by government in China. However, the effectiveness of these policies has rarely been evaluated. In this study, the potential and spatial distribution of agricultural non-point source pollution in the Baiyangdian Basin are reported. This investigation considers multiple parameters under various policies with county as a basic unit. The results for the potential pollution from chemical oxygen demand (COD), ammonia nitrogen (NH3-N), total nitrogen (TN) and total phosphorus (TP) are 60.89×104, 3.93×104, 87.05×104 and 15.10×104 Mg, with corresponding intensities of 190, 12, 272 and 47 kg ha-1 for the Baiyangdian Basin in 2016. The highest pollution from COD is attributed to livestock and poultry breeding, whereas TN and TP are dominantly produced by rural domestic sources, and NH3-N is mostly derived from planting. Spatially, distribution of the counties producing larger non-point source pollution presented a northeast to southwest direction, consistent with the Taihang mountain alignment in the basin. The counties with high pollution intensities are mostly in the south and east of the basin. Agricultural non-point source pollution control and prevention policies contributed in pollution reduction. Compared with 2016, the total potential pollution of COD, NH3-N, TN and TP in 2020 decrease by 45.1%, 14.7%, 37.9% and 37.4%, respectively, whereas for an assumed future time (F2), the decreases are 59%, 51.4%, 56.2% and 55.7%, respectively. Prevention measures should focus on reducing pollution from livestock and poultry breeding as well as planting., Competing Interests: The authors have declared that no competing interests exist.

Human-dominated waterways contain thousands of chemicals. Determining which chemical is the most important stressor is important, yet very challenging. The Toxicity Identification Evaluation (TIE) procedure from the US Environmental Protection Agency uses a series of chemical and physical manipulations to fractionate compounds within a matrix and systematically identify potential toxicants through laboratory bioassay testing. Although this may provide useful information, it lacks ecological realism because it is subject to laboratory-related artifacts and is resource intensive. The in situ Toxicity Identification Evaluation (iTIE) technology was developed to improve this approach and has undergone a number of modifications over the past several years. The novel prototype 3 consists of an array of iTIE ambient water fractionation units. Each unit is connected to a peristaltic pumping system with an organism exposure chamber that receives water from a resin chamber to chemically fractionate test site water. Test organisms included freshwater and marine standard toxicity test species. Postfractionation waters are collected for subsequent chemical analyses. Currently, the resins allow for separation of ammonia, metals, and nonpolar organics; the subsequent toxicity responses are compared between treatments and unfractionated, ambient exposures. The iTIE system was deployed to a depth of 3 m and evaluated in streams and marine harbors. Chemical analyses of water and iTIE chemical sorptive resins confirmed chemical groups causing lethal to sublethal responses. The system proved to be as sensitive or more so than the traditional phase 1 TIE test and required almost half of the resources to complete. This iTIE prototype provides a robust technology that improves stressor-causality linkages and thereby supports strong evidence for ecological risk weight-of-evidence assessments. Environ Toxicol Chem 2020;39:1746-1754. © 2020 SETAC., (© 2020 SETAC.)

The Yangtze River Delta (YRD) is one of the regions with air pollution and high ammonia (NH 3 ) emission in China. A high-resolution ammonia emission inventory for the YRD region was developed based on the updated source-specific emission factor (EFs) and the county-level activity data. The 1 × 1 km gridded emissions were allocated by using the appropriate spatial surrogate. The total NH 3 emissions changed insignificantly from 2006 to 2014 and varied in the range of 981.65 kt - 1014.30 kt. The fertilizer application and livestock were the major contributors of total emission. Humans, biomass burning and vehicles were the top three contributors of non-agricultural sources, accounting for 37.24%, 31.02% and 10.85%, respectively. Vehicles were calculated to be the non-agricultural source with the fastest annual growth rate. NH 3 emissions from the nitrogen fertilizer application generally peaked in summer, corresponding to the planting schedule and relatively high temperature. High NH 3 emissions occurred in the north as opposed to low emissions in the south of the YRD. The cities of Xuzhou, Yancheng and Nantong with more agricultural activities were demonstrated to have relatively high NH 3 emissions, contributing 10.0%, 9.0 and 7.1% of total emissions, respectively. The validity of the emission estimates was further evaluated based on the uncertainty analysis by Monte Carlo simulation, comparison with previous studies, and correlation analysis between NH 3 emission density and observed ground NH 3 concentration. A detailed NH 3 emission inventory is the basis of regional-scale air quality model simulation and can provide valuable information for understanding the formation mechanism of pollutants., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

Agriculture is the largest source of ammonia (NH 3 ) emissions. As NH 3 is an indirect greenhouse gas, NH 3 measurements are crucial to improving greenhouse gas emission inventory estimates. Moreover, NH 3 emissions have wider implications for environmental and human health. Only a few studies have measured NH 3 emissions from pastures in the tropics and subtropics and none has compared emissions to inventory estimates. The objectives of this study were to (1) measure NH 3 emissions from dairy pastures in tropical and subtropical regions; (2) calculate NH 3 emissions factors (EF) for each campaign; and (3) compare measured EF with those based on the 2006 Intergovernmental Panel on Climate Change (IPCC) Tier 1, 2019 Refinement to the 2006 IPCC Tier 1, and the European Monitoring and Evaluation Programme/European Environmental Agency (EMPE/EEA) Tier 2 inventory estimates. Pasture NH 3 emissions were measured on 3 dairy farms in Costa Rica. On each dairy, NH 3 emissions were measured twice during the wet season and once during the dry season using a micrometeorological integrated horizontal-flux mass-balance method. Emissions were measured from excreta (dung and urine) deposited by grazing cattle and the subsequent application of organic (slurry) or synthetic fertilizer (ammonium nitrate or urea). Measured EF for all campaigns [from grazing cattle excreta and any subsequent slurry or fertilizer application; 4.9 ± 0.9% of applied nitrogen (mean ± SE)] were similar to those of the EMEP/EEA Tier 2 approach (6.1 ± 0.9%; mean ± SE) and 4 times lower than 2006 IPCC and 2019 Refinement to 2006 IPCC Tier 1 default estimates (17.7 ± 1.4 and 18.2 ± 0.9%, respectively; mean ± SE). Measured EF for excreta deposited on pasture and excreta both deposited on pasture and slurry application [3.9 ± 2.1 and 4.2 ± 2.1% (mean ± 95% CI), respectively] were 5 times lower than default EF assumed by 2006 IPCC and 2019 Refinement to 2006 IPCC methodology (both 20 and 21%, respectively), whereas EMEP/EAA estimates were similar [6.0 and 4.6 ± 0.3% (mean ± 95% CI), respectively]. This suggests an overestimation of EF from excreta deposited on pasture and slurry applications in tropical and subtropical regions by IPCC methodologies. Furthermore, rainfall, which is not included as a parameter in the current EMEP/EEA Tier 2 methodology, appeared to reduce NH 3 emissions, suggesting that accounting for this in the inventory methodologies could improve inventory estimates., (Copyright © 2020 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.)

Large ammonia (NH 3 ) emissions contribute approximately 8-30% to the fine particle pollution in China and highlight the need for understanding the emission trends and mitigation effects of NH 3 in the future. The purpose of this study is to predict the NH 3 emissions and analyze the mitigation potential up to year 2040 by scenario analysis based on the established new NH 3 emission inventory from anthropogenic sources for the Beijing-Tianjin-Hebei (BTH) region. The results showed that the total NH 3 emission in the BTH region was estimated at 966.14 Gg in 2016. Under the Business-as-Usual (BAU) scenario, the total NH 3 emissions in 2030 and 2040 would increase by 13% and 26% compared with 2016 levels, with average annual growth rates of 0.9% and 1.0%, respectively. Livestock will continue to dominate NH 3 emissions in the future, with the proportions of total emissions increasing from 57% in 2016 to 64% in 2030 and 68% in 2040. The share of the second-largest NH 3 emission source, synthetic fertilizer application, will decrease from 36% in 2016 to 31% in 2030 and 27% in 2040. Among five other sources, the largest change occurred in waste disposal, increasing notably by 3.31 times from 2016 to 2040 owing to rapid urbanization. Under the Combined Options (CO) scenario, the total NH 3 emissions could be reduced by as much as 34% by 2030 and 50% by 2040 compared with the BAU scenario, which is attributed to livestock (24% in 2030, 37% in 2040) and synthetic fertilizer application (10% in 2030, 13% in 2040), respectively. This study can give a reliable estimation of anthropogenic NH 3 emission in the BTH region during 2020-2040 and provide a valuable reference for effective mitigation measures and control strategies for policy makers., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ammonia has drawn great concern worldwide due to its ubiquity in surface water and high toxic effect. In China, ammonia pollution issues in the Liao River were highlighted from the Ministry of Ecology and Environment annual report. In this study, water quality criteria (WQC) for two types of ammonia (total ammonia nitrogen (TAN) and un-ionized ammonia (NH 3 -N)) and related temporal concentration distributions and ecological risks in the Liao River were investigated. For sampling sites (2014) and national monitoring sites (2008, 2013, 2016, 2017 and 2018) of the Liao River, there were seasonal variations identified for TAN and NH 3 -N. More specifically, high concentrations of TAN and NH 3 -N occurred separately in winter and summer, and there were increasing trends for TAN and NH 3 -N from 2013 to 2018. The acute and chronic WQC values for TAN based on the toxicity values of the Liao River species were 16.86 and 4.39 mg/L (pH of 7.0 and temperature of 20 °C), and the acute and chronic WQC values for NH 3 -N were 0.067 and 0.017 mg/L. The exceedance probabilities of 5% species affected for long-term exposure of TAN and NH 3 -N were ≥30% in 2014. In addition, the increasing trend of concentrations and ecological risks posed by NH 3 -N from 2013 should be paying more attention. This study could provide useful information for ammonia environmental risk management in China and ecological risk assessment procedure for NH 3 -N and TAN exposure in similar surface waters worldwide., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Atmospheric ammonia (NH 3 ) as the most important alkaline gas in the atmosphere has attracted much attention in recent years due to its critical role in haze formation, especially on the North China Plain (NCP). Comprehensive studies are needed for investigating diurnal variations of NH 3 and underlying mechanisms in different seasons and their potential impacts on atmospheric chemistry. In this study, continuous long-term observation (Mar. 2016 to May 2017) of NH 3 at a rural site in the NCP was used to characterize the diurnal variation of NH 3 in different seasons and to unveil its causes and potential impacts on atmospheric chemistry. NH 3 concentrations displayed rapid increases during the morning, reaching very prominent peaks mostly between 8:00 to 11:00 LT. Such frequent (55%) morning peaks were mainly caused by the evaporation of dew and guttation water droplets. Average dew and guttation water volume concentrations of 750 mL m -2 was estimated for spring, which resulted in approximate NH 3 emissions of 800 ng m -2 s - 1 . Such high emission fluxes from dew and guttation water evaporation have never been reported before, suggesting dew and guttation droplets to be significant night-time reservoirs and strong morning sources for NH 3 . In light of recent studies putting forward that NH 3 can promote the heterogeneous formation of HONO and nitrate under high humidity conditions, we investigated the differences in HONO and aerosol chemical composition diurnal variations between days with and without NH 3 morning spikes during November. HONO, nitrate and sulfate concentrations were significantly higher for days with NH 3 morning spikes, with HONO displaying a morning peak near that of NH 3 . These results demonstrate that the prevailing NH 3 morning spikes on the NCP have significant influences on aerosol formation and atmospheric chemistry. NH 3 emission mitigation strategies and regulations are urgently needed., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Mixing ratios of atmospheric ammonia (NH 3 ), nitric oxide (NO), carbon monoxide (CO), nonmethane hydrocarbons (NMHCs), and methane (CH 4 ) were measured to investigate the vehicular emissions, which are a dominant source of atmospheric NH 3 in urban sites of Delhi, India from January 2013 to December 2014. The annual average mixing ratios of NH 3 , NO, CO, NMHCs, and CH 4 were 21.2 ± 2.1 ppb, 21.2 ± 6.1 ppb, 1.89 ± 0.18 ppm, 0.67 ± 0.21 ppm and 3.11 ± 0.53 ppm, respectively. Considering NO as a tracer of vehicular plume, ambient NH 3 was correlated with NO during peak traffic hour in the morning (7:00-10:00 h) and evening (17:00-19:00 h) and observed significant positive correlation between them. Result reveals that the mixing ratio of atmospheric NH 3 significantly positive correlated with traffic related pollutants (NO, CO, and NHHCs) during all the seasons (winter, summer, and monsoon). During winter, the average mixing ratio of atmospheric NH 3 was increased by 1.2-3.5 ppb in the morning peak hour, whereas increased by 0.3-1.6 ppb in the evening peak hour. Similarly, an increase in NH 3 mixing ratio was observed during summer (morning: 1.2-2.7 ppb and evening: 1.5-1.6 ppb) and monsoon (morning: 0.4-3.6 ppb and evening: 0.9-1.4 ppb) seasons. The results emphasized that the traffic could be one of the dominant source of ambient NH 3 at the urban site of Delhi, as illustrated by positive relationships of NH 3 with traffic related co-pollutants (NO, CO and NMHCs).

Objectives: With the increasing demand for the detection of occupational hazard factors in workplaces, the national standard determination method for ammonia (sampling with absorbing solution-analysis with Nessler reagent spectrophotometry) in the air of workplace presents many drawbacks during application in China. This review summarized the improvement and the alternate methods of the current sampling and analysis procedures for ammonia, aiming to provide reference to establish an appropriate method for the determination of ammonia in workplace air., Methods: Scientific publications in English and Chinese and the standard methods of the Deutsche Forschungsgemeinschaft (DFG) in Germany, the National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) in the United States, and Ministry of Health in China for airborne ammonia collection and analysis in the workplace were reviewed., Results: The measures to improve the current sampling and analysis procedures for ammonia in China were firstly summarized. For sampling, the decrease of absorbing solution concentration and the methanesulfonic acid solution as the alternate sampling solution were suggested. For analysis, the anti-interference measures and the optimum reaction condition between ammonia and Nessler reagent were discussed. The alternate methods including sampling conducted using solid sorbent tubes and analysis performed by ion chromatography were then considered for the determination of ammonia., Conclusions: The methods-sampling with acid-treated solid sorbent tubes and analysis with ion chromatography-were more suitable for the determination of ammonia in workplace air. However, some details about ammonia sampling and analysis still need further investigation., (© 2019 The Authors. Journal of Occupational Health published by John Wiley & Sons Australia, Ltd on behalf of The Japan Society for Occupational Health.)

The availability of quality water is imperative to human health and ecosystem functioning. This study was aimed at determining the water quality index and examining its suitability to different water uses. Water samples were collected in dry and rainy seasons to capture the influence of seasonal variation. Water quality indicators (pH, electric conductivity (EC), temperature, total dissolved solids (TDS), turbidity, total suspended solids (TSS), nitrate, phosphate, and ammonia) were analyzed in the laboratory, and weighted arithmetic index method was employed to determine the quality index. The water quality index (WQI) showed higher value 870.3 and 1,313 for dry and rainy seasons which indicates that the water is unfit for human use, and the status of the water body is hypereutrophic. With cautions handling, the water appeared to be suitable for irrigation and livestock production but undesirable for aquatic life and resulted in an impairment of the ecosystem. The statistical analysis revealed a significant difference in water quality parameters between dry and rainy seasons (p < 0.05). The overall water quality status demonstrated concerns that could pose a significant risk; hence, measures should be taken to improve the quality and manage water to safeguard human health and environmental safety.

As the most important gas-phase alkaline species, atmospheric ammonia (NH 3 ) contributes considerably to the formation and development of fine-mode particles (PM 2.5 ), which affect air quality and environmental health. Recent satellite-based observations suggest that the North China Plain is the largest agricultural NH 3 emission source in China. However, our isotopic approach shows that the surface NH 3 in the intraregional urban environment of Beijing-Tianjin-Shijiazhuang is contributed primarily by combustion-related processes (i.e., coal combustion, NH 3 slip, and vehicle exhaust). Specifically, the Batch fractionation model was used to describe the partitioning of gaseous NH 3 into particles and to trace the near-ground atmospheric NH 3 sources. With the development of haze pollution, the dynamics of δ 15 N-NH 4 + were generally consistent with the fractionation model. The simulated initial δ 15 N-NH 3 values ranged from -22.6‰ to -2.1‰, suggesting the dominance of combustion-related sources for urban NH 3 . These emission sources contributed significantly (92% on hazy days and 67% on clean days) to the total ambient NH 3 in urban cities, as indicated by a Bayesian mixing model. Based on the Batch fractionation model, we concluded the following: 1) δ 15 N-NH 4 + can be used to model the evolution of fine-mode aerosols and 2) combustion-related sources dominate the near-ground atmospheric NH 3 in urban cities. These findings highlight the need for regulatory controls on gaseous NH 3 emissions transported from local and surrounding industrial sources., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Determining inorganic nutrient profiles to support understanding of nitrogen transformations in stream sediments is challenging, due to nitrification and denitrification being confined to particular conditions in potentially heterogeneous sediment influenced by benthic microalgae, rooted aquatic plants and/or diel light cycles. The diffusive gradients in thin films (DGT) and diffusive equilibration in thin films (DET) techniques allow in situ determination of porewater concentration profiles, and distributions for some solutes. In this study, DGT, DET and conventional porewater extraction (sectioning and centrifugation) methods were compared for ammonium and nitrate in stream sediments under light and dark conditions. Two-dimensional distributions of Fe(ii) and PO4-P were also provided to indicate the degree of spatial and temporal heterogeneity in sediment porewater, which can explain the sources and sinks of ammonium at various depths in the sediments. Although the conventional porewater extraction method consistently measured higher NH4-N concentrations than the DGT and DET techniques, the study showed that the DET measurements were the most reliable indicator of porewater NH4-N concentrations, with the DGT data being usefully supplementary. However, a large proportion of the NO3-N concentrations measured by DGT and DET were close to or below the method detection limits. Therefore, further development of these techniques is required to reduce the blanks and detection limits to allow natural low sediment porewater NO3-N concentrations to be accurately monitored using DGT and DET. The study indicated that benthic microalgae had direct and indirect influences on porewater nutrient distributions over light-dark cycles. Overall, DGT and DET techniques can be useful for monitoring porewater nutrient concentrations and profiles and for determining how biological processes drive changes in sediment nutrient concentrations and distributions.

For determining setback distances considering multiple air pollutants, a comprehensive study was conducted to simulate the atmospheric dispersion of odour, ammonia (NH 3 ), hydrogen sulfide (H 2 S), and respirable dust using an US EPA air dispersion model AERMOD for a commercial dairy, broiler, and cage-layer barn in the Canadian Prairies. The simulation was conducted using five years of meteorological data. Setback distances were determined with the input of varying monthly emission rates of all four air pollutants and odour impact criteria specifically developed for all three odour sources. Results showed the layer barn had the greatest odour impact area (maximum 3023 m for an annual average odour concentration of 0.01 OU m -3 ) followed by the broiler and dairy barns. Due to the prevailing south wind for all three barns, odour traveled farthest in the north. Using the suggested odour impact criteria by the Government of Saskatchewan defined for all odour sources, maximum setback distances were decreasing from 1941 to 641 m for the layer barn and from 980 to 320 m for the broiler barn along with the increasing of odour concentration (OC) thresholds (1-6 OU m -3 ), all in the north direction. While for the dairy barn, setback distances were determined only under an OC limit of 1 OU m -3 ; maximum 205 m in the north and minimum 171 m in the south. Using the newly developed odour impact criteria specifically for the three odour sources, maximum setback distance of 558 m in the north was determined for the layer barn under an odour threshold of 9 OU m -3 . Additionally, the results suggest the use of odour impact criteria for determining setback distance rather than using gas/respirable threshold limits set in ambient air quality standards as the former always requires much greater setback distances than the latter., (Copyright © 2019 Elsevier B.V. All rights reserved.)

Fine particulate matter (i.e., PM 2.5 ) has gained extensive attention owing to its adverse effects. The impacts of PM 2.5 may vary in time and space due to the spatiotemporal variations of PM 2.5 number size distribution and chemical compositions. This research analyzed the latest PM 2.5 chemical compositions measurements with an aim to better understand the dynamic changes of PM 2.5 in response to emission reductions due to the new regulations. The particulate measurements from the Southeastern Aerosol Research and Characterization (SEARCH) network between 2001 and 2016 were analyzed for the spatiotemporal variations of PM 2.5 and inorganic PM 2.5 (iPM 2.5  = SO 4 2- + NH 4 + + NO 3 - ) chemical compositions in the Southeastern United States (U.S.). It was discovered that PM 2.5 and iPM 2.5 mass concentrations exhibited significant downward trends in 2001-2016. Both PM 2.5 and iPM 2.5 mass concentrations were higher at urban and inland sites than rural/suburban and coastal sites. The higher iPM 2.5 concentrations at agricultural sites were attributed to the influences of ammonia (NH 3 ) emissions from animal feeding operations (AFOs). The iPM 2.5 was the dominant contributor to PM 2.5 in 2001-2016 at the coastal sites, whereas organic carbon matter (OCM) was the major contributor to PM 2.5 after 2011 at the inland sites. Our data analysis suggests that significant decrease of PM 2.5 concentrations is attributed to the reductions in nitrogen oxides (NO x ) and sulfur dioxide (SO 2 ) emissions in 2001-2016. Findings from this research provide insights into the development of effective PM 2.5 control strategies and assessment of air pollutants exposure.

Since NH 3 is a significant precursor to ammonium in PM 2.5 and contributes significantly to atmospheric nitrogen deposition but largely remains unregulated in China, the insight into the source of NH 3 emissions by the isotopic investigation is important in controlling NH 3 emissions. In this study, atmospheric concentrations of NH 3 and water-soluble ion composition in PM 2.5 as well as nitrogen isotope ratios in NH 4 + (δ 15 N-NH 4 + ) in Xiamen, China, were measured. Results showed that average NH 3 concentration for the five sites in Xiamen was 7.9 μg m -3 with distinct higher values in the warm season and lower values in the cold season, and PM 2.5 concentration for the two sites (urban and suburban) was 59.2 μg m -3 with lowest values in summer. In the PM 2.5 , NH 4 + concentrations were much lower than NH 3 and showed a stronger positive correlation with NO 3 - than that with SO 4 2- suggesting the formation of NH 4 NO 3 and equilibrium between NH 3 and NH 4 + . Although the concentrations of NH 3 at the urban site were significantly higher than those at the suburban site, no significant spatial difference in NH 4 + and δ 15 N-NH 4 + was obtained. The distinct heavier δ 15 N-NH 4 + values in summer than in other seasons correlated well with the equilibrium isotopic effects between NH 3 and NH 4 + which depend on temperature. The initial δ 15 N-NH 3 values were in the range of waste treatment (- 25.42‰) and fossil fuel combustion (- 2.5‰) after accounting for the isotope fractionation. The stable isotope mixing model showed that fossil fuel-related NH 3 emissions (fossil fuel combustion and NH 3 slip) contributed more than 70% to aerosol NH 4 + . This finding suggested that the reduction of NH 3 emissions from urban transportation and coal combustion should be a priority in the abatement of PM 2.5 pollution in Xiamen.

Air pollutants accumulated in confined livestock barns could impact the health of animals and staff. Particulate matter (PM) and ammonia (NH 3 ) concentrations are typically high in enclosed livestock houses with weak ventilation. The objective of this study was to investigate the distribution of PM in different size fractions and the levels of NH 3 in a high-rise nursery (HN) barn and a high-rise fattening (HF) barn on a swine farm and to analyse the physicochemical properties of fine PM (PM 2.5 , PM with aerodynamic diameter ≤ 2.5 μm). The concentrations of total suspended particles (TSP, PM with aerodynamic diameter ≤ 100 μm), inhalable PM (PM 10 , PM with aerodynamic diameter ≤ 10 μm), PM 2.5 and NH 3 were monitored continuously for 6 d in each barn. The results showed that the concentrations of PM and NH 3 varied with position, they were significantly higher inside the barns than outside (P < 0.01) and significantly higher in the forepart than at the rear of the two barns (P < 0.05). In the HF barn, the values of the two parameters were 0.777 ± 0.2 mg m -3 and 26.7 ± 7 mg m -3 , respectively, significantly higher than the values observed in the HN barn at all monitored sites (P < 0.05). The PM concentrations increased markedly during feeding time in the two barns. Chemical characteristics analysis revealed that the main sources of PM 2.5 in the two barns may have consisted of blowing dust, feed, mineral particles and smoke. In conclusion, the air quality at the forepart was worse than that at the rear of the barns. Activities such as feeding could increase the PM concentrations. The components of PM 2.5 in the two barns were probably blowing dust, feed, mineral particles and smoke from outside., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Ammonia (NH 3 ) emissions from traffic have received particular attention in recent years because of their important contributions to the growth of secondary aerosols and the negative effects on urban air quality. However, few studies have been performed on the impacts of traffic NH 3 emissions on adjacent soil and plants. Moreover, doubt remains over whether dry nitrogen (N) deposition still contributes a minor proportion of plant N nutrition compared with wet N deposition in urban road environments. This study investigated the δ 15 N values of road dustfall, soil, moss, camphor leaf and camphor bark samples collected along a distance gradient from the road, suggesting that samples collected near the road have significantly more positive δ 15 N values than those of remote sites. According to the SIAR model (Stable Isotope Analysis in R) applied to dustfall and moss samples from the roadside, it was found that NH 3 from traffic exhaust (8.8 ± 7.1%) contributed much less than traffic-derived NO 2 (52.2 ± 10.0%) and soil N (39.0 ± 13.8%) to dustfall bulk N; additionally, 68.6% and 31.4% of N in mosses near the roadside could be explained by dry N deposition (only 20.4 ± 12.5% for traffic-derived NH 3 ) and wet N deposition, respectively. A two-member mixing model was used to analyse the δ 15 N in continuously collected mature camphor leaf and camphor bark samples, which revealed a similarity of the δ 15 N values of plant-available deposited N to 15 N-enriched traffic-derived NO x -N. We concluded that a relatively high proportion of N inputs in urban road environments was contributed by traffic-related dustfall and NO x rather than NH 3 . These information provide useful insights into reducing the impacts of traffic exhaust on adjacent ecosystems and can assist policy makers in determining the reconstruction of a monitoring network for N deposition that reaches the road level., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Phytoplankton and epipelon assemblages form the main constituents, and they are producers in aquatic ecosystems, such as streams and rivers. This study was carried out between May 2008 and April 2009 to determine the impacts of polluted water on species variations, compositions, and community metrics in phytoplankton and epipelon at six stations on Ankara Stream. A total of 231 taxa were recorded during the study period, with 131 Bacillariophyta, 3 Charophyta, 41 Chlorophyta, 30 Cyanobacteria, 25 Euglenophyta, and 1 Ochrophyta. Heterogeneity of the stream stations was determined by the use of hierarchical cluster analysis (HCA). Community metrics were compared by using non-parametric tests, while canonical correspondence analysis (CCA) was used for the relationships between environmental variables and species. Variations in water quality and species composition along the stream flow revealed a significant spatial heterogeneity (p < 0.05). However, the upper stations of the stream were represented by unpolluted water quality with low nutrients and conductivity, and the mid- and downstream stations were characterized by high concentrations of ammonia (up to 60 mg L -1 ) and o-phosphate (up to 25 mg/L), with low concentrations of dissolved oxygen (< 1 mg L -1 ). The results, clearly supported by indicator taxa, showed that various domestic and industrial discharges affected the increase in pollution and the spatial heterogeneity. The findings obtained in this study will contribute to future improvements in Ankara Stream watershed studies.

Excess ammonia (NH 3 ) emissions and deposition can have negative effects on air quality and terrestrial ecosystems. Identifying NH 3 sources is a critical step for effectively reducing NH 3 emissions, which are generally unregulated around the world. Stable nitrogen isotopes (δ 15 N) of ammonium (NH 4 + ) in precipitation have been directly used to partition NH 3 sources. However, nitrogen isotope fractionation during atmospheric processes from NH 3 sources to sinks has been previously overlooked. Here we measured δ 15 NNH 4 + in precipitation on a daily basis at a rural forested site in Northeast China over three years to examine its seasonal pattern and attempt to constrain the NH 3 sources. We found that the NH 4 + concentrations in precipitation ranged from 5 to 1265 μM, and NH 4 + accounted for 65% of the inorganic nitrogen deposition (20.0 kg N ha -1 yr -1 ) over the study period. The δ 15 N values of NH 4 + fluctuated from -24.6 to +16.2‰ (average -6.5‰) and showed a repeatable seasonal pattern with higher values in summer (average -2.3‰) than in winter (average -16.4‰), which could not be explained by only the seasonal changes in the NH 3 sources. Our results suggest that in addition to the NH 3 sources, isotope equilibrium fractionation contributed to the seasonal pattern of δ 15 NNH 4 + in precipitation, and thus, nitrogen isotope fractionation should be considered when partitioning NH 3 sources based on δ 15 NNH 4 + in precipitation., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

Current estimates of China's ammonia (NH 3 ) volatilization from paddy rice differ by more than twofold, mainly due to inappropriate application of chamber-based measurements and improper assumptions within process-based models. Here, we improved the Jayaweera-Mikkelsen (JM) model through multiplying the concentration of aqueous NH 3 in ponded water by an activity coefficient that was determined based on high-frequency flux observations at Jingzhou station in Central China. We found that the improved JM model could reproduce the dynamics of observed NH 3 flux (R 2  = 0.83, n = 228, P < 0.001), while the original JM model without the consideration of activity of aqueous NH 3 overstated NH 3 flux by 54% during the periods of fertilization and pesticide application. The validity of the improved JM model was supported by a mass-balance-based indirect estimate at Jingzhou station and the independent flux observations from the other five stations across China. The NH 3 volatilization losses that were further simulated by the improved JM model forced by actual wind speed were in general a half less than previous chamber-based estimates at six stations. Difference in wind speed between the inside and outside of the chamber and insufficient sampling frequency were identified as the primary and secondary causes for the overestimation in chamber-based estimations, respectively. Together, our findings suggest that an in-depth understanding of NH 3 transfer process and its robust representation in models are critical for developing regional emission inventories and practical mitigation strategies of NH 3 .

Although it is generally accepted that δ 15 N in lichen reflects predominating N isotope sources in the environment, confirmation of the direct correlation between lichen δ 15 N and atmospheric δ 15 N is still missing, especially under field conditions with most confounding factors controlled. To fill this gap and investigate the response of lichens with different tolerance to atmospheric N deposition, thalli of the sensitive Evernia prunastri and the tolerant Xanthoria parietina were exposed for ten weeks to different forms and doses of N in a field manipulation experiment where confounding factors were minimized. During this period, several parameters, namely total N, δ 15 N and chlorophyll a fluorescence, were measured. Under the experimental conditions, δ 15 N in lichens quantitatively responded to the δ 15 N of released gaseous ammonia (NH 3 ). Although a high correlation between the isotopic signatures in lichen tissue and supplied N was found both in tolerant and sensitive species, chlorophyll a fluorescence indicated that the sensitive species very soon lost its photosynthetic functionality with increasing N availability. The most damaging response to the different N chemical forms was observed with dry deposition of NH 3 , although wet deposition of ammonium ions had a significant observable physiological impact. Conversely, there was no significant effect of nitrate ions on chlorophyll a fluorescence, implying differential sensitivity to dry deposition versus wet deposition and to ammonium versus nitrate in wet deposition. Evernia prunastri was most sensitive to NH 3 , then NH 4 + , with lowest sensitivity to NO 3 - . Moreover, these results confirm that lichen δ 15 N can be used to indicate the δ 15 N of atmospheric ammonia, providing a suitable tool for the interpretation of the spatial distribution of NH 3 sources in relation to their δ 15 N signal., (Copyright © 2018. Published by Elsevier B.V.)

Struvite recovered from swine wastewater can be used as a good slow release fertilizer. Nevertheless, the presence of heavy metals would be easily precipitated with struvite and increase the ecological risk for its agricultural use. This paper investigated the possibility of using process variables for heavy metal (Cu 2+ , Zn 2+ and Cr 3+ ) minimization during struvite crystallization in swine wastewater. The heavy metal content, effect ratios (ER) of the citric acid concentration under varying conditions were tested and their SEM, EDS and XRD patterns were compared for morphology analysis. The results show that an increase in pH decreased the content of Cu, Zn and Cr in recovered precipitates. Heavy metal content in the precipitates increased markedly with their initial concentrations in the solution. The effect ratio calculation indicates that Cr has the strongest co-precipitation potential, followed by Zn and Cu. An increase in citric acid concentration reduced the heavy metal removal efficiency (14.3, 27.7 and 28.1% for Cu, Zn and Cr, respectively) but did not decrease their content in struvite precipitates. What is more, increase of total ammonia nitrogen (TAN) to soluble phosphate molar ratio significantly decreased Cu, Zn removal efficiency (52.2 and 50% respectively), while Mg:PO 4 P molar ratio had much less effect., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

An ozone abatement strategy for the South Coast Air Basin (SoCAB) has been proposed by the South Coast Air Quality Management District (SCAQMD) and the California Air Resources Board (ARB). The proposed emissions reduction strategy is focused on the reduction of nitrogen oxide (NO x ) emissions by the year 2030. Two high PM 2.5 concentration episodes with high ammonium nitrate compositions occurring during September and November 2008 were simulated with the Community Multi-scale Air Quality model (CMAQ). All simulations were made with same meteorological files provided by the SCAQMD to allow them to be more directly compared with their previous modeling studies. Although there was an overall under-prediction bias, the CMAQ simulations were within an overall normalized mean error of 50%; a range that is considered acceptable performance for PM modeling. A range of simulations of these episodes were made to evaluate sensitivity to NO x and ammonia emissions inputs for the future year 2030. It was found that the current ozone control strategy will reduce daily average PM 2.5 concentrations. However, the targeted NO x reductions for ozone were not found to be optimal for reducing PM 2.5 concentrations. Ammonia emission reductions reduced PM 2.5 and this might be considered as part of a PM 2.5 control strategy. Implications: The SCAQMD and the ARB have proposed an ozone abatement strategy for the SoCAB that focuses on NO x emission reductions. Their strategy will affect both ozone and PM 2.5 . Two episodes that occurred during September and November 2008 with high PM 2.5 concentrations and high ammonium nitrate composition were selected for simulation with different levels of nitrogen oxide and ammonia emissions for the future year 2030. It was found that the ozone control strategy will reduce maximum daily average PM 2.5 concentrations but its effect on PM 2.5 concentrations is not optimal.

The condition of Baiyangdian Lake (BYDL) will improve as the Xiongan New Area evolves and fulfills its role of easing overcrowding and supporting economic growth. Water and sediment samples from BYDL were analyzed to provide information on nitrogen (N) contamination in BYDL. The mean ammonium N (NH 4 + -N), nitrate N, and total N concentrations in the water samples were 0.36, 0.12, and 2.22 mg/L, respectively, and the ranges were 0.003-8.38, 0.06-0.30, and 1.25-10.34 mg/L, respectively. The N concentrations in water gradually increased from the north to the south of BYDL. Sediment at 90% of the sampling sites was in or above the moderately contaminated class (1000-2000 mg/kg) defined in US Environmental Protection Agency total N pollution standards. Positive NH 4 + -N fluxes were found for 28 of the 34 sediment core samples, so the potential for NH 4 + -N being released from sediment was relatively high. The NH 4 + -N fluxes were 5.35-48.76 mg/m 2 /day, and the mean and maximum fluxes were 8.71 and 48.76 mg/m 2 /day, respectively. Benthic organisms will be affected more by NH 4 + -N and NH 3 ·H 2 O in the surface sediment pore water (mean concentrations 4.93 and 0.13 mg/L, respectively) than by the other forms of N., (Copyright © 2018. Published by Elsevier B.V.)

Atmospheric particulate matter (PM) and ammonia pollution from livestock feeding have gradually become the environmental concerns due to the spring up of livestock farms in worldwide. However, researches about the formation of atmospheric particulate matter related to ammonia are still limited. Therefore, a study to survey the total suspended particles (TSP), PM with the diameter less than 10 μm (PM 10 ), PM 4 , PM 2.5 , PM 1 , and ammonia was conducted at four types of hog houses distinguished by its building design as well as manure handling methods in South China. Four hog houses were monitored during three fattening periods from 2016 to 2017. The emissions of NH 3 per hog house averaged 210.42 μg s -1 . The emissions of PM per hog house averaged 2.017 μg h -1 for PM 1 , 2.149 μg h -1 for PM 2.5 , 2.305 μg h -1 for PM 4 , 3.950 μg h -1 for PM 10 , and 9.317 μg h -1 for TSP. The emissions of PM per hog house average 2.017 μg h -1 , 2.149 μg h -1 , 2.305 μg h -1 , 3.950 μg h -1 , and 9.317 μg h -1 , respectively for PM 1 , PM 2.5 , PM 4 , PM 10 , and PM 10 . In each hog house, while the quantity of manure determined the concentration of NH 3 , biological fermentation bed was able to control the ammonia volatilization compared with other three manure handling methods. The largest percentage of fine PM (< 10 μm) is produced by the manual waterless method for manure handling. When it came to the manual waterless method, largest amount of fine PM (< 10 μm) was founded to form. Among various contributions of secondary inorganic PM to PM 1 , the NH 3 was a dominant factor. Based on our experiment, the absolute concentration of NH 3 was inversely proportional to the concentration of PM 1 when the background influence was removed.

Mobile in situ concentration and meteorology data were collected for the Chino Dairy Complex in the Los Angeles Basin by AMOG (AutoMObile trace Gas) Surveyor on 25 June 2015 to characterize husbandry emissions in the near and far field in convoy mode with MISTIR (Mobile Infrared Sensor for Tactical Incident Response), a mobile upwards-looking, column remote sensing spectrometer. MISTIR reference flux validated AMOG plume inversions at different information levels including multiple gases, GoogleEarth imagery, and airborne trace gas remote sensing data. Long-term (9-yr.) Infrared Atmospheric Sounding Interferometer satellite data provided spatial and trace gas temporal context. For the Chino dairies, MISTIR-AMOG ammonia (NH 3 ) agreement was within 5% (15.7 versus 14.9 Gg yr -1 , respectively) using all information. Methane (CH 4 ) emissions were 30 Gg yr -1 for a 45,200 herd size, indicating that Chino emission factors are greater than previously reported. Single dairy inversions were much less successful. AMOG-MISTIR agreement was 57% due to wind heterogeneity from downwind structures in these near-field measurements and emissions unsteadiness. AMOG CH 4 , NH 3 , and CO 2 emissions were 91, 209, and 8200 Mg yr -1 , implying 2480, 1870, and 1720 head using published emission factors. Plumes fingerprinting identified likely sources including manure storage, cowsheds, and a structure with likely natural gas combustion. NH 3 downwind of Chino showed a seasonal variation of a factor of ten, three times larger than literature suggests. Chino husbandry practices and trends in herd size and production were reviewed and unlikely to add seasonality. Higher emission seasonality was proposed as legacy soil emissions, the results of a century of husbandry, supported by airborne remote sensing data showing widespread emissions from neighborhoods that were dairies 15 years prior, and AMOG and MISTIR observations. Seasonal variations provide insights into the implications of global climate change and must be considered when comparing surveys from different seasons., (Copyright © 2018. Published by Elsevier Ltd.)

Ammonia emissions vary greatly at a local scale, and effects (eutrophication, acidification) occur primarily close to sources. Therefore it is important that spatially distributed emission estimates are located as accurately as possible. The main source of ammonia emissions is agriculture, and therefore agricultural survey statistics are the most important input data to an ammonia emission inventory alongside per activity estimates of emission potential. In the UK, agricultural statistics are collected at farm level, but are aggregated to parish level, NUTS-3 level or regular grid resolution for distribution to users. In this study, the Modifiable Areal Unit Problem (MAUP), associated with such amalgamation, is investigated in the context of assessing the spatial distribution of ammonia sources for emission inventories. England was used as a test area to study the effects of the MAUP. Agricultural survey data at farm level (point data) were obtained under license and amalgamated to different areal units or zones: regular 1-km, 5-km, 10-km grids and parish level, before they were imported into the emission model. The results of using the survey data at different levels of amalgamation were assessed to estimate the effects of the MAUP on the spatial inventory. The analysis showed that the size and shape of aggregation zones applied to the farm-level agricultural statistics strongly affect the location of the emissions estimated by the model. If the zones are too small, this may result in false emission "hot spots", i.e., artificially high emission values that are in reality not confined to the zone to which they are allocated. Conversely, if the zones are too large, detail may be lost and emissions smoothed out, which may give a false impression of the spatial patterns and magnitude of emissions in those zones. The results of the study indicate that the MAUP has a significant effect on the location and local magnitude of emissions in spatial inventories where amalgamated, zonal data are used., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Intensification of farming and an increase in motorised traffic have led to elevated nitrogen (N) emissions and thus to eutrophication of the environment, which threatens the nutrient balance in ecosystems. Earlier studies have demonstrated the suitability of mosses as biomonitors for measuring N deposition by comparing the N concentration in moss with that in precipitation. In our study however, we extended the comparison to the dry deposition of gases (nitrogen dioxide, nitric acid, ammonia) and aerosols (nitrate, ammonium), which, together with the N in precipitation, represent the main contributions to total N deposition. The aim of including several N compounds was to see whether the correlation with the N concentration in moss could be improved. We determined total N input from the atmosphere to the ecosystem at 24 sites in Switzerland and compared this value to the N concentration in two moss species collected <1000 m from these sites. Including the gases and aerosols improved the correlation between the N concentration in moss and N deposition. Ammonia was found to be the most important of the additionally included compounds at these sites. Especially at sites with a relatively high ammonia concentration in the air, the inclusion of ammonia improved the correlation of the comparison. We also demonstrate that the particular moss species tested had no influence on the correlation between N in moss and total N deposition. Our data supports the suitability of mosses as biomonitors for estimating N input into ecosystems., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Freshwater quality detection is important for pollution control. Three important components of water quality are pH, ammonia and dissolved H 2 S and there is an urgent need for a high-precision sensor for simultaneous and continuous measurement. In this study, all-solid-state electrodes of Eh, pH, NH 4 + and S 2- were manufactured and mounted to a wireless chemical sensor with multiple parameters. Calibration indicated that the pH electrode had a Nernst response with slope of 53.174 mV; the NH 4 + electrode had a detection limit of 10 -5 mol/L (Nernst response slope of 53.56 mV between 10 -1 to 10 -4 mol/L). Ag/Ag 2 S has a detection limit of 10 -7 mol/L (Nernst response slope of 28.439 mV). The sensor was cylindrical and small with low power consumption and low storage demand to achieve continuous in-situ monitoring for long periods. The sensor was tested for 10 days in streams at Trawsgoed Dairy farm in Aberystwyth, UK. At the intensively farmed Trawsgoed, the concentration of NH 4 + in the stream rose sharply after the application of slurry to adjacent fields. Further, the stream was overhung with extensive vegetation and exhibited changes in pH, which correlated with photosynthetic activity. Measurements of S 2- were stable throughout the week. Our data demonstrate the applicability of our multiple electrode sensor.

Enhanced ammonia (NH 3 ) emissions and deposition caused negative effects on air quality and ecosystems. Precipitation is an efficient pathway to remove NH 3 and particulate ammonium (p-NH 4 + ) from the atmosphere into ecosystems. However, precipitation scavenging of p-NH 4 + in chemical transport models has often considered fine p-NH 4 + , with inadequate constraints on NH 3 and coarse p-NH 4 + . Based on distinct δ 15 N values between NH 3 and NH 4 + in PM 2.5 (particulate matters with aerodynamic diameters ≤ 2.5 μm) or TSP (total suspended particulates), this paper interpreted intra-event variations of precipitation NH 4 + concentrations and δ 15 N values (δ 15 N-NH 4 + values) at Guiyang (Xiao et al., 2015). Generally decreased NH 4 + concentrations across rain events reflected decreasing scavenging of NH 3 and p-NH 4 + . Using a Bayesian isotope mixing model, we found that differing contributions between 15 N-depleted NH 3 and 15 N-enriched p-NH 4 + were responsible for the three-stage variations of intra-event δ 15 N-NH 4 + values. The decreases of δ 15 N-NH 4 + values across the first and third stages indicated more decreases in scavenging p-NH 4 + than NH 3 , while the increases of δ 15 N-NH 4 + values across the second stage were resulted primarily from more increases in scavenging p-NH 4 + (particularly fine p-NH 4 + ) than NH 3 . These results stressed influences of differing scavenging between NH 3 and p-NH 4 + on precipitation δ 15 N-NH 4 + values, which should be considered in modeling precipitation scavenging of atmospheric p-NH 4 + ., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The molecular marker-based chemical mass balance (MM-CMB) method performs well in the source apportionment of organic carbon (OC) but has some difficulty with contributions from primary sources to inorganic secondary ions when apportioning PM 2.5 (particles with aerodynamic diameter of 2.5 μm or less) sources. Positive matrix factorization (PMF) with the input of inorganic and organic tracers can properly estimate the contributions of primary and secondary sources to inorganic secondary ions; however, PMF is unable to apportion several PM 2.5 sources with large fractions of organic carbon and few elemental compositions. In this study regarding data collected in 2011 and 2012 at three sites in Wuhan, China, the MM-CMB model was used to apportion OC in the PM 2.5, and the PMF model was used to apportion the inorganic ions (sulfate, nitrate, and ammonia), dust, and EC. The source contributions of PM 2.5 were estimated by reconstructing masses of bulk chemical components that had been apportioned to real-world sources using suitable source apportionment methods. Good performance of this hybrid source apportionment strategy was observed with ten resolved factors, explaining 70-80% of measured PM 2.5 mass on average. The hybrid strategy takes the advantages of both models in PM 2.5 source apportionment and yields unique source apportionment results for PM 2.5 bulk chemical components, which could provide new information for optimizing air quality regulations for the emission abatement of target PM mass and compositions for countries around the world., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The sources of aerosol ammonium (NH 4 + ) are of interest because of the potential of NH 4 + to impact the Earth's radiative balance, as well as human health and biological diversity. Isotopic source apportionment of aerosol NH 4 + is challenging in the urban atmosphere, which has excess ammonia (NH 3 ) and where nitrogen isotopic fractionation commonly occurs. Based on year-round isotopic measurements in urban Beijing, we show the source dependence of the isotopic abundance of aerosol NH 4 + , with isotopically light (-33.8‰) and heavy (0 to +12.0‰) NH 4 + associated with strong northerly winds and sustained southerly winds, respectively. On an annual basis, 37-52% of the initial NH 3 concentrations in urban Beijing arises from fossil fuel emissions, which are episodically enhanced by air mass stagnation preceding the passage of cold fronts. These results provide strong evidence for the contribution of non-agricultural sources to NH 3 in urban regions and suggest that priority should be given to controlling these emissions for haze regulation. This study presents a carefully executed application of existing stable nitrogen isotope measurement and mass-balance techniques to a very important problem: understanding source contributions to atmospheric NH 3 in Beijing. This question is crucial to informing environmental policy on reducing particulate matter concentrations, which are some of the highest in the world. However, the isotopic source attribution results presented here still involve a number of uncertain assumptions and they are limited by the incomplete set of chemical and isotopic measurements of gas NH 3 and aerosol NH 4 + . Further field work and lab experiments are required to adequately characterize endmember isotopic signatures and the subsequent isotopic fractionation process under different air pollution and meteorological conditions., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Poultry-emitted air pollutants, including particulate matter (PM) and ammonia, have raised concerns due to potential negative effects on human health and the environment. However, developing and optimizing remediation technologies requires a better understanding of air pollutant concentrations, the emission plumes, and the relationships between the pollutants. Therefore, we conducted ten field experiments to characterize PM (total suspended particulate [TSP], particulate matter less than 10 μm in aerodynamic diameter [PM 10 ], and particulate matter less than 2.5 μm in aerodynamic diameter [PM 2.5 ]) and ammonia emission-concentration profiles from a typical commercial poultry house. The emission factors of the poultry house, which were calculated using the concentrations and fan speed, were 0.66 (0.29-0.99) g NH 3 -N bird -1 d -1 for ammonia, 52 (44-168) g d -1 AU -1 (AU = animal unit = 500 kg) for TSP, 3.48 (1.16-9.03) g d -1 AU -1 for PM 10 , and 0.07 (0.00-0.36) g d -1 AU -1 for PM 2.5 . PM and ammonia emission concentrations decreased as distance from the fan increased. Although emission concentrations were similar in the daytime and nighttime, diurnal and nocturnal plume shapes were different due to the increased stability of the atmosphere at night. Particle size distribution analysis revealed that, at a given height, the percentage of PM 10 and PM 2.5 was consistent throughout the plume, indicating that the larger particles were not settling out of the airstream faster than the smaller particles. Overall, the direction of the measured air pollutant emission plumes was dominated by the tunnel fan ventilation airflow rate and direction instead of the ambient wind speed and direction. This is important because currently-available air dispersion models use ambient or modeled wind speed and direction as input parameters. Thus, results will be useful in evaluating dispersion models for ground-level, horizontally-released, point sources and in developing effective pollutant remediation strategies for emissions., (Published by Elsevier Ltd.)

Abundance and spatial distribution of benthic foraminifera were used to evaluate the impacts of anthropogenic activities on sediment quality in a coastal lagoon in the Gulf of California. In 1985 and 2013, 27 samples of superficial sediments were collected. The foraminifera genera Ammonia, Cribroelphidium, Quinqueloculina and Peneroplis were dominant in both years. The abundance of Ammonia increased from 41% to 60%, while Peneroplis abundance decreased from a maximum of 50% in 1985 to 7% in 2013. The greater abundance of Ammonia and the greater spatial coverage of Ammonia and Cribroelphidium suggest a marked environmental deterioration in the quality of the sedimentary environment, which contrasts with studies of trace elements in the sediment of this lagoon. The Foram Stress Index indicates that sediment quality has deteriorated over time, likely due to the effects of anthropogenic activities around the lagoon., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Ammonia levels were evaluated in the urban environment of Madrid City, Spain. A total of 110 samplers were distributed throughout the city. Vehicle traffic density, garbage containers and sewers were identified as local emission sources of ammonia. The average ammonia concentrations were 4.66 ± 2.14 µg/m 3 (0.39-11.23 µg/m 3 range) in the winter and 5.30 ± 1.81 µg/m 3 (2.33-11.08 µg/m 3 range) in the summer. Spatial and seasonal variations of ammonia levels were evaluated. Hotspots were located in the south and center of Madrid City in both winter and summer seasons, with lower ammonia concentrations located in the north (winter) and in the west and east (summer). The number of representative points that were needed to establish a reliable air quality monitoring network for ammonia was determined using a combined clustering and kriging approach. The results indicated that 40 samplers were sufficient to provide a reliable estimate for Madrid City.

Excessive nitrogen (N) fertilizers are often used in China, and a large proportion of the N can be lost as ammonia (NH 3 ). However, quantifying the NH 3 emission from paddy fields is always affected by large uncertainties due to different measuring methods and other factors such as climate. In this study, using a standardized method, we measured the NH 3 emissions in three typical annual rice cropping systems: single rice, double rice and rotation with other crops. The measurements were conducted for 2 years with a total of 3131 observations across China. Results showed that NH 3 emissions accounted for 17.7% (14.4-21.0%) of the N applied under current farm practice, which was 33.1% (10.6-52.6%) higher than previous estimates. Nitrogen application rate was the dominant factor influencing NH 3 emission rate, which exponentially increased with the N fertilizer rate (p < .001). Total NH 3 emissions from paddy fields were estimated at 1.7 Tg N yr -1 in 2013 in China, several times the amount of N lost through leaching or runoff. This suggests that mitigation measures for non-point source pollution from cropland should take into account not only the N lost to water, but also to air, thereby improving air quality., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Ammonia (NH 3 ) emissions are linked to eutrophication, plant toxicity and ecosystem shifts from N to P limitation. Bryophytes are key components of terrestrial ecosystems, yet highly sensitive to N deposition. Hence, physiological responses of mosses may be indicative of NH 3 -related impacts, and thus useful to foresee future ecosystem damages and establish atmospheric Critical Levels (CLEs). In this work, samples of Hypnum cupressiforme Hedw. were seasonally collected along a well-defined NH 3 concentration gradient in an oak woodland during a one-year period. We performed a comprehensive evaluation of tissue chemistry, stoichiometry, metabolic enzymes, antioxidant response, membrane damages, photosynthetic pigments, soluble protein content and N and C isotopic fractionation. Our results showed that all the physiological parameters studied (except P, K, Ca and C) responded to the NH 3 gradient in predictable ways, although the magnitude and significance of the response were dependent on the sampling season, especially for enzymatic activities and pigments content. Nutritional imbalances, membrane damages and disturbance of cellular C and N metabolism were found as a consequence to NH 3 exposure, being more affected the mosses more exposed to the barn atmosphere. These findings suggested significant implications of intensive farming for the correct functioning of oak woodlands and highlighted the importance of seasonal dynamics in the study of key physiological processes related to photosynthesis, mosses nutrition and responses to oxidative stress. Finally, tissue N showed the greatest potential for the identification of NH 3 -related ecological end points (estimated CLE=3.5μgm -3 ), whereas highly scattered physiological responses, although highly sensitive, were not suitable to that end., (Copyright © 2017 Elsevier B.V. All rights reserved.)

Ammonia monitoring is important to control anaerobic digestion (AD) process due to inhibition effect. Here, an electrolysis cell (EC) was integrated with a complete nitrification reactor as an alternative approach for online monitoring of ammonia during AD processes. The AD effluent was pumped into nitrification reactor to convert ammonia to nitrate, followed by the introduction of nitrate-rich effluent to EC cathode. It was first evaluated with synthetic ammonia-rich digesters and was observed that the current at 5 min were linearly corresponding to the ammonia levels (from 0 to 7.5 mM NH 4 + -N, R 2  = 0.9673). The linear relationship was always observed regardless of different wastewater pH and external voltage. Pre-removal of other electron acceptors from digestate at cathode could eliminate their disturbances to sensor performance. Finally, the accuracy of biosensor was verified with real digestate test. The simple and reliable biosensor showed great promising for online ammonia monitoring of AD processes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)