Atmospheric Environment: X最新文献

{"title":"Quantifying the impact of the uncertainty arising from spatial allocation on public health using CMAQ","authors":"Fulya Cingiroglu ,&nbsp;Ezgi Akyuz ,&nbsp;Mete Tayanc ,&nbsp;Alper Unal","doi":"10.1016/j.aeaoa.2025.100338","DOIUrl":"10.1016/j.aeaoa.2025.100338","url":null,"abstract":"<div><div>The spatial allocation of emissions in air quality models introduces uncertainties that significantly impact pollution exposure assessments. This study quantified the effects of emission allocation uncertainty on atmospheric concentrations and exposure levels using the CMAQ modeling system. The research focused on the Afşin-Elbistan Power Plant (AP), with substantial emissions of SO₂ (∼300,000 t/y) and PM_2.5 (∼6000 t/y), evaluating the variability in concentrations from emission allocation in gridded inventories. 13 model simulations were conducted, including a base case (<strong>c0</strong>) where emissions were spatially allocated based on intersection ratios and 12 scenario cases (<strong>c1–c12</strong>) where emissions were assigned to different grids for 2018. Results showed significant variability in pollution levels and population exposures across scenario cases. In the Maximum Impact Zone (MIZ), annual mean PM_2.5 concentrations ranged from 5.0 to 41.3 μg/m³, with differences up to 24.9 μg/m³ from the base case. SO₂ exhibited even greater variability, with maximum differences reaching 338.2 μg/m³. The 95 % probability range of uncertainty for PM_2.5 was estimated at −45 % to +96 %, while for SO₂, it reached −84 % to +240 %. Grids A–F represent six selected regions with high population density, used to evaluate differences in concentration and exposure across scenarios. In Grid A-F, meteorology influenced these patterns, with low wind speeds causing pollutant build-up in Grid A, while pollutant transport affected Grids D–F in summer. Annual population exposure in Grid C ranged from 1.0 to 2.1 kg/y for PM_2.5 and from 3.9 to 16.7 kg/y for SO₂. This paper highlights the importance of not only absolute emission inventories but also spatial emission allocation in air quality models to enhance regulatory effectiveness and protect public health.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100338"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144240853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Addressing underestimated carbon monoxide emissions in Taiwan using CMAQ and impacts on local ozone concentration","authors":"Chieh-Sen Tsai ,&nbsp;Ping-Chieh Huang ,&nbsp;Hsin-Chih Lai ,&nbsp;John C. Lin ,&nbsp;Hui-Ming Hung","doi":"10.1016/j.aeaoa.2025.100325","DOIUrl":"10.1016/j.aeaoa.2025.100325","url":null,"abstract":"<div><div>Emission inventories play a crucial role in understanding and managing air quality. This research centers on carbon monoxide (CO), a low-reactivity species with a lifetime of 2 months, acting as a tracer for local pollutants. The investigation delves into the potential uncertainties within its emissions and the impacts. CO is significantly underestimated in the current air quality model using Taiwan Emission Data System 9.0 (TEDS 9.0) for Taiwan. The present CMAQ simulation underestimates CO in Taiwan by a factor of ∼3 compared to observations. With the minimum root mean square error (RMSE) analysis between simulation and observation, the optimal emission correction factors are estimated as 2, 4, and 3.6 for northern, central, and southern Taiwan, respectively. The simulated underestimation of CO concentrations, coupled with relatively consistent NOx concentrations compared to observations, might indicate possible uncertainties in emission sources, especially for sources with high CO/NOx ratios, such as vehicles. This discrepancy further suggests the possibility of underestimating other combustion chemical species, such as volatile organic compounds (VOCs), which are not adequately quantified in the ambient environment. Our findings indicate that the adjustment would increase local O₃ concentration (up to 3 ppbv), with a minor decreased influence on NOx (less than 0.5 ppbv), underscoring the importance of accurate emission inventories in air quality modeling and the reassessment of the validity of CO and NOx emissions in a NOx-saturated environment. Our analysis of the potential emission sources highlights the importance of implementing stricter local emission controls and monitoring.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100325"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143829188","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Characterization of emissions from a turbojet engine running on sustainable aviation fuels, blends and conventional jet A1","authors":"Jana Moldanová ,&nbsp;Åsa M. Hallquist ,&nbsp;Michael Priestley ,&nbsp;Kristoffer Danèl ,&nbsp;Bengt Fallenius ,&nbsp;Omar Abdalal ,&nbsp;Annika Potter ,&nbsp;Bo Strandberg","doi":"10.1016/j.aeaoa.2025.100321","DOIUrl":"10.1016/j.aeaoa.2025.100321","url":null,"abstract":"<div><div>Aviation contributes to air pollution and significantly impacts climate change. Sustainable aviation fuels (SAFs) offer a potential solution to reduce CO₂ emissions with the possible co-benefit of reducing emissions of particles. This study evaluates emissions of a turbojet engine using conventional Jet A1 fuel, Biojet fuel (alcohol-to-jet synthetic kerosene with aromatics, ATJ-SKA), hydrotreated vegetable oil (HVO), and their blends. Emissions of particulate matter, gaseous pollutants (NOx, CO, total hydrocarbons, THC), polycyclic aromatic hydrocarbons (PAHs), volatile organic compounds (VOCs) and aldehydes were measured across different engine loads (Taxi, Cruise and Take-Off). The results show that SAFs, particularly neat Biojet and HVO, significantly reduced particle emissions, by 20 – &gt;99 % compared to Jet A1, especially in the Take-Off mode in case of the Biojet fuel. This reduction is likely connected to the differences in the chemical composition of the fuels including higher content of hydrogen and lower content of aromatics and naphthalenes. Emissions of VOCs, PAHs and aldehydes were reduced by 40–50 % in the Taxi mode, which has the highest emission factors and is also responsible for majority of emissions during the LTO cycle, while an increase was observed for the Take-Off mode. Biojet use exhibited improved engine performance at the Take-Off, but fuel blends showed mixed effects on efficiency. This study shows that SAFs present a promising route to reducing aviation's environmental footprint, with co-benefit of reduced impact on air pollution and non-CO₂ climate forcing from reduced particle emissions. Further research is required especially on impact of fuel blends on engine performance and emission characterization.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100321"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Identifying PM2.5-bound metal pollution sources in Southern Thailand using positive matrix factorization and principal component analysis","authors":"Siwatt Pongpiachan ,&nbsp;Sarunpron Khruengsai ,&nbsp;Teerapong Sripahco ,&nbsp;Radshadaporn Janta ,&nbsp;Rungruang Janta ,&nbsp;Jompob Waewsak ,&nbsp;Danai Tipmanee ,&nbsp;Saran Poshyachinda ,&nbsp;Patcharee Pripdeevech","doi":"10.1016/j.aeaoa.2025.100337","DOIUrl":"10.1016/j.aeaoa.2025.100337","url":null,"abstract":"<div><div>This study presents the first integrated source apportionment and health risk assessment of PM_2.5-bound metals in Southern Thailand using Positive Matrix Factorization (PMF) and Principal Component Analysis (PCA). PM_2.5 samples were collected across three urban-industrial provinces, Nakhon Si Thammarat (NST), Phuket (PKT), and Songkhla (SKA), during multiple months in 2023. PMF successfully resolved five major emission sources, including industrial processes, vehicular traffic, maritime fuel combustion, waste incineration, and fossil fuel combustion, explaining 58.4 % of the variance in the dataset. PCA offered complementary insight but lacked the resolution to isolate mixed-source tracers such as vanadium (V) and nickel (Ni), with lower total explained variance. Metal concentrations and source contributions exhibited distinct spatial and seasonal patterns, reflecting dynamic emission influences across the region. Phuket emerged as a hotspot for toxic metal exposure, with the highest hazard index (HI = 1.63) and cancer risk (4.79 × 10⁻⁴), exceeding international safety thresholds. In contrast, NST showed elevated Zn and Ag from traffic-related sources, while SKA was dominated by V and Ni from maritime emissions. Enrichment factor analysis further highlighted anthropogenic signatures, with exceptionally high values for Hg (Log EF = 6.09) in PKT and arsenic (As) (39 % of total metal mass) in SKA. Our findings provide new regional-scale evidence of metal-specific health risks and emission patterns in an understudied Southeast Asian context. This work supports the urgent need for strengthened regulatory policies targeting industrial and vehicular emissions, improved waste management, and expanded air quality monitoring to mitigate public health impacts from PM_2.5-bound metals in Southern Thailand.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100337"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144124961","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Comprehensive assessment of air pollutant emissions, climate scenario projections, and mitigation strategies in Iran","authors":"Saeed Sharafi,&nbsp;Maryam Lorvand","doi":"10.1016/j.aeaoa.2025.100330","DOIUrl":"10.1016/j.aeaoa.2025.100330","url":null,"abstract":"<div><div>Given the escalating environmental degradation and public health concerns resulting from severe air pollution in Iran, this study presents a comprehensive assessment of historical trends and future projections of air pollutant emissions. Focusing on key greenhouse gases (CO₂ and CH₄) and air pollutants (NO₂ and SO₂), the research employs Shared Socioeconomic Pathways (SSPs), Representative Concentration Pathways (RCPs), and the innovative Pattern Mining Engine (PME) model. Covering the period from 1960 to 2100, the study identifies pivotal trends and key change points in emission trajectories. The analysis reveals significant surges in CO₂ and NO₂ emissions, particularly during the late 1980s and mid-1990s, driven by socio-economic transitions and policy shifts. PME projections highlight a sharp increase in CO₂ emissions from 96.6 to 359.08 Mt, and a substantial rise in NO₂ emissions under the RCP_1.9 scenario from 10.44 to 68.48 Mt. Similarly, SO₂ emissions experienced notable growth, with critical inflection points in the late 1980s and mid-1990s, while CH₄ emissions exhibited variable patterns, reflecting divergent source behaviors and mitigation measures. Future projections offer a nuanced perspective on potential emission pathways, indicating significant reductions in CH₄ and SO₂ under SSP1 and SSP5 scenarios, contrasted with continued increases under SSP3 and SSP4 due to slower technological progress. Despite the implementation of ambitious climate policies, the anticipated CO₂ reductions of 23–29 % by 2050 remain insufficient to meet climate targets, underscoring persistent challenges in aligning policy aspirations with tangible outcomes. Sectoral analyses further identify the industrial sector as a major contributor to NO₂ and SO₂ emissions, although SSP1 and SSP5 scenarios foresee marked declines by 2100, driven by cleaner technologies and stricter regulatory measures. This study distinguishes itself through its comprehensive analysis of emission dynamics across multiple scenarios and its critical insights into the effectiveness of various mitigation strategies. The findings emphasize the urgent need for more aggressive, integrated approaches to emission control and climate policy to effectively address rising pollutant levels and curb environmental degradation.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100330"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced thermal performance and hydrochloric acid gas (HCl) emission mitigation in ammonium perchlorate (AP)-Based solid propellants with potassium permanganate (KMnO4)/AP dual oxidisers","authors":"Izzat Najmi Yaacob ,&nbsp;Ezanee Gires ,&nbsp;Adi Azrif Basri ,&nbsp;Kamarul Arifin Ahmad ,&nbsp;Kamsani Kamal ,&nbsp;Nor Afizah Salleh ,&nbsp;Suraya Shahedi ,&nbsp;Fikri Rasih ,&nbsp;Zakwan Azizi ,&nbsp;Sharul Sham Dol ,&nbsp;Norkhairunnisa Mazlan","doi":"10.1016/j.aeaoa.2025.100329","DOIUrl":"10.1016/j.aeaoa.2025.100329","url":null,"abstract":"<div><div>The conventional propellant used in rocket boosters and tactical missiles commonly utilises ammonium perchlorate (AP). However, the release of harmful chloride fumes resulting from the combustion of AP during rocket launches contributes to a 1 % increase in air pollution. Generally, the perchlorate-based propellants contribute to pollution by hydrochloric acid (HCl), which can contaminate launch sites and potentially deplete the ozone layer. Several techniques have been employed to convert standard AP-based composite solid propellant (CSP) into green propellant. This study designed a minimum chlorine content propellant containing potassium permanganate, KMnO₄/AP as a dual oxidiser and examined its properties in CSP formulation. This novel KMnO₄/AP was characterised in terms of morphological structure, elemental analysis, and thermal decomposition properties by using scanning electron microscope (SEM), energy dispersive X-ray analysis (EDX), and differential scanning calorimetry (DSC) and thermogravimetry analysis (TGA), respectively. Additionally, heat of combustion analysis was examined through bomb calorimetry. The chlorine content investigations were experimentally carried out, and the results were compared with conventional AP-based CSP using gas bubbling and Mohr’s titration method. From thermal decomposition analysis, sample KMnO₄/AP (40:60) shifted high temperature decomposition (HTD) of AP to a lowest temperature of 331.32 °C with the highest heat release of 3721.2 J/g. Besides, sample KMnO₄/AP (80:20) shows the highest reduction of chlorine concentration content with a reduction percentage of 58.25 %. Besides, KMnO₄/AP (40:60) sample resulted in the highest value of heat of combustion with a value of 1254.01 cal/g. This study contributes to the development of environmentally friendly and sustainable oxidisers for solid rocket propellant applications.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100329"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143935806","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Impact of wildfire smoke on air pollution-related premature mortality in rapidly growing Kathmandu Valley","authors":"Sajesh Kuikel ,&nbsp;Him Kiran Paudel ,&nbsp;Dipesh Kuinkel ,&nbsp;Khagendra Prasad Joshi ,&nbsp;Saugat Sapkota ,&nbsp;Nabin Malakar ,&nbsp;S.- Y. Simon Wang ,&nbsp;Binod Pokharel","doi":"10.1016/j.aeaoa.2025.100334","DOIUrl":"10.1016/j.aeaoa.2025.100334","url":null,"abstract":"<div><div>The dangers of urban population growth in highly polluted regions are starkly illustrated by the Kathmandu Valley, where nearly half of the days each year exceed the national PM_2.5 air quality guideline of 40 μg/m³. Wildfire smoke, particularly during the pre-monsoon season, is a major contributor to air quality degradation. Using diverse datasets, including in-situ observations, satellite data, and machine learning classification, we identified 311 wildfire smoke days between 2003 and 2023, with smoke events contributing significantly to the valley's persistent poor air quality. While PM_2.5 concentrations showed no significant trend over the study period, premature adult deaths rose dramatically from 1000 in 2004 to 12,600 in 2021. The exponential increase in mortality was largely influenced by rapid population growth from 0.52 million to 4.1 million adults in the valley, rather than solely by worsening air quality. The stable but consistently poor air quality became lethal at a larger scale simply because more people were exposed, with wildfire smoke alone contributing to an average of 70 adult deaths annually. Despite the mortality rate per 100,000 people showing only modest increases, the sheer growth in the exposed population has transformed a persistent air quality problem into a major public health crisis. Our findings demonstrate how population growth in regions with chronically poor air quality can dramatically amplify public health impacts even without air quality deterioration, emphasizing the urgent need for air quality management in rapidly urbanizing regions.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"26 ","pages":"Article 100334"},"PeriodicalIF":3.8,"publicationDate":"2025-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144106499","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On-Board measurement of emissions on a dual fuel LNG powered cruise ship: A sea trial study","authors":"Benoit Sagot ,&nbsp;Guilhem Giraudier ,&nbsp;François Decuniac ,&nbsp;Lise Lefebvre ,&nbsp;Aurelia Miquel ,&nbsp;Amandine Thomas","doi":"10.1016/j.aeaoa.2025.100313","DOIUrl":"10.1016/j.aeaoa.2025.100313","url":null,"abstract":"<div><div>The use of liquefied natural gas (LNG) in dual-fuel engines is expanding in the maritime industry, enabling compliance with sulfur and nitrogen oxide emissions regulations, while also reducing atmospheric emissions of particulate pollutants. LNG further allows for a reduction in direct CO₂ emissions compared to liquid fuels such as marine gas oil (MGO), which also helps meet greenhouse gas emission (GHG) reduction requirements in maritime transport. However, unburned methane emitted by dual-fueled engines remains an area for improvement. In this study, we monitored the atmospheric emissions of unburned methane, along with other gaseous and particulate pollutants, from a 4-stroke dual-fuel engine during sea trials of a new cruise ship, using both LNG and MGO fuels that these engines can operate on. During this ship's commissioning phase, we were able to perform measurements across a wide range of engine loads and confirm higher emission factors for unburned methane at low loads: the emission factor remains relatively stable at around 2.3 g.kWh⁻¹ between 60% and 95% engine load, but increases at lower loads, reaching 8.5 g.kWh⁻¹ at 25% load. For fine particulate emissions, characterized by the number of particles larger than 23 nm (PN₂₃), we established that switching from MGO to LNG results in a reduction factor of approximately 136 in PN₂₃ particles emitted by the engine at high load. The measured emission levels in MGO mode were relatively independent of engine load but tended to increase in LNG mode as engine load decreased. Based on our measurements of methane and CO₂, we propose a comparison of GHG emission levels as a function of engine load, which shows that switching from LNG to MGO at 75% load results in an 18% relative increase in CO₂ equivalent emissions. Finally, we had access to engine load monitoring (ELM) during commercial operation over a 3-month period. The load distribution obtained shows that the diesel-electric architecture, which adjusts the number of engines in operation and their load according to the vessel's energy demands, leads to a limitation in the use of the engine at low load. As a result, less than 7% of the engine operating time is spent at a load below 30%, a threshold beyond which the studied engine emits less than the default FuelEU value of 3.1%. When considering a usage-weighted average, based on the emission factors measured on board and the load distribution derived from the Engine Load Monitoring (ELM), we obtain an emission factor of 3.2 g.kWh⁻¹, or 1.7% of the fuel use. This value of 1.7% is lower than that specified by the FuelEU regulation, and it appears to be representative of the actual emissions of this vessel and its usage under operational conditions.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"25 ","pages":"Article 100313"},"PeriodicalIF":3.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158868","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Estimation of the primary air pollutant emission levels of in-use gasoline vehicles and their influencing factors in Beijing, China","authors":"Yangyang Cui ,&nbsp;Yan Shen ,&nbsp;Lijun Zhu ,&nbsp;Huawei Yi ,&nbsp;Guanghan Huang ,&nbsp;Han Li ,&nbsp;Linzhen Qu ,&nbsp;Aijun Shi ,&nbsp;Yifeng Xue","doi":"10.1016/j.aeaoa.2024.100310","DOIUrl":"10.1016/j.aeaoa.2024.100310","url":null,"abstract":"<div><div>Gasoline vehicles (GVs) have become one of the main emission sources of NOx and volatile organic compounds (VOCs) in Beijing, and determining the pollutant emission levels of in-use GVs is crucial. In this study, we assessed the emission levels, exceedance rates, and factors influencing primary air pollutants (NO, CO, and hydrocarbons (HCs) from GVs, including 7.46 million GVs in Beijing from 2019 to 2023. We predicted the variation in the exceedance rate after implementing the standard b-limit and assessed the social stability risk. In general, the emissions of GVs in Beijing were relatively low. According to the simple driving mode conditions, the CO, HC and NO concentrations in the top 50% of the cumulative probability distributions of emissions were 0.04%, 10.3 ppm and 77.0 ppm, respectively, which account for only 1/10∼1/8 of the standard a-limit values. However, we found that the pollutant concentrations corresponding to the top 10% and 90% of the cumulative probability distributions significantly differed. For example, the NO concentrations in the top 10% were 220 times greater than those in the top 90%, namely, approximately 36.5% greater than the standard limit. The greater risk of exceeding the standards was related to the occurrence of carbon deposits on the valves and cylinder heads of engines, of which medium-duty trucks (MDTs) exhibited the highest rate of exceeding the standards (34.5%) due to vehicle deterioration under high-intensity use. GVs exhibited the highest exceedance rate among all the vehicle types, at 38.7%, whereas China VI vehicles exhibited an exceedance rate of only 0.2%. If the more stringent standard b-limit were implemented, the number of vehicles exceeding the standard would increase, and the exceedance rate of GVs under the standard b-limit would be slightly greater than that under the a-limit. Overall, the exceedance rate showed a decreasing trend with increasing emission stage, with the proportion of the exceedance rate at the different emission stages also varying.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"25 ","pages":"Article 100310"},"PeriodicalIF":3.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Investigating the effects of animal-specific δ15N-NH3 values volatilized from livestock waste on regional NH3 source partitioning","authors":"Dong Liu ,&nbsp;Zhi Quan ,&nbsp;Yingying Wang ,&nbsp;Kai Huang ,&nbsp;Quanping Zhang ,&nbsp;Linlin Song ,&nbsp;Shaonan Huang ,&nbsp;Yanzhi Wang ,&nbsp;Zhifeng Xun ,&nbsp;Deze Liu ,&nbsp;Chang Liu ,&nbsp;Yunting Fang ,&nbsp;Jianping Sun","doi":"10.1016/j.aeaoa.2025.100314","DOIUrl":"10.1016/j.aeaoa.2025.100314","url":null,"abstract":"<div><div>The natural ¹⁵N abundance of ammonia (δ¹⁵N-NH₃) emitted from livestock waste within a specific area (δ¹⁵N-NH₃-LW) can be used to estimate its contribution to atmospheric NH₃ through an isotope mixing model. However, the limited availability of reports on δ¹⁵N-NH₃-LW hinders the accuracy of regional NH₃ source partitioning. In this study, we conducted research in the suburbs of Shenyang, China, and combined our results (n = 71) with data from published literature (n = 56) to develop a δ¹⁵N-NH₃ spectrum emitted from cattle, pig, sheep, and poultry waste. We also explored the national and global spatial distribution of δ¹⁵N-NH₃-LW based on the proportion of NH₃ emissions from these four types of livestock waste. Our results showed that the δ¹⁵N-NH₃ values ranged from −59.9‰ to −7.7‰, with a mean value of −27.3‰. This value was significantly lower than that from non-agricultural sources, such as coal combustion and motor vehicle exhaust, but overlapped with values from fertilizer N volatilization. Specifically, the δ¹⁵N-NH₃ values emitted from cattle, pig, sheep, and poultry waste were −32.1 ± 15.9‰, −20.7 ± 7‰, −24.3 ± 5.9‰, and −19.1 ± 4.9‰, respectively. Considering regional differences in livestock farming structures, δ¹⁵N-NH₃-LW exhibited a gradual decreasing trend from Southeast to Northwest across China. For example, Fujian Province, located on the southeastern coast, exhibited the highest δ¹⁵N-NH₃-LW value of −19.8‰, owing to its high proportion of poultry farming, while the Tibet Autonomous Region, in the western inland, displayed the lowest δ¹⁵N-NH₃-LW value of −30.8‰, due to its high proportion of cattle farming. Globally, the δ¹⁵N-NH₃-LW value was highest in Southeast Asia (−23.4‰) and lowest in East Africa (−30.4‰). Overall, our study revealed significant spatial variation in δ¹⁵N-NH₃-LW at both national and global scales. To more accurately assess the regional contributions of NH₃ emissions from livestock waste, it is essential to use region-specific δ¹⁵N-NH₃-LW values for future NH₃ source partitioning.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"25 ","pages":"Article 100314"},"PeriodicalIF":3.8,"publicationDate":"2025-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143158161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}