Atmospheric Environment: X最新文献

{"title":"Influence of meteorological variables on PM2.5 concentrations in cities heated with solid fuels: A case study from Temuco, Chile","authors":"Aner Martinez-Soto ,&nbsp;Mark F. Jentsch ,&nbsp;Victoria Martinez-Gallegos ,&nbsp;Jonas Duchêne ,&nbsp;Alexander Zipf","doi":"10.1016/j.aeaoa.2025.100401","DOIUrl":"10.1016/j.aeaoa.2025.100401","url":null,"abstract":"<div><div>Understanding how meteorological conditions influence fine particulate matter (PM_2.5) is crucial in cities where residential biomass combustion is a dominant emission source. This study analyses the effects of temperature, wind speed, relative humidity, atmospheric pressure and precipitation on PM_2.5 concentrations during the 2019 winter heating season in Temuco, Chile — a city largely dependent on wood for space heating. Data from 11 monitoring stations reveal that PM_2.5 levels increase with low temperatures and wind speeds, showing inverse correlations with both, temperature (r = −0.36 to −0.09) and wind speed (r = −0.30 to −0.24). Atmospheric pressure displays a weak positive correlation (r = 0.03–0.30), while humidity and precipitation show variable, site-specific effects. Extreme pollution episodes with PM_2.5 &gt;500 μg/m³ coincide with periods of meteorological stability and an increased need for space heating. These results demonstrate that high PM_2.5 concentrations arise from the combined effect of strong local emissions and meteorological conditions that inhibit dispersion. The findings provide quantitative evidence to support weather-based air quality forecasting and targeted emission reduction strategies for biomass-dependent urban areas.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100401"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145692200","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":"Capturing well integrity loss through measurements of methane and ethane emissions from surface casing vents and soils surrounding oil and gas wells","authors":"Khalil El Hachem ,&nbsp;Meghan Flood ,&nbsp;Sarah Kennedy ,&nbsp;Scott P. Seymour ,&nbsp;David Risk","doi":"10.1016/j.aeaoa.2026.100419","DOIUrl":"10.1016/j.aeaoa.2026.100419","url":null,"abstract":"<div><div>Oil and gas wells (OGWs) can leak and lead to methane (CH₄), ethane, and other contaminant emissions through gas migration (GM) and surface casing vents (SCV)s. Studies assessing the relationship between SCV and GM emissions using field measurements, as well as those measuring GM variability with well parameters, are limited. Moreover, studies based on industry-reported data are constrained by data limitations and often yield contradictory results. Here, we used static chambers to make 1241 measurements of soil CH₄ emissions, indicative of GM, near 60 OGWs in Alberta and British Columbia, Canada. Additionally, we screened for SCV emissions at 41 of the 60 GM-measured wells and measured SCV flows at 37 wells using a regulatory-compliant flowmeter. We found that soil CH₄ emissions varied by well status, produced fluid and the presence of hydrogen sulfide, and we observed a correlation between the occurrence of GM and SCV emissions. We estimated a GM occurrence rate of 21.6 %, with plugged and unplugged abandoned wells having the largest occurrence rates of 30 and 25 %, respectively. In terms of SCVs, our screening tests revealed that 70.7 % of them (29 of 41) had emissions indicative of subsurface leaks, while flowmeter measurements showed positive SCV flows in 48.6 % of the measured SCVs (18 of 37). In Alberta, out of 31 wells not listed in the SCV flow and GM report, 6 had soil emissions indicative of GM, and 15 of 23 tested SCVs had positive emissions. Overall, our results suggest that provincial data may under-detect and under-report both GM and SCV emissions, particularly at plugged abandoned wells, underscoring the need for improved monitoring approaches.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100419"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188004","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":"Assessment of ammonia emission mitigation efficiency of established and novel field application techniques for anaerobically digested slurry","authors":"Johanna Pedersen ,&nbsp;Sasha D. Hafner ,&nbsp;Cristiane Romio ,&nbsp;Andreas S. Pacholski","doi":"10.1016/j.aeaoa.2026.100415","DOIUrl":"10.1016/j.aeaoa.2026.100415","url":null,"abstract":"<div><div>Biogas can be produced from anaerobic digestion of animal slurry. In Denmark, recalcitrant biomasses are often added along with slurry, resulting in a high dry matter digestate with a high potential for ammonia emission following field application. A total of 12 field trials were conducted to quantify the effects of two digestate treatments and four application techniques on ammonia emissions after field application. Digestate was treated by low dose acidification and separation and applied by trailing hose, trailing shoe, a novel combination of trailing shoe and harrowing tine, and open slot injection. Emissions were determined with a system of dynamic flux chambers and cavity ring-down spectroscopy. Measured ammonia emissions varied substantially among trials and were clearly related to digestate source. Acidification with 1 kg concentrated sulfuric acid per ton slurry effectively reduced emissions in some cases, but the effect was inconsistent and most likely related to dry matter content of the digestate. There were lower cumulative emissions from the liquid fractions after separation compared to the unseparated digestate in all cases, but the reduction effect varied considerably (33–83 %). There was no clear difference between trailing hose and trailing shoe. But the modified trailing shoe with harrowing tine significantly reduced cumulative emissions compared to the trailing shoe only (34–39 %). Based on the data, it is not feasible to recommend one universal application approach or treatment strategy for consistently reducing emission under all conditions. Future work should investigate the sources of variation in emission mitigation, to understand when specific measures are effective.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100415"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146187951","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":"From release rates to annual emissions: Developing emission factors for excavation damaged underground natural gas distribution pipelines","authors":"Trevor B. Webber ,&nbsp;J.R.R. Navodi Jayarathne ,&nbsp;Kathleen M. Smits","doi":"10.1016/j.aeaoa.2026.100418","DOIUrl":"10.1016/j.aeaoa.2026.100418","url":null,"abstract":"<div><div>Estimating natural gas emissions from excavation damage in underground distribution pipelines currently lacks a standardized procedure, resulting in high uncertainty and inconsistent inventories. While previous research has focused on preventing and analyzing leak events, there remains a gap in using excavation event data to understand emissions. This study develops four sets of emission factors based on quantified release rates from operator-reported data. Using publicly available records of 1492 reported significant incidents from 2010 to 2024, we quantified release rates for 246 excavation-related events using two methods: an empirical approach based on reported release volumes, assumed leak durations, and a physics-based approach incorporating pipeline pressure and leak geometry. For each approach, emission factors were generated by calculating an average across all samples, and by applying k-means clustering to group the samples into ten distinct clusters. The two release rate approaches combined with the two emission factor techniques produced four annual natural gas emission estimates, ranging from 291,147 to 746,721 kg. The empirical method produced emission estimates 2.5 times higher than the physics-based method, while grouping increased estimates by 11% over using the single emission factor estimates. All four methods achieved a 95% confidence interval under 34% for annual emissions, a significant improvement to the 1925% interval from current estimates. By leveraging operator-reported data, physics-based models, and clustering, this study provides a reliable foundation for estimating annual natural gas emissions from excavation-induced pipeline leaks and supports more accurate inventory development for regulators and operators seeking consistent emission inventories.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100418"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188044","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":"An update of emission factors for nitric oxide emissions from croplands and grasslands","authors":"Gokul Prasad Mathivanan ,&nbsp;Andreas Gattinger ,&nbsp;Roland Fuß","doi":"10.1016/j.aeaoa.2025.100410","DOIUrl":"10.1016/j.aeaoa.2025.100410","url":null,"abstract":"<div><div>Nitric Oxide (NO), an intermediate product in the soil nitrogen cycle, is also an air pollutant causing adverse health effects, including contribution towards the formation of fine particulate matter and tropospheric ozone. Accurate quantification of NO emissions is necessary to mitigate these impacts, but current emission factors used in national greenhouse gas and air pollutant inventories are associated with substantial uncertainty, necessitating an updated assessment based on recent field measurements. In this study, we compiled a comprehensive dataset of 692 field observations of NO measurements from 128 studies conducted globally. Using Bayesian generalised linear mixed-effects models, we derived new emission factors that account for synthetic and organic fertiliser inputs, climate zones and crop groups. The new global emission factor (expressed as mass fraction of nitrogen) for synthetic nitrogen inputs to common crops and grasslands was 0.0042 kg NO-N (kg N)⁻¹ (95 % credible interval: 0.0035–0.0049), while organic nitrogen inputs exhibited a negligible fertiliser induced emission factor of 0.0001 kg NO-N (kg N)⁻¹ (95 % CI: 0.0003 – 0.0005). The emission factors varied markedly upon stratification by climate zones and crop groups, with higher emission factors from synthetic fertilisers in the tropical rainforest regions, while paddy rice cultivation exhibited negligible fertiliser-induced NO emissions and tea plantations showed exceptionally high emissions with a factor of 0.0155 kg NO-N (kg N)⁻¹ (95 % CI: 0.0101–0.0225). The new emission factors are considerably lower than the Tier 1 value of 0.0133 (0.0015–0.0317) kg NO-N (kg N)⁻¹), currently recommended in the EMEP/EEA guidelines. Application to nitrogen fertiliser input data from EU member states' 2025 Informative Inventory Reports indicates that, adopting the new emission factors would result in reported emissions from synthetic fertilisers being lower by approximately 65 %. These findings highlight the need for refined inventory methodologies, replacing the default emission factor with climate and crop specific values, to better inform strategies for nitrogen management and air quality monitoring.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100410"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146077692","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":"The aqueous film formed on aerosol surfaces enhances the absorption of urban locally emitted free amino acids during the dust event","authors":"NengJian Zheng ,&nbsp;Ren-Guo Zhu ,&nbsp;Meiju Yin ,&nbsp;Yaping Li ,&nbsp;Yujun Ma ,&nbsp;Yuanyuan Zhu ,&nbsp;LingShuang Deng ,&nbsp;Hao Xiao ,&nbsp;Yichen Zou ,&nbsp;Hua-Yun Xiao","doi":"10.1016/j.aeaoa.2025.100407","DOIUrl":"10.1016/j.aeaoa.2025.100407","url":null,"abstract":"<div><div>Free amino acids (FAAs) are essential bioavailable organic nitrogen compounds, yet their atmospheric concentrations, distributions, sources, and secondary formation processes during dust events remain poorly understood. Here, we investigated FAA concentrations, molecular distributions, and δ¹⁵N signatures in PM_2.5 collected from four cities in the Beijing-Tianjin-Hebei air pollution transport channel during spring 2018 to investigate the impact of a dust event on the concentrations, sources and formation mechanism of FAAs in PM_2.5. During the dust event, total FAA (TFAA) concentrations across all sites were substantially higher than those environments not influenced by the dust events and exhibited a strong linear correlation with PM₁₀ (<em>r</em> = 0.6, <em>p</em> &lt; 0.01), indicating that dust events significantly enhance FAA levels. We observed regional variability in the average TFAA concentration during the dust event. The concentrations in Beijing, Tianjin, Shijiazhuang and Taiyuan increased by factors of 1.05, 1.36, 1.55 and 1.63, respectively. Among these four sites, Taiyuan exhibited the most pronounced increase, with its TFAA concentration rising from 0.24 ± 0.07 μg m⁻³ during the non-dust period to 0.39 ± 0.003 μg m⁻³ during the dust event (<em>p</em> &lt; 0.05). These regional differences underscore the influence of local sources and atmospheric quality parameters. The consistent FAA composition profiles and δ¹⁵N values of TFAA and glycine between dust and non-dust periods across all sites further supported that local sources, rather than long-range transport from the Gobi Desert, was the major contributor to atmospheric FAA pool even during the dust event. In Taiyuan, temporal variations of aerosol liquid water (ALW) were highly correlated with total and subgrouped FAAs (r &gt; 0.8, <em>p</em> &lt; 0.01), identifying ALW as a key factor controlling FAA concentrations. It suggested that even under the low relative humidity conditions of dust events, hygroscopic aerosol growth can facilitate the partitioning of FAAs into the particle phase, leading to higher observed FAA concentrations. Our findings provide new insights into the impact of dust events on FAAs in polluted urban environments and provide a basis for assessing the ecological effects of atmospheric dust transport.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100407"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145924771","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 on-road emissions of heavy-duty vehicles under China VI","authors":"Mingda Wang ,&nbsp;Mingming Yang ,&nbsp;Rui Zhou ,&nbsp;Jing Qin ,&nbsp;Yiqiang Pei","doi":"10.1016/j.aeaoa.2026.100427","DOIUrl":"10.1016/j.aeaoa.2026.100427","url":null,"abstract":"<div><div>The implementation of China VI emission standards for heavy-duty vehicles (HDVs) necessitates a thorough evaluation of their real-world emission performance beyond conventional laboratory certification procedures. This study assesses the on-road emissions of China VI-compliant HDVs by collecting and analyzing Portable Emissions Measurement System (PEMS) data from 40 vehicles across various categories. The results show that while work-based Moving Average Window (MAW) emission measurements meet China VI regulatory limits, the application of European Union (EU) cold-start inclusion criteria leads to a 100 % to 150 % increase in NOx emissions for N2 and N3 vehicle classes. Additionally, the proportion of low-load work windows for N2 vehicles ranges from 45% to 85%, whereas for N3 vehicles, this proportion typically remains below 50 %. Consequently, the power threshold defining the valid work window significantly impacts NOx emissions in N2 category vehicles. In contrast, compared to NOx emissions, the experimental conditions and calculation methodologies employed in PEMS testing exhibit relatively minor effects on the emission outcomes for carbon monoxide (CO) and particle number (PN).</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100427"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147394896","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":"Ship fuel consumption and emissions during low load manoeuvring conditions","authors":"Mojibul Sajjad ,&nbsp;Thuy Chu-Van ,&nbsp;G.M. Hasan Shahariar ,&nbsp;Kabir Adewale Suara ,&nbsp;Nicholas Surawski ,&nbsp;Timothy A. Bodisco ,&nbsp;Zoran D Ristovski ,&nbsp;Richard J. Brown ,&nbsp;Ali Zare","doi":"10.1016/j.aeaoa.2025.100398","DOIUrl":"10.1016/j.aeaoa.2025.100398","url":null,"abstract":"<div><div>Ship engine loading typically follows the propeller law, with fuel consumption models primarily using engine load as a predictor. However, this study highlights the limitations of propeller laws in accurately representing engine behaviour in port and coastal areas under transient operational conditions (e.g. manoeuvring/running under partial loading at slower speeds). This study presents a comparative analysis of on-board ship measurements and a laboratory study using a testbed diesel engine operating under a custom-designed propeller law transient cycle. Results indicate that the test engine's measured load profile lagged during acceleration and led during deceleration, with this effect intensifying at higher ramp rates. Brake-specific fuel consumption (BSFC) peaked at low loads and decreased at higher loads in departure/arrival scenarios, highlighting the critical role of engine speed under partial loading in operational safety, asset life, and emissions. Additionally, ship EFs (g/kg of fuel) were disproportionately high at low operating loads under partial loading, reflecting increased fuel-specific emissions due to unstable operating conditions. Particle number (PN) and particulate mass (PM₁) EFs are over-estimation at loads &lt;5 % and &lt;4 % respectively, and underestimation for loads &gt;5 % and &gt;4 %, respectively. Low load (≤20 %) correction factors overestimate NO_x, CO, and PM₁ at &lt;5 % load. Above 5 % load, NO_x is underestimated but aligns during approaching to Port of Gladstone (POGL). CO is overestimated leaving Port of Brisbane (POB) but aligns during approaching to POGL. Testbed findings of emissions for different ramps match modelled low load correction factor values, though deceleration EFs (during 8–15 % load) exceed predictions. At ≤10 % load for both acceleration and deceleration states, the low load correction factors differ significantly; at higher loads, they align with the modelled predictions. Testbed engine results align with standard low load correction factors through transient cycle studies, highlighting the need to account for partial loading and dynamic conditions in emission estimates. With the aid of the propeller law drive cycle, the ship activity during the port manoeuvring demonstrated in a testbed engine. Testbed responses under acceleration-deceleration transient run, identified significance differences in specific emissions, and this study bridges a key gap in emission modelling with real-world data and empirical models.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100398"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145625000","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":"Utilization of catalytically cracked waste transformer oil in compression ignition engines: Effects of combustion chamber geometry on efficiency and emission characteristics","authors":"S. Prasanna Raj Yadav ,&nbsp;Seetharaman Sathyanarayanan ,&nbsp;C.G. Saravanan ,&nbsp;D. Damodharan ,&nbsp;S. Balasaraswathy ,&nbsp;Femilda Josephin JS ,&nbsp;Edwin Geo Varuvel ,&nbsp;Jonas Matijošius ,&nbsp;Artūras Kilikevičius ,&nbsp;Haiter Lenin Allasi","doi":"10.1016/j.aeaoa.2025.100402","DOIUrl":"10.1016/j.aeaoa.2025.100402","url":null,"abstract":"<div><div>Research on alternative fuels has received increased attention in recent years because they not only address the sustainability issues associated with fossil fuels but also mitigate the harmful gases released during combustion. This study focuses on the use of recycled transformer oil (WTO) in diesel engines, aiming to harness its energy content, which is typically discarded as waste. The WTO was recycled via catalytic cracking, and CCWTO50 (a 50 % CCWTO and 50 % neat diesel blend) was used as the test fuel. Furthermore, a re-entrant combustion chamber (RCC) and a hemispherical open-type combustion chamber (HCC) were employed to investigate the combustion and emission characteristics of WTO. The combustion characteristics, engine performance, and exhaust gas emission levels were recorded when the CCWTO50 powered the engine for both HCC and RCC geometries. The results indicate that CCWTO50 improved engine performance and reduced emissions compared to diesel fuel. Further improvements were observed when RCC was employed. A higher heat release rate of 169.3 kJ/m³/°C and a peak pressure of 61.54 bar were observed for CCWTO50-RCC. CCWTO50-RCC improved brake thermal efficiency by 3 % compared to diesel-HCC. In addition, CCWTO50-RCC reduced emissions of hydrocarbons (HC), carbon monoxide (CO), and smoke by 8 %, 6 %, and 5 %, respectively, compared to diesel-HCC. Thus, the authors suggest that CCWTO50 with RCC can be effectively used in diesel engines to enhance engine performance and reduce exhaust gas emissions.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100402"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145737856","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":"Difference in ammonia air concentration at two sampling heights from ground surface: implications for deposition research","authors":"Claire Boerée-Kamphorst ,&nbsp;Serigne Lô ,&nbsp;Wietske Dohmen ,&nbsp;Huifang Deng ,&nbsp;Roel Vermeulen ,&nbsp;Gerard Hoek ,&nbsp;René Verburg ,&nbsp;Dick Heederik","doi":"10.1016/j.aeaoa.2026.100424","DOIUrl":"10.1016/j.aeaoa.2026.100424","url":null,"abstract":"<div><div>Monitoring atmospheric ammonia levels (NH₃) is essential for accurately assessing nitrogen deposition, especially in agricultural regions. Conventional dry deposition measurement techniques are costly, complex, and often sparsely deployed, especially in emission hotspots. This limits the empirical basis for evaluating spatial and temporal variability and uncertainty in dry deposition estimates. In this study, we evaluated a low-cost passive sampling approach to monitor vertical NH₃ concentration gradients between two heights (100 cm and 180 cm) across 70 locations in the Netherlands, covering rural, semi-urban, and natural areas. We assessed whether systematically observed NH₃ air concentration gradients can serve as a proxy for estimating near-surface deposition processes. Over 1600 monthly measurement sets were collected and analyzed.</div><div>We observed a consistent and statistically significant vertical concentration gradient, with higher concentrations at 1.8m height than at 1.0m height. The difference (Δ) averaged 0.49 μg/m³, about 4% of the overall sampling area average ambient ammonia concentration. This vertical gradient was detectable despite measurement uncertainty and a low signal-to-noise ratio. Total variability in Δ was only partly explained by spatial and temporal factors, but remained largely unexplained (residual variation) and thus reflected analytical and sampling errors. Spatial and temporal variables which were related to (a higher) Δ were in particular proximity to livestock farms and wind speed.</div><div>Rather than providing direct flux estimates, our findings indicate that vertical NH₃ gradients can function as a diagnostic, proxy for surface atmosphere exchange patterns at local scales. By demonstrating that statistically significant gradients can be detected using low-cost passive samplers when spatial coverage and replication are sufficient, this study extends previous NH₃ monitoring work that has largely focused on single-height concentration measurements. Our study offers a scalable approach to empirically explore spatial variability and uncertainty in dry deposition assessments, particularly in regions with high agricultural emission where conventional flux measurements remain impractical.</div></div>","PeriodicalId":37150,"journal":{"name":"Atmospheric Environment: X","volume":"29 ","pages":"Article 100424"},"PeriodicalIF":3.4,"publicationDate":"2026-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146188046","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}