In agriculture, plant protection products (i.e. pesticides) protect crops from pests, weeds and diseases. However, pesticides introduced into our environment can also contaminate the air, partly due to volatilisation after pesticide application. Measuring volatilisation in field crops requires trapping techniques, which are costly and time-consuming. There is therefore a strong need for metrological developments to implement (1) analysers that can measure pesticide concentrations continuously over a short period of time, (2) the monitoring of pesticide emissions over a sufficiently long period to capture the entire volatilisation period and (3) the acquisition of data sets in little-explored situations, particularly in wine-growing practices.

The aim of the Online-PTR4-Pest project was to develop the measurement of concentration and volatilisation for three pesticides using proton transfer mass spectrometry (PTR-MS). This technique should eventually enable real-time measurement of pesticide concentrations in the air, as well as field measurement of pesticide volatilisation (using inverse modelling or possibly turbulent covariance methods).

Three pesticides were selected: Prosulfocarb, Pendimethalin (two herbicides used in field crops) and Cyflufenamide (a vine fungicide). Several analysers were used: gas chromatography with thermodesorption mass spectrometry (TD-GC-MS) and PTR-MS. Measurement of the two herbicides was validated using the highly sensitive PTR-Qi-TOF-MS (a time-of-flight mass spectrometer with a proton transfer ionisation source and quad used as an ion guide). Gas-phase calibration is a key stage in the metrological development of PTR-MS measurements. A permeation calibration system was developed and successfully tested, enabling the PTR-MS to be calibrated over a concentration range of 3 ppt to 10 ppb for prosulfocarb and 1 ppt to 3 ppb for pendimethalin.

A three-week field campaign was carried out at the ‘BioEcoAgro’ cross-border joint research unit of INRAE in Mons, with measurements on wheat plots. Air concentrations of Proculfocarb and Pendimethalin were quantified (using both analytical chains and a time step of 5 minutes). These air concentrations varied between 0 and 15 µg m 3 for Prosulfocarb and 0 to 3 µg m 3 for Pendimethalin. Volatilisation fluxes for these two herbicides were estimated using two different methods (aerodynamic gradient and inverse modelling). Over the first few days of field measurements, volatilization of Prosulfocarb was around ten times higher than that of Pendimethalin, regardless of the method used. However, the two methods gave different volatilisation values, as the inverse modelling method was made more uncertain by the applications of these pesticides in the surrounding fields. Finally, the Volt'air-Veg model of pesticide volatilisation was tested on the two datasets. The feasibility of measuring gaseous pesticides in the air in real time using a PTR-MS has been demonstrated.

How to cite: Loubet, B., Lafouge, F., Decuq, C., Ciuraru, R., Buysse, P., Esnault, B., and Gros, V.: Online fluxes of pesticides over bare soil in France with a PTRMS: results from French the Online-PTR4-Pest study, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17390, https://doi.org/10.5194/egusphere-egu25-17390, 2025.

Agriculture is a major source of volatile organic compounds (VOCs), key precursors of secondary air pollutants such as ozone and aerosols. These VOCs react with atmospheric oxidants (e.g., hydroxyl radicals, ozone, nitrate radicals) to form more oxidized compounds with a low volatility that can condense to the particulate phase, driving the formation of secondary organic aerosols (SOA). SOA, a major component of atmospheric aerosols, significantly impacts air quality, climate, and human health. However, estimating SOA production remains highly uncertain due to the complexity of these processes and the diversity of precursors. The shift toward sustainable agriculture has increased the use of organic fertilizers, such as sewage sludge, compost, and animal waste. Given the vast agricultural land area, the spreading of organic fertilizers represents a potentially significant source of VOC emissions. However, their impact on the atmosphere remains poorly understood, mainly due to a lack of studies. The general aim of this work is to improve our knowledge on the impact of spreading these organic fertilizers on air quality, as a source of VOCs. Laboratory study was carried out to analyze VOC emissions from organic fertilizers (sewage sludge, compost and methanization digestate) and to assess the impact of temperature on these emissions. An experimental set-up combining a proton transfer reaction time-of-flight mass spectrometer (PTR-ToF-MS), an emission chamber and a multi-valve system was employed to assess VOC emission from three different organic fertilizers, at three temperatures (10°C, 20°C and 30°C).The analysis revealed a total emission of 118 VOCs from digestate, 99 from sewage sludge and 200 from compost. One notable observation is the perceptible diversity in the chemical composition of these three organic fertilizers. Specifically, each fertilizer presents hydrocarbon, oxygenated and nitrogenated compounds, with hydrocarbons and oxygenated compounds dominating in all three fertilizers. On the other hand, sulfur compounds are only present in sludge and compost, while digestate had a significantly higher prevalence of nitrogenated compounds. Acetone (C₃H₆O) is the most emitted compound from digestate and sewage sludge, while methanol (CH₄O) predominates in compost emissions.  In addition, compounds such as monoterpenes (C₁₀H₁₆), cresols (C₇H₈O) and phenols (C₆H₆O), known SOA precursors, were among the most emitted compounds. Secondly, most compounds showed a positive response to temperature, with some increasing linearly and others exhibiting exponential response. Conversely, very few VOCs, such as acetic acid, unexpectedly decreased with rising temperatures. The impact of temperature variations on VOC emissions and the mechanisms driving these patterns will be discussed. Lastly, the potential of organic fertilizers to form ozone through VOC emissions has been estimated for each emitted molecule. Compost had the highest ozone-forming potential followed by sewage sludge and digestate. For digestates and composts, the primary species responsible for ozone formation were hydrocarbons (63% and 60%, respectively), even though oxygenated compounds dominated their emissions. In contrast, for sewage sludge, 56% of the ozone were produced by oxygenates. The results suggested that, from the perspective of air quality, digestate may be a preferable organic fertilizer compared to compost and sewage sludge.

How to cite: khazma, M., Wortham, H., Kammer, J., and Temime-roussel, B.: FERTIPAS: Emissions of organic FERTIlizers as Secondary Organic Aerosol Precursors, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-8992, https://doi.org/10.5194/egusphere-egu25-8992, 2025.

Intensive agricultural systems are a main source of greenhouse gas (GHG) emissions. The nitrogen (N) fertilizers that are applied to crops to increase crop productions during growing season can lose approximately half of the applied N to the atmosphere as nitrous oxide (N₂O) and ammonia (NH₃).This results in growers’ financial losses and can cause environmental pollutions. Quantification of gas emissions not only helps to develop inventories of regional and national emissions but also to improve management practices to mitigate the emissions. However, accurate quantification of the gas emissions at farm scale is challenging as the natural reactive ammonia gas is a “sticky” gas, and N₂O has spatialand temporal variability. There is a need of proper techniques to continually measure a suite of gases including N₂O and NH₃simultaneously to reduce the complexity of using multiple gas sensors for measurements.

A trial was conducted in July 2024 to measure N₂O, NH₃, and CH₄emissions following the fertilizer and fertilizer inhibitor applications at a commercial sugarcane farm in Queensland, Australia. Two separate plots were chosen, one plot was for a control plot with urea fertilizer and the second one was for the treatment plot applying urea and urea inhibitor. At each plot, a slant-path Fourier transform infrared spectrometer (slant-path FTIR) was deployed to measure a suite of gas concentrations for three weeks, including N₂O, NH₃, and CH₄, simultaneously.Thirty-min averaged wind statistics and the coordinates of locations of equipment and experimental plots were collected. These measurements of gas concentration and wind statistics were used to calculate gas fluxes using a micrometeorological technique. The fluxes of N₂O, NH₃, and CH₄from control and treatment plots showed that the effects of inhibitor on reduction of N₂O and CH₄ emissions were significant over the measurement period but NH₃ flux reduction was only triggered by the irrigation event.

How to cite: Sukdanont, P., Bai, M., Kee Lam, S., Suter, H., and Chen, D.:  The use of open-path FTIR techniques to measure nitrous oxide, ammonia, and methane emissions from a sugarcane farm in Australia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-20286, https://doi.org/10.5194/egusphere-egu25-20286, 2025.

The impact of climate change on agricultural emissions becomes important, and strongly affects pollutant levels such as NH₃ in the atmosphere. Atmospheric NH₃ levels and emission rates are very sensitive to meteorology factors such as temperature and precipitation. Being one of the major pollutants emitted from agriculture, NH₃ becoming increasingly important, both because it is a pollutant itself and it contributes to the formation of secondary particulate matter. Long-term assessment of IASI NH₃ retrievals showed localized consistent hotspots in some regions of Türkiye, often associated with agricultural activities. Although, the reported emission levels do not chance, there was significant temporal variation observed in the NH₃ retrievals in those regions.

In this study, twelve years of NH₃ retrievals were spatially processed to obtain annual, seasonal and monthly NH₃ distribution maps with a 1x1 km² gridded domain covering whole Türkiye. The results indicated significant temporal variability which also changes according to different regions. The temporal changes of NH₃ for three localized hotspots with significant agricultural activity among the highest NH₃ levels in Türkiye were selected and evaluated as; Igdir (Cold semi-arid), Izmir (Hot summer Mediterranean) and Samsun (Humid sub-tropical). The selection was performed to identify the different climatic conditions, crop and fertilizer types. Level-2 IASI NH₃ retrievals, yearly agricultural statistics, and meteorological measurements were utilized for understanding the changes in NH₃ levels. Among these hotspots, Igdir has the highest seasonal variation with maximum late spring to summer, and Samsun is with least seasonal variation. Within the years investigated, 2015, 2018-2019 and 2022-2023 showed highest number of extreme NH₃ retrievals. This study aims to provide a new approach to the assessment of agricultural NH₃ variability by the long-term assessment to obtain region-specific temporal profiles which the regional air quality models strongly depend on.

Keywords: ammonia, meteorological factors, temporal variation

Acknowledgements: IASI is a joint mission of EUMETSAT and the Centre National d'Etudes Spatiales (CNES, France). The authors acknowledge the AERIS data infrastructure for providing access to the IASI data in this study and ULB-LATMOS for the development of the retrieval algorithms. This study was supported by the Scientific and Technological Research Council of Türkiye under the grant number 123Y364.

How to cite: Tokgoz, S., Alban, A. M., Saracoglu, S., and Kaynak, B.: Long-Term NH3 Assesment with Meteorological Parameters to Obtain Temporal Profiles in Agricultural Regions, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-17924, https://doi.org/10.5194/egusphere-egu25-17924, 2025.

The Colorado Front Range urban corridor and the plains to the east are important source regions of ammonia (NH₃), an unregulated pollutant primarily emitted from agricultural activities. Upslope flows driven by the mountain-plains circulation and synoptic scale storm circulations periodically transport these emissions into Rocky Mountain National Park located 50 km west, where excess reactive nitrogen (N) deposition is a historical problem with well documented impacts on the ecosystem. A combination of low-cost Radiello passive sampler NH₃ measurements and NH₃ total column retrievals from the Infrared Atmospheric Sounding Interferometer (IASI) are used to assess temporal and spatial variability in NH₃ across three distinct land use categories in the region: agricultural, urban, and rural. The NH₃ mixing ratio from passive measurements was strongly correlated with the number of confined animal feedlot operations (CAFOs) within a 12 km radius, confirming the importance of that emission source category. Ground-level passive NH₃ measurements have a strong correlation with monthly gridded IASI satellite retrievals. Using satellite retrievals, we find an increasing NH₃ trend of approximately 3% per year in agricultural and urban sub-regions. We attribute less than 0.2% of the increasing NH₃ trend to reductions in particle sulfate. The absolute trend follows the spatial distribution of CAFOs. In the agricultural sub-region, the absolute NH₃ trend is on average greater than 2 times larger than that observed in the urban sub-region. The ground-based observations do not have a trend. The lack of ground-based trend is attributed to increasing boundary layer height and dilution of concentrations, through analysis of ERA5 reanalysis data. Lofting NH₃ higher into the atmosphere can increase atmospheric lifetime, associated with transport and deposition further from source regions and increased particle formation. Elevated NH₃ from wildfire smoke was observed in August 2020, a period of active wildfire activity in northern Colorado, from IASI satellite retrievals. This elevation was less apparent in surface measurements, likely also due to the lofting of the smoke plume. Modeled smoke plumes from the Hazard Mapping System were used to assess the potential impacts of wildfires on observed NH₃ trends.

How to cite: Naimie, L., Pan, D., Sullivan, A. P., Corwin, K. A., Benedict, K., Low, L., and Collett, J. L.: Leveraging In Situ and Satellite Data to understand Changing Ammonia above an Agricultural Hotspot, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-13536, https://doi.org/10.5194/egusphere-egu25-13536, 2025.

Over the past century, ammonia (NH₃) emissions have increased with the growth of livestock and fertilizer usage. The abundant NH₃ emissions lead to secondary fine particulate matter (PM_2.5) pollution, climate change, and a reduction in biodiversity, and they affect human health. Up-to-date and spatially and temporally resolved information on NH₃ emissions is essential to better quantify their impact. In this study we applied the existing Daily Emissions Constrained by Satellite Observations (DECSO) algorithm to NH₃ observations from the Cross-track Infrared Sounder (CrIS) to estimate NH₃ emissions. Because NH₃ in the atmosphere is influenced by nitrogen oxides (NO_x), we implemented DECSO to estimate NO_x and NH₃ emissions simultaneously. The emissions are derived over Europe for 2020 on a spatial resolution of 0.2°×0.2° using daily observations from both CrIS and the TROPOspheric Monitoring Instrument (TROPOMI; on the Sentinel-5 Precursor (S5P) satellite). Due to the limited number of daily satellite observations of NH₃, monthly emissions of NH₃ are reported. The total NH₃ emissions derived from observations are about 8 Tg yr⁻¹, with a precision of about 5 %–17 % per grid cell per year over the European domain (35–55° N, 10° W–30° E). The comparison of the satellite-derived NH₃ emissions from DECSO with independent bottom-up inventories and in situ observations indicates a consistency in terms of magnitude on the country totals, with the results also being comparable regarding the temporal and spatial distributions. The validation of DECSO over Europe implies that we can use DECSO to quickly derive fairly accurate monthly emissions of NH₃ over regions with limited local information on NH₃ emissions

How to cite: Ding, J., van der A, R., Eskes, H., Dammers, E., Shephard, M., Wichink Kruit, R., Guevara, M., and Tarrason, L.: Ammonia emission estimates using CrIS satellite observations over Europe, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-6101, https://doi.org/10.5194/egusphere-egu25-6101, 2025.

Excess ammonia (NH₃) emissions from human activities pose critical risks to global ecosystems and human health. Despite the urgent need for NH₃ emission controls, a comprehensive evaluation of the cost-effectiveness of mitigation strategies remains underdeveloped. In this study, we adopt a multi-model framework to assess the cost and impact of 32 mitigation measures across seven key sectors in 185 countries. Our results indicate that targeted implementation of these measures, particularly in the agricultural sector, could reduce global NH₃ emissions by 49% (36–57%). The estimated implementation cost of $279±69 billion outweighs the projected environmental, health, and resource benefits of $568±182 billion. China and India emerge as critical regions for prioritizing NH₃ mitigation, offering the highest societal returns, while Sub-Saharan Africa shows limited economic viability. Future scenario analysis reveals that sustainable policy pathways could reduce NH₃ emissions by 55% by 2050. Conversely, weak climate action and inadequate nitrogen regulations may result in a 19% increase in emissions, exacerbating environmental degradation and hindering progress toward sustainable development goals. Our findings underscore the urgent need for coordinated global efforts and region-specific policies to establish and achieve effective NH₃ mitigation targets.

How to cite: Zhang, X., Gu, B., Winiwarter, W., van Grinsven, H., Sutton, M., and Zhang, S.: Global ammonia emission could be halved with cost-effective measures, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-2618, https://doi.org/10.5194/egusphere-egu25-2618, 2025.

The use of mineral fertilizers in Sub-Saharan Africa (SSA) is crucial for enhancing agricultural productivity but also raises concerns about emissions of nitrous oxide (N₂O), a potent greenhouse gas. Despite their importance for agriculture, N₂O emissions remain poorly understood in SSA, limiting the development of accurate emissions inventories and the adoption of climate-smart agricultural practices.

In the N2O-SSA project, we quantified N₂O emissions from maize and potato cropping systems under nitrogen application rates of 50 kg N/ha and 100 kg N/ha, compared to control plots, using automated static chamber methods. Fertilizer treatments included urea and triple superphosphate (TSP), and control plots received no nitrogen. Preliminary results showed significant temporal and treatment-specific variability in N₂O emissions, with peaks following fertilizer applications and rainfall events, highlighting the interaction between nitrogen availability and soil moisture. Cumulative annual N₂O emissions were found to vary widely depending on nitrogen application rates and crop types, with fertilizer treatments driving the majority of emissions. Emission factors (EFs) were within ranges consistent with previous studies, highlighting differences between crops such as maize and potatoes. Control plots consistently showed negligible emissions, underlining the critical role of nitrogen inputs in driving N₂O fluxes.

These findings underline the importance of crop-specific nitrogen dynamics in shaping N₂O emissions, and the need for tailored nitrogen management strategies to balance agricultural productivity with environmental sustainability. In the next phase of the project, we will analyze soil samples for N₂O isotopic composition, measuring δ¹⁵N-NH₄ and δ¹⁵N-NO₃, in addition to analyzing gas samples to provide further insights into the sources of N₂O emissions. This will inform more efficient nitrogen management practices for sustainable agricultural systems in Sub-Saharan Africa.

How to cite: Ouma, T., Agredazywczuk, P., Barthel, M., Otinga, A., Njoroge, R., Leitner, S., Zhu, Y., Oduor, C., Oluoch, K. C., Obozinski, G., Six, J., and Harris, E.: Improving nitrous oxide (N₂O) emissions accounting in Kenya: Insights and measurement results relating to fertilizer practices, environmental drivers, and N isotopic composition , EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-452, https://doi.org/10.5194/egusphere-egu25-452, 2025.

Two key forms of reactive nitrogen (Nr) in the atmosphere are nitrogen oxides (NO+NO2) and ammonia (NH3). Both species are abundantly emitted from anthropogenic sources (fossil fuel combustion, agriculture) with devastating consequences on the environment, human health and climate. Complementing sparse ground-based measurements, current satellite sounders provide daily coverage of their global distribution. However, the spatial resolution of these instruments (>20 km² for NO2 and >100km² for NH3) is orders of magnitudes greater than the typical size of the main Nr sources (industries, farms, roads), which makes identification of the emitters, and corresponding quantification of their emission strengths particularly challenging.

To understand and address the impacts of a perturbed nitrogen cycle, and in response to the current observational gap, a dedicated satellite for the monitoring of NO2 and NH3 at high spatial resolution has been conceptualised, called Nitrosat. Its main objective is to quantify simultaneously the emission sources of NH3 and NOx at the landscape scale (<0.25 km²) and to characterize seasonal patterns (<1 month) in their emissions. The two imaging spectrometers onboard Nitrosat will operate respectively in the infrared for NH3 and the visible for NO2, offering gapless coverage in a single swath.

Starting from representative examples of measurement techniques that are presently used to derive emission fluxes from NH3 and NO2 satellite observations, we discuss the limitations of current sounders. We introduce the Nitrosat measurement concept and, exploiting both model simulations and aircraft campaign data, provide examples from the EE11 Phase 0 studies of how Nitrosat will enable retrieval of emission fluxes from local and diffuse sources in a way that will not be possible with other current or planned missions.

How to cite: Levelt, P. and Coheur, P. and the Nitrosat Team: Nitrosat, a satellite mission concept for mapping reactive nitrogen at the landscape scale, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-11422, https://doi.org/10.5194/egusphere-egu25-11422, 2025.

Crop production is a major source of agricultural carbon emissions, yet the life cycle carbon footprints (LCCFs) of key global staple crops remain underexplored. This study quantifies the LCCFs of three major grain crops—maize, rice, and wheat—using a hybrid approach that integrates machine learning (ML) models and life cycle assessment (LCA) for the period from 2006 to 2019. We systematically calculated the cradle-to-farm-gate carbon footprint (CF), accounting for emissions from upstream inputs, transportation, and field operations. Emission factors (EFs) and CF compositions were assessed over different time periods. Additionally, we developed a novel Supply-Demand Balanced Carbon Allocation Model (SD-CAM) to trace the sources and flows of upstream CF. Our results reveal a steady increase in the CF of these crops over time, with significant regional variations in both EFs and CF composition. The primary carbon footprint of global rice production is mainly attributed to field carbon emissions, with nitrogen fertilizers as the secondary carbon source. In contrast, nitrogen fertilizers are the dominant carbon source for maize and wheat. Interestingly, while maize's total field emissions are a net carbon source, wheat production acts as a carbon sink. The majority of the CF is concentrated in a few key grain-producing countries, such as China, India, and the United States. Regarding the upstream carbon footprint (IUCCF), major producing countries like China and Canada have consistently been the primary sources of upstream carbon inputs throughout the study period. However, with the rise of global economic initiatives like the Belt and Road, emerging upstream contributors such as Morocco and Vietnam have increasingly become significant contributors in upstream carbon emissions. This study provides valuable insights into the environmental impacts of agricultural production over time, offering guidance for sustainable agricultural policies, carbon responsibility allocation, and international low-carbon cooperation.

How to cite: Liu, S., He, Y., Liu, Y., and Jiang, Q.: Tracing the life cycle carbon footprint of global staple crops: an integrated approach combining machine learning and life cycle assessment, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-4965, https://doi.org/10.5194/egusphere-egu25-4965, 2025.