The transport of ozone from the stratosphere to the troposphere is a key contributor to the tropospheric ozone budget. It is estimated that the stratosphere-to-troposphere flux of ozone (STT) leads to ~500 Tg of ozone transported into the troposphere each year, which is comparable to the net chemical production of ozone within the troposphere. 

We will present an analysis of the tropospheric ozone budget in the CCMI2022 experiments performed with UKESM-StratTrop, a whole atmosphere chemistry-climate model. 

We focus on the specified dynamics experiments covering 1982-2018, during which there was significant ozone depletion.  We intercompare the ozone budget from the derived using the complementary approaches of Ox and Oy species, and use idealised tracers to examine in detail the role of stratosphere-to-troposphere transport on tropospheric composition.  Where possible, these model simulations are compared with in-situ calculation of ozone production and loss rates derived from observations.

How to cite: Griffiths, P., Keeble, J., and Abraham, L.: Analysis of UKESM1-StratTrop CCMI2022 experiments with a focus on ozone trends, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-20001, https://doi.org/10.5194/egusphere-egu24-20001, 2024.

The European megacity of Paris with 11 million habitants provides a unique research platform for atmospheric science. Since 2011, our group has continuously operated a high-resolution Fourier-transform infrared spectrometer (FTS-Paris) for the study of atmospheric composition above Paris. The measurements cover alternatively the near-infrared spectral domain related to the TCCON[1] network (since 2014) and the thermal infrared related to NDACC-IRWG[2] network. So far, there has been limited research into the origins of air masses over Paris. However, understanding the dynamics of the air masses over Paris is crucial for comprehending and studying the city’s atmospheric composition. Consequently, we have studied the seasonal variability of the air mass passing through Paris in the period 2011 to 2020 by using the Hybrid Single-Particle Lagrangian Integrated Trajectory (Hysplit) model. Furthermore, we combined our NDACC-IRWG measurement data with simulated trajectories from Hysplit to investigate the characteristics of the potential source of the specific trace gases by applying Weighted Potential Source Contribution Function (WPSCF). The results illustrated that the air masses above Paris were predominantly contributed from the west the north, while the eastern sector, despite its minor contribution, emerged as a significant source of the specific trace gases from the WPSCF results.

How to cite: Fu, H., Té, Y., Janssen, C., Jeseck, P., Boursier, C., Marie-Jeanne, P., and Rouille, C.: Ten-year air masses contribution study and potential source of specific components in Paris, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19728, https://doi.org/10.5194/egusphere-egu24-19728, 2024.

The stellar occultation technique detects Earth’s atmospheric components by measuring the absorption of the stellar spectrum. In this paper, A method of air density retrieval using stellar occultation transmission data in oxygen absorption A band is studied. In this method, the average single-band transmission in oxygen A-band is used to calculate the effective optical depth of each layer of atmosphere by using the peeling onion algorithm. Then, the effective optical depth of each layer and prior atmospheric temperature data are used to obtain the oxygen number density profile by using the retrieval method. Finally, the stable proportion of oxygen in the atmosphere is taken into account. By introducing the iterative algorithm of atmospheric static equilibrium and ideal gas state equation, the accuracy of air density retrieval is improved under the condition of deviation of prior temperature. The results of simulation retrieval are presented in this paper. This method overcomes the negative influence of prior temperature deviation on the retrieval accuracy, and provides a new method and theoretical basis for stellar occultation detection and air density detection.

How to cite: Li, Z., Wu, X., Yang, J., Tu, C., Hu, X., and Yan, Z.: The Iteration Method for Air Density Retrieval in The Stellar Occultation Measurement, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2664, https://doi.org/10.5194/egusphere-egu24-2664, 2024.

After completion of the robot installation on the International Space Station (ISS) in early March 2017 as an external hosted science payload, the Stratospheric Aerosol and Gas Experiment (SAGE) III became the newest member to the family of space-based solar occultation instruments operated by NASA to investigate the Earth’s upper atmosphere since the late 1970s. One of three identical instruments, the SAGE III/ISS mission was revived in the early 2010s with a primary objective to monitor the vertical distribution of aerosol, ozone and other trace gases to enhance understanding of ozone recovery and climate change processes in the upper atmosphere. The 51.6-degree inclined orbit of the ISS is well-suited for solar occultation and provides near-global observations on a monthly basis with coverage of low and mid-latitudes similar to that of the SAGE II mission, which operated over two decades – outliving its platform.  International commitment to continuing ISS as a science outpost throughout this decade enables SAGE III to serve as a bridge to future stratospheric composition missions.

The nominal science products, derived from sampling spectra covering 290nm to 1030nm and a photo-diode near 1550 nm, include high resolution vertical profiles of ozone, nitrogen dioxide and water vapor, along with multi-wavelength aerosol extinction. Although in the visible portion of the spectrum the brightness of the Sun is a million times that of the full Moon, the SAGE III instrument design covers this large dynamic range, performing lunar occultations on a routine basis to augment the solar products. The standard lunar products include ozone and nitrogen trioxide. Routine observations began June 2017 and continue to the present. This has enabled observations of significant perturbations of the stratosphere induced by multiple episodic terrestrial events - wildfires (two of which were record setting) and volcanic eruptions - and dynamical forcings such as phase changes of the Quasi-Biennial Oscillation (QBO).  Here is presented stratospheric variability as represented in the standard SAGE III/ISS data products since 2017.  The stability of observations afforded by the solar occultation technique is superb for quantifying long-term changes in stratospheric composition.  Thus, comparisons with variability recorded by previous SAGE missions are also shown. 

How to cite: Flittner, D., Roell, M., Manion, R., and Leavor, K.: Stratospheric composition variability observed from the International Space Station (ISS) by the Stratospheric Aerosol and Gas Experiment III (SAGE III/ISS), EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14152, https://doi.org/10.5194/egusphere-egu24-14152, 2024.

The life cycle of a spacecraft starts and ends in the atmosphere: it interacts with the atmosphere right after the launch and during the atmospheric reentry when it usually mostly ablates. Both phases induce emissions of gases and solid particles, providing a source of these components in the middle atmosphere. Little is known about the exact nature, composition and effects of these emissions on the atmosphere and climate, but their impact is expected to rise as more and more orbiting satellites are launched. Ever since the years 2000, the number of space rockets launched per year has increased by a factor 3 globally. At the same time, the number of satellites launched in orbit around the Earth per year has been multiplied by about 30. One may wonder whether changes in the anthropogenic material injected in the terrestrial stratosphere can be detected and what its influence may be. 

In order to study the cosmic dust particles arriving on Earth, the NASA Johnson Space Center (JSC) has been systematically collecting solid dust particles from the Earth’s stratosphere by aircraft equipped with dedicated particle collectors since 1981. So far, 25 catalogs have been published, covering campaigns of collection from 1981 to 2020, with a total of 5071 solid particles that have been preliminary characterized and curated. In this work, we use the preliminary classification of the dust particles. Based on SEM images and X-ray EDS composition the collected dust is separated into four groups: C (Cosmic), TCN (Terrestrial Contaminant Natural), TCA (Terrestrial Contaminant Artificial) and AOS (Aluminum Oxide Sphere). The AOS being mostly generated by solid rocket propellant, they also belong to the TCA class. Our analysis of the data published indicates that from 1980 to 2009 the cosmic dust particles typically represent on average 40% of the collection with TCA and TCN corresponding to about 30% each. In the recent years, the TCA fraction has doubled to about 60% of the collection (2010-2020). This increase in anthropogenic particles is likely due to the overall human space activity and its recent increase. We will present the properties of the solid stratospheric dust particles collected and their evolution with time.

Future work will be dedicated to better classify the natural and anthropogenic particles collected and described in the existing databases. We will use numerical modelling to produce quantitative estimates of the injected mass, the lifetime of particles in the middle atmosphere (stratosphere) and the relative abundance of the anthropogenic particles with respect to the stratospheric background particle population.

How to cite: Lasue, J., Määttänen, A., Zolensky, M., Ravetta, F., and Grunewald, A.: Assessing stratospheric aerosols contamination due to space activities, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-14286, https://doi.org/10.5194/egusphere-egu24-14286, 2024.

Ethane-based chlorofluorocarbons and hydrochlorofluorocarbons can have multiple isomers that are difficult to separate using gas chromatography with detection by electron capture (GC-ECD) or even mass spectrometry (GC-MS). Examples include CFC-113 and CFC-113a; CFC-114 and CFC-114a; CFC-112 and CFC-112a; and HCFC-124 and HCFC-124a.  As a result, atmospheric histories reported in the past by most laboratories for the more abundant isomer can represent an ill-defined combination of both chemicals.  This is especially true for CFC-113 over the past decade, as mole fractions of CFC-113a have increased rapidly during that time and the contribution of this isomer to our understanding of atmospheric changes measured ostensibly for CFC-113 has not been known. Being able to accurately and routinely determine atmospheric abundances for each of these isomers separately from one another is important as these isomers have different environmental impacts (ozone-depleting potentials and global warming potentials) and different sources likely contribute to their emissions.  Here we demonstrate a technique for quantifying the abundances of co-eluting isomers using GC-MS even when ions unique to the different isomers are unavailable.  Initial results for CFC-113 and 113a will be presented that allow a reassessment of the atmospheric decline and global emission rate of CFC-113 over the past decade, and they confirm the rapid increases in the atmospheric abundance of CFC-113a.  Co-variations between the measured CFC-113a atmospheric mole fractions and other gases are observed at particular sites (e.g., Mauna Loa, Hawaii) that help identify regions where CFC-113a emissions are currently substantial, contributing to its rapid global increase.

How to cite: Montzka, S., Vimont, I., Hall, B., and Clingan, S.: Making atmospheric measurements of difficult-to-separate isomers of CFCs routine: a case study of CFC-113 and CFC-113a that refines our understanding of recent atmospheric changes for both of these chemicals., EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-19613, https://doi.org/10.5194/egusphere-egu24-19613, 2024.

The solar absorption spectroscopy has been established as a powerful tool to monitor the trace gas composition of the atmosphere and is used in world wide networks such as TCCON (Total Carbon Column Observing Network) and NDACC (Network for Detection of Atmospheric Composition Change). The solar absorption measurements have the disadvantage that in Arctic regions there are no measurements possible during polar night leading to significant gaps in the data record. To fill those gaps we deploy a Bruker Vertex 80 spectrometer in emission geometry at the AWIPEV station in Ny-Ålesund, Svalbard. For highest possible resolution of 0.08 cm⁻¹, one-sided interferograms are recorded. Total power calibration procedures with two reference black bodies developed for double-sided interferograms (having lower resolution) are adjusted to obtain radiometrically calibrated zenith viewing emission spectra. The optimal estimation method is used to retrieve atmospheric water vapor and methane for cloud-free scenes. Results are compared to radiosondes and TCCON measurements. We investigate in detail the influence of black body emissivity and temperature uncertainty as quality check of our setup. The importance of spectral resolution is tested to prepare our retrieval to work with other instruments such as the 1 cm⁻¹ resolution E-AERI deployed during the MOSAiC campaign.

How to cite: Heizmann, L., Palm, M., Notholt, J., and Buschmann, M.: Infrared emission spectroscopy for trace gas retrievals in the Arctic, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9742, https://doi.org/10.5194/egusphere-egu24-9742, 2024.

Ammonia (NH₃) has direct adverse effects on ecosystems and environment regarding the eutrophication and acidification of soils and water (Cape et al., 2009; Krupa, 2003). As the main alkaline molecule in the atmosphere, NH₃ is also a gaseous precursor of other major secondary pollutants, such as inorganic fine particles: sulphate and ammonium nitrate particles (Seinfeld, and Pandis, 2006), which are very harmful to public health. Ammonia is an atmospheric pollutant mainly emitted by agricultural activities (e.g 80% of the emissions worldwide and 95% of the emissions in Europe) (Génermont et al., 2018; Skorupka and Nosalewicz, 2021) with part from traffic that is highly uncertain in urban areas (Cao et al., 2021). Ammonia emissions are projected to increase in the future due to population growth, rise in food demand and climate change.

Despite its environmental impacts, ammonia is one of the least documented precursors of PM_2.5 in France which is strongly related to the crucial lack of routine ammonia observations. One of the scientific reasons comes from the difficulty to measure atmospheric ammonia in situ due to its polar, sticky, volatile, and highly water-soluble nature (von Bobrutzki et al., 2010) resulting in strong interactions with sampling systems, recently well documented during the French AMICA^* campaign.

An innovative and very promising alternative for monitoring atmospheric ammonia is infrared remote sensing, from the ground or from space. The first multiyear time series of atmospheric NH₃ ground-based measurements over a European megacity (Paris) was performed using Observations of the Atmosphere by Solar absorption Infrared Spectroscopy (OASIS) FTIR observatory, based on the NDACC stations’ methodology, and located in the Paris suburbs (France) (Tournadre et al., 2020). In this presentation, we test different a priori profiles and retrieval methods in order to investigate the robustness of the NH₃-OASIS retrievals. We show the potential of the observatory to assess diurnal variability of ammonia focusing on spring pollution events such as in March 2012 (Kutzner et al., 2021) and compare the measured NH₃-OASIS total columns to simulations from the CAMS data assimilation system (Inness et al., 2019).

*: AMICA consortium : Analysis of Multi-Instrumental Concentrations of Ammonia

References

Cape, J. N., et al., Environmental Pollution, 2009, 157(3), 1033–1037, https://doi.org/10.1016/j.envpol.2008.09.049

Krupa, S. V., Environmental Pollution, 2003, 124, Issue 2, 179–221, https://doi.org/10.1016/S0269-7491(02)00434-7

Seinfeld, J. H. and Pandis, S. N.: Atmospheric Chemistry and Physics: from Air Pollution to Climate Change, third ed., John Wiley & Sons, New York, 1121 pp., 2016

Génermont, S., et al., Data in Brief, 2018, 21, 1119–1124 https://doi.org/10.1016/j.dib.2018.09.119

Skorupka, M., and Nosalewicz, A., Agriculture, 2021, 11(9). https://doi.org/10.3390/agriculture11090822

Cao H., et al., Environmental Science & Technology Letters, 2022 9 (1), 3-9 https://doi.org/10.1021/acs.estlett.1c00730

von Bobrutzki, et al., Atmos. Meas. Tech., 2010, 3, 91–112, https://doi.org/10.5194/amt-3-91-2010

Tournadre, B., et al., Atmos. Meas. Tech., 13, 3923–3937, https://doi.org/10.5194/amt-13-3923-2020, 2020.

Kutzner, R. D., et al., Atmos. Chem. Phys., 21, 12091–12111, https://doi.org/10.5194/acp-21-12091-2021, 2021.

Inness, A., et al., Atmos. Chem. Phys., 19, 3515–3556, https://doi.org/10.5194/acp-19-3515-2019, 2019.

How to cite: Chelin, P., Kutzner, R. D., Brochet, J., Caville, S., Ray, M., Landsheere, X., Cuesta, J., Siour, G., Roustan, Y., Hase, F., and Camy-Peyret, C.: Impact of new retrieval settings on time-series and diurnal variation of retrieved ammonia total columns by ground-based remote sensing (OASIS observatory) over Greater Paris, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-18503, https://doi.org/10.5194/egusphere-egu24-18503, 2024.

Air quality depends on emissions, but climate and meteorology also play a role in it. To understand better the contribution of each of these factors, we have to study the evolution of air pollution by varying these drivers. In this study, we are investigating the role that changes in emissions play in air-quality following the RCP4.5 and RCP8.5 scenarios for the 2026-2035 and 2046-2055 decades. We assume that the changes of climate conditions are negligible in comparison to changes in emissions, thus isolating the contribution of emission changes in future air pollution. To carry out the study, a simulation with present-day (2010-2019 decade) emissions and meteorology was performed, and another four simulations with future emissions are being carried out at the moment. The emission input for 2010-2019 was compiled using the Flexible Universal Processor for Modeling Emissions (http://www.fume-ep.org/), and the two future decades were created by applying scaling factors on the present-day emissions based on the mentioned RCPs. The simulations are being performed both by the Weather Research and Forecast with online chemistry version 4.0.3 (WRF-Chem) model and the Comprehensive Air-quality Model with Extensions (CAMx) version 7.20. The present-day simulation is being validated by studying several pollutants (such as NO2, O3, SO2, CO, PM10 and PM2.5) and meteorological variables and comparing them with observational data.

How to cite: Prieto Perez, A. P., Huszar, P., and Karlicky, J.: Understanding the role of emissions in future air-quality scenarios over Central Europe, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5436, https://doi.org/10.5194/egusphere-egu24-5436, 2024.

High levels of atmospheric pollution degrade air quality, affect the climate and have significant impacts on human health. The climate maps show that the region of South-Eastern Romania (SERO) has started to be to be affected by significant climate changes. Therefore, the spatial variations of the trace gases (NO₂, CO, SO₂, and O₃) by investigating their levels and variations in the atmosphere both from ground based measurements, but also from remote sensing in different areas of this region need to be investigated. The selected sites (urban, suburban and rural types) are subject to different sources of pollution and represent well the pollution spread over a larger area within SERO region. A database (2019-2021) was created for each site considering the ground-based data retrieved from Romanian National Air Quality Network, the remote-sensing data retrieved from the Sentinel 5P TROPOMI instrument and also, for one of the sites studied, we used the data available from Pandonia Global Network Pandora instrument. The meteorological parameters were extracted from the European Centre for Medium-Range Weather Forecasts (ECMWF) Era5 single level products and pressure level products.

During the observation period, univariate and bivariate LISA cluster maps indicate the spatial and temporal behavior is linked to local and regional pollution sources, social behavior and the level of economic development. Trans-regional pollution between different areas within SERO region was found to be very strong. Moreover, the statistical analysis of studied trace gasses (NO₂, CO, SO₂, and O₃) in the areas with lowest concentrations and highest concentrations confirmed the need to take in consideration more factors than just pollution sources (such as traffic, industry type, agricultural and biomass burning activities etc.). Results show that the complexity of atmospheric pollution is related to more than just the identification of pollution sources. It implies the necessity to take into account additional metadata. They also highlights important information on the distribution and variation of selected trace gases, with the potential to help the policy makers in addressing measures to reduce these pollutants.

Acknowledgment: BM work was supported by the University of Bucharest, PhD research grant. The partial support from NO Grants 2014-2021, under Project EEA-RO-NO-2019-0423, contract no 31/01.09.2020 is also acknowledged. We thank R.V. Chiritescu for providing LISA maps.

How to cite: Mihalache, B., Stefan, S., and Iorga, G.: Trans-regional pollution between different areas within South – Eastern Romania is very strong, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-9756, https://doi.org/10.5194/egusphere-egu24-9756, 2024.

The Task Force on Measurements and Modelling (TFMM), established in 1999, operates within the framework of the Cooperative Programme for Monitoring and Evaluation of the Long-range Transmission of Air Pollutants in Europe (EMEP). TFMM serves as a platform for the Parties of the United Nations Economic Commission for Europe’s (UNECE) Convention on Long-range Transboundary Air Pollution to exchange knowledge, share experiences, and develop recommendations on air quality issues.   

TFMM offers a valuable opportunity for the Parties and EMEP Centres to engage in discussions regarding the performance of measurements and models. The focus is on getting improvements in methodologies, considering their diverse applications such as national assessments of air quality, evaluation of transboundary fluxes and their impact on air quality, trend analyses, and more.   

Previous initiatives have encompassed comprehensive measurement campaigns and collaborative modelling exercises, contributing to the understanding of atmospheric processes across national borders.   

In the upcoming 2024-2025 work plan a key focus will be a targeted measurement campaign.  Additionally, TFMM aims to conduct a comprehensive modelling exercise specifically geared towards the studying the impact of volatile organic compounds (VOCs) on ozone formation under heatwave conditions. In parallel, the work involves the exploration of the representation of aerosol chemical composition in air quality models.    

Being a hub for collaborative efforts and scientific advancements within the EMEP framework, TFMM extends an open invitation to the scientific community and academia to actively join the TFMM experts’ community.  

How to cite: Struzewska, J. and Labrador, L.: TFMM: Advancing Air Quality Insights and Collaboration within the EMEP Framework  , EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-16374, https://doi.org/10.5194/egusphere-egu24-16374, 2024.

Anthropogenic activity has caused a dramatic decrease in biodiversity with an estimated 100-1000 fold larger extinction rate compared to the natural background. This biodiversity loss has profound effects on the functioning and stability of ecosystems and consequent adverse societal and economic impacts. Increased deposition of reactive nitrogen (Nr) is one of the major drivers of biodiversity loss, alongside land-use change, biotic exchange, and climate change. The large increase in the input of anthropogenic Nr to the environment is mainly due to combustion, industrial and agricultural processes. The Nr excess is also responsible for degraded soil quality and groundwater pollution.

Emissions of nitrogen oxides (NO_x) and ammonia (NH₃) are the primary sources of atmospheric Nr, while nitric acid (HNO₃) and NH₃ drive most of Nr deposition (more than 90% globally). The cycling of N species in the atmosphere is modulated by aerosol acidity, as it drives the partitioning of each species between the gas and particle phase. In particular, the fraction of HNO₃ partitioning to the condensed phase decreases with acidity, whereas NH₃ has the opposite behavior. Changes in environmental conditions, namely temperature (T) and relative humidity (RH), directly affect aerosol acidity (e.g., a higher RH increases the aerosol water content and decreases the overall acidity – while T has a strong effect in the partitioning constant). Given the large difference in deposition velocity between gas and particles, it is essential to constrain atmospheric acidity to characterize the atmospheric deposition of Nr accurately.

In our study, we used data from the Swiss National Air Pollution Monitoring Network and the ISORROPIA-Lite model to examine aerosol acidity trends over several years, focusing on two Swiss sites: Payerne (agricultural) and Rigi (prealpine). In Payerne, winter brings increased nitrate but reduced acidity due to higher liquid water content. At Rigi, ammonia and sulfate concentrations peak in late spring and summer, about three times higher than in winter, influenced by nearby farming and atmospheric conditions. Despite these variations, aerosol pH at Rigi remains consistently around 3 to 3.5, balanced by the parallel seasonality of ammonia and sulfate. Over the past 14 years, sulfate levels have halved at both sites, as a result of successful emission reduction policies. However, aerosol acidity has remained largely unaffected due to the buffering capacity of ammonia.

Furthermore, we assessed aerosol sensitivity to changes in ammonia and nitrate, along with their deposition patterns. We find that aerosols remain sensitive to both ammonia and nitrate levels throughout the year, although their deposition regimes vary. For instance, in Payerne, nitrate deposition is rapid in summer but slows down in winter. At Rigi, similar patterns are observed for nitrate, with deposition slowing down on about 50% of winter days. Ammonia deposition is consistently fast at both sites, but it slows down for 10-20% of winter days in Rigi.

We conclude by exploring the consequences of these trends for nitrogen emission control strategies and the impact of energy transitions and future climate scenarios on Switzerland's nitrogen cycle, air quality and policy effectiveness.

How to cite: Nenes, A., Baccarini, A., and Waseem, A.: The effect of atmospheric acidity on the reactive nitrogen cycle in Switzerland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-17788, https://doi.org/10.5194/egusphere-egu24-17788, 2024.

  Burning firework is a traditional custom in China during Chinese Spring festival period, and the smoke plums releasing from firework burning are responsible for high concentrations of particles (especially trace metals) and gases. In this work，results from in-situ measurements of chemical components of PM2.5 aerosols and trace gases during three successive spring festival campaigns (2016-2018) are reported. The campaigns were carried out at a regional background station, SORPES, located in the western part of the Yangtze River Delta in eastern China. 

Table 1. Median value of selected trace metals, PM2.5 mass, organic carbon, elemental carbon, ions and trace gas concentration during firework events (FW) and background (BG) periods in three campaigns.

Median concentrations of selected PM2.5 chemical species and trace metals are summarized in Table1. Clear elevations of Sr, Ba, Cu, K and Cl were observed during firework event period than background period, while no clear elevation were found for other species. Time series illustrated in Fig.1 suggested that in our case, Sr followed by Ba were recognised as the best fireworks tracers because their concentration were very high during firework episode and comparable with the detection limits of instrument during the background period. Similar founding was also observed in Spain (Moreno et al., 2010). The higher Sr/PM2.5 ratio (Table 1) suggest higher contribution of firework emission pollution to PM2.5 during firework events compare to background period (5 to 10 times).

Figure 1. Time series of Sr and Ba during three campaigns in 2016-2018.

  Extremely high enrichment factor was determined for Sr, Ba, Cu, Zn and Pb, suggests that they have anthropogenic origin. Mass concentrations of the trace elements and OC, EC data were input into EPA PMF5.0 model to elucidate the possible dominant source. The results suggest that the dominant sources in three campaigns were firework, coal burning, industry, and traffic. Further analysis on PMF and back trajectory statistics are still need to be done.        

How to cite: Chi, X., Wang, L., and Zhu, C.: Effect of fireworks events on urban background PM2.5 composition:  measurement of trace elements at SORPES during spring festival periods 2016-2018, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2199, https://doi.org/10.5194/egusphere-egu24-2199, 2024.

The air quality in Ireland was once significantly deteriorated by air pollutants emitted from domestic coal combustion activities in the 1980s. Thanks to the smoky coal ban which was put into force in 1990, the air pollution in Ireland has been improved gradually and surely. However, extreme air pollutions with the mass concentration of submicron aerosols (PM₁) exceeding 300 μg m^-3 were still observed sporadically during cold months, which were mainly related to domestic solid fuel combustion, and the disproportionate impacts from so-called “low-carbon” and “carbon-neutral” solid fuels (e.g., peat and wood). Moreover, due to the increasing wood stove advertisements and significant fuel price increase caused by Ukrainian-Russian war, the emissions from local solid fuel combustion activities could greatly impair the air quality in Ireland in the future. Since the situation is changing year to year, it’s very critical to conduct continuous field aerosol measurements and have a deeper insight into the medium/long-term variations for more targeted and effective regulations in the future. In this study, based on the parallel real-time measurements of submicron aerosol species at three representative sites over Ireland, the multi-year variations of aerosol chemical composition and source emissions have been analyzed.

The air quality in Dublin has been improved gradually since 2016, with the annual average mass concentration of PM₁ decreased from 8.0 μg m^-3 in 2016 to 4.1 μg m^-3  in 2022, and the total number of days when PM₁ concentration exceeds the WHO recommendation value (15 μg m^-3) has decreased to 11 days in 2022. Specifically, the extreme air pollutions have been reduced significantly, e.g., the maximum hourly PM₁ concentration has decreased to 77 μg m^-3 in 2022 compared to 317 μg m^-3 in 2016.  The high PM₁ concentrations in Dublin were more related to local emissions, especially domestic solid fuel burning, characterized by large contributions from primary organic aerosols. While long-range transport also plays an important role with high fractions of inorganics especially Nitrate (NO₃). The chemical composition of PM₁ in Dublin was similar over the years, i.e., dominated by Organics (Org) and then followed by NO₃ or sulfate (SO₄). However, it’s worrisome to find that the mass concentration of SO₄ has been increasing since 2021 and showed higher contribution to PM₁ especially during cold months, indicating that the sharply increasing fuel prices recently may have led to a change in fuel usage, possibly with more coal and solid fuel combustion in households. This could indicate severe air pollution episodes that need further and more effective regulations in the near future to ensure good enough air quality.  

How to cite: Lei, L., Fossum, K., Lin, C., Ceburnis, D., Afzal, A., Spohn, T., Chevassus, E., O'Dowd, C., and Ovadnevaite, J.: Multi‐year variations of submicron aerosol composition and sources in Ireland, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-2653, https://doi.org/10.5194/egusphere-egu24-2653, 2024.

Biomass burning has been identified as a major cause of poor regional air quality and the dominant source of particulate matter (PM) in the Amazon basin. In this study, we analyse the impact of the upper-level jet on PM_2.5 (PM with an aerodynamic diameter ≤ 2.5 μm) concentrations in tropical South America (SA) from December to February during the period 2003-2022, using the Copernicus Atmosphere Monitoring Service (CAMS) and ERA5 reanalyses. Furthermore, we investigate the response of air pollutants to the joint modulation of the upper-level jet and El Niño-Southern Oscillation (ENSO). First, a climatological analysis shows that PM in the region is largely composed of organic matter and black carbon, with the highest concentrations and temporal variability in Colombia and northeastern Brazil. Regarding the link with the upper-level circulation, we find that PM_2.5 concentrations in northeastern Brazil are reduced on days when the subtropical jet (STJ) is absent, due to increased convection and precipitation over the region. This improvement in air quality is independent of the ENSO phase. Conversely, a prominent STJ inhibits convection and contributes to dry conditions that favour increased biomass burning and elevated pollutant concentrations in the lower troposphere. At a 3-day persistence of these STJ conditions, there is a 90% probability of exceeding the World Health Organisation threshold of 15 μg m^-3. In addition, the co-occurrence of a prominent STJ with an El Niño phase acts synergistically to increase pollutant concentrations, as both reduce precipitation in northeastern Brazil. In combination with La Niña, this upper-level pattern does not modulate PM2.5 concentrations because the wet conditions favoured by this ENSO phase prevail, reducing biomass burning. This study provides new insights into the modulation of air quality by the upper-level atmospheric circulation in tropical SA. The results have the potential to improve short-term predictability and can serve as a first step towards the development of a warning system.

How to cite: Ordóñez, C., Collazo, S., and García-Herrera, R.: Impact of Upper-Level Atmospheric Circulation and El Niño-Southern Oscillation Phases on Particulate Matter Concentrations in Tropical South America, EGU General Assembly 2024, Vienna, Austria, 14–19 Apr 2024, EGU24-5307, https://doi.org/10.5194/egusphere-egu24-5307, 2024.