This study compares air quality in two European cities with contrasting characteristics during July–October 2024: Leon (Spain) and Gliwice (Poland). Concentrations of PM10, PM2.5, particulate matter chemical composition, and trace gases were analysed alongside meteorological data. The results show that both cities were influenced by local emissions, primarily from traffic, as well as by Saharan dust transport events. Leon, located closer to North Africa, experienced an intense dust intrusion episode with a PM10 peak of 116 µg m−3, whereas Gliwice reached 62 µg m−3. The comparison revealed differences in aerosol intensity and composition, which are determined by geographic location and atmospheric conditions. This analysis highlights the importance of integrating local and regional data to understand urban aerosol dynamics in Europe.

Abstract. Prescribed fires were conducted in two shrubland communities dominated by Genista hispanica subsp. occidentalis and Calluna vulgaris in La Cueta, León, Spain, to characterise particulate and gaseous emissions during combustion. Distinct fire dynamics were observed: Calluna exhibited a Modified Combustion Efficiency (MCE) of 90.6, indicative of flaming combustion, while Genista showed an MCE of 70.8, characteristic of smouldering conditions. Gas-phase analysis revealed notably higher concentrations of CO2, CO, CH4, C2H6, and total organic carbon (TOC) in Calluna compared to Genista, with CO2 showing the greatest difference. Conversely, Genista exhibited slightly elevated NO and NO2 levels. Most gas concentrations were higher for Calluna, except for hydrogen fluoride (HF), which was more abundant in Genista. Elemental carbon (EC) and organic carbon (OC) accounted for 28.1 % and 32.9 % of PM2.5 mass in Calluna and Genista, respectively. Water-soluble inorganic ions contributed 6.9 % and 4.5 % to PM2.5 mass, with most ions more abundant in Calluna, except chloride (Cl⁻), which was higher in Genista. In both cases, Cl-, SO42-, Na+, Mg2+, and Ca2+ dominated the ionic composition. Morphological analysis revealed a population dominated by tar balls (submicrometer spherical particles) and aggregates with thick organic coatings. Derived emission factors are expected to provide valuable input for numerical models evaluating the impacts of prescribed and unplanned forest fires in the Mediterranean region.

The Iberian Peninsula is highly susceptible to Saharan dust intrusions, which have become increasingly frequent and intense in recent years. In March 2022, an exceptional winter dust outbreak affected north-western Spain, producing record PM10 levels across several locations. This study characterises the chemical, optical, and morphological properties of aerosols associated with the event that impacted León (NW Spain) between 14 and 16 March 2022. A month-long sampling campaign (1 – 31 March) was conducted downtown, and PM10 samples were analysed for water-soluble inorganic ions, trace elements, and organic and elemental carbon. Aerosol light absorption and column-integrated optical properties were also evaluated, and selected samples were examined using SEM-EDS. During the intrusion, PM10 reached 370 μg m-3, far exceeding the WHO 24-hour guideline. Average concentrations increased from 16 ± 7.7 μg m-3 under non-dust conditions to 89 ± 115 μg m-3 during the outbreak. Organic carbon rose markedly, reaching 11 μg m-3 compared with 2.2 ± 0.9 μg m-3 in background air. Strong enhancements in crustal elements (Si, Ca, Al, Fe, K, Mg) and major ions (SO42-, Ca2+, NO3-) were consistent with intense mineral dust transport. Aethalometer-derived iron concentrations confirmed substantial dust loading, while an increase in the Ångström Absorption Exponent indicated enhanced UV–visible absorption by dust particles. These results demonstrate severe air-quality deterioration during winter Saharan intrusions and highlight the value of integrating chemical, optical, and morphological analyses to characterise extreme dust events affecting south-western Europe.

Measurements during episodes of African dust, made with two wideband integrated bioaerosol spectrometers (WIBSs), one on the northeastern coast of Puerto Rico and the other in the city of León, Spain, show unmistakable, bioaerosol-like fluorescing aerosol particles (FAPs) that can be associated with these dust episodes. The Puerto Rico event occurred during a major incursion of African dust during June 2020. The León event occurred in the late winter and spring of 2022, when widespread, elevated layers of dust inundated the Iberian Peninsula. Satellite and back-trajectory analyses confirm that dust from northern Africa was the source of the particles during both events. The WIBSs measure the size of individual particles in the range from 0.5 to 30 µm, derive a shape factor, and classify seven types of fluorescence from the FAPs. In general, it is not possible to directly determine the specific biological identity from fluorescence signatures; however, measurements of these types of bioaerosols in laboratory studies allow us to compare ambient fluorescence patterns with whole microbial cells measured under controlled conditions. Here we introduce some new metrics that offer a more quantitative approach for comparing FAP characteristics derived from particles measured under different environmental conditions. The analysis highlights the similarities and differences at the two locations and reveals differences that can be attributed to the age and history of the dust plumes, e.g., the amount of time that the air masses were in the mixed layer and the frequency of precipitation along the air mass trajectory.

Abstract. Measurements during episodes of African dust, made with two Wideband Integrated Bioaerosol Spectrometers (WIBS), one on the northeastern coast of Puerto Rico and the other in the city of León, Spain, show unmistakable, bioaerosol-like fluorescing aerosol particles (FAP) that can be associated with these dust episodes. The Puerto Rico events occurred during a major incursion of African dust during June 2020. The León events occurred in the late winter and spring of 2022 when widespread, elevated layers of dust inundated the Iberian Peninsula. Satellite and back trajectory analyses confirm that dust from Northern Africa was the source of the particles during both events. The WIBS measures the size of individual particles in the range from 0.5 µm to 30 µm, derives a shape factor and classifies seven types of fluorescence from the FAP. In general it is not possible to directly determine the specific biological identity from fluorescence signatures, however, measurements of these types of bioaerosols in laboratory studies allow us to compare ambient fluorescence patterns with whole microbial cells measured under controlled conditions. Here we introduce some new metrics that offer a more quantitative approach for comparing FAP characteristics derived from particles measured under different environmental conditions. The analysis highlights the similarities and differences at the two locations and reveals differences that can be attributed to the age and history of the dust plumes, e.g., the amount of time that the air masses were in the mixed layer and the frequency of precipitation along the air mass trajectory.

The impact on indoor air quality during metal casting processes using the 3D printing (3DP) binder jetting technique to manufacture moulds is analyzed in this research. This study investigates the particle size distribution and gas concentration during the manufacturing stages of 3DP moulds, with focus on particle deposition in the human respiratory system. The goal is to understand the risks associated with particle and gas emissions in binder jetting 3D printing, and thus improve worker safety. The results indicate that particle emission rates are lowest during printing (0.01 1011particles min-1) but increase during post-processing and melting-pouring phases (3.07 1011 particles min � 1). During melting and pouring, the emission of particles was mainly in the range 7.9-71 nm, with values 10 times higher than in the previous phases. The study calculates the deposition of inhaled particles in different parts of the respiratory tract and reveals a 2.39 times higher extrathoracic mass deposition during 3DP mould manufacturing stages compared to melting-pouring stages. Additionally, alveolar mass deposition is higher during melting-pouring stages due to an increase in ultrafine emission rates. The study emphasizes the importance of insulation equipment and workplace ventilation in indoor spaces, particularly during heating processes that generate ultrafine particles through nucleation, so that health risks can be mitigated.

Fungal spores, commonly found in the atmosphere, can trigger important respiratory disorders. The glycoprotein Alt a 1 is the major allergen present in conidia of the genus Alternaria and has a high clinical relevance for people sensitized to fungi. Exposure to this allergen has been traditionally assessed by aerobiological spore counts, although this does not always offer an accurate estimate of airborne allergen load. This study aims to pinpoint the key factors that explain the presence and variation of Alt a 1 concentration in the atmosphere in order to establish exposure risk periods and improve forecasting models. Alternaria spores were sampled using a Hirst-type volumetric sampler over a five-year period. The allergenic fraction from the bioaerosol was collected using a low-volume cyclone sampler and Alt a 1 quantified by Enzyme-Linked ImmunoSorbent Assay. A cluster analysis was executed in order to group days with similar environmental features and then analyze days with the presence of the allergen in each of them. Subsequently, a quadratic discriminant analysis was performed to evaluate if the selected variables can predict days with high Alt a 1 load. The results indicate that higher temperatures and absolute humidity favor the presence of Alt a 1 in the atmosphere, while time of precipitation is related to days without allergen. Moreover, using the selected parameters, the quadratic discriminant analysis to predict days with allergen showed an accuracy rate between 67 % and 85 %. The mismatch between daily airborne concentration of Alternaria spores and allergen load can be explained by the greater contribution of medium-to-long distance transport of the allergen from the major emission sources as compared with spores. Results highlight the importance of conducting aeroallergen quantification studies together with spore counts to improve the forecasting models of allergy risk, especially for fungal spores.

Alternaria genus contains more than 300 ubiquitous fungal species, and thus its spores can be found in both outdoor and indoor environments. Many species of this genus are catalogued as plant pathogens that affect different crops, causing important losses in the agricultural sector. Moreover, Alternaria spores have also been described as a significant source of allergens, with Alt a 1 glycoprotein being the major allergen. This allergen reacts with over 90% of IgE serum in patients sensitized to Alternaria and can be present in the air even low airborne spore concentrations. Traditionally, forecasting models for risk periods associated with environmental exposition to this fungus have been based only on aerobiological spore counts combined with some meteorological factors such as temperature and precipitation. However, other parameters such as land use and prevailing winds also significantly influence the airborne allergen load. For that reason, the aim of this study is to identify the major emission sources of Alternaria spores and Alt a 1 allergen to improve the forecasting models of environmental exposure to this aeroallergen. This study was carried out in León (Spain) over a five-year period (2016-2020). Airborne spores were sampled using a Hirst-type volumetric sampler, following the methodology proposed by CEN legislation EN 16868:2019. The samples were analysed under a light microscope at 400x magnification using two longitudinal transects in the effective collecting area. Furthermore, the allergenic fraction was collected by a cyclone low-volume sampler and the major allergen Alt a 1 was quantified by ELISA on daily samples The land use data within a 30 km radius of monitoring station were obtained from Castilla y León crops and natural maps, which use satellite imagery from the Copernicus programme with a spatial resolution of 10 m. Additionally, wind parameters, in combination with spore and allergen concentration, were analyzed using conditional probability functions plots. The results show that areas covered by cereal crops or pastures act as the major sources of Alternaria conidia and Alt a 1 allergen. However, there are discrepancies between the airborne transport of spores and allergen since the highest mean spore concentration values occurs with wind speed from 1 to 2 m s -1; whereas wind speed between 2 and 4 m s-1 favor the highest Alt a 1 allergen concentrations. This may indicate a greater contribution of long-medium transport of allergen than spores, highlighting the need to perform aerobiological spore counts in combination with allergen quantification for a better assessment of atmospheric allergenic load. Finally, this also underscores the importance of considering the land cover and the location of emission sources, as well as the main atmospheric transport routes, to improve the risk forecasting models for environmental exposure to this aeroallergen.

The use of frequencies well into the extra high frequency (EHF) band (30–300 GHz) is a key element in 5G and beyond technologies. Rain attenuation is the major impairment affecting terrestrial radio links in this band. In the absence of enough experimental measurements, rain attenuation can be estimated by using physical models of radiowave scattering in raindrops combined with information about the raindrop size distributions (DSD). In this work, the characterization of rain attenuation in the 80–200 GHz frequency range is carried out from a large database of 12 years of experimental DSD gathered in Madrid, Spain. Rain attenuation is estimated for each collected minute of rain using two approaches: a first one based on the assumption of raindrops as spherical and the application of the Mie theory, and a second one that uses a non-spherical raindrop model and electromagnetic simulations and is consequently more realistic. The main results show that the currently used International Telecommunications Union-Radiocommunications Sector (ITU-R) model generally underestimates rain-specific attenuation; the influence of polarization becomes smaller and negligible as the frequency approaches 200 GHz; and rain-specific attenuation significantly varies due to the spread of the DSD. Moreover, a model for this variability of rain attenuation is also proposed.

Alternaria spores are a common component of the bioaerosol. Many Alternaria species are plant pathogens, and their conidia are catalogued as important aeroallergens. Several aerobiological studies showing a strong relationship between concentrations of airborne spore and meteorological parameters have consequently been developed. However, the Alternaria airborne load variation has not been thoroughly investigated because it is difficult to assess their sources, as they are a very common and widely established phytopathogen. The objective of this study is to estimate the impact of vegetation and land uses as potential sources on airborne spore load and to know their influence, particularly, in cases of long-medium distance transport. The daily airborne spore concentration was studied over a 5-year period in León and Valladolid, two localities of Castilla y León (Spain), with differences in their bioclimatic and land use aspects. Moreover, the land use analysis carried out within a 30 km radius of each monitoring station was combined with air mass data in order to search for potential emission sources. The results showed a great spatial variation between the two areas, which are relatively close to each other. The fact that the spore concentrations recorded in Valladolid were higher than those in León was owing to prevailing winds originating from large areas covered by cereal crops, especially during the harvest period. However, the prevailing winds in León came from areas dominated by forest and shrubland, which explains the low airborne spore load, since the main Alternaria sources were the grasslands located next to the trap. Furthermore, the risk days in this location presented an unusual wind direction. This study reveals the importance of land cover and wind speed and direction data for establishing potential airborne routes of spore transport in order to improve the Alternaria forecasting models. The importance of conducting Alternaria aerobiological studies at a local level is also highlighted.

The below cloud scavenging of aerosols by snow has been analysed in León (NW Spain). Six snow events were registered over the course of one year of study. Ultrafine and accumulation aerosol particles were measured using a scanning mobility particle sizer spectrometer, while hydrometeors were characterized using a disdrometer. Furthermore, the chemical composition of the melted snow-water samples (soluble and insoluble fractions) was analysed. The scavenging coefficient (λ) showed a great variability among events. An effective washing of particles was observed during the first 30 min of snowfall. The mean change in the scavenging efficiency (%ΔC) of particle number concentration (PNC) and λ coefficient during this time interval were: i) nucleation mode: 36.3 % and 3.02 · 10-4 s-1; ii) Aitken mode: 30.4 % and 2.37 · 10-4 s-1 and iii) accumulation mode: 22.4 % and 1.77 · 10-4 s-1. The range of particle sizes that is less efficiently scavenged by snowfall was observed between 400 and 600 nm. When analyzing the whole snow event, an increase of PNC was observed. Two possible explanations underlie this behaviour: it could be caused by changes in air masses or by the resuspension of aerosol particles scavenged by snowflakes upon reaching the ground. A clear relationship was observed between Ca2+, SO42- and NO3- concentrations of aerosol particles before the snow event and the concentrations registered in the melted snow-water. The largest and smallest changes in aerosol number concentrations were caused by snowflakes of 3 and 6 mm in diameter, respectively. The particle size distributions (PSD) were fitted to log-normal distributions and the parameters were compared before and after snowfall.

This study focuses on the analysis of the distribution, both spatial and temporal, of the PM10 (particulate matter with a diameter of 10 µm or less) concentrations recorded in nine EMEP (European Monitoring and Evaluation Programme) background stations distributed throughout mainland Spain between 2001 and 2019. A study of hierarchical clusters was used to classify the stations into three main groups with similarities in yearly concentrations: GC (coastal location), GNC (north–central location), and GSE (southeastern location). The highest PM10 concentrations were registered in summer. Annual evolution showed statistically significant decreasing trends in PM10 concentration in all the stations covering a range from −0.21 to −0.50 µg m−3/year for Barcarrota and Víznar, respectively. Through the Lamb classification, the weather types were defined during the study period, and those associated with high levels of pollution were identified. Finally, the values exceeding the limits established by the legislation were analyzed for every station assessed in the study.

Worldwide coal is still used for household heating purposes not only because it is available and cheap but also due to behavioural issues. Regional variability in fuels and combustion appliances make accurate emission estimates from this source hard to achieve. In the present study, gaseous (CO, VOCs, SO2 and NOX) and particulate matter (TSP) emission factors (EFs) were determined for Spanish household coal combustion covering three commercial coals and distinct combustion stages and mimicking usage patterns in real households. TSP samples were analysed to determine water-soluble inorganic ions, metal(loid)s, and organic and elemental carbon (OC and EC). Additionally, the morphology of the emitted particles was also characterised.

Real-time measurements of particles in the 15-736 nm range have been obtained by a Scanning Mobility Particle Sizer to characterize the evolution of particle size distribution and new particle formation (NPF) events in an urban background area. The annual, weekly and diurnal variations of the modal (nucleation (Nnuc), Aitken (NAit) and accumulation (Nacc)) particle concentrations were characterised. The NAit and Nacc registered their maximums in cold months during rush hours, in the morning (0600-0900 UTC) and in the afternoon (1700-2000 UTC), while the maximums for Nnuc were reached in warm months during midday hours. NAit, Nacc and Ntotal showed a significant negative correlation with wind speed and a different relationship with the planetary boundary layer (PBL) height by periods. In the warm period, a positive significant correlation between PBL and Nnuc was registered, indicating that the higher dispersion promoted by a high PBL causes favourable conditions for the occurrence of NPF events (a low polluted atmosphere). NPF processes are one of the main sources of ultrafine particles (<100 nm) in the warm period. After a visual-based classification, 45 NPF events of type Ia (strong and with a good confidence level) were identified and analysed, occurring primarily between 1100 and 1500 UTC, mainly in spring and summer. In addition, a two-step method was developed for identifying NPF events: cluster analysis followed by discriminant analysis. The application of discriminant analysis to one of the clusters, grouping 93 days, enabled us to identify 55 of the 56 NPF events days included in the cluster. This method is a valuable tool for identifying NPF events quickly and effectively.

The radiative forcing before and after rain events was studied between 12 February 2016 and 14 March 2017 in Leon, Spain. For this purpose, the radiative forcing fluxes were calculated using the Radiative Transfer Model Global Atmospheric ModEl (RTM GAME). After the application of a set of selection criteria (based on the availability of AERONET data, rain characteristics and lightning maps), 16 stratiform rain events were identified, concentrated in spring and winter, and 15 convective rain events were found concentrated in spring and summer. Rainfall events were grouped according to the atmospheric forcing (Delta F-ATM) before rain: "low" or "high" (lower or higher than 30 W m(-2)). The threshold has been set at this value because it is the mean Delta F-ATM of all the selected events before rain. There were significant statistical differences between stratiform and convective events in rain duration, mean raindrop diameter and parameters a and b of radar reflectivity Z and rainfall intensity R relationship (Z = a R-b). When comparing "low" and "high" groups, raindrop diameter was similar in stratiform (0.51 +/- 0.08 vs 0.48 +/- 0.12 mm) and convective events (0.96 +/- 0.98 vs 0.83 +/- 0.63 mm), registering higher values for the latter. In stratiform events, the rain scavenging effect on aerosol particles is clearly observed in the "high" group with a decrease of radiative forcing of -27.0 +/- 25.3%, and to a lesser extent, in the "low" group, probably because of a lower aerosol load in the atmosphere. In stratiform events, the mode of the raindrop size gamma distribution presented statistical differences between "low" (0.25 +/- 0.13 mm) and "high" (0.35 +/- 0.05 mm) groups. We claim that this points towards a relationship between radiative forcing before rain and the specific characteristics of rainfall measured at ground level. This study increases our knowledge on the important role of rainwater as a clean agent of the atmosphere and its impact on climate (through radiative forcing).

Black carbon (BC) aerosol characteristics have been analysed from January 2016 to March 2017 in an urban background area (Leon, Spain), located in a coal-mining region, where this fuel is commonly used. The monthly and seasonal variations of BC and source contributions were examined. The mean equivalent BC concentration (eBC) during cold and warm months were 1.0 & PLUSMN; 0.5 and 0.6 & PLUSMN; 0.2 mu gm(-3), respectively. eBC can be further divided into eBC(ff) (eBC from liquid fossil fuel) and eBC(bb+cc) (eBC from biomass burning plus coal combustion), with mean annual values of 0.6 & PLUSMN; 0.3 and 0.3 & PLUSMN; 0.3 mu gm(-3) (cold months) and 0.4 & PLUSMN; 0.2 mu gm(-3) and 0.1 & PLUSMN; 0.1 mu g m(-3) (warm months), respectively. The eBC obtained from the aethalometer and the elemental carbon (EC) quantified through a Thermal Optical Transmittance method presented a significant strong positive correlation in both warm (r = 0.82) and cold (r = 0.88) periods. A mass absorption cross-section (MAC) of 4.46 & PLUSMN; 0.16 between two techniques has been obtained. In the cold period, a multilinear regression model to decouple eBC(bb) from eBC(cc) was established (r(2) = 0.85) based on two tracers: arsenic for coal combustion and potassium for biomass burning. The model application enabled us to distinguish the contributions to eBC(bb+cc) (as a function of the variance explained by the tracers) in the cold period: 74% from biomass burning and 26% from coal combustion. The highest eBC(cc) concentration was estimated for December 2016 and January 2017 (0.18 mu g m(-3)). This result was supported by the Absorption Angstrom Exponent (AAE), which showed the maximum value in January 2017 (1.43 & PLUSMN; 0.37) due to the high biomass burning and coal combustion contributions.

Domestic chores are an important part of the household's daily routine and can contribute significantly to personal exposure. In this study, the particulate mass and number concentrations were assessed when using two irons (steam iron and steam iron with boiler) under distinct conditions (minimum ventilation and indoor doors open) and in the background air. The detailed PM10 chemical characterisation included organic and elemental carbon, elements and organic speciation. Particle number emission rates ranged from 8.1 +/- 0.09 x 10(11) to 15 +/- 3.5 x 10(11) particles min(-1). Ratios of peak to background levels indicate that ironing can elevate the ultrafine particle number concentrations by a factor ranging from 35 to 194. PM10 emission rates from steam iron, under minimum ventilation conditions (6.6 +/- 1.4 mu g s(-1)), were higher than those from steam iron with the doors open (1.9 +/- 1.6 mu g s(-1)). The highest particle number and mass emission rates were recorded when the steam iron with boiler was used. Regarding the chemical composition of particles, elemental carbon and strontium were only detected during ironing. Bromide concentrations increased noticeably over background levels (9-51 times) during ironing. PM10 samples encompassed a wide range of organic compounds, part of which can be attributed to the handling of textiles and the use of detergents, fabric softeners, cosmetics and personal care products. Substances emitted by volatilisation or shedding of textile fibres, or due to handling, can contribute to human exposure through inhalation. The cancer risks associated with inhalation of metals and PAH were found to be negligible.

Bioaerosols play a major role in the plant life of ecosystems. In addition, they have a profound impact on human health, since they may cause lung diseases or allergies. The key objective of this study is to assess the below cloud scavenging effect of rainfall on pollen concentration. The analysis is based on a sampling carried out in León, Spain, between 2015 and 2018. The rainfall variables and the pollen concentrations have been obtained with a disdrometer and a volumetric Hirst type spore-trap, respectively. In order to evaluate the scavenging, three parameters have been calculated: scavenging efficiency (through the concentration-weighted average (%ΔC)), the scavenging coefficient (λ) and the percentage of events with a decrease in pollen concentration (%ES) also called events with effective scavenging. 71% of rain events presented an effective scavenging that affected all types of pollen. The %ΔC mean value of total pollen was 24 ± 18% (positive values indicate an effective scavenging) and the types of pollen with the highest values were Castanea and Cupressaceae (71 and 40%, respectively). A linear model (R2 = 0.94) to estimate the pollen concentration after rain was built with variables such as pollen concentration before rain and other variables from a weather station and a disdrometer. Furthermore, we have shown the possibility of knowing in real time the probable Cupressaceae pollen concentration, from the initial pollen concentration and the physical parameters of rain (such as raindrop size, rain intensity or volume swept by raindrops in their falling path).

This paper studies the below-cloud scavenging caused by precipitation on ultrafine and accumulation modes, as well as the role of the different raindrop sizes in an urban environment. The equipment used to measure aerosol particles and raindrop variables includes a scanning mobility particle sizer spectrometer-SMPS and a Laser Precipitation Monitor (LPM), respectively. An analysis of the scavenging efficiency and the scavenging coefficient (A) by modes and rain intensities was carried out. The main results observed have been: i) the nucleation (between 14 and 30 nm), Aitken (between 30 and 100 nm), accumulation 1 (between 100 and 300) and accumulation 2 (between 300 and 1000 nm) modes presented a scavenging efficiency of 15, 4, 22 and 21%, respectively; ii) events with rain intensities between 1 and 3 mm h-1 caused less scavenging in all modes; iii) raindrop sizes between 1.25 and 3.5 mm scavenged mainly particle sizes between 70 and 250 nm. Lower scavenging was observed on particle sizes >300 nm, and particle sizes >600 nm were only scavenged by raindrop sizes >4.75 mm; iv) the respirable fraction before and after the rain events presented a statically significant decrease of -35%. The combination in this study of SMPS and disdrometer measurements has resulted in a more detailed characterization of the influence of this process on the submicrometer aerosol fraction, noting that below-cloud scavenging is one of the main removal pathways for submicrometer aerosol particles. This study thus contributes to improving the current state of knowledge of below-cloud scavenging.