This study is an analysis of 344 days with rainfall recorded during five years in a remote regional background EMEP (Cooperative Programme for the Monitoring and Evaluation of the Long Range Transmission of Air Pollutants in Europe) station in Spain. The chemical composition of the rainwater associated with air masses (nine categories) and weather types (26 categories) was characterized. The chemical composition of rainwater was dominated by calcium (Ca2+) and sulphate (SO42–S), with VWM (Volume Weighted Mean) during the period studied (2002–2006), with 55 μeq/L and 34 μeqS/L, respectively. Calcium, sodium (Na+), ammonium (NH4+-N) and magnesium (Mg2+) seem to be dominant components in the neutralization of the rainwater. By applying Pearson correlations, principal component analysis and enrichment factors, it is possible to identify source types for the precipitation constituents. Interannual and intra-annual variability was also been studied. High calcium levels are associated with the frequent intrusions of Saharan dust that occur during the summer, and the maximums of chlorine and sodium in the winter may be due to the greater amount of maritime air recorded during this season. Wet deposition was determined by focusing on nitrogen deposition, registering mean annual values of 155 mgN/m2/year (from the NO3−-N) and 165 mgN/m2/year (from the NH4+-N).

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.

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.

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.

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.

- This work deals with the current state of the art of tools applicable to the laboratory practices in the university subjects of Physics. The situation caused by the SARS-CoV-2 coronavirus has triggered the number of companies that develop virtual laboratories and the development of multiple tools, free or not, applicable to online practices. A description of the main tools available in included. In addition, the results of the same practice carried out online and on-site on Stokes's law are compared. It has been observed that both modes presented similar academic results, with a shorter duration and a lower associated cost for online practice. Finally, a reflection on the future application of 3D virtual practices and their joint use with on-site practices is included.

The daily evolution of seventeen sugar compounds (seven saccharides, seven alcohol-saccharides and three anhydrosaccharides) in atmospheric aerosol samples collected between 9 March 2016 and 14 March 2017 was studied in Le ' on (Spain). The main links between the concentration of sugar compounds and various chemical species, pollen, fungal spores and meteorological conditions were investigated. The results showed that, in spring, when high levels of metabolic activity of the plants occur and temperatures increase, glucose, sucrose, 2-methyl-erithritol, mannitol, arabitol and inositol, are significantly correlated with airborne pollen concentrations. Between spring and autumn, Alternaria air concentrations are significantly correlated with temperatures, arabitol and sorbitol + adonitol concentrations. Furthermore, during rainy days, Alternaria is also correlated with mannitol. In autumn, lower temperatures cause an increase in the concentrations of levoglucosan, mannosan and galactosan, probably due to the increased use of domestic heating devices. These anhydrosugars and arabinose, fructose and glucose, are significantly correlated with K, NO3- , EC, OC, Cu, Zn, Se, Pb, V and Ni, while mannosan also correlates with As, showing that these anhydrosaccharides can be emitted from different anthropogenic sources. Precipitation causes an increase in glucose and sucrose concentrations, due to the break of pollen particles that produce hundreds of fine size particles. Besides, precipitation causes an increase in arabitol concentrations, due to the release and growth of fungi.

A sampling campaign was conducted in the Liberdade Avenue tunnel (Braga, Portugal) during a week (with 56,000 vehicles) to monitor black carbon (eBC-equivalent black carbon) by means of an Aethalometer AE-31, and gaseous pollutants (CO2, CO, NOx). Inside the tunnel, the mean eBC mass concentration was 21 ± 10 μg m-3, reaching a maximum hourly value of 49.0 μg m-3. An hourly and weekday-weekend study was carried out. Regarding the Absorption Ångström exponent (AAE), a mean value of 0.97 ± 0.10 was obtained, for a source of practically pure traffic. There was a positive significant correlation between eBC and the number of light vehicles (r = 0.47; p < 0.001) and between eBC and the gaseous emissions: CO (r = 0.67; p < 0.001), CO2 (r = 0.71; p < 0.001), NO (r = 0.63; p < 0.001) and NO2 (r = 0.70; p < 0.001). The mean black carbon emission factors (EFBC) inside the tunnel were 0.31 ± 0.08 g (kg fuel)-1 and 0.11 ± 0.08 mg veh-1 km-1, similar to those found in other studies for gasoline and diesel vehicles in road tunnels.

In order to describe the means, variability and trends of the aerosol radiative effects on the southwest Atlantic coast of Europe, 11 years of aerosol light scattering (sigma(sp)) and 4 years of aerosol light absorption (sigma(sp)) are analyzed. A 2006-2016 trend analysis of sigma(sp) for D < 10 mu m indicates statistically significant trends for March, May-June and September-November, with a decreasing trend ranging from -1.5 to - 2.8 Mm(-1)/year. In the 2009-2016 period, the decreasing trend is only observed for the months of June and September. For scattering Angstrom exponent (SAE) there is an increasing trend during June with a rate of 0.059/year and a decreasing trend during October with - 0.060/year. The trends observed may be caused by a reduction of Saharan dust aerosol or a drop in particle loading in anthropogenic influenced air masses. The relationship between SAE and absorption Angstrom exponent is used to assess the aerosol typing. Based on this typing, the sub-micron particles are dominated by black carbon, mixed black and brown carbon or marine with anthropogenic influences, while the super-micrometer particles are desert dust and sea spray aerosol. The mean and standard deviation of the dry aerosol direct radiative effect at the top of the atmosphere (DRETOA) are -4.7 +/- 4.2 W m(-2). DRETOA for marine aerosol shows all observations more negative than - 4 W m(-2 )and for anthropogenic aerosol type, DRETOA ranges from -5.0 to -13.0 W m(-2). DRETOA of regional marine aerosol ranges from -3 to -7 W m(-2), as it consists of a mixture of sea salt and anthropogenic aerosol. The variability in DRETOA is mainly dependent on AOD, given that variations in backscatter fraction and the single scattering albedo tend to counteract each other in the radiative forcing efficiency equation. The results shown here may help in interpretation of satellite retrieval products and provide context for model evaluation.

Saharan air masses can transport high amounts of mineral dust particles and biological material to the Iberian Peninsula. During winter, this kind of events is not very frequent and usually does not reach the northwest of the Peninsula. However, between 21 and 22 February 2016 and between 22 and 23 February 2017, two exceptional events were registered in León (Spain), which severely affected air quality. An integrative approach including: i) typical synoptic conditions; ii) aerosol chemical composition; iii) particle size distributions; iv) pollen concentration; v) aerosol optical depth (AOD); vi) radiative forcing and vii) estimation of the impact of aerosols in the respiratory tract, was carried out. In the global characterization of these events, the exceedance of the PM10 daily limit value, an increase in the coarse mode and a rise in the iron concentration were observed. On the 2016 event, an AOD and extinction-related Ångström exponent clearly characteristic of desert aerosol (1.1 and 0.05, respectively) were registered. Furthermore, pollen grains not typical of flowering plants in this period were identified. The chemical analysis of the aerosol from the 2017 event allowed us to confirm the presence of the main elements associated with mineral sources (aluminum, calcium, and silica concentrations). An increase in the SO42−, NO3− and Cl− concentrations during the Saharan dust intrusion was also noted. However, in this event, there was no presence of atypical pollen types. The estimated dust radiative forcing traduced a cooling effect for surface and atmosphere during both events, corroborated by trends of radiative flux measurements. The estimated impact on the respiratory tract regions of the high levels of particulate matter during both Saharan dust intrusions showed high levels for the respirable fraction.

Aerosol black carbon (BC) is the second strongest contributor to global warming, after CO2, and it is linked to many adverse health effects. A sampling campaign of 15 months was carried out in Leon (Spain) in order to evaluate the scavenging of BC with an ensemble aethalometer-disdrometer. The aethalometer provides the concentration of equivalent black carbon (eBC), and the disdrometer, the raindrop size distribution. A total of seventy-five rain events were studied and in 73% of them there was an effective (eBC(initial) > eBC(final)) scavenging, with a mean decrease of 48 +/- 37% in long rain events (>8 h) and 39 +/- 38% in short rain events. The scavenging of BC is strongly related to its source. Thus, the scavenging coefficient (SC) mean value of the BC from fossil fuel (eBC(ff)) for short and long rain events was 5.110(-5) and 1.3 10(-5) s(-1), respectively. For the BC from biomass burning (eBC(bb)), the SC values were 1.6 10(-4) and 2.8 10(-5) s(-1) in short and long events, respectively. There was a significant positive correlation between the SC and the number of drops with diameters between 0375 and 2.5 mm. Rain scavenging of eBC was analyzed depending on the air mass origin obtaining an effective scavenging for air masses from Atlantic, Arctic and Africa. A linear model (R-2 = 0.72) was built to estimate the Delta eBC values with variables from an aethalometer, a disdrometer and a weather station: eBC concentration before rain, swept volume and precipitation accumulated. A Kolmogorov-Smirnov statistical test confirmed the goodness of fit of the model to the measured data. (C) 2018 Elsevier Ltd. All rights reserved.

Residential dust is recognized as a major source of environmental contaminants, including polycyclic aromatic hydrocarbons (PAHs) and plasticizers, such as phthalic acid esters (PAEs). A sampling campaign was carried out to characterize the dust fraction of particulate matter with an aerodynamic diameter smaller than 10 µm (PM10), using an in situ resuspension chamber in three rooms (kitchen, living room, and bedroom) of four Spanish houses. Two samples per room were collected with, at least, a one-week interval. The PM10 samples were analyzed for their carbonaceous content by a thermo-optical technique and, after solvent extraction, for 20 PAHs, 8 PAEs and one non-phthalate plasticizer (DEHA) by gas chromatography-mass spectrometry. In general, higher dust loads were observed for parquet flooring as compared with tile. The highest dust loads were obtained for rugs. Total carbon accounted for 9.3 to 51 wt% of the PM10 mass. Plasticizer mass fractions varied from 5 µg g−1 to 17 mg g−1 PM10, whereas lower contributions were registered for PAHs (0.98 to 116 µg g−1). The plasticizer and PAH daily intakes for children and adults via dust ingestion were estimated to be three to four orders of magnitude higher than those via inhalation and dermal contact. The thoracic fraction of household dust was estimated to contribute to an excess of 7.2 to 14 per million people new cancer cases, which exceeds the acceptable risk of one per million.

Biogenic aerosols may play an active role in various diseases. Pollutant gases and bioaerosols coexist in the atmosphere with the possibility of interacting with each other increasing their adverse impacts on human health. The study of long-term trends and the correlation between the pollen concentration from selected taxa (especially those related to allergies) and both the main atmospheric pollutants and the meteorological parameters has enabled us to identify the main factors that affect pollen concentration in the atmosphere. This study analyzes the long-term trend in CO, NO, NO2, PM10, SO2 and O-3 from 1997 to 2016 and Praxinus, Poaceae and Populus pollen concentrations in the city of Leon from 1994 to 2016. In general, there is a significant decreasing trend in atmospheric pollutant concentrations and a significant increasing trend in Praxinus pollen concentrations. In addition, the influence of air pollutants and climatic factors on pollen concentrations and pollination period duration was studied using the Spearman correlation, showing that the flowering and pollination periods depend largely of the weather conditions before these periods and are influenced by air pollutant concentrations.

Presently, both in rural areas and in cities open fireplaces are still present and large quantities of wood are combusted every year. The present study aims to characterize aerosol size distribution, chemical composition and deposition in the human respiratory tract of particles emitted during the combustion of logs of oak in an open fireplace installed in the living room of a typical village house. CO2 and CO levels and aerosol size distribution have been continuously monitored and a PM10 sampler with two types of filters for chemical and microscopic analysis was also installed. The increment, between the operating periods and the indoor background, in the organic carbon and PM10 concentration due to the use of the fireplace is 15.7 ± 0.6 (mean ± standard deviation) and 58.5 ± 6.2 μg m−3, respectively. The two main polluting processes during the operation of the fireplace are the ignition with the subsequent refueling and the final cleaning of the residual ashes. In both phases mean values around 1800 particles cm−3 with CMD of 0.15 μm were measured. However, while PM10 levels of 130 ± 120 μg m−3 were estimated for the ignition stage, values of 200 ± 200 μg m−3 were obtained during the final cleaning step. Assessment conducted according to ISO standard 7708:1995, demonstrated that a person who stays in a living room when an open fireplace is lit will inhale, on average, 217 μg m−3 and 283 μg m−3 during the ignition and the refueling stages, respectively. Subsequent refueling proved to be much less polluting. The ashes removal can also be very polluting and dangerous to health if there are hidden small incandescent embers among the ashes (estimated PM10 of 132 μg m−3), reaching a CO2 level of 1940 ppm and a dangerous level of CO of 132 ppm.

La obtención y gestión de bases de datos completas que recojan datos de las características de las gotas de los diferentes eventos de lluvia en cada lugar concreto resulta sumamente útil en Meteorología.La recogida de estos datos exige de instrumentos meteorológicos especializados, como los disdrómetros, y concretamente el disdrómetro óptico Laser Precipitation Monitor (LPM) de Thies Clima es uno de los más comunes. Este disdrómetro ha sido utilizado por la Universidad de León para el estudio de las gotas desde el año 2006, generando una base de datos tan grande y pesada que resulta muy complicada de gestionar y analizar.Es por tanto de alto interés para fines de investigación diseñar un programa informático que gestione las bases de datos y que permita realizar consultas de periodos de interés de una manera automática, extrayendo aquellas estadísticas y valores que resulten de mayor utilidad.Por lo tanto, el objetivo de este trabajo es diseñar una aplicación que permita procesar los registros obtenidos durante más de 10 años por un disdrómetro LPM Thies clima, y almacenarlos en texto plano en datos válidos para su posterior tratamiento. Para ello, hacemos uso del lenguaje Java que lee los datos, los procesa y los sube al servidor de base de datos. Una vez estos datos son almacenados, se pasan a mostrarse en una aplicación Web que, de forma gráfica, puede presentarlos por fechas, tamaños o velocidades, aportando una información válida para estudio de las precipitaciones. Esta aplicación fue implementada con un Login de seguridad para controlar el acceso de usuarios, y con un interfaz de usuario sencillo que permite que usuarios sin conocimientos en Java puedan ejecutar la aplicación sin ningún tipo de problema.

The temporal variation of aerosol size distribution in León, Spain, was analyzed with an optical spectrometer, in order to identify changes associated with the summer-autumn transition. For each hour and day of the week, we have studied the temporal variation of the particle number during the day. As the summer progresses, the total particle number increases from 1000 ± 600 in August to 1500 ± 1000 particles cm−3 in October, mainly due to more intense road traffic after the summer holidays and to the beginning of the new academic year in the study area in September. The particle number was higher on weekdays than on weekends in September and October. However, in August the values were similar, due to lower activity in the city, coinciding with the main holiday period. The aerosol size distributions were bimodal. In the fine mode, both the highest concentration (573 particles cm−3) and the lowest count median diameter (0.08 μm) were recorded in October. The contribution of particles from forest fires and Saharan dust intrusions had a negative impact on the air quality of the city during the summer. Considering the estimated respirable fraction in healthy adults (after the Standard ISO 7708:1995), on weekdays the highest values are obtained between 0600 and 1000 UTC (around 15 μg m−3) and in the afternoon, between 1700 and 2000 UTC (around 12 μg m−3), coinciding with the rush hour.

The aim of this study is to improve the estimation of the characteristic uncertainties of optic disdrometers in an attempt to calculate the efficient sampling area according to the size of the drop and to study how this influences the computation of other parameters, taking into account that the real sampling area is always smaller than the nominal area. For large raindrops (a little over 6 mm), the effective sampling area may be half the area indicated by the manufacturer. The error committed in the sampling area is propagated to all the variables depending on this surface, such as the rain intensity and the reflectivity factor. Both variables tend to underestimate the real value if the sampling area is not corrected. For example, the rainfall intensity errors may be up to 50% for large drops, those slightly larger than 6 mm. The same occurs with reflectivity values, which may be up to twice the reflectivity calculated using the uncorrected constant sampling area. The Z-R relationships appear to have little dependence on the sampling area, because both variables depend on it the same way. These results were obtained by studying one particular rain event that occurred on April 16, 2006.