Assessment of CO2 and aerosol (PM2.5, PM10, UFP) concentrations during the reopening of schools in the COVID-19 pandemic: The case of a metropolitan area in Central-Southern Spain.

Public health authorities have been paramount in guaranteeing that adequate fresh air ventilation is promoted in classrooms to avoid SARS-CoV-2 transmission in educational environments. In this work it was aimed to assess ventilation conditions (carbon dioxide, CO2) and suspended particulate matter (PM2.5, PM10 and UFP) levels in 19 classrooms - including preschool, primary and secondary education - located in the metropolitan area of Ciudad Real, Central-Southern Spain, during the school's reopening (from September 30th until October 27th, 2020) after about 7 months of lockdown due to COVID-19 pandemic. The classrooms that presented the worst indoor environmental conditions, according to the highest peak of concentration obtained, were particularly explored to identify the possible influencing factors and respective opportunities for improvement. Briefly, findings suggested that although ventilation promoted through opening windows and doors according to official recommendations is guaranteeing adequate ventilation conditions in most of the studied classrooms, thus minimizing the risk of SARS-CoV-2 airborne transmission, a total of 5 (26%) surveyed classrooms were found to exceed the recommended CO2 concentration limit value (700 ppm). In general, preschool rooms were the educational environments that registered better ventilation conditions, while secondary classrooms exhibited the highest peak and average CO2 concentrations. In turn, for PM2.5, PM10 and UFP, the concentrations assessed in preschools were, on average about 2-fold greater than the levels obtained in both primary and secondary classrooms. In fact, the indoor PM2.5 and PM10 concentrations substantially exceeded the recommended limits of 8hr-exposure, established by WHO, in 63% and 32% of the surveyed classrooms, respectively. Overall, it is expected that the findings presented in this study will assist the establishment of evidence-based measures (namely based on ensuring proper ventilation rates and air filtration) to mitigate preventable environmental harm in public school buildings, mainly at local and national levels.

One-pot, microwave (MW)-assisted production of furfural from almond-, oil-, and wine-derived co-products through biorefinery-based approaches.

This work outlines the first microwave (MW)-assisted protocol for the production of biofuel precursor furfural (FF) from the raw agricultural waste almond hull (AH), olive stone (OS), and the winemaking-derived grape stalk (GS), grape marc (GM) and exhausted grape marc (EGM) through a one-pot synthesis process. To enhance the overall yield, a catalytic process was firstly developed from xylose, major constituent of hemicellulose present in lignocellulosic biomass. This method afforded FF with 100 % selectivity, yielding over 85 % in isolated product when using H2SO4, as opposed to a 37 % yield with AlCl3·6H2O, at 150 °C in only 10 min. For both catalysts, the developed methodology was further validated, proving adaptable and efficient in producing the targeted FF from the aforementioned lignocellulosic raw materials. More specifically, the employment of AlCl3·6H2O resulted in the highest selectivity (up to 89 % from GM) and FF yield (42 % and 39 % molar from OS and AH, respectively), maintaining notable selectivity for the latter (61 and 48 % from AH and OS). At this regard, and considering the environmental factor of sustainability, it is important to point out the role of AlCl3·6H2O in contrast to H2SO4, thus mitigating detrimental substances. This study provides an important management of agricultural waste through sustainable practises for the development of potential bio-based chemicals, aligning with Green Chemistry and process intensification principles.

Assessment of atmospheric levels of carbonyls in an urban environment of Argentina.

It is well-documented that carbonyl compounds have adverse effects on human health. On the other hand, these oxygenated volatile organic compounds (OVOCs) are precursors of secondary pollutants such as tropospheric ozone or peroxy acetyl nitrate (PAN). In particular, formaldehyde, the simplest carbonyl, is the most abundant carbonyl in the air generated from the degradation of most volatile organic compounds (VOCs). This work presents for the first time the characterization and determination of levels of carbonyl compounds by passive monitoring performed from April-December 2021 in the city of Córdoba, Argentina, the second most populated Mediterranean city located in the center of the country. Annual concentrations, considering the 11 carbonyls measured, were in the range of 0.13-8.75 µgm-3. Formaldehyde and acetaldehyde were the carbonyls detected in the highest annual average concentrations of 4.44 ± 1.75 µgm-3 and 3.85 ± 1.44 µgm-3, respectively. These carbonyls represent a contribution of around 40-57% on total carbonyls measured. Statistical analysis to determine significant differences and Pearson correlations with the meteorological parameters were performed. Spring and summer were found to be the seasons with the highest carbonyl concentration linked to forest fire episodes, especially in springtime. The values for the C1/C2 and C2/C3 ratios showed that sources of carbonyl formation are anthropogenic. In addition, the prop-Equiv concentration was determined, where formaldehyde and acetaldehyde were the main producers of tropospheric ozone. The ozone formation potential (OFP) showed that spring and summer are the seasons where carbonyls contribute to the formation of tropospheric ozone.This study represents a first approach of the carbonyl concentration in the city and of the influence of meteorological parameters on the behavior of carbonyls.

Microwave radiation-assisted synthesis of levulinic acid from microcrystalline cellulose: Application to a melon rind residue.

The circular economy considers waste to be a new raw material for the development of value-added products. In this context, agroindustrial lignocellulosic waste represents an outstanding source of new materials and platform chemicals, such as levulinic acid (LA). Herein we study the microwave (MW)-assisted acidic conversion of microcrystalline cellulose (MCC) into LA. The influence of acidic catalysts, inorganic salt addition and ball-milling pre-treatment of MCC on LA yield was assessed. Depolymerization and disruption of cellulose was monitored by FTIR, TGA and SEM, whereas the products formed were analyzed by HPLC and NMR spectroscopy. The parameters that afforded the highest LA yield (48 %, 100 % selectivity) were: ball-milling pre-treatment of MCC for 16 min at 600 rpm, followed by MW-assisted thermochemical treatment for 20 min at 190 °C, aqueous p-toluenesulfonic acid (p-TSA) 0.25 M as catalyst and saturation with KBr. These optimal conditions were further applied to a lignocellulosic feedstock, namely melon rind, to afford a 51 % yield of LA. These results corroborate the suitability of this method to obtain LA from agroindustrial wastes, in line with a circular economy-based approach.

Kinetic study of the gas phase reactions of a series of alcohols with the NO3 radical.

The rate coefficients for the reaction of NO(3) radical with 2-butanol, 3-methyl-2-butanol, and 2,3-dimethyl-2-butanol were determined using relative rate technique in a 50 L glass pyrex photoreactor using in situ FT-IR spectroscopy at room temperature and a pressure of 350-670 Torr. The rate coefficient for the reaction of 2-methyl-2-butanol with NO(3) radical was also determined using, in this case, GC/MS. The rate coefficients calculated (in units of cm(3) molecule(-1) s(-1)) were (2.51 ± 0.42) × 10(-15), (3.06 ± 0.52) × 10(-15), (2.67 ± 0.3) × 10(-15), and (1.57 ± 0.16) × 10(-15), respectively. Results indicate that the reaction occurs by an initial H-abstraction of the alcohols by the NO(3) radical and that NO(3) is more reactive toward a H atom attached to a tertiary carbon than that attached to a secondary or primary carbon. Results are also discussed as related to their homologous structural alkanes and in comparison with the reactivity of other atmospheric oxidants. Atmospheric relevance of the considered reactions is evaluated, concluding that they are potential ozone generators, they have no significant influence on global warming, and the dominant atmospheric loss process for these alcohols is their daytime reaction with OH radicals.

Formaldehyde, acrolein and other carbonyls in dwellings of university students. Levels and source characterization.

Fifteen carbonyl compounds were investigated in the living rooms and bedrooms of 25 university student flats in the urban area of Ciudad Real (Central Southern Spain) in wintertime. Carbonyls were sampled using Radiello ® passive samplers refilled in the laboratory according to the method described in ISO 16000-3 Standard. The most abundant carbonyls in the living rooms and bedrooms were formaldehyde, acetone, acetaldehyde, hexaldehyde and butyraldehyde. The median concentration levels in the living rooms and bedrooms were: 28.6 and 34.2 µg m-3 for formaldehyde, 18.3 and 23.1 µg m-3 for acetone, 14.3 and 15.8 µg m-3 for acetaldehyde, 11.4 and 14.1 µg m-3 for hexaldehyde and 10.8 and 12.4 µg m-3 for butyraldehyde. The median concentration of formaldehyde, benzaldehyde, valeraldehyde and hexaldehyde was significantly higher in the bedrooms than in the living rooms. Indoor concentrations were significantly higher than outdoor concentrations for all carbonyl measured, indicating that sources in the indoor environment are prevailing in all flats. Principal component analysis, multiple linear regressions and Spearman correlation coefficients were used to investigate the origin, the indoor pollutants determinants and to establish common sources between carbonyls. Eight components were extracted from the application of PCA to the indoor and outdoor measurements accounting for 97.7% of the total variance. Formaldehyde, acetone, acetaldehyde and acrolein presented different indoor sources. In the multiple linear regression analysis, higher formaldehyde concentrations were found in those living rooms with wood floor and smoking was positively associated to acetone, propionaldehyde, benzaldehyde and isovaleraldehyde. Formaldehyde, acetaldehyde, acrolein, acetone, propionaldehyde and benzaldehyde concentrations were compared with relevant international guidelines, being their concentrations below recommended values except acrolein, where all measured flats exceeded the reference levels; it would be important to focus on the characterization of emission sources of acrolein in indoor air in order to minimise the exposure and health risk.

Atmospheric degradation of 3-ethoxy-1-propanol by reactions with Cl, OH and NO3.

An experimental kinetic and mechanistic study of the reactions of 3-ethoxy-1-propanol (CH3CH2OCH2CH2CH2OH) with Cl atoms and OH and NO3 radicals has been carried out at room temperature and atmospheric pressure. FTIR (Fourier Transform Infrared Spectroscopy) and GC-MS (Gas Chromatography/Mass Spectrometry) were used as detection techniques. The rate coefficients were measured with a relative method (units cm3 molecule-1 s-1): (3.46 ± 0.22) × 10-10, (3.48 ± 0.19) × 10-11 and (1.08 ± 0.07) × 10-14 for Cl, OH and NO3 reactions, respectively. Qualitative and quantitative products analysis was carried out and formaldehyde, ethyl formate, ethyl 3-hydroxypropanoate and nitrated compounds were positively identified. A reaction mechanism has been proposed which involves attack by the oxidant at the methylene group in the α-position to an oxygen atom of the ether or alcohol groups, followed by the subsequent reactions of the resulting radicals. The tropospheric reactivity of 3-ethoxy-1-propanol (3E1P) has been compared with the reactivity of other hydroxy ethers to extend our knowledge of this type of compound. The atmospheric implications for 3E1P have been established by estimating parameters such as lifetimes, global warming potential (GWP) and the Photochemical Ozone Creation Potential (POCPE). According to the calculated tropospheric lifetimes, the dominant loss process of 3E1P is its daytime reaction with the OH radical and this has an impact on a local scale.

Ambient levels of volatile organic compounds and criteria pollutants in the most industrialized area of central Iberian Peninsula: intercomparison with an urban site.

This work presents observations of volatile organic compounds (VOCs), including carbonyls, particulate matter 2.5 (PM2.5) (included in the most recent ambient air quality standards because of its harmful effect on health), PM10 and other important pollutants, CO, SO2, NOx and ozone, over the most industrialized area in the central Iberian Peninsula. Nearly two years of data obtained through a mobile laboratory are used for this purpose. Different concentration ratios and correlations were calculated to assess the effect of the anthropogenic or biogenic processes on the observed VOC levels. The diurnal profile for SO2 is different in Puertollano and it does not coincide with the maxima of the other primary pollutants such as benzene, toluene and xylenes (BTX), CO and NO. This behaviour could be attributed to the fact that SO2 mainly comes from industrial activities. However, an impact of the industry on air quality was detected not only by the results obtained for SO2, but also by the toluene/benzene, T/B, ratio (7.5). Finally, correlations between meteorological conditions and pollution distribution have been considered; also, the analysis of the back trajectories together with Spearman correlation coefficients have been carried out to understand the origin and pathway in some events with unusual high pollutant values.

Characterization of particulate polycyclic aromatic hydrocarbons in an urban atmosphere of central-southern Spain.

Over 1-year period, 13 polycyclic aromatic hydrocarbons (PAHs) associated with particulate matter PM10 have been monitored for the first time in the atmosphere of Ciudad Real, situated at the central-southern Spain. PM10-bound PAHs were collected using a high-volume sampler from autumn 2012 to summer 2013 and were analyzed by HPLC with fluorescence detector. The most abundant PAHs were pyrene, chrysene, benzo[b]fluoranthene, dibenzo[a,h]anthracene and benzo[g,h,i]perylene. The ∑PAH concentrations in Ciudad Real were 888, 368, 259 and 382 pg m(-3) for winter, spring, summer and autumn seasons, respectively. The diurnal variation of PAH was also investigated presenting the highest concentrations during the evening (19:00-23:00). Benzo[a]pyrene concentrations ranged from 2.4 to 110 pg m(-3), these values are lower than the target value proposed by the European legislation, 1 ng m(-3). Diagnostic ratios were used to identify potential sources of PAHs. Results suggest that vehicle emissions are the major source of identified PAHs, with a higher contribution of diesel engines although other anthropogenic sources could also have an impact on the PAH levels.

Levels and sources of volatile organic compounds including carbonyls in indoor air of homes of Puertollano, the most industrialized city in central Iberian Peninsula. Estimation of health risk.

Twenty nine organic air pollutants including carbonyl compounds, alkanes, aromatic hydrocarbons and terpenes were measured in the indoor environment of different houses together with the corresponding outdoor measurements in Puertollano, the most industrialized city in central Iberian Peninsula. VOCs were sampled during 8 weeks using Radiello(®) passive samplers, and a questionnaire on potential VOCs sources was filled out by the occupants. The results show that formaldehyde and hexanal was the most abundant VOCs measured in indoor air, with a median concentration of 55.5 and 46.4µgm(-3), respectively followed by butanal (29.1µgm(-3)), acetone (28.4µgm(-3)) and acetaldehyde (21.4µgm(-3)). After carbonyls, n-dodecane (13.1µgm(-3)) and terpenes (α-pinene, 13.4µgm(-3) and limonene, 13.4µgm(-3)) were the compounds with higher median concentrations. The indoor/outdoor (I/O) ratios demonstrated that sources in the indoor environment are prevailing for most of the investigated VOCs especially for limonene, α-pinene, hexanal, formaldehyde, pentanal, acetaldehyde, o-xylene, n-dodecane and acetone with I/O ratio >6. Multiple linear regressions were applied to investigate the indoor VOC determinants and Spearman correlation coefficients were used to establish common sources between VOCs. Finally, the lifetime cancer risk associated to formaldehyde, acetaldehyde and benzene exposure was estimated and they varied from 7.8×10(-5) to 4.1×10(-4) for formaldehyde, from 8.6×10(-6) to 3.5×10(-5) for acetaldehyde and from 2.0×10(-6) to 1.5×10(-5) for benzene. For formaldehyde, the attributed risk in most sampled homes was two orders of magnitude higher than the one (10(-6)) proposed as acceptable by risk management bodies.

Study by ³¹P NMR spectroscopy of the triacylglycerol degradation processes in olive oil with different heat-transfer mechanisms.

The thermal degradation of olive oil using conventional and microwave heating under the same experimental conditions were compared. A powerful identification and quantification technique based on (31)P NMR has been developed to characterise the differences between the minor components including diacylglycerol and free fatty acids in the heated samples. The (31)P NMR spectra of the degraded olive oils, which contain OH groups derivatised with a phosphorus reagent, showed that conventional heating is more detrimental to the oil than microwave technique. Conventional heating leads to a significant increase in the diacylglycerol and free fatty acid contents as well as in the number of degradation compounds, which damage the olive oil quality. However, the main process that takes place on using microwave heating is isomerisation between diacylglycerols, a change that could give a potential longer shelf life to the olive oil.

Nivel de conocimiento sobre terminologías médicas en Guaraní de los profesionales de salud del Hospital Regional de Coronel Oviedo / Level of knowledge about medical terminology in Guaraní of the health professionals of the Regional Hospital of Coronel Oviedo

Introducción: según el Censo de 2002, el 50% de la población manifiesta hablar las dos lenguas "Guaraní y Castellano", el 37% monolingüe en Guaraní. El Guaraní es necesario para establecer un buen vínculo común entre pacientes y profesionales de la salud. Objetivo: evaluar el nivel de conocimiento sobre la terminología médica básica en Guaraní de los profesionales de salud del Hospital Regional de Coronel Oviedo. Método: estudio observacional, descriptivo con componente analítico de corte transversal con muestreo no probabilístico de casos consecutivos. Los datos se recogieron por medio de una encuesta auto administrado con las variables de interés. El nivel de conocimiento fue clasificado en bajo, medio y alto. Resultados: se incluyeron 100 sujetos de entre 23 a 70 años (35 ± 7,5 años), de los cuales el 54% son femeninos. Los años de servicio van de 1 a 47 años (13,15 ± 11,63 años). El 40% de los médicos y el 54% de los enfermeros tuvieron un rendimiento bueno. La correlación en los médicos entre los años de servicio y el porcentaje obtenido fue del 22% (R2= 22,94 p<0,05). Conclusión: el nivel de conocimiento sobre la terminología médica básica en Guaraní tanto de médicos como enfermeros es clasificado como bueno. Gran porcentaje de los profesionales encuestados afirma que el conocimiento de terminologías médicas es muy útil en su profesión.

Introduction: according to the 2002 Census, 50% of the population speak the two languages "Guaraní and Castellano", 37% monolingual in Guaraní. Guaraní is necessary to establish a good common bond between patients and health professionals. Objective: to evaluate the level of knowledge about the basic medical terminology in Guaraní of the health professionals of the Regional Hospital of Coronel Oviedo. Method: observational, descriptive study with cross - sectional analytical component with non - probabilistic sampling of consecutive cases. The data were collected through a self-administered survey with the variables of interest. The level of knowledge was classified as low, medium and high. Results: 100 subjects aged 23-70 years (35 ± 7.5 years) were included, of whom 54% were female. The years of service range from 1 to 47 years (13.15 ± 11.63 years). 40% of the doctors and 54% of the nurses performed well. The correlation among the doctors between the years of service and the percentage obtained was 22% (R2 = 22.94 p <0.05). Conclusion: The level of knowledge about basic medical terminology in Guaraní of both physicians and nurses is classified as good. A large percentage of professionals surveyed said that knowledge of medical terminology is very useful in their profession.

Night-time atmospheric chemistry of methacrylates.

BACKGROUND, AIM, AND SCOPE: Methacrylates are α, ß-unsaturated esters that are widely used in the polymer plastics and resins production. Kinetic information of NO(3) radical reactions is especially scarce and a good understanding of all the atmospheric oxidation processes of these compounds is necessary in order to determine lifetimes in the atmosphere and to evaluate the impact of these reactions on the formation of ozone and other photooxidants. MATERIALS AND METHODS: The experiments have been carried out using the relative technique in a static Teflon reactor at room temperature and atmospheric pressure (N(2) as bath gas) using gas chromatography (GC)-flame ionization detection (FID) as detection system. Products were analyzed using solid phase microextraction (SPME)-GC-mass spectrometry (MS) technique and Fourier transform infrared spectroscopy (FTIR) using air as bath gas. RESULTS: The following rate coefficients were obtained (in cm(3) molecule(-1) s(-1)): methyl methacrylate + NO(3) = (3.55 ± 0.62) × 10(-15), ethyl methacrylate + NO(3) = (5.42 ± 1.90) × 10(-15), butyl methacrylate + NO(3) = (7.87 ± 3.86) × 10(-15). Methylpyruvate, ethylpyruvate, and butylpyruvate/butanol were identified as main degradation products respectively in the GC-MS analysis. Nitrates compounds were also identified in the FTIR study. DISCUSSION: The reactivity increases with the substitution and with the chain of the alkyl group in -C(O)OR. An electrophilic addition mechanism is proposed as dominant degradation process. Estimations of the atmospheric lifetimes clearly indicate that the dominant atmospheric loss process for methacrylate esters is their daytime reaction with the hydroxyl radical. NO(3) and ozone are the main oxidants at night time. RECOMMENDATIONS AND PERSPECTIVES: A detailed products analysis including quantification could elucidate the mechanism for butanol generation for butyl methacrylate reaction.

Relevamiento del estado de salud bucal de una población preescolar con test predictivo en base al grupo mutans y a estudios clínicos / Oral health state survey in a preschool children population with predictable test based on the mutans group and clinical studies

Se relevó una población de niños de 2 a 5 años durante 3 años, se siguieron criterios bacteriológicos y clínicos, con recuento de M.st en saliva no estimulada a los niños de 3, 4 y 5 años. Se encontró como Alaluusua correlación entre el nivel de M.st en saliva y número de caries. Como en ese estudio, se obtuvieron resultados de un alto número de niños con bajo recuento y libres de caries. El mayor número de caries aparece en niños con altos recuentos. La mayor incidencia de caries en esta población aparece en los niños de 4 años. Se debe recordar que es un grupo etario con características específicas. Que la caries es una enfermedad multifactorial y polimicrobiana y que el recuento del M.st sería muy significativo para determinar riesgo tempranamente pero debería evaluarse tomando en conjunto todos los parámetros. Su valor predictivo no es suficiente por sí sólo (17) pero de indiscutido valor en la detección de pacientes de riesgo en edad temprana (2). Por lo tanto el tratamiento debería ser el resultado de un diagnóstico etiológico orientado a la prevención una vez valorados todos los parámetros relacionados con la enfermedad caries