Characterization of PAHs bound to ambient ultrafine particles around runways at an international airport.

The impact of airport activities on air quality, is not sufficiently documented. In order to better understand the magnitude and properly assess the sources of emissions in the sector, it is necessary to establish databases with real data on those pollutants that could have the greatest impact on both health and the environment. Particulate matter (PM), especially ultrafine particles, are a research priority, not only because of its physical properties, but also because of its ability to bind highly toxic compounds such as polycyclic aromatic hydrocarbons (PAHs). Samples of PM were collected in the ambient air around the runways at Barajas International Airport (Madrid, Spain) during October, November and December 2021. Samples were gathered using three different sampling systems and analysed to determine the concentration of PAHs bound to PM. A high-volume air sampler, a Berner low-pressure impactor, and an automated off-line sampler developed in-house were used. The agreement between the samplers was statistically verified from the PM and PAH results. The highest concentration of PM measured was 31 µg m-3, while the concentration of total PAH was 3 ng m-3, both comparable to those recorded in a semi-urban area of Madrid. The PAHs showed a similar profile to the particle size distribution, with a maximum in the 0.27-0.54 µm size range, being preferentially found in the submicron size fractions, with more than 84% and around 15-20% associated to UFPs. It was found that the ratio [PAHs(m)/PM(m)] was around 10-4 in the warmer period (October), whereas it more than doubled in the colder months (November-December). It is significant the shift in the relative distribution of compounds within these two periods, with a notable increase in the 5 and 6 ring proportions in the colder period. This increase was probably due to the additional contribution of other external sources, possibly thermal and related to combustion processes, as supported by the PAH diagnostic ratios.

Outdoor and indoor particle characterization from a large and uncontrolled combustion of a tire landfill.

A large and uncontrolled fire of a tire landfill started in Seseña (Toledo, Spain) on May 13, 2016. An experimental deployment was immediately launched in the area for measuring regulated and non-standard air quality parameters to assess the potential impact of the plume at local and regional levels. Outdoor and indoor measurements of different parameters were carried out at a near school, approximately 700m downwind the burning tires. Real time measurements of ambient black carbon (BC) and total number particle concentrations were identified as good tracers of the smoke plume. Simultaneous peaks allowed us to characterize situations of the plume impact on the site. Outdoor total particle number concentrations reached in these occasions 3.8×105particlescm-3 (on a 10min resolution) whereas the indoor concentration was one order of magnitude lower. BC mass concentrations in ambient air were in the range of 2 to 7µgm-3, whereas concentrations<2µgm-3 were measured indoor. Indoor and outdoor deposited inhalable dust was sampled and chemically characterized. Both indoor and outdoor dust was enriched in tire components (Zn, sulfate) and PAHs associated to the tire combustion process. Infiltration processes have been documented for BC and particle number concentrations causing increases in indoor concentrations.

Chemometric study of selected polychlorinated biphenyls in ambient air of Madrid (Spain).

Monthly ambient air and surface soil samples were taken for analysis in the outskirts of Madrid in an open urban area from November 1998 to October 1999. Thirty-one polychlorinated biphenyl congeners were analysed, selection being done according to their abundance in environmental samples. The present work shows the results obtained when factor analysis (FA) and cluster analysis were applied to concentration data of seventy-one ambient air samples (polyurethane foam plugs and filters). Both chemical parameters (concentrations and total suspended particulate) and two meteorological parameters (temperature and wind velocity) were determined weekly during the sampling period. A bivariate correlation analysis was previously performed to estimate relationships between PCBs and, also between soil and filter medium.

Volatile organic compounds in the area of Madrid: a chemometrical approach.

Multivariate techniques have been applied to the set of data obtained after one year sampling of volatile organic compounds (VOCs), including volatile aldehydes in the area of Madrid in order to evaluate the possible correspondence among groups of analysed compounds, as far as modelling of different emission sources in relation to location and season. The measurements were carried out at four sites in Madrid, characteristic for urban and suburban areas. Additionally, as reference, a rural area 100 km far from the city was considered. Results of correlation analysis, factor and cluster analysis are presented. Higher correlations were found between variables related with traffic emissions. Factor analysis results showed two main significant variables related to anthropogenic and biogenic emissions respectively. In relation to cluster analysis, samples were grouped according to sampling site and seasonal variations.

Distribution of volatile organic compounds in Madrid (Spain).

From November 1995 to October 1996, airborne concentrations of VOCs were measured in the Madrid area to study the organic pollution in general, and the correlation between different pollutants in relation to such parameters as location and season. Mean concentrations for up to 90 compounds were measured at four test sites, including both urban and suburban areas. At the urban sites, maximum concentrations occurred in the autumn and winter, whereas minimum concentrations were reached in summer and spring. Similar changes were obtained for the less contaminated site located in the SE of the city, whereas a different pattern was found at the site in the NW of the city due to meteorological aspects. Mean levels of hydrocarbons in Madrid were quite similar to those found in other European cities. Chemometrical techniques were applied to the set of data in order to assess the influence of such factors as traffic, temperature and seasonal variations on the VOC levels.

Measurements of selected PCBs in open urban ambient air of Madrid (Spain): First results.

The focus of this study was to characterize the concentration levels of selected PCBs and compare them to compiled data in order to contribute to the international database. The sampling site is located in the outskirts of Madrid and can be considered an open urban area. 32 samples of air were taken from February 1998 to June 1998 by using a high volume air sampler. Glass fiber filters and polyurethane foam (PUF) were used to collect the paniculate and gas phase material, respectively. PUF plugs were Soxhlet extracted and filters were ultrasonically extracted by using pesticide-grade hexane and dichloromethane, respectively. The cleanup procedure was carried out on a florisil column with hexane and hexane/dichloromethane as elution solvents. GC/MS in a selected ion monitoring mode was used for quantification and 29 selected PCBs congeners were analyzed.

Epidemiological study of the prevalence of Helicobacter pylori infection in the general population in Asturias, Spain.

BACKGROUND: Helicobacter pylori is a worldwide infection, and it is estimated that approximately 50% of the general population is affected. However, its distribution varies considerably between developed and developing countries. AIMS: in the present study we report the results of an epidemiological investigation of the prevalence of H. pylori infection in the general population in Asturias (Northern Spain), in order to describe the current state of this infection in our region, and obtain figures for comparison with the results obtained in different communities of Spain and other countries. EXPERIMENTAL DESIGN: a descriptive transversal, epidemiological study, based on the serological determination of the IgG antibodies against H. pylori was carried out in the general population of a randomly selected sample of subjects without previous gastroduodenal antecedents. PARTICIPANTS: we analyzed 480 serum samples obtained from the general population of Asturias. These were divided into decades according to the age pyramid and tested for the presence of antibodies against H. pylori with a commercially available latex agglutination technique (Pyloriset). RESULTS: the global prevalence of H. pylori infection in our study was 226/480 (49.2%), and was slightly higher in women (50.6%) compared to men (47.6%). No significant differences were found between sexes (p = 0.51). In the first decade mean prevalence was 13.6%. In the second this figure was 25.4%, and it increased steadily to a maximum in the sixth decade of 76.4%. Thereafter, the prevalence decreased to 66.6% in persons over 80 years of age. CONCLUSIONS: we found a high prevalence approximately 50% of H. pylori infection in the general population of Asturias, as in other epidemiological studies in Spain and other European countries. The distribution according to age shows a clear tendency to increase, from childhood to adolescence and adult life (50-60 years), when prevalence is highest (76%). From this decade onwards it begins to decrease, showing a clear cohort effect with a pattern intermediate between that of developed and developing countries.

[Detection of HIV antibodies in saliva using a rapid diagnostic immunoenzyme assay]. / Detección de anticuerpos anti-VIH en saliva con un enzimoinmunoensayo de diagnóstico rápido.

The usefulness of an enzyme-immunoassay (EIA) monotest (TESTPACK HIV-1/HIV-2, ABBOTT) was evaluated in the rapid diagnosis of anti-HIV antibodies in whole saliva in an intravenous drug abuser population (IVDA). Anti-HIV antibodies were simultaneous and prospectively measured in serum and whole saliva from 70 IVDA patients. To improve the sensitivity of the test 100 microliters of saliva were added instead of the recommended serum volume. In the 35 seropositive subjects saliva yielded a distinct positive result (Sensitivity=1), and in the 35 seronegative subjects a negative result (Specificity = 1). A statistically significant association between serum and saliva antibody levels was observed. These findings show the usefulness of a EIA monotest with whole saliva as an alternative sample to serum in the measurement of HIV-antibodies in high-risk patients.

[Serology of the human immunodeficiency virus in saliva]. / Serología del virus de la inmunodeficiencia humana en saliva.

BACKGROUND: The presence of immunoglobulins in saliva has allowed it to be proven that they are specific against certain antigens. Antibodies to the human immunodeficiency virus (HIV) have been observed in saliva. The aim of this study was to evaluate the detection of the same by commercial enzymoinmmunoassay (EIA) and standardize the technique. METHODS: In 78 intravenous drug user patients the presence of antibodies against HIV in serum and saliva were determined by recombinant EIA (Abbott HIV-1/HIV-2 recombinant EIA). The determinations in saliva were made taking volumes of 10 and 50 microliters. RESULTS: In 43 patients the presence of antibodies against HIV-1 was demonstrated in serum, 42 of which were positive in saliva in the determination with 50 microliters and 16 with 10 microliters. No false positives were reported. With the use of 50 microliters of saliva the test showed a sensitivity of 0.98, specificity of 1, predictive value of a positive result of 1, predictive value of negative result of 0.98 and diagnostic efficacy of 0.99. CONCLUSIONS: The determination of antibodies against HIV in saliva in intravenous drug users is a highly sensitive and specific method with the use of volumes of 50 microliters in the tests.