Gabriela V. Silva

Qualidade do ar interior e sintomas respiratórios em escolas do Porto

Aim: To evaluate the association between the indoor air quality in Porto schools and the prevalence of allergic and respiratory symptoms in adolescents. n nMaterial and methods: Temperature, relative humidity, carbon dioxide (CO2) and volatile organic compound (VOC) concentrations were evaluated in nine Porto schools. Questionnaires were distributed to 9 classes of 7th, 8th and 9th year students in each school, total 1607 adolescents, with a mean age of 14.0 years (standard deviation = 0.3). Information was collected on participants’ socio-demo-graphic and social characteristics, behaviour, and housing conditions. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to evaluate respiratory symptoms. n nResults: 5.8% of participants stated they had had asthma, 9.2% wheezing, 22.0% sneezing and 6.6% itchy rash In the 12 months preceding the evaluation. n nAfter adjustment for parental educational attainment level, CO2 > 2100 ppm values were associated with exercise-induced wheeze [OR = 1.86 (95%CI:1.20-2.89)] and night cough [OR = 1.40 (4.20-2.89)]. We observed an increasing odds ratio in wheezing symptoms over the last 12 months, in asthma ‘at some point’ and asthma over the last 12 months, and night cough at schools with higher VOC values. The association was not statistically significant, however. n nConclusion: Lower indicators of indoor air quality, particularly CO2, were associated with a greater respiratory symptomatology. n nRev Port Pneumol 2008; XIV (4): 487-507

Indoor air quality and respiratory symptoms in Porto schools.

AIMnTo evaluate the association between the indoor air quality in Porto schools and the prevalence of allergic and respiratory symptoms in adolescents.nnnMATERIAL AND METHODSnTemperature, relative humidity, carbon dioxide (CO2) and volatile organic compound (VOC) concentrations were evaluated in nine Porto schools. Questionnaires were distributed to 9 classes of 7th , 8th and 9th year students in each school, total 1607 adolescents, with a mean age of 14.0 years (standard deviation=0.3). Information was collected on participants socio-demographic and social characteristics, behaviour, and housing conditions. The International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire was used to evaluate respiratory symptoms.nnnRESULTSn5.8% of participants stated they had had asthma, 9.2% wheezing, 22.0% sneezing and 6.6% itchy rash In the 12 months preceding the evaluation. After adjustment for parental educational attainment level, CO2 > 2100 ppm values were associated with exercise- induced wheeze [OR=1.86 (95%CI:1.20-2.89)] and night cough [OR=1.40 (4.20-2.89)]. We observed an increasing odds ratio in wheezing symptoms over the last 12 months, in asthma at some point and asthma over the last 12 months, and night cough at schools with higher VOC values. The association was not statistically significant, however.nnnCONCLUSIONnLower indicators of indoor air quality, particularly CO2, were associated with a greater respiratory symptomatology.

Assessment of indoor airborne contamination in a wastewater treatment plant

The main objective of this work was to quantify and characterize the major indoor air contaminants present in different stages of a municipal WWTP, including microorganisms (bacteria and fungi), carbon dioxide, carbon monoxide, hydrogen sulfide ammonia, formaldehyde, and volatile organic compounds (VOCs). In general, the total bacteria concentration was found to vary from 60 to >52,560xa0colony-forming units (CFU)/m3, and the total fungi concentration ranged from 369 to 14,068xa0CFU/m3. Generally, Gram-positive bacteria were observed in higher number than Gram-negative bacteria. CO2 concentration ranged from 251 to 9,710xa0ppm, and CO concentration was either not detected or presented a level of 1xa0ppm. H2S concentration ranged from 0.1 to 6.0xa0ppm. NH3 concentration was <2xa0ppm in most samples. Formaldehyde was <0.01xa0ppm at all sampling sites. The total VOC concentration ranged from 36 to 1,724xa0μg/m3. Among the VOCs, toluene presented the highest concentration. Results point to indoor/outdoor ratios higher than one. In general, the highest levels of airborne contaminants were detected at the primary treatment (SEDIPAC 3D), secondary sedimentation, and sludge dehydration. At most sampling sites, the concentrations of airborne contaminants were below the occupational exposure limits (OELs) for all the campaigns. However, a few contaminants were above OELs in some sampling sites.

Volatile components of Cistus ladanifer leaves

Volatile components of Cistus ladanifer leaves from the north of Portugal were analysed by gas chromatography–mass spectrometry (GC–MS), gas chromatography–FID and preparative gas chromatography coupled to a sniffing system. Eighteen compounds were identified and among those, the norisoprenoid 2,6,6-trimethylcyclohex-2-enone was isolated by preparative-GC and identified as an important Cistus ladanifer constituent by EI mass spectrometry and NMR spectroscopy. Copyright

Determination of gaseous polycyclic aromatic hydrocarbons by a simple direct method using thermal desorption–gas chromatography–mass spectrometry

In the last decade, the development of novel analytical methodologies enabled the identification of several environmental pollutants responsible for health problems associated with indoor exposure. Polycyclic aromatic hydrocarbons (PAHs) are among the potential hazardous chemicals present in ambient air. Due to their bioaccumulation potential and carcinogenic/mutagenic effects, 16 PAHs are currently listed as priority air pollutants. The main goal of this work was to implement a new and simple method for sampling and determination of PAHs in air by using a thermal desorption (TD) technique followed by gas chromatography coupled with mass spectrometry analysis. A detailed study was carried out to optimise the experimental method in each of its phases, including (active) sampling, TD and chromatographic analysis. The results demonstrate that this approach allowed the detection and quantification of the six more volatile PAHs, namely, naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, and anthracene. Acceptable precision and good linearity over the explored range were obtained. No carry-over was observed during experimental tests and the method provided a reproducible answer. The applicability of the novel methodology was tested in real environment, namely, on the roof of a building in an urban area, in a domestic kitchen and in a collective car garage. The method enabled the identification of two PAHs in the field samples, specifically, naphthalene (two rings) and phenanthrene (three rings). With regard to PAHs sample composition, the most abundant PAH found, in the three different locations, was naphthalene, accounting for about 84–100xa0% of the total PAH mass detected.

Presentation of a New Method for Determination of Diffusion Coefficients of Gaseous Pollutants in Cladding Wall Materials Indoors

Diffusion and partition coefficients are two key parameters of importance for the characterization of building materials as sources and sinks of air pollutants indoors. The number of coefficients for each pair ‘chemical compound – material surface’ available in the literature are still scarce and with a high discrepancy in the results obtained by different methods, even for the same method [1]. The objectives of this study were (1) to develop a simple and rapid experimental method for directly measuring the diffusion coefficient (D), and (2) to perform determinations with both the new and the cup method comparing the results obtained. The new method is based on two existent methodologies, the passive sampling on Tenax TA and the dry cup method, proposed by Haghighat et al. [1] and also developed by this research team [2]. The experiments were carried for three different building materials (cork based material, gypsum board and PVC) and three different compounds (cyclohexane, n-octane and m-xylene). The discussion of the results obtained for D by the two methods is presented in this paper. Observed differences were not of the same order of magnitude for the pairs compound/material studied, varying from the order of 101 in the case of PVC to 102 in the gypsum and in the cork. However some facts were the same: the gypsum board presents the higher values of D and PVC the lower values of D for the three compounds studied in both methods. One of the causes of these marked differences could be high difference of the concentration of the compound in the air between the methods, saturation value in cup method (dozens g/m3) and low values typical from indoor environments (few mg/m3) in the proposed method.

Improvement of the Modified Dry-Cup Method for Determination of the Diffusion Coefficients of Gaseous Pollutants in Building Materials

Diffusion and partition coefficients are key parameters for the characterization of building materials as sources and sinks of air pollutants indoors. A simple and rapid experimental method for direct measurement of the diffusion coefficient (D) was presented in a previous article [1]: the modified dry cup method. This method was based upon two existent methodologies, the passive sampling on Tenax TA and the dry cup method, proposed by Haghighat et al. [2]. In the present article, some improvements were made in the experimental set-up in order to obtain more precise results. The previous cup was modified by increasing the number of Tenax tubes, connected to the bottom of the cup, from one to five. The results obtained with both cups were compared. Measurements with single compounds and with three compounds simultaneously were compared in order to evaluate the influence of competition between molecules of different compounds.

NICKEL(II) COMPLEXES OF IMIDAZOLE-DERIVED LIGANDS WITH AN AMIDE GROUP: SOME COMPOUNDS WITH COMPLEX MAGNETIC BEHAVIOUR

ABSTRACT NiL4X2·xH2O compounds [L=1-(2-carbamoylethyl)-4-methylimidazole (C4MIm), 1-(2-carbamoylethyl)benzimidazole (CBIm) or 1-(2-carbamoylethyl)-5,6-dimethylbenzimidazole (CMMBIm)] have been prepared and characterised and the effect of different axial ligands, X, on the magnetic properties of the complexes has been examined. Diamagnetic and paramagnetic complexes with CMMBIm have been obtained. With C4MIm and CBIm, only paramagnetic compounds could be isolated. The CBIm ligand afforded complexes with unusual magnetic behaviour: NiCl2(CBIm)4 is believed to exhibit a spin-singlet ground state with a low-lying spin triplet state and NiBr2(CBIm)4 shows magnetic properties indicating structural changes over the temperature range studied. Structures of the compounds have been proposed based on spectroscopic and magnetic data and on powder X-ray diffraction patterns.