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Substantial knowledge is available on the association of the indoor school environment and its effect among schoolchildren. In the same context, the SINPHONIE (School indoor pollution and health: Observatory network in Europe) conducted a study to collect data and determine the distribution of several indoor air pollutants (IAPs), physical and thermal parameters and their association with eye, skin, upper-, lower respiratory and systemic disorder symptoms during the previous three months. Finally, data from 115 schools in 54 European cities from 23 countries were collected and included 5175 schoolchildren using a harmonized and standardized protocol. The association between exposures and the health outcomes were examined using logistic regression models on the environmental stressors assessed in classroom while adjusting for several confounding factors; a VOC (volatile organic compound) score defined as the sum of the number of pollutants to which the children were highly exposed (concentration > median of the distribution) in classroom was also introduced to evaluate the mul tiexposu re - outcome association. Schoolchildren while adjusting for several confounding factors. Schoolchildren exposed to above or equal median concentration of PM2.5, benzene, limonene, ozone and radon were at significantly higher odds of suffering from upper, lower airways, eye and systemic disorders. Increased odds were also observed for any symptom (sick school syndrome) among schoolchildren exposed to concentrations of limonene and ozone above median values. Furthermore, the risks for upper and lower airways and systemic disorders significantly increased with the VOCs score. Results also showed that increased ventilation rate was significantly associated with decreased odds of suffering from eye and skin disorders whereas similar association was observed between temperature and upper airways symptoms. The present study provides evidence that exposure to IAPs in schools is associated

In this work we explore the relationship between particulate matter (PM) and small ion (SI) concentration in a typical indoor elementary school environment. A range of important air quality parameters (radon, PM, SI, temperature, humidity) were measured in two elementary schools located in urban background and suburban area in Belgrade city, Serbia. We focus on an interplay between concentrations of radon, small ions (SI) and particulate matter (PM) and for this purpose, we utilize two approaches. The first approach is based on a balance equation which is used to derive approximate relation between concentration of small ions and particulate matter. The form of the obtained relation suggests physics based linear regression modelling. The second approach is more data driven and utilizes machine learning techniques, and in this approach, we develop a more complex statistical model. This paper attempts to put together these two methods into a practical statistical modelling approach that would be more useful than either approach alone. The artificial neural network model enabled prediction of small ion concentration based on radon and particulate matter measurements. Models achieved median absolute error of about 40 ions/cm3 and explained variance of about 0.7. This could potentially enable more simple measurement campaigns, where a smaller number of parameters would be measured, but still allowing for similar insights.

To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m−3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m−3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.

The current compliance networks of automatic air-quality monitoring stations in large urban environments are not sufficient to provide spatial and temporal measurement resolution for realistic assessment of personal exposure to pollutants. Small low-cost sensor platforms with greater mobility and expected lower maintenance costs, are increasingly being used as a supplement to compliance monitoring stations. However, low-cost sensor platforms usually provide data with uncertain precision. To improve the precision, these sensor platforms require in-field calibration. Our paper aims to demonstrate that data from each individual sensor system can be corrected using that sensor system's own data to achieve much improved data quality compared to a reference. However, in this procedure, there are practical difficulties such as individual sensor outputs from the multi-sensor system not being sufficiently available due to malfunctions for instance. We explore how this can be dealt with. In our opinion, this is a novel approach, of practical importance both to users and manufacturers. We present a detailed comparative analysis of Linear Regression (univariate), Multivariate Linear Regression and Artificial Neural Networks used with a specific aim of calibrating field-deployed low-cost CO and O3 sensors. For Artificial Neural Network models, the performance of three common training algorithms was compared (Levenberg-Marquardt, Resilient back-propagation and Conjugate Gradient Powell-Beale algorithm). Data for this study were obtained from two campaigns conducted with 25 multi-sensor AQMESH v.3.5 platforms used within the activities of the CITI-SENSE project. The platforms were co-located to reference gas monitors at the Automatic Monitoring Station Stari Grad, in Belgrade, Serbia. This paper demonstrates that Multivariate Linear Regression and Artificial Neural Network calibration models can improve the output signal. This improvement can be measured by changes in the median a

Mass concentrations of particulate matter (PM) fractions were measured in educational buildings in the city of Nis, Serbia. Two sampling campaigns were conducted in winter periods. The first campaign was in the period from 21 February to 15 April 2010 at the Faculty of Occupational Safety (FOS) and the second campaign was from 20 March to 4 April 2013 at the primary school Void Karadorde (VK). PM measurements were carried out with low volume samplers Sven/Leckel LVS3. The average daily PM10 concentration inside the FOS (47.0 +/- 21.8 mu g/m(3)) was lower than PM10 concentration in outdoor air (50.7 +/- 28.1 mu g/m(3)). The average daily PM10 concentration inside the VK (54.6 +/- 17.6 mu g/m(3)) was higher than in outdoor air (47.9 +/- 22.8 mu g/m(3)). The 24-hours, average PM10 concentrations at FOS exceeded the EU limit value (50 mu g/m(3)) during 34% of days outdoors and 39% of days indoors. The 24-hours average PM10 concentrations at VK exceeded the limit value during 35% of days outdoors and 53% of days indoors. The 24-hours average PM2.5 concentrations at VK exceeded the WHO daily mean guideline value (25 mu g/m(3)) during 71% of days outdoors and 88% of days indoors. The average PM10 I/O ratio at VK was 1.57 during teaching hours, and 1.00 during no teaching hours. Similarly, average PM2.5 I/O ratio at VK was 1.11 during teaching hours and 0.90 during no teaching hours. Average daily PM2.5/PM10 ratio in the ambient air at VK was 0.87 and 0.82 at FOS. Very strong correlations between the indoor and outdoor PM concentrations were observed at VK during no teaching hours (r gt 0.8). Moderate to strong negative correlations were found between the wind speed and PM at both schools. High outdoor PM concentrations and resuspension of particles are possible reasons for the elevated indoor PM concentrations found in the study., U radu su prikazani rezultati merenja suspendovanih čestica frakcija PM10 i PM2.5 u dve izabrane obrazovne ustanove u Nišu. Kampanje merenja sprovedene su u zimskom periodu. Prva u periodu od 21.02. do 15.04.2010. na Fakultetu zaštite na radu (FOS), a druga u periodu od 20.03. do 04.04.2013. u osnovnoj školi Vožd Karađorđe (VK). Uzorkovanje suspendovanih čestica vršeno je uzorkivačima Sven/Leckel LVS3, simultano, unutar i izvan odabranih ustanova. Prosečna dnevna koncentracija čestica PM10 unutar objekta FOS (47,0±21,8 μg/m3) bila je niža u odnosu na prosečnu dnevnu koncentraciju PM10 u ambijentalnom vazduhu (50,7±28,1 μg/m3). Prosečna dnevna koncentracija čestica PM10 unutar objekta VK (54.6±17.6 μg/m3) bila je viša u odnosu na prosečnu dnevnu koncentraciju PM10 u ambijentalnom vazduhu (47.9±22.8 μg/m3). Srednje dnevne koncentracije čestica PM10 izmerene na lokaciji FOS u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost (50 ìg/m3) tokom 34% dana trajanja kampanje merenja. Srednje dnevne koncentracije čestica PM10 izmerene unutar objekta FOS prelazile su dnevnu graničnu vrednost tokom 39% dana trajanja kampanje merenja. Srednje dnevne koncentracije čestica PM10 izmerene na lokaciji VK u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost tokom 35% dana trajanja kampanje merenja, odnosno tokom 53% dana trajanja kampanje u unutrašnjosti objekta VK. Srednje dnevne koncentracije čestica PM2,5 izmerene na lokaciji VK u ambijentalnom vazduhu prelazile su dnevnu graničnu vrednost (25 ìg/m3) tokom 71% dana trajanja kampanje, odnosno tokom 88% dana u unutrašnjosti objekta VK. Prosečan dnevni odnos unutra/spolja čestica frakcije PM10 na lokaciji VK iznosio je 1,57 u vreme nastave, odnosno 1,00 kada nije bilo nastave. Prosečan dnevni odnos unutra/spolja čestica frakcije PM2,5 na lokaciji VK iznosio je 1.11 u vreme nastave, odnosno 0.90 kada nije bilo nastave. Prosečan dnevni odnos PM2,5/PM10 u ambijentalnom vazduhu na lokaciji VK bio je 0,87, odnosno 0,82 na

This study investigated seasonal variation of PAHs and their partition between gas and particulate-bounded phases in indoor and outdoor air in 4 schools In Serbia located at different locations. The sampling campaigns were conducted during one workweek at each school successively. Campaigns were conducted in schools during heating and non-heating seasons in December 2011 and June 2012. Seasonal variations of gas and particle-bounded PAHs concentrations were observed with higher levels during heating season. The highest total PAH values were associated with the gas phase in both sampling periods. The total PAHs concentration at indoor and at the outdoor sites, during heating season, ranged from 88.45 to 447.72 ng/m(3) and 201.69 to 1017.15 ng/m(3), respectively. During non-heating season, the total PAHs concentration ranged from 36.91 to 271.57 ng/m(3) in Indoor environment and 27.00 to 132.32 ng/m(3) in outdoor environment. Most of the I/O ratios were less than 1, which indicated that the indoor PAHs were mostly from outdoor sources. The use of diagnostic ratio showed that traffic emission and coal combustion are the major sources of PAHs. Only the diagnostic ratios for the school located near the industrial area showed significant deviation compared to other schools., U ovom radu su istraživane sezonske promene PAH i njihova raspodela, u gasnoj fazi i respirabilnim česticama u vazduhu unutrašnjeg prostora i spoljašnje sredine u 4 škole u Srbiji koje se nalaze na različitim lokacijama. Kampanja uzorkovanja je sprovedena tokom jedne radne nedelje u toku grejnog i negrejnog perioda (od decembra 2011. do juna 2012.) u svakoj školi. Uočene su sezonske promene nivoa PAH u gasnoj fazi i česticama, sa višim koncentracijama tokom grejnog perioda. Izmerena je veća vrednost zbira ukupnih PAH tokom oba perioda u gasnoj fazi nego PAH u česticama. Ukupna koncentracija PAH tokom grejnog perioda u unutrašnjem prostoru se kretala u opsegu od 88,45 do 447,72 ng/m3, a u spoljašnjoj sredini od 201,69 do 1017,15 ng/m3. Tokom negrejnog perioda, ukupna koncentracija PAH-ova je bila 36,91-271,57 ng/m3 u unutrašnjem prostoru, dok je u spoljašnjoj sredini bila 27,00-132,32 ng/m3. Većina I/O odnosa je bila manja od 1, što ukazuje da PAH u unutrašnjem prostoru uglavnom potiču iz spoljašnjeg vazduha. Na osnovu dijagnostičkih odnosa zaključeno je da su saobraćaj i sagorevanje uglja glavni izvori PAH. Jedino dijagnostički odnosi za školu koja se nalazi u blizini industrijske zone pokazuju značajno odstupanje u poređenju sa drugim školama.