Mass Concentrations and Indoor-Outdoor Relationships of Pm in Selected Educational Buildings in Nis, Serbia

Abstract

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 lokaciji FOS. Detektovana je veoma jaka korelacija između koncentracija suspendovanih čestica unutar i izvan objekta VK u periodu kada nije bilo nastave (r gt 0.8). Umerena do jaka korelacija detektovana je između brzine vetra i koncentracija suspendovanih čestica na obe lokacije (FOS i VK). Visoke koncentracije suspendovanih čestica u ambijentalnom vazduhu i resuspenzija čestica najverovatniji su razlog koji utiče na povećane koncentracije suspendovanih čestica u unutrašnjem prostoru posmatranih obrazovnih ustanova.