Content and composition of indoor and outdoor air pollution in school environments in Serbia

[M. Živković]

94 стр.

Hemija - Analitička hemija / Chemistry -Analitical chemistry

Ova disertacija predstavlja kompleksnu analizu kvaliteta vazduha u školskim sredinama i doprinosi boljim saznanjima o nivoima zagađujućih materija prisutnih u obliku čestica i gasova u vazduhu unutrašnjeg prostora škola i njihovom okruženju. U ovoj disertaciji merene su prioritetne zagađujuće materije vazduha za unutrašnji prostor: VOC, NO2, O3, PM2,5, PM10, TSP, kao i PAH-ova u svim frakcijama čestica i gasnoj fazi. Uzorkovanje je vršeno u ukupnom trajanju od tri meseca, sukcesivno u šest osnovnih škola i dva vrtica u Srbiji, koji se nalaze u različitom okruženju. VOC-ovi, NO2 i O3 bili su uzorkovani pomoću pasivnih uzorkivača, dok su frakcije čestica (PM2,5, PM10, TSP) i gasna faza PAH-ova uzorkovani aktivno, pomoću pumpi male zapremine. Nađeno je da su nivoi VOC-ova u unutrašnjem prostoru škola bili daleko viši nego u spoljašnjoj sredini. Rezultati PCA analize ukazali su da ozonoliza i fotohemijske reakcije, emisije iz građevinskih materijala i organski rastvarači, emisije iz sredstava za čišćenje i spoljašnji izvori emisije značajno utiču na nivoe VOC-ova u unutrašnjem prostoru škola. Veće koncentracije čestica u unutrašnjem prostoru i spoljašnjoj sredini zabeležene su tokom grejnog perioda u svim školama, pa je zaključeno da uticaj grejanja tokom zimskih meseci, kao i položaj škole ima bitan uticaj na nivoe PM u učionicama. Takođe, rezultati su pokazali da su koncentracije čestica u unutrašnjem prostoru više nego u spoljašnjoj sredini. Zapaženi su viši nivoi PM2,5 u učionicama tokom školskih sati u poređenju sa nivoima kada su učionice bile prazne. Pokazano je da infiltracija spoljašnjih čestica i njihova naknadna resuspenzija može dovesti do povišenih nivoa čestica u unutrašnjem prostoru škola, a samim tim i do povećanih nivoa PAH-ova. Ispitivanjem raspodele PAH-ova između gasne i čestične faza uočeno je da su najdominantniji PAH-ovi u gasnoj fazi bili Nap, Phe i Flu, dok su najdominantniji u čestičnoj fazi bili BgP, Ind i BbF. Primećeno je da su PAH-ovi sa 5 i 6 benzenovih prstenova uglavnom bili adsorbovani na česticama manjih dimenzija, tj. PM2,5-10 (10-60%) i PM2,5 (78-89%). S druge strane, PAH-ovi sa 2 i 3 benzenova prstena bili su najdominantniji tokom obe sezone u gasnoj fazi (95-100%). Primenjene su tri metode u cillju identifikacije izvora PAH-ova (DR, PCA-MLR i PMF). PMF metoda je dala daleko bolji uvid u potencijalne izvore i njihove doprinose u odnosu na PCA-MLR i DR. Stacionarni izvori, sagorevanje uglja i biomase identifikovani su kao glavni izvori ukupnih PAH-ova u unutrašnjem prostoru i spoljašnjoj sredini škola tokom grejnog perioda. Rezultati su pokazali da su deca u školskim sredinama u Srbiji bila izložena povišenim nivoima zagađujućih materija, pre svega VOC-ova i čestica u unutrašnjem prostoru škola tokom oba perioda. Uočeno je da su nivoi benzena, PM2,5, PM10 i PAH-ova u vazduhu, bili viši od graničnih ili preporučenih vrednosti. Izračunati indikatori za procenu rizika usled izloženosti PAH-ovima su pokazali da su deca bila pod povećanim rizikom za nastanak raka

This dissertation presents a complex analysis of air quality in school environments and contributes to better knowledge about the pollutants levels present in the form of particles and gases in indoor and outdoor air. In this dissertation, priority indoor air pollutants were measured: VOC, NO2, O3, PM2.5, PM10, TSP, as well as PAHs in all particle fractions and PAHs in gas phase. Sampling was carried out over a period of three months, successively in six elementary schools and two kindergartens in Serbia, which are in different environments. VOCs, NO2 and O3 were sampled using passive samplers, while particulate fractions (PM2.5, PM10, TSP) and gas phase PAHs were sampled using low volume pumps. It was found that the levels of VOCs in the indoor space of the schools were much higher than in the outdoor environment. VOC levels in schools were found to be higher indoors than outdoors. The results of the PCA analysis indicated that ozonolysis and photochemical reactions, emissions from building materials and organic solvents, emissions from cleaning agents and outdoor emission sources significantly affect the levels of VOCs in the indoor environment of schools. Higher concentrations of particles in the indoor and outdoor environment were recorded during the heating season in all schools, so it was concluded that the influence of heating during the winter months, as well as the location of the school, have a significant impact on PM levels in classrooms. The results also showed that the concentrations of particles were higher indoor than outdoor. Higher levels of PM2.5 were observed in the classrooms during school hours compared to levels when the classrooms were empty. It has been shown that the infiltration of outdoor particles and their resuspension can lead to elevated levels of indoor particles, and therefore to increased levels of PAHs. By examining the distribution of PAHs between the gas and the particle phases, it was observed that the most dominant PAHs in the gas phase were Nap, Phe and Flu, while the most dominant PAHs in the particulate phase were BgP, Ind and BbF. It was observed that PAHs with 5 and 6 benzene rings were mainly adsorbed on smaller particles, PM2.5-10 (10-60%) and PM2.5 (78-89%). On the other hand, PAHs with 2 and 3 benzene rings were the most dominant during both seasons in the gas phase (95-100%). Three methods were applied in order to identify the potential sources of PAHs (DR, PCA-MLR and PMF). The PMF method provided much better insight into potential sources and their contributions comparedto PCA-MLR and DR. Stationary sources, coal and biomass burning were identified as the main sources of total PAHs in the indoor and outdoor environment of schools during the heating season. The results showed that children in school environments in Serbia were exposed to elevated levels of pollutants, primarily VOCs, PM and PAHs during both seasons. It was observed that the levels of benzene, PM2.5, PM10 and PAHs in air, were higher than the limit values or recommended values. The calculated indicators for risk assessment due to exposure to PAHs showed that children were at an increased risk of developing cancer.

kvalitet vazduha, zagađenje vazduha, respirabilne čestice, VOC-ovi, PAH-ovi, receptorsko modelovanje, procena rizika

air quality, air pollution, respirable particles, VOCs, PAHs, receptor modeling, risk assessment

543.26:504.5(043.3)

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