Hemijski sastav i oksidativni potencijal respirabilnih čestica u urbanoj sredini i u industrijskom okruženju

Abstract

U ovoj disertaciji ispitan je hemijski sastav i oksidativni potencijal (OP) dve frakcije respirabilnih čestica (PM2.5 i PM10), u različitim sredinama. Za utvrĎivanje sezonskih promena, prvo istraţivanje sprovedeno je u urbanoj (UB) i urbano-industrijskoj (UI) sredini tokom leta i zime. Kako bi se ispitale promene OP-a tokom dana, drugo istraţivanje sprovedeno je u urbanoj sredini pod uticajem saobraćaja. Rezultati prvog istraţivanja ukazuju da su prosečne koncentracije obe ispitivane frakcije čestica, u UB i UI, bile vrlo slične tokom leta. Tokom zime, u UB koncentracije PM2.5 bile su tri puta više, a PM10 dvostruko više u odnosu na koncentracije izmerene u UI. U obe ispitivane sredine, tokom obe sezone, PM2.5/PM10 odnos bio je visok, što ukazuje na značajan udeo finih čestica u gruboj frakciji, koje prvenstveno imaju antropogeno poreklo. Dominantnu vrstu u obe frakcije čestica, kao i u obe ispitivane sredine, činila je organska materija, čiji je procenat varirao u zavisnosti od godišnjeg doba. Prosečni OC/EC odnosi, kao i koncentracije WSOC-a, u obe frakcije čestica, bili su značajno viši tokom zimskog perioda u UB, što je posledica prisustva velike količine sekundarnih organskih aerosola. Prosečne koncentracije jonskih vrsta i 22 kvantifikovana elementa, tokom obe sezone, bile su više u UI. Primenom DTT i DCFH eseja, u obe ispitivane sredine, više vrednosti OP-a utvrĎene su za PM2.5, a primenjeni eseji pokazali su suprotne trendove. U obe ispitivane sredine, primenom DTT eseja, OP vrednosti bile su više tokom letnjeg perioda, dok su DCFH esejom više vrednosti utvrĎene tokom zime. U drugom istraţivanju, najveća količina ROS-ova izmerena je oko 14 h, što moţe biti posledica maksimalne količine saobraćaja ili velikog doprinosa SOA. Umerena, statistički značajna korelacija utvrĎena je izmeĎu BPEAnit i DCFH eseja, što ukazuje na veću toksičnost koja potiče od organskih vrsta prisutnih u vazduhu. Kombinovanjem rezultata više eseja preciznije je utvrĎen kvalitet vazduha u različitim sredinama, što predstavlja osnovu za detekciju konkretnih izvora zageĎanja.

In this dissertation, the chemical content and oxidative potential (OP) of two fractions of respirable particles (PM2.5 and PM10) were examined in different еnvironments. The first study was conducted in urban (UB) and urban-industrial (UI) environments during summer and winter to determine the seasonal changes. The second study was conducted in an urban environment influenced by the traffic to examine the differences in OP during the day. The results of the first study indicate that the average concentrations of both analyzed particle fractions, in UB and UI, were very similar during the summer. During the winter, PM2.5 levels in UB were three times higher and PM10 twice as high as in UI level. In both examined environments, during both seasons, the PM2.5/ PM10 ratio was high, which indicates a significant contribution of fine particles in the coarse fraction, which are primarily of anthropogenic origin. In both examined environments, the dominant particle fraction was the organic matter, the percentage of which varied depending on the season. Average OC/EC ratios, as well as WSOC concentrations, in both particle fractions, were significantly higher during the winter period in UB, due to the presence of a large amount of secondary organic aerosols. The average concentrations of ion species and 22 quantified elements, during both seasons, were higher in the UI. Using DTT and DCFH assays, in both examined environments, higher OP values were determined for PM2.5, and the applied assays showed opposite trends. In both urban environments, using DTT assays, OP values were higher during the summer period, while DCFH assays were higher values determined during the winter. In another study, the largest amount of ROS was measured around 2 p.m., which may be due to maximum traffic or a significant contribution from SOA. A moderate, statistically significant correlation was found between BPEAnit and DCFH assays, indicating higher toxicity derived from organic species present in the air. By combining the results of several essays, the air quality in different environments was more precisely determined, which is the basis for the detection of specific sources of pollution.