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Namen naše raziskave je bil določanje okolju nevarnih organskih spojin adsorbiranih na prašne delce PM10. Vzorce smo odvzeli v skladu s standardom SIST EN 12341:2014. Po gravimetrijskem določanju delcev PM10 smo vzorce uporabili še za določitev kemične sestave in preučitev pomembnih sezonskih razlik v sestavi organskih snovi, ki jih vsebujejo delci PM10. V ta namen smo razvili analizno metodo za določevanje organskih spojin v ekstraktih vzorcev prašnih delcev PM10 s plinsko kromatografijo in masno spektrometrijo. S pomočjo kemometrijskih metod smo določili pomembne sezonske in lokacijske razlike sestave organskih spojin v zraku nad Mariborom. Določali smo sestavo spojin, ki označujejo onesnaženost in ugotavljali, katere spojine so antropogenega izvora. Ugotavljali smo, kako se sestava razlikuje glede na letni čas in odvzemno mesto vzorčenja. PM10 je frakcija respirabilnih prašnih delcev s premerom 10 μm ali manj. Suspendirani delci v zraku so naravnega (gozd, cvetni prah, padavine, neurja, vegetacija, vulkanski pepel...) ali antropogenega izvora (emisije industrije, prometa, sežig fosilnih goriv, biomase, kmetijstvo). Glede na izvor delce razdelimo na primarne in sekundarne. Primarni delci se sproščajo v ozračje direktno. Velik del organskih aerosolov v atmosferi je mogoče pripisati sekundarnim organskim aerosolom (SOA), ki nastajajo pri oksidaciji hlapnih organskih spojin (VOC) z atmosferskimi oksidanti kot so O3, OH• radikali in NO3• radikali. Fotokemični procesi vplivajo na kemično sestavo organskih spojin in njihove fizikalno-kemijske lastnosti kot so hlapnost, higroskopičnost ali kondenzacijsko aktivnost SOA spojin. Zakonsko predpisana 24-urna mejna koncentracija za delce PM10 je 50 μg/m3. Preseganja dnevnih mejnih vrednosti PM10 so praviloma v zimskem letnem času. Povišana raven delcev PM10 je predvsem posledica lokalnih izpustov. Dve tretjini vseh izpustov delcev PM10 v Sloveniji je posledica kurjenja lesa gospodinjstev. Raziskovalno delo zaznave in določanja spojin organskih onesnaževal vključuje 120 standardno odvzetih vzorcev prašnih delcev (standard SIST EN 12341:2014) z uporabo nizko volumskega vzorčevalnika, ter analitsko določevanje s plinsko kromatografijo in masno spektrometrijo (GC/MS). Za določanje polarnih organskih spojin smo uporabili sililiranje kot kemijsko tehniko derivatizacije. Nabor organskih spojin v ekstraktih prašnih delcev PM10 vključuje maščobne kisline, n- in izo-alkane, ftalatne estre, siloksane, sterole, sladkorje, sladkorne alkohole, dikarboksilne kisline, spojine razgradnje lignina in lesnih smol, policiklične organske ogljikovodike, organske dušikove spojine ter produkte sekundarne oksidacije monoterpenskih spojin. S pomočjo kemijske karakterizacije smo določili sezonske in lokacijske razlike merilnih mest. Za proučevanje smo uporabili kemometrijske metode kot so korelacijska analiza, metoda glavnih osi, hierarhično razvrščanje, analiza variance (ANOVA). V toplejših letnih časih prevladujejo na prašnih delcih adsorbirane biogene spojine nad antropogenimi spojinami. Pozimi prevladujejo antropogene organske spojine. Najbolj reprezentativne spojine zimskih vzorcev zraka so: levoglukozan, manozan, spojine ftalatnih estrov, spojine razgradnje ligninov in palmitinska kislina. Poleti prevladujejo derivati sladkorjev in sladkornih alkoholov. Na razlike vzorcev glede na sestavo organskih spojin najbolj vplivajo spojine PAHov, 1,3,5-trifenilbenzen, pinonska kislina, DEHP, glicin, nonanojska kislina (C9:0), ter jabolčna kislina in adipinska kislina. V številnih vzorcih je bil prisoten razpotegnjen kromatografski vrh neločene kompleksne mešanice (NKM), ki se razlikuje glede na letni čas in sestavo. Izvor NKM pozimi pripisujemo kurjenju fosilnih goriv ter izpuhov motornih vozil, poleti pa fotooksidacijskim procesom monoterpenov. Do lokacijskih razlik v sestavi organskih spojin adsorbiranih na ekstraktih vzorcev PM10 prihaja zaradi različnih antropogenih in biogenih izpustov, obremenjenosti posamezne The aim of our study was the determination of environmentally hazardous organic compounds adsorbed on dust particles PM10. The samples were taken according to SIST EN 12341: 2014. After the gravimetric determination of PM10 the samples were used for the determination of composition and examination of significant seasonal differences of organic compounds adsorbed on dust particles PM10. For this purpose we developed an analytical method for the determination of organic compounds adsorbed on PM10 by gas chromatography and mass spectrometry. Using chemometric methods, we determined relevant seasonal and location differences in composition of organic compounds in the air above Maribor. We determined the composition of compounds, which indicate contamination, and measured, which compounds are of anthropogenic origin. We investigated how the composition varies depending on the time of year and the sampling location. PM10 is a fraction of respirable dust particles with a diameter of 10 μm or less. Suspended particles in the air are of natural (forests, pollen, rain, thunderstorms, vegetation, volcanic ash ...) or anthropogenic origin (industrial emissions, traffic, combustion of fossil fuels, biomass, agriculture). Depending on the origin of the particles are divided into primary and secondary. Primary particles are emitted directly into the atmosphere. A large portion of the organic aerosol in the atmosphere can be attributed to secondary organic aerosol (SOA), produced in the oxidation of volatile organic compounds (VOC) with atmospheric oxidants such as O3, OH• radicals and NO3• radicals. Photochemical processes affect the chemical composition of organic compounds and their physicochemical properties such as volatility, hygroscopicity or condensation activity of SOA compounds. Legally prescribed 24-hour limit concentration of PM10 is 50 μg/m3. Exceedances of daily PM10 limit values are generally in the winter season. Elevated levels of PM10 are mainly due to local emissions. Two-thirds of all PM10 emissions in Slovenia is the result of wood burning by households. The reaserch work of determination of organic compounds in atmospheric particulate matter includes 120 samples of collected dust particles PM10. Sampled according to SIST EN 12341:2014 reference method, using a low-volume air sampler and the analytical determination by gas chromatography and mass spectrometry (GC/MS). Silylation as derivatisation method was used for the determination of polar organic compounds. The set of organic compounds on the dust particles PM10 include of fatty acids, n-alkanes and iso-alkanes, phthalate esters, siloxanes, different sterols, various sugars and sugar alcohols, compounds of lignin and resin acids, dicarboxylic acids from photochemical reactions, PAHs, organic nitrogen compounds and products from secondary oxidation of monoterpenes were determined. With the chemical characterization we determined seasonal and locational differences of sampling points. For the study we used chemometric methods such as correlation analysis, regression, cluster analysis, analysis of variance (ANOVA). In warmer seasons adsorbed on dust particles biogenic compounds dominate over anthropogenic compounds. In winter anthropogenic compounds dominate. The most representative compounds of winter air samples are levoglucosan, manosan, phthalate esters, decomposition compounds of lignin and palmitic acid. In summer derivatives of sugars and sugar alcohols dominate. The variations of samples according to the composition of organic compounds are mostly influenced by PAHs, 1,3,5- triphenylbenzene, pinonic acid, DEHP, glicine, nonanoic acid, malic acid and adipic acid. In a number of samples was present an elongated chromatographic peak of unresolved complex mixture (UCM), which varied according to the season and composition. Source of UCM in winter are the burning of fossil fuels and exhaust of motor vehicles, while in summer the photoxidation processes of VOC. Locat |
