Polar Organic Compounds In PM_2.5in The Urban Areas

Atmospheric environment is complex and changeable in urban areas.Volatile organic compounds?VOCs?from biogenic and anthropogenic and the secondry organic aerosols?SOAs?produced by VOCs are the important component of aerosols in urban aeras.Biomass burning has significant impact on aerosols.Combined with the intensive human activities,there are a variety of pollutants,multiple mechanisms exist at the same time and mutual influence in urban areas.Economy is developing rapidly in Cina,environmental pollutions caused by energy consumption are very serious.Air pollution has affected people's production and life order which frequently occurring in recent years.It is very important to study the formation,distribution of the components of aerosols and those contribution in urban areas,in order to develop effective and targeted pollution prevention and control policies.Two hundred and twenty five PM_2.5 samples were collected in four seasons at three sites in Jinhua,and were analyzed with gas chromatography/mass spectrometry?GC/MS?.Ten polar organic tracers were identified and quantified,including five tracers of SOA:three for isoprene,one for?-pinene and one for toluene,and five tracers of primary organic aerosols?POA?:two for fungal spores and three for biomass burning.The concentration levels of each component,temporal and spatial distribution were analyzed,and the contribution of each component to organic carbon were estimated,the main conclusions are as follows:?1?The average concentrations of the SOA tracers for isoprene were 11.5ng/m³,which 2-methyltetrols were 2.75 ng/m³,and 2-methylglyceric acid were 8.73 ng/m³.The average concentrations of?-pinene SOA tracer 3-methyl-1,2,3-butanetricarboxylic acid were 6.65 ng/m³.Seasonal variations of the concentrations of the SOA tracers for isoprene and ?-pinene were summer>autumn?spring>winter in Jinhua.There are highest level in summer of both,which may because of the emission of isoprene and?-pinene and photochemical oxidation on the ambient temperature in summer.?2?2-methylglyceric acid was the mian isoprene SOA tracer,It was verified that 2-methyltetrols and 2-methylglyceric acid were produced by different channals by correlation analysis.NO_X-channel was the major channal in Jinhua,so there were more 2-methylglyceric acid.The ratio of 2-methylglyceric acid and 2-methyltetrols were higher in winter and autumn than spring and summer because of biomass burning.The average concentrations of arabitol and mannitol were 4.23 ng/m³ and 10.8 ng/m³ respectively,which were the tracers of fungal spores.The concentratons of fungal spores tracers were lowest in winter,and there was positive correlations between the tacers and temperature,it indicated that higher temperature in favor of the formation of fungal spores.?3?The concentrations of the SOA tracers for toluene were 4.75³9.8ng/m³,and the average concentrations were 9.74ng/m3.Seasonal variations of the concentrationsoftheSOAtracersfortoluenewere autumn>summer>spring>winter in Jinhua,which may because of the photochemical oxidation on the ambient temperature in summer and the accumulation in special meteorological conditions in autumn.There were positive correlations between O₃ and the SOA tracers,it indicated that O₃ had a great influence on the formation of SOA.?4?The concentrations of levoglucosan were 16.8⁷32 ng/m³,and the average concentrations were 119ng/m³,which was the highest level of polar organic tracers in this study.Seasonal variations of the concentrations of levoglucosan were autumn>winter>spring>summer in Jinhua,higher concentration of levoglucosan caused by more biomass burning in autumn and winter.The mian sources of biomass burning were herbs and hardwoods in Jinhua.?5?It was estimated that 3.03%²4.5%of the OC was contributed by the SOA from toluene,and 1.23⁴2.8%of the OC was from biomass burning,indicating that SOA from anthropogenic emissions and biomass burning were two important sources of the fine particles in Jinhua.The organic carban from fungal spores had a small contribution to OC of fine particles in Jinhua.