| In order to understand the characteristics of air quality,characterization of water soluble species in PM2.5 and PM10,and the sources of carbon and nitrogen,high precision data of meteorological parameters and air quality was monitored on line,the total nitrogen and carbon isotope compositions(?15N-TN and?13C-TC)of PM2.5 and PM10 on filter were determined off line from January 1 to February 18,2017 in a serous polluted city,Pingxiang.The results showed that:?1?During the sampling period,PM2.5 was?82.45±43.04??g/m3,which exceeded the day average concentration?75?g/m3?of Grade?criteria in China;PM10,SO2 and NO2were?112.98±68.66??g/m3,?23.85±14.32??g/m3,and?32.68±14.4??g/m3.Two pollution episodes occurred from Jan 1 to Jan 5,2017 and during The Spring Festival?Jan 27 to Feb2?in this period.The analysis of the backward trajectory of air masses city shows that the aerosol pollution sources are mainly local pollution sources and the air masses transmitted over long distance are few,in Pingxiang.?2?Theorderofwatersolublespeciestotalconcentrationis SO42->NO3->NH4+>Na+>K+>Ca2+>Cl->LMOA>Mg2+,of PM2.5 and PM10 on filter,Pingxiang.SO42-?NO3-and NH4+are the main cation,had significant correlations,maybe they can exist in the form of?NH4?2SO4 and NH4NO3 in the atmosphere,while NH4NO3accounts for a relatively high proportion.Temperature,relative humidity,wind speed and other meteorological parameters have important effects on the composition of water-soluble ions.The concentrations of SO42-?NO3-and NH4+are relatively high,accounting for about91%of the water-soluble components,which may be due to the high degree of secondary aerosol pollution leading to common air pollution events,during the NPE period.The ratio of NO3-/SO42-in PM2.5 and PM10 is less than 1,during sampling period and spring period in pingxiang city,and the contribution of fixed source?coal burning?is higher than that of mobile source?motor vehicle exhaust?;therefore,motor vehicle exhaust contributed more,During the NPE period;the relatively low ratio may be attributed to fewer vehicle trips and the large amount of SO2 released by fireworks,during the SFH.The average concentration of K+,Cl-and Mg2+is about three times that of the whole sampling period,which may be the main contribution of fireworks discharge and cause serious pollution events,during the Spring Festival.?3?The correlation analysis showed that the main sources of aerosols are fireworks,secondary aerosols,coal burning and biomass combustion;the main factor analysis showed that the main sources were secondary aerosols,fireworks,coal burning,biomass burning,and crustal sources,in the water-soluble composition of PM2.5 and PM10.?4?The concentration of TN and TC were?9.73±5.99??g/m3 and?12.68±9.53??g/m3 in PM2.5,?15.15±7.9??g/m3 and?18.7±9.11??g/m3 in PM10,respectively.The?15N and?13C were+6.32‰±4.11‰and+6.89‰±4.44‰in PM2.5,-25.1‰±0.89‰and-25.55‰±1.25‰in PM10.The result showed that:C source is mainly coal burning and motor vehicle exhaust,accompanied by C3 plant combustion;There are three main sources of N source,which are vehicle exhaust,coal combustion and C3 plant combustion.The reason may be the increasing use of motor vehicles and coal burning in Pingxiang city,and the small contribution of biomass burning.The composition of?15N and?13C of the two air pollution events,is similar to the whole sampling period,and the main source may be vehicle exhaust and coal combustion emissions,and part of the source is C3 plant combustion. |
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