Analysis Of The Composition Of 16 Polycyclic Aromatic Hydrocarbons And 4 Water-soluble Ions In Atmospheric PM_2.5 In Lanzhou City

Atmospheric particulate matter is an important component of the atmosphere.It is also a carrier for the reaction of various pollutants in the air,and it is also an important key to the occurrence of secondary pollution.Among atmospheric particles,PM_2.5.5 particles have relatively small particle sizes,are rich in large amounts of toxic and harmful substances,and have long residence times and long transport distances in the atmosphere,thus having a greater impact on human health and the quality of the air environment.This study mainly monitored and analyzed the polycyclic aromatic hydrocarbons and water-soluble inorganic ions in PM_2.5,and carried out the principal component analysis of these two types of pollutants in PM_2.5.5 in Lanzhou City.To determine the main polycyclic aromatic hydrocarbon pollutants and the main contribution of water-soluble ions to the environment in environmental air in Lanzhou city.Therefore,through the analysis of the composition of PM_2.5.5 pollutants and water-soluble ions in the atmosphere of Lanzhou City,this study studied the main substances of PM_2.5.5 polycyclic aromatic hydrocarbons and water-soluble ions in Lanzhou City to provide some rich resources for the prevention and control of atmospheric pollution and the tracing of sources.This study established the determination method of PAHs and water-soluble ions,and analyzed the samples of different areas in Chengguan District and Xigu District in2015 and 2016 to determine the change trend of PAHs in the monitoring points in Chengguan District and Xigu District.And the main pollutant components,the following studies were carried out:?1?Taking PM_2.5.5 in the atmospheric environment as the research object,the optimal instrument conditions were established after optimizing the parameters of various instruments of HPLC,and the pretreatment conditions of PAHs in PM_2.5.5 samples in the environment were investigated,and the optimal pretreatment conditions were determined.A quantitative and qualitative method was established for the detection of 16 PAHs by HPLC.Compared with the known chromatography and chromatographic tandem mass spectrometry,the method has simple and rapid sample pretreatment.Instrument operation is convenient and time saving;It greatly shortens the detection period of large quantities of samples,reduces the waste of solvents,and ensures the stability of detection limits and precision.In addition,four kinds of water-soluble inorganic ions were detected by ion chromatography,the optimal pretreatment condition of water-soluble inorganic ions was determined,and the qualitative and quantitative detection of four kinds of ions was established.Through the determination of PAHs and water soluble inorganic ions in PM_2.5samples in atmospheric environment,the established method satisfies the determination of actual samples.?2?Based on the established detection method,PAHs in environmental samples were tested and analyzed.The experimental results show that among the monitoring points in Chengguan District,PAHs emissions from January to March and from October to December are mainly based on 4-ring PAHs,and 3-Ring PAHs are the main ones from April to September;From January to February and December,PAHs emissions in Xigu District are mainly based on 4-ring PAHs,and from March to November,they are mainly based on 3-Ring PAHs.The relatively high contribution substances in the monitoring componentsofthemonitoringpointsintheChengguanDistrictare Acenaphthene,Fluoranthene,Pyrene,andBenzene[A]Flumene,Benzenecombined[B]Flumene,Benzenecombined[K]Flumene and Benzene merge[A]Pyrene;The relatively high contributions of the monitoring components of the monitoring points in the Xigu area are acenaphthene,Fluorene,Anthracene,Phenanthrene,Fluoranthracene,Pyrene,and Benzene[A]Fluoranthrene,Dendrobium,Benzene[B]Flumeneand Dipheny[A,H]Anthracene.Both Chengguan District and Xigu District have relatively high contributions to Fluorene and Benzene[A]Flumene,Benzene combined[B]Flumene and Benzene merge[K]Fluanthene.?3?Based on the established detection method,the water-soluble ions in environmental samples were detected and analyzed.The test results showed that the water-soluble Ionic pollutants in PM_2.5.5 in Lanzhou were mainly SO₄^2-,and NO₃^-,CL^-and NH₄⁺were followed.This may be related to the geographical location,climatic conditions,and heating conditions of Lanzhou City at a specific time.Lanzhou is located in the Northwest,on the edge of the Hexi Corridor,and the terrain is narrow and narrow,with a temperate continental climate,a generally dry climate,low rainfall,and sparse vegetation.These conditions have caused pollutants to be difficult to degrade or evacuate,and have affected the concentration of water-soluble inorganic ions in PM_2.5.5 in Lanzhou City.