| PM2.5 refers to the fine particles with a diameter less than 2.5?m.Its chemical composition is different in different spaces and at different times,and its impact on human health and atmospheric environment will be different.However,the relationship between PM2.5 components and adverse health effects is still unclear.In this study,based on Jinan's long-term PM2.5 pollution history due to its geographical environment,two sample collection points were selected in urban and suburban areas,with Jinan as a typical area.The chemical composition and toxicological effects of PM2.5 from two sites were studied and the comparative analysis was carried out in summer and winter.In this study,PM2.5 was collected from two sampling sites in Jinan in summer and winter using glass fiber filter membranes;The collected samples were subjected to chemical composition analysis by electrospray high-resolution aerosol mass spectrometry and inductively coupled plasma mass spectrometry(ICP-MS);At the same time,it was extracted by ultra-pure water ultrasonic method,and PM2.5 suspension with concentration of 1?g/mL,25?g/mL,50?g/mL,100?g/mL and 200?g/mL was prepared by the culture solution containing 10%fetal bovine serum.The human lung epithelial cells(A549)cultured in vitro were used as the research object for the poisoning treatment.The results of CCK-8 and LDH kits were used to investigate the toxic effects of different samples on human lung epithelial cells.Using the air pollution data of Jinan for two consecutive years,including fine particles(PM2.5),respirable particulate matter(PM10),sulfur dioxide(SO2),nitrogen dioxide(NO2),carbon monoxide(CO)and ozone(O3),and daily average temperature(T),daily sea level pressure(SLP),daily average relative humidity(H),daily total precipitation(PP)and daily average wind speed(V)at the same time,construct a nonlinear dynamic inversion model to study meteorological factors,atmospheric pollution and seasonal factors on the formation of PM2.5 concentration.Chemical composition analysis showed that the high composition of the CxHyNp+ ion family(19%)in the average water soluble organic matter(WSOM)of the four samples,and the ratio of nitrogen to organic matter(N/C=0.130±0.006)in organic mass spectrometry were higher than that reported in other studies,indicating the importance of nitrogen in PM2.5;The results of the CCK-8 and LDH kits showed that when the PM2.5 concentration was 1?g/mL,the cell activity and proliferation capacity were almost unaffected.When the concentration reached 25?g/mL and 50?g/mL,the cell survival rate was reduced.The toxicity of PM2.5 in winter was significantly higher than that in summer,and the difference between the sample groups in winter and summer is large.Overall,PM2.5 toxicity was higher in urban areas than in suburbs.However,in winter,the toxicity of PM2.5 in urban areas and suburbs is relatively close.Especially at high concentrations(100?g/mL,200?g/mL,the toxicity of PM2.5 in suburbs is higher than that in urban areas;The change of PM2.5 concentration is mainly affected by other air pollution factors.The meteorological factors with seasonal characteristics also have a certain driving force on it,of which temperature and daily precipitation have a relatively large contribution rate.The formation of PM2.5 was affected by confounding factors.This study provides a method to compare the toxicity differences of PM2.5 in different regions and seasons in typical regions,and connects chemical characterization with toxicity comparison,and at the same time,analyzes the formation of PM2.5 concentration.It is of great help to limit pollution sources and make prevention and control measures in different regions and periods,so as to provide valuable information for air quality supervision decision-making and risk assessment,and provide scientific basis for more effective protection of human health. |
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