| Atmospheric particulate matter has an increasingly serious impact on people’s health hazards,and this impact can vary depending on the source and particle size.In this study,because of the long-term airborne particulate matter pollution problem in Imperial Valley,California,USA,Imperial Valley was used as a typical polluted area to collect ambient particulate matter and compare it with atmospheric particulate matter in Parlier and Sacramento to study the chemical composition and toxicity analysis of PM of different particle sizes and to conduct acute exposure effect study.In this study,atmospheric particulate matter was collected from a typical contaminated area in California(Imperial Valley)and two control areas(Parlier and Sacramento)by a PM sampling and measurement platform.The collected PM particulate matter was extracted using a multi-solvent extraction method.Next to these extracts,chemical characterization was performed using ion mass spectrometry and aerosol mass spectrometry.Based on the GEO public database,data analysis of the toxic effects of atmospheric particulate matter was performed using cluster analysis and functional enrichment analysis methods.Finally,the validation of inflammatory factors was performed in human immortalized macrophages(U937),and the toxic effects of different samples of particulate matter on macrophages under acute exposure were investigated.The results of chemical composition analysis showed that the main components of all three particulate matter of PMiv were organic,with the highest proportion of nitrate in PM10-Ⅳ.The main components of ultrafine and fine particulate matter of PMPA were chloride.And the main component of PM10-PA is organic matter,with ammonium salts and nitrates significantly higher than the other two PM.the main component of PM2.5-SC is organic matter.The proportions of C,H,O,and N in organic matter were 25%,4%,24%,and 1%,respectively.Based on the results of the cluster analysis,it can be seen that the inflammatory factors to be explored all belong to one category,indicating that PM2.5 is involved in regulating the expression of the relevant genes in mice,and this regulation is positive.From the GO enrichment results,it can be found that the "inflammatory response" function will be enriched.This indicates that the corresponding inflammatory response genes are present in mice exposed to PM2.5.This is direct evidence that the involvement of PM2.5 causes an inflammatory response in mice.Similarly,two biological processes,"immune response" and "immune system processes",suggest that mice are exposed to PM2.5 to produce a corresponding immune stress response.This also demonstrates the inflammatory effects of PM2.5 exposure on mice.Toxicity analysis of PM samples showed that:1.PM particles other than PM0.1-Ⅳ,PM10-PA showed a "V" shape in relation to exposure time,and the toxic effect of PM10-PA increased with exposure time.2.PM2.5 and PM0.1 had stronger toxic effects compared to the control group(PBS).In the Parlier area,PM0.1 showed a more significant physiological response.3.PM2.5 in urban areas(Sacramento)showed a stronger toxic response than in agricultural areas(Imperial Valley,Parlier).In summary,by examining the chemical composition analysis and the toxicity effects of acute exposure to different particle sizes in typical polluted areas of California,USA,compared to two areas,the above findings can provide insight into the effectiveness of current and future control of primary and secondary pollution in typical polluted areas,as well as make the link between sources and atmospheric particulate concentrations clearer,thus providing more effective information for reducing toxicity control strategies for organisms.provide more effective information. |
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