| Objective:Through the monitoring of atmospheric PM2.5 mass concentration and the components analysis of PAHs,metals and ions,monitor the amount of outpatients in the hospital's internal medicine department and the respiratory system and circulatory system,to grasp the characteristics and sources of atmosphere PM2.5 pollution of Nanchang and Wuyuan,analyze the impact of atmospheric PM2.5 pollution on the health of the general population,and provide a technical basis for air pollution prevention and control and crowd health protection.Methods:Set up a sampling point in Qingshanhu District of Nanchang City and Wuyuan County,collected PM2.5 samples from 10-16 every month in 2018,determined the PM2.5 mass concentration,and high performance liquid chromatography,inductance Coupled plasma mass spectrometry,ion chromatography were used to determine the content of PAHs,metals and metalloid elements,and water-soluble ions in samples,analyzed the characteristics of atmospheric PM2.5 pollution at monitoring points,and used factor analysis to analyze the source of PM2.5 pollution.Simultaneously,collected the data of air pollutants,meteorology,hospital outpatient of two consecutive years,used a generalized linear model based on Poisson regression and controled the longtime trend,meteorological factors,"day of the week"and"holiday"effects,analyzed the impact of atmosphere PM2.5 on the outpatient visits.Results:?1?The annual atmospheric PM2.5 mass concentration in Nanchang and Wuyuan presented a"U"-shaped fluctuation,with medians of 0.068 mg/m3 and 0.028 mg/m3,and annual over-standard rates of 42.9%and 1.2%respectively.The mass concentration of atmospheric PM2.5 in Nanchang was significantly higher than that in Wuyuan.The pollution level in Nanchang in the first and fourth quarters was significantly higher than that in the second and third quarters,and the pollution level in Wuyuan in the first quarter was significantly higher than in other quarters.?2?The content of water-soluble ions in PM2.5 of Nanchang was significantly higher than that in Wuyuan,and the median mass concentration for the year were23.848?g/m3 and 8.290?g/m3 respectively.The content of water-soluble ions in PM2.5of Nanchang changed in an"U"shape,the pollution level in the first and fourth quarters was significantly higher than that in the second and third quarters,the mass fraction:NO3->SO42->NH4+>Cl-.The ion content of PM2.5 in Wuyuan was lower in the third quarter,with the mass fraction of SO42->NH4+>NO3->Cl-.?3?The content of metal elements in PM2.5 of Nanchang was significantly higher than that in Wuyuan,and the median annual mass concentrations were 224.981 ng/m3and 128.613 ng/m3,respectively.The content of metal elements in PM2.5 of Nanchang showed an"L"type change,the pollution level in the first quarter was significantly higher than that in other quarters,the mass fraction:Al>Pb>Mn>As>Se>Sb>Cd>Ni>Cr>Tl.The metal element content of PM2.5 in Wuyuan was higher in February and April,the pollution level in the first half of the year was higher than that in the second half,the mass fraction:Al>Pb>Mn>As>Se>Sb>Cd>Cr>Ni>Tl.?4?The content of PAHs in PM2.5 of Nanchang was significantly higher than that in Wuyuan,with the median mass concentration of 3.935 ng/m3 and 1.595 ng/m3respectively.The concentration of PAHs in PM2.5 of Nanchang was obviously"U"-shaped,the concentration level was high in the first and fourth quarters,the mass fraction:BPE>BbF>IPY>FLT>PYR>BaP>CHR>PHE>BkF>BaA>FLU.The concentration of PAHs in PM2.5 of Wuyuan changed in an"L"shape,the concentration level in the first quarter was relatively high,the mass fraction:BPE>IPY>BaP>BbF>FLT>CHR>BkF>BaA>PYR>PHE>FLU.?5?The water-soluble ions and metal elements in atmospheric PM2.5 of Nanchang mainly came from motor vehicle exhaust?43.0%?,secondary aerosols?11.7%?,dust?10.8%?,coal combustion?7.7%?,the total contribution rate was 73.2%.The water-soluble ions and metal elements in PM2.5 of Wuyuan mainly came from motor vehicle exhaust?43.0%?,biomass combustion?11.2%?,coal combustion?9.2%?,and the total contribution rate was 63.4%.The main sources of PAHs in atmospheric PM2.5 at the two monitoring sites were similar,the sources of motor vehicle exhaust and coal-fired were the main sources with total contribution rate of 90.2%and 91.6%.The motor vehicle exhaust contribution rates in Nanchang and Wuyuan were 77.1%and 80.0%,and the coal-fired contribution rates were 13.1%and 11.6%,respectively.?6?For an increase of 10?g/m3 PM2.5 in Nanchang,medical outpatients increased by 0.40%?95%CI:0.28%0.51%?and respiratory system outpatients increased by 0.40%?95%CI:0.03%0.78%?,circulatory system outpatients increased by 0.37%?95%CI:0.17%0.58%?in the same day?lag0?;medical outpatients increased by 0.59%?95%CI:0.46%0.73%?and respiratory system outpatients increased by 0.66%?95%CI:0.23%1.09%?in the seventh day?lag6?.For an increase of 10?g/m3 PM2.5 in Wuyuan,medical outpatient visits increased by 0.60%?95%CI:0.01%1.19%?.Conclusions:Atmospheric PM2.5 pollution in urban areas of Nanchang was mainly light pollution,the main sources were motor vehicle exhaust,secondary aerosols,construction site dust,and coal combustion;Wuyuan County has excellent air quality,and the main source of atmospheric PM2.5 is motor vehicles exhaust,biomass combustion,coal combustion.The increase in atmospheric PM2.5 concentration could cause an increase in the number of outpatients in hospitals,effective measures should be taken to reduce the level of PM2.5 and protect the health of the population. |
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