| As one of the air pollution transmission channels around Beijing,Tianjin and Hebei area,Puyang frequently suffers from severe air pollution in autumn and winter.In order to study the characteristics and main sources of fine particulate matter pollution in the autumn and winter of Puyang,manual membrane sampling of PM2.5 and chemical composition analysis was conducted.The data of PM2.5 concentration and its components were obtained by online monitoring instrumentat.Based on the data,combined with the PMF receptor model,a source analysis of fine particulate matter was carried out,and secondary source analysis was carried out based on emission inventory.This study uses Reg AEMS model to simulate four typical heavy pollution processes,combined with the PMF receptor model,a refined source analysis based on heavy pollution process was carried out.The main research results are as follows:?1?The pollution characteristics of fine particulate matter in autumn and winter in Puyang were analyzed,the pollution of organic matter is serious,and the content of NO3-in water-soluble ions is high,while the concentration of SO42-is low.In the autumn and winter of 2017-2018,the average mass concentration of PM2.5 was 86.03?g/m3,and the pushuihe management office was the most polluted.The main groups of PM2.5were water-soluble ions?52.33%?,carbonaceous components?25.32%?and crustal elements?7.88%?.In the autumn and winter of 2018-2019,the concentration of fine particles increased by 15.06?g/m3 compared with the previous year.The hualong district was the most polluted.The main groups of PM2.5 were water-soluble ions?48.35%?,carbonaceous components?22.86%?and crusted elements?11.29%?.When heavy pollution occurs,the concentration of SO42-,Cl-and K+in PM2.5 increases greatly,while the concentration of crustal elements decreases.The mean sulfur and nitrogen conversion rates in autumn and winter of 2017-2018 were 0.22 and 0.22 respectively,and the mean sulfur and nitrogen conversion rates in autumn and winter of 2018-2019were 0.24 and 0.31 respectively.The conversion rate of sulfur and nitrogen of Puyang is high,and the atmospheric oxidation is strong.The conversion of sulfur and nitrogen to form secondary aerosols plays an important role in the occurrence of heavy pollution,among which the sulfur conversion may play a more important role.The combination and Mg?NO3?2 in particulate matter,and the existence form of K+is K2SO4.?2?Based on sampling analysis and on-line monitoring,the source of fine particulate matter in autumn and winter in Puyang was analyzed quantitatively.It can be seen that secondary transformation plays an important role in the formation of heavy air pollution.Other industries and biomass stoves are important emission sources of air pollution in autumn and winter in Puyang.Source analysis showed that the main sources of PM2.5 in the autumn and winter of 2017-2018 were secondary inorganic salts?37.00%?,industrial sources?16.33%?,secondary organic aerosol?14.00%?,and biomass combustion?12.33%?.Secondary source analysis shows that the primary source of PM2.5 pollution is biomass stoves?17.92%?,followed by civil combustion?16.39%?and other industries?15.21%?.The major sources of PM2.5 in autumn and winter of 2018-2019 were secondary inorganic salts?31.00%?,industrial sources?18%?,secondary organic aerosol?14.00%?,coal?13%?,and biomass combustion?12%?.Secondary source analysis shows that other industries?19.12%?are the most important contributors to PM2.5 pollution,followed by biomass stoves?18.65%?and industrial boilers?15.37%?.In the winter and spring of 2019,online monitoring of PM2.5components was carried out,and PMF model was used for source analysis.The results show that secondary salt?36.1%?was the largest contributor to PM2.5,followed by industrial sources?26.1%?,biomass combustion?15.8%?,and mobile?13.3%?.Secondary source analysis results show that other industries contribute the most to PM2.5 pollution?26.53%?,followed by biomass stoves?21.08%?and non-road mobile sources?14.66%??3?A numerical source analysis method combining the regional atmospheric environment model Reg AEMS with the receptor model PMF was developed,and the characteristics and sources of four typical heavy pollution processes were analyzed.The peak concentration of PM2.5 of the first heavy pollution process was 388?g/m3,this process was influenced by local emission pollution,CO and NOxconcentrations significantly increased,source apportionment results show that the sources of PM2.5were nitrate?34%?,sulfate?28%?,mobile?16%?and biomass burning?9%?,The results of secondary source analysis show that the major secondary pollution sources were non-road moving sources?15.43%?and road moving sources?15.36%?.The second pollution process developed rapidly,with the hourly AQI value increasing by 113.PM10was the main pollutant,which was mainly affected by the dust transport in northwest China.Source apportionment results show that the sources of PM2.5 were sulfate?35%?,mobile?22%?,dust?17%?and nitrate?11%?,The results of secondary source analysis show that the major secondary pollution sources were electric heating?19.44%?and non-road moving sources?16.7%?.In the process of heavy pollution under adverse meteorological conditions,puyang was in the front of the high pressure equal-pressure field for a long time,which was controlled by the weak warm advection.The atmosphere was static and stable,with poor diffusion conditions.The relative humidity was maintained at 100%in a long period of time,and the atmosphere reached the saturation state.Source apportionment results show that the sources of PM2.5 were coal?29%?,secondary inorganic salt?25%?,industrial source?22%?and dust?10%?,The results of secondary source analysis show that the major secondary pollution sources were industrial boilers?30.13%?and other industries?21.06%?.The fourth pollution was caused by the discharge of fireworks and firecrackers during the Lantern Festival,causing an explosive increase in fine particulate concentrations,with PM2.5concentrations peaking at 631?g/m3.The concentration of indicator factors K+,Cl-and SO42-related to the discharge of fireworks all showed significant characteristic increases.Source apportionment results based on the numerical model show that the sources of PM2.5 were combustion?32%?,sulfate?20%?,industrial source?17%?and dust?16%?.Under the adverse meteorological conditions such as weak pressure field,high humidity,static wind,low mixing layer height and temperature inversion,the complex chemical reaction and secondary transformation of the primary pollutants in the atmosphere occur under the action of local discharge and regional transmission.In summary,this paper studies the characteristics of atmospheric particulate matter pollution in Puyang in autumn and winter,the source of fine particulate matter in autumn and winter was analyzed quantitatively based on sampling analysis and on-line monitoring,and with the regional atmospheric environment model combined with the receptor model,the characteristics and sources of four typical heavy pollution processes in autumn and winter were analyzed.The research results can provide a certain scientific basis for the air pollution control in Puyang. |
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