Characteristics And Sources Apportionment Of Atmospheric Particulate Matter In Luohe City

In recent years,with the rapid economy development in China,some cities experienced large-scale heavy pollution continuously.Particulate matter(PM)pollution has also become an important environmental problem in some cities dominated by light industry.Research on the characteristics of particulate matter pollution is very limited in such cities.So Luohe City was selected as a representative for this kind of city in this study.During the period from May 2017 to February 2018,PM2.5 and PM10 filter were collected in three sampling points in the built-up area of Luohe City(Water Conservancy Bureau,Party School of the Municipal Party Committee,3515 factory)in each season.The mass concentration and chemical components(carbon components,watersoluble ions and elements)of PM2.5 and PM10 were analyzed,and the CMB model was used for source apportionment.This research can be used to understand the characteristics of atmospheric particulate matter pollution and provide scientific support for the prevention and control of atmospheric pollution for this kind of city.The research results are as follows:(1)The concentration of particulate matter was higher in autumn and winter than in spring and summer in Luohe City.During the sampling period,the average concentrations of PM2.5 and PM10 were 72.20?g/m3 and 126.40?g/m3,respectively.The mass concentration of PM2.5 in each season(descending ordere)were 96.70?g/m3(autumn),95.96?g/m3(winter),50.52?g/m3(spring)and 38.41?g/m3(summer).The mass concentration of PM10 in each season(descending ordere)were 166.32?g/m3(autumn),163.02?g/m3(winter),104.35?g/m3(spring)and 61.02?g/m3(summer).The values of PM2.5/PM10 in spring,summer,autumn and winter were 0.50,0.61,0.56 and 0.57 respectively.There were three heavy atmospheric pollution processes in the autumn and winter in Luohe City.Unfavorable meteorological conditions were important factors causing heavy pollution.Correlation analysis showed that PM2.5 and PM10 were positively correlated with SO2,NO2 and CO(P<0.01)significantly,indicating that these pollutants may come from the same sources.(2)The chemical composition of PM2.5 and PM10 were obtained in each season.During the sampling period,the mass concentrations of total carbon in PM2.5 and PM10 were 15.48?g/m3 and 21.71?g/m3,and the proportion of particulate matter was 21.38% and 17.16%,respectively.The correlation between OC and EC in summer was the worst,indicating that the sources were different in summer.The annual average of total inorganic water-soluble ions in PM2.5 and PM10 were 34.76 ?g/m3 and 46.40 ?g/m3,accounting for 46.72% and 35.67% of the particulate matter,respectively.The total inorganic watersoluble ion was highest in winter and lowest in summer.The anion-cation balance calculation indicated PM2.5 and PM10 is alkaline.The sum of the elemental components in PM2.5 and PM10 was 6.41 ?g/m3 and 18.49 ?g/m3,which accounted for 8.88% and 14.62% of the particulate matter,respectively.They were highest in autumn and lowest in summer.The constructed mass concentration of PM2.5 and PM10 accounted for 83% and 77% of the actual weighing mass.The main compounds were MIN(Mineral dust),OM(Organic matter),sulfate and nitrate.OM and nitrate were higher in autumn and winter.(3)Base on localized source spectrum,the CMB model was used to analyze the source of PM2.5 and PM10 in Luohe City.The main sources of PM2.5 were motor vehicles,dust sources,industrial sources and farming source.The share of PM2.5 was 36.48%,10.36%,9.45% and 9.28%,respectively.The main source of PM10 was dust sources,motor vehicles,industrial sources and farming source.The share of PM10 was 33.18%,26.48%,6.86% and 6.75%,respectively.Comparing the PM sources of each season,it is known that the dust source contributed the most to the particulate matter in spring,and the motor vehicle exhaust dust contributed the most in summer,and the secondary particulate matter contributed the most in autumn and winter.It can be seen from the above research that dust,motor vehicle exhaust,industrial and farming sources are the focus for airborne particulate pollution prevention and control.