The Particle Size Distribution Of Carbon Aerosol And The Inspiration Of Secondary Organic Aerosol (SOA)

As the primary pollutant in the atmosphere in recent years,particulate matter has an increasingly negative impact on human life.The particulate matter contains more carbonaceous components,mainly organic carbon?OC?and elemental carbon?EC?.In order to study the concentration of particles in the indoor and outdoor ambient air,the particle size distribution of the mass concentration,and the content of carbon aerosols,the experiment used ELPI+14 particle size segments to sample the particles,and the concentration of each particle size segment,The analysis of mass concentration and carbon aerosol content and estimation of secondary organic aerosol?SOA?production mainly led to the following conclusions:?1?The concentration of PM10 number in ambient air ranges from 865 to161602 particles·cm^-3,with an average of 28397 particles·cm^-3.The nucleation mode number concentration is the largest and the mass concentration is the largest for coarse particle mode.At the same time,according to the correlation analysis of mass concentration and number concentration of atmospheric particulates,it can be concluded that the superfine particles and coarse particles in the atmosphere have similar sources.?2?Precipitation has a certain removal effect on particulate matter in accumulation mode and coarse particle mode.Among them,precipitation has a better removal rate to the number and mass concentration of particles in coarse particle mode,and to a certain extent to reduce the mass concentration of particulate matter in the accumulation mode,but the removal effect of the number concentration is not obvious.?3?there are carbon aerosol pollution and secondary aerosol pollution in the atmosphere.The results showed that the concentration of PM_2.5 in atmospheric PM_2.5was 8.24??·m^-3?2.62??·m^-3,during the sampling period,and the concentration of OC and EC was the largest.The maximum fraction of EC was 0.256-0.382?m,the ratio was 29.52 and 15.29,and the range of OC/TC was 61.97 and 99.46,and the average OC value was 80.62,which was the main component of TC.The OC/TC value of the Aitken nuclear mode particle is the largest among the OC/TC ratios of the different particle size segments,but the other three modes have little difference.There is a weak correlation between OC and EC in the atmosphere?R²=0.43?,which indicates that the origin of EC is more complex,which may be due to the decrease of the correlation between OC and EC due to the formation of SOC.?4?The carbon aerosol in the printing room is more serious than in the atmosphere.OC concentration of PM_2.5 in print room was 21.24??·m^-3,EC was4.57??·m^-3,OC concentration of PM_2.5 in bedroom was 1.42??·m^-3,the concentration of EC in print room was obviously higher than that in dormitory.The highest percentage of OC/EC was 0.256-0.382?m in print room and dorm room,but the maximum value of OC/EC in printing room was higher than that in bedroom,which indicated that the pollution of carbon aerosol in printing room was more severe than that in bedroom From the OC/TC of each particle size level,there is no significant difference between the print room and the bedroom.There was significant correlation between OC and EC?R²=0.80?.The correlation between OC and EC in the bedroom was even more significant?R²=0.95?,which indicated that the OC?EC in the print room and the bedroom had similar or common sources.?5?the maximum concentration of OC?EC in indoor and outdoor air was found at the particle size range of 0.256-0.382?m in the accumulation mode.?6?The carbon aerosol and SOC in outdoor atmosphere are mainly influenced by coal combustion and vehicle exhaust.The minimum value of OC/EC in outdoor atmosphere is mainly in the 7th grade?particle size range of 0.256⁰.603?m?,and the minimum value of OC/EC in indoor environment is in the eighth grade?particle size range of 0.382⁰.60?m?.?7?Compared with other cities in China,the concentration of SOC in atmospheric PM2.5 of Nanchang is close to that of other cities in China,but it is obviously lower than that in Beijing.The average value of SOC in PM_2.5 in outdoor atmosphere is 4.79??·m^-3.The existence of secondary organic pollution in all cities indicates that the present situation of SOC pollution is very serious.?8?The concentration of SOC in PM₁₀ and PM_2.5 in printing room was higher than that in ambient air and in room PM₁₀,the concentration of SOC in PM₁₀ was12.28??·m^-3 and the concentration of SOC in PM_2.5 was 10.57??·m^-3.