Physical And Chemical Characteristics Of Singleaerosol Particles In Fengfeng Mining Area

The development and utilization of numerous coal resources will produce certain atmospheric pollutants,which will affect the air quality of the mining area,and even affect the air quality of nearby cities.In this study,Fengfeng mining area was selected,aerosol single particles were collected under different weather conditions in different seasons,and the morphological features,particle size and the composition of chemical elements of the particles were analyzed by TEM-EDX and SEM.The single particles were classified into soot aggregates,mineral particles,spherical particles and other particles to the microscopic morphology of the aerosol under the SEM.Also,basing on the aerosol microscopic morphology and elemental composition under the TEM-EDX,five categories were classified:soot aggregates,sulfate/nitrate particles,fly ash,mineral particles and metal particles.Through images of TEM were showed,it is mainly irregular particles in spring,which is related to the air dust caused by dry climate and high wind speed in spring;there are more spherical particles in summer,mainly due to strong secondary reactions.And there are mainly spherical particles found in autumn,and particles with large air humidity are prone to weathering in autumn.Samples of winter are collected during the Lantern Festival,the irregular particles mostly produced by setting off fireworks.Some of the number-particle size distribution map of atmospheric particulate matter in the mining area are multi-peak distribution and single-peak distribution,it is mainly multi-peak.The primary of atmospheric particle size in spring is between 0.5-0.6μm,the primary of particle size in summer is between 0.9-1.0μm,and the primary peak of non-haze climate is distributed between 0.6-0.7μm.The primary of particle size in autumn haze days and non-haze days is between 0.6-0.7μm.In winter,the primary peak of particulate matter is between 0.3-0.4μm,and the peak of non-haze days is distributed between 0.7-0.8μm.In winter,the air humidity is large,and the water absorbent particle size of particulate matter is obviously larger than that of grain particles in haze days.The needle-like ratio characteristics of particulate matter were analyzed,the circularity of particles was good in summer and aging was serious.Hygroscopic particles with nuclear shell structure,the hygroscopicity of haze days is stronger than in non-haze days in summer and autumn.Aging particles with nuclear shell structure,the particles of haze days are more serious than non-haze days in summer and autumn.Comparing the chemical element composition of atmospheric particles in the four seasons,the elements of Si,S,Na,Al,Ca,K are distributed in this area.The content of Si elements in spring is high,which is related to the wind and sand;In summer,the content of S element is high,the vulcanization is serious,and the content of K element is high due to biomass combustion.Si and S are present in almost every particle in autumn.Most of the particulate matter in winter contains a small amount of S.As the sampling period is during the Lantern Festival,and the firework can generate K₂S after ignition,resulting in 46%of the particulate matter containing K element.The analysis of single particle EXD energy spectrum shows that there are 10 types of mineral particles in the four seasons in Fengfeng mining area,which are“Si-rich”,“Ca-rich”,“K-rich”,“S-rich”,“Fe-rich”,“N-rich”,“Mg-rich”,“Na-rich”,“Al-rich”and“Cl-rich”.The Al+Ca+Fe-Si-S triangle phase diagram of mineral particles observed in the four seasons was found that the S content in summer is higher than that in other seasons.