Size, composition, and mixing state of individual aerosol particles in a South China coastal city

Aerosol samples were collected in summer in Macao,a coastal city of the Pearl River Delta Region in China.Morphology,size,elemental composition,and mixing state of individual aerosol particles were determined by scanning electron microscopy coupled energy dispersive X-ray(SEM/EDX) and transmission electron microscopy(TEM).Based on the morphologies of 5711 aerosol particles,they consist of soot(32%),mineral(17%),secondary(22%),and unknown fine particles(29%).The sizes of these particles were mostly distributed between 0.1 and 0.4 μm.Compositions of 202 mineral particles were obtained by SEM/EDX.Mineral particles were mainly classified into three types:Si-rich,Ca-rich,and Na-rich.The compositions of typical mineral particles can indicate their sources in sampling location.For example,mineral particles,collected along the main street,were associated with trace amounts of heavy metals,such as Zn,Ti,Mn,Ba,Pb,and As.TEM observations indicate that most Na-rich particles were aged sea salt particles(e.g.,Na2SO4 and NaNO3) which formed through heterogeneous chemical reactions between sea salt and acidic gases.Additionally,aging time of soot was short in Macao due to high humidity,high temperature,and high levels of sunlight in Macao.Most of soot and fine mineral dust particles were internally mixed with secondary particles.     

历史上四月发生的危险化学品事故

石油化工.福建省漳州市腾龙芳烃(漳州)有限公司“4?6”爆炸着火事故.2015年4月6日,位于福建省漳州市古雷港经济开发区的腾龙芳烃(漳州)有限公司二甲苯装置发生重大爆炸着火事故,造成6人受伤,另有13名周边群众留院观察,直接经济损失9457万元。事故的直接原因是公司在二甲苯装置开工引料过程中出现压力和流量波动,引发液击,致使存在焊接质量问题的管道焊口断裂,物料外泄。