Traffic emissions are a significant source of airborne particulate matter(PM)inambient environments.These emissions contain an abundance of toxic metals and thus poseadverse effects on human health.Individual particles were collected at Tang-lang Hill Tunnel inShenzhen and background,and analyzed by TEM-EDX.The results indicated that the individualaerosol particles from vehicle emission in tunnel were classified into the following seven groups:soot aggregates,organic particles,sulfate particles,mineral particles,metal particles,fly ash andmixed particles.The individual particles from vehicle emission in tunnel were mostly includesulfate,soot,mineral and mixed particles,and these four types account for 90%of all the particles.The geometric mean diameter of particles in tunnel was relatively smaller than the background.Sulfate particles easily form an organic coatings in tunnel,and core-shell ratio of sulfate withcoatings was relatively bigger than the background,this phenomenon indicated that the tunnelenvironment may help to form organic coatings on sulfates,but not conducive to further grow up.For the core-shell particles,the cores were mostly mineral,metal and sulfate,the shell was mostlyorganic.The core-shell ratio of core-shell particles was smaller than the sulfate particles,thisphenomenon indicated that the particles with core of mineral and metal were easier to grow up inthe atmosphere.Particle diameter increases with increasing relative humidity.