The term “atmospheric aerosol particles” means the particles suspended in the air, generally about 0.001 to 100 μm in size (Willeke and Baron 1993).

Since there are many aerosol sources, atmospheric aerosol particles composed of various materials are present in a wide size range. Thus the atmospheric aerosols form a size spectrum that extends over about four orders of magnitude. After the generation, the growth of particles occurs by coagulation and gas-to-particle conversion processes in the atmosphere. The growth corresponds to the modifi cation of aerosol particles and would make aerosol particles of mixed composition.