Aerosol research needs various analytical instruments.
Many of the aerosol particles are less than one micrometer in size, which makes it difficult to observe under an optical microscope. Electron microscope is used to investigate different types of particles and their characteristics. Unlike optical microscope, which uses light to magnify the image of an object (such as magnifying glasses), electron microscope uses electron beam, which has much shorter wavelength and theoretically enables to observe an atomic level of objects. By using electron microscope and the sample's interference effect, their compositions, crystal structure, and chemical bonding state can be analyzed.
There are two different types of electron microscope; TEM and SEM. The difference between the two are that TEM uses transmitted electron beam to analyze the sample, while SEM uses secondary or backscattering electrons. TEM has following advantages: 1) it can observe the internal structures of a sample and 2) it obtains higher resolution. On the other hand, since TEM uses a transmitted electron beam, the sample must be thin, and TEM needs high voltage and high vacuum. On the other hand, SEM uses secondary electron which makes it easier to analyze the surface of samples. The weakness of using SEM is that an electron beam spread within a samples, making it difficult to gain a high resolution mages. TEM is normally used to observe the inner structure of particles smaller than 1 micrometer, and SEM is used when particles are bigger than that.
Some aerosol particles contain Nitrate, Sulfate, Chloride, and Ammonium. In order to understand the compositions and amount of aerosol particles in the atmosphere, we use IC.