This chapter is primarily concerned with natural radioactive decay. Generally speaking, there are two types of natural radioactive decays:  alpha-decays "which contain two neutrons and two protons"  emitted from radon gas . Additionally, nuclear  decay by emission of photons (γ-decay) .

This chapter aims to describe γ and alpha loss of nuclei. Demonstrate how to measure the radioactive material naturally using SSNTDs and HPGD. Also it will be presented methods of measuring the different characteristics of the alpha particle using the track profile  method. Finally results will be presented in the alpha measurement and radon measurements. The concentration of aerosols has attracted much attention by many researchers in the past decade. Research has shown that aerosols are responsible for harmful chemical reactions that lead to the physical degradation of the stratospheric ozone layer. Moreover, aerosols increase the risk of developing cancer in humans when inhaled in large proportions. Therefore, the application of a neutron activation analysis (NAA) to measure these concentrations is a very important application