They are categorized as alpha, beta and gamma radiations. Alpha particles are positively charged helium-4 nuclei , beta particles are high energy-high speed electrons while gamma rays unlike alpha and beta radiation have no mass and charge and are short electromagnetic waves consisting of high energy photons. While alpha and beta radiations have low and moderate risk of damage, gamma rays can cause severe damage to internal organs and even death on skin exposure. A brief description of various types of radioactive emissions is given below
i)Alpha radiation alpha particles are helium nuclei with 2 protons and 2 neutrons and hence are positively charged due to which they readily interact with material. Natural alpha radiations have very low penetration power and cannot harm through skin exposure but inhalation of source substances can be quite dangerous.
ii)Beta radiation they are high speed- high energy electrons with penetration power greater than alpha particles due to which the risk of harmful effects to the health of living beings is more.
iii)Gamma radiation they are electromagnetic waves of very short wavelengths with highest penetration power. Unlike alpha and beta radiation they are high energy photons which do not possess mass and charge. They are very harmful for living beings and can cause severe damage to internal organs, DNA mutation and even death.
In case of coal based thermal power plants peoples and authoritys concern seem to be limited to environmental pollution caused by pollutants like carbon dioxide(CO2) ,methane, CFCs( which are responsible for greenhouse effect), oxides of nitrogen and sulphur (which increase atmosphere acidity) and soot particles, organic chemicals( which cause lung problems to the people in the vicinity of plant).