MEASUREMENT AND ASSESSMENT OF INDOOR AND OUTDOOR AMBIENT RADIATION LEVELS AT THE TAKE-OFF SITE
CHAPTER ONE
INTRODUCTION
1.1 Background to the Study
Radiation is any form of energy propagated as rays, waves, or stream of particles which could be ionizing and non-ionizing. Ionizing radiation produces ionization when it passes through matter and is more harmful than non-ionizing radiation (IAEA, 1986). Ionizing radiation is that type of radiation which is able to produce ions that is capable of disrupting life processes. Non ionizing radiations are not able to create ions, although they may adversely affect human health in other ways. Man is by the very nature of his environment exposed to varying amounts of ambient radiation with or without his consent. The ambient radiation encompasses both the natural and man-made (artificial radioactivity) ionizing radiation in the environment (Farai and Vincent, 2006). Natural radioactivity has great ionizing radiation effect on the world population due to its presence in our surrounding at different amounts. Natural radioactive materials are found in rocks, soil, air, food and drinking water.
The natural environment therefore is a major source of radiation to which man is exposed. Ionizing radiation from natural sources that we are all exposed to at all times is called natural background radiation. Man-made radiation is generated in range of medical, commercial and industrial activities. The most familiar and, in national terms, the largest of these sources of exposure is medical X-rays (Hunt, 1987). We are all exposed to ionizing radiation from natural sources at all times. Natural background radiation is inevitably present in our environment (Hunt, 1987). Levels can vary greatly. A lot of our natural exposure is due to radon, a gas which seeps from the earth crust and is present in the air we breathe. The main sources of natural radiation are the following: terrestrial radiation, soil, gas, cosmic radiation and natural radioactivity in the body (Osiga, 2014). International Commission on Radialogical Protection (ICRP, 1990) set worldwide annual equivalent dose rate of ionizing radiation to 2.4 mSv/yr limit for protection of human being. At high doses, ionizing radiation is dangerous. The geology of Dutsin-Ma in which the school is situated, reveals that it is highly enriched in granite rocks. The specific levels of radiation are related to the types of rock from which the soils originate. Higher radiation levels are associated with igneous rocks, such as granite, and lower levels with sedimentary rocks (Sadiq and Agba, 2012). It is therefore necessary to know the level of radiation within our living environment because of its health implications to life.
1.2 Aim and Objectives of the Study
In line with the study problems stated above, the aim of this work is to measure and analyze the indoor and outdoor ambient radiation levels at the take-off campus of Federal University Dutsin-Ma, Katsina State. The specific objectives of this study are:
i. To measure the ionization radiation in and outside the buildings of Federal University Dutsin-Ma take-off campus.
ii. To compute from the data of the field radiation measurements the annual absorbed dose in the air and the distribution of effective dose in land and buildings in milliSeviet per year (mSv/yr).
iii. To compare and check the safety of human beings as a result of the computed radiation distribution for the study area using the ICRP (1990) worldwide average equivalent dose rate of 2.4 mSv/yr for human being protection as basis.