The purpose of the M-l-a District is to encourage the development of manufacturing, wholesale business establishments and research activities which are clean, quiet and free of significant amounts of hazardous or objectionable elements such as noise, odor, dust, smoke, gas, vibration, glare, carcinogens, explosive, toxic or radioactive materials; operate freely within enclosed structures and generate little industrial traffic. This district is further designed to act as a transitional use between heavy - manufacturing uses and other less intensive business and manufacturing uses.