§ 47. Mr. John Hallasked the Secretary of State for Education and Science what further investigations the Medical Research Council's Air Pollution Research Unit has made into the effect of benzpyrene likely to be inhaled each day by residents of densely populated cities, in view of the fact that on the basis of their own estimates the intake of benzpyrene into the lungs under such conditions is three times the amount likely to be inhaled by a smoker smoking 44 cigarettes a day; and what evidence there is that the greater part of the smoke particles inhaled are not retained in the lungs.
§ Mr. Goronwy RobertsThe Medical Research Council's Air Pollution Research Unit (in collaboration with the Statistical Research Unit) has studied mortality in gas workers who in the course of their occupation have been exposed to amounts of benzpyrene over 100 times higher than normal levels in city air.
132WEven in this high concentration of benzpyrene mortality from lung cancer is less than twice that of city residents generally, a finding which supports the view that benzpyrene in the urban atmosphere is not a major factor in the causation of lung cancer. Other long-term epidemiological studies on the effects of air pollution are continuing.
From studies on the inhalation and retention of small particles, particularly in connection with the pneumoconioses, it has been shown that the greater part of these are not permanently retained in the lungs.