§ Mr. Boswell
To ask the Secretary of State for Transport what evidence he has of the extent of airborne pollution from motorways and of what contribution this makes towards the build-up of toxic heavy metals in the soil; and what action he proposes to take to ameliorate the position.
§ Mr. Peter Bottomley
The Department has collected evidence of the levels of airborne pollution at sites on the M4, M11, M25 and M40 motorways and continues to monitor levels at a site on the M4.
A report prepared in 1974 by the Transport and Road Research Laboratory, "Measurements of Particulate Lead on the M4 Motorway at Harlington", found that lead from vehicle emissions did not significantly affect the composition of the soil at distances in excess of 15 m from the edge of the road. This finding has recently been confirmed by other workers in the field. A copy of this report has been deposited in the Library.
We are beginning to see the beneficial effects of the phased reductions of over 60 per cent. in recent years of the permitted lead content of fuel. The Government have already announced that the vast majority of new cars produced in the United Kingdom after 1990 must be capable of running on lead-free fuel. We expect this action to result in a further substantial reduction of air pollution from vehicles.