• LAURA Kirkwood repeats the canard, so recently refuted here, that impeding traffic will make air pollution worse, (Object to the Judd Street scheme, September 20).

As we have shown, we will not get air that is safe to breathe without reducing traffic. It is easy to confuse motor traffic with rain. Both descend on our streets. The drains carry away what the weather brings.

But cars and vans do not fall from the sky. Their volume is a function of vehicle and fuel prices and taxes, of road and parking capacity, and the availability of alternatives. These are products of public policy, not nature.

Building or widening roads raises traffic volume; narrowing or closing them reduces it. Fewer essential motor trips will be made in other ways or not at all; the essential ones Ms Kirkwood worries about will still be made.

KATHIE CONN, DORO MARDEN, BEN PAUL,
STEPHEN TAYLOR and RACHEL WRANGHAM
Camden Air Action