Toxic air: problems and solutions

Channel 4 Dispatches has regularly broadcast investigations into our polluted air. In February, it had the easy target of New Street rail station in Birmingham. Tonight's programme was more worrying, as it concentrated on a primary school in suburban North London. A group of pupils was given back-packs which measured such dangerous pollutants as nitrogen dioxide and nanoparticles. The investigators found that nitrogen dioxide levels occasionally exceeded international safety standards. A more surprising finding was that in addition to particles produced from internal combustion engines, there were also tiny fragments of artificial rubber from tyres and what appeared to be brake dust. Even if we go all-electric, these two will continue to be a hazard.

Reduction of vehicle emissions affecting the school was achieved by the obvious expedient of forcing children to walk to school rather than be dropped off from a car by a family member. One wonders how long this self-denial continued after the experiment, in spite of the demonstrated health benefits. As a primary school governor for a short time, I know how difficult it is to persuade parents - and quite often grandparents who like to feel useful - to give up the children's car-rides. And that was in a school where most of the teachers were onside.

The experiment included greening the school by draping ivy on walls where the leaves could trap pollutants and also making a garden for the children. It was not clear how much these efforts contributed to the marked reduction in air pollution by the school. A proper experiment would have needed two or three very similar schools but with different measures to be carried out, and over a longer time-scale than a half-hour TV documentary could afford. (The bill for the modifications to the school in tonight's programme totalled £30,000, though this did include a sophisticated air purification unit for the worst affected classroom.)

We in Wales have our roadside pollution black-spots, too, and the experts say that far more than the seven most obvious areas targetted by the Welsh government experience damaging levels of pollution.