The Guardian, 19 February 2017:

Air pollution is not just a London problem (Editorial, 17 February). Of the 43 zones currently monitored in the UK, 38 fail EU standards for NO2, so any strategy has to be nationwide and not left to individual councils.

The most likely government response is an extension of clean air zones, but there are serious doubts as to whether this will improve public health. First, designating certain areas as clean does nothing to reduce total emissions; it merely diverts them elsewhere. Second, the health effects of NO2 and particulates are without threshold, so reducing levels below an arbitrary limit may make sense politically, but will have little effect biologically. Third, the projected improvement in air quality is predicated upon new vehicles producing less NO2 in line with stricter EU vehicle emission tests, but we already know that emissions of NO2 “on the road” are four to five times greater than in laboratory tests, a discrepancy that even applies to the latest Euro 6 engines. Finally, studies of London schoolchildren showed no improvement in lung function after three years living in a low-emission zone.

As your leader proposes, we are in urgent need of a new Clean Air Act that hastens the demise of diesel and other highly polluting technologies, something the government could and should have championed more than 20 years ago.

Dr Robin Russell-Jones
Former chair CLEAR, Campaign for Lead Free Air, Stoke Poges, Buckinghamshire