Boris Johnson and London’s toxic air | Letters

Despite claims in your editorial (Boris Johnson leaves London breathing uneasy, 24 February), London's air quality is improving as a direct result of the many bold measures introduced by the mayor to reduce health impacts. Since 2008 these have helped halve the number of Londoners living in areas exceeding legal limits, with the greatest improvements by roads, where people are most exposed. We know this as the mayor and boroughs work with many organisations, including King's College, to deliver a multitude of testing and monitoring systems that are some of the most comprehensive in the world.

The editorial failed to mention that no other country in the world has proposed an ultra-low emission zone with standards as tight as the mayor's. However, its introduction requires a measured approach to take into account the many people who bought vehicles in good faith and have subsequently been let down by Brussels' historic failure to regulate vehicle emissions and approach to dieselisation.