Sir — I am sorry to read that Susan Thomas (Letters, September 26) is concerned about bus fumes. I can reassure her that the Oxford Bus Company has taken enormous strides in reducing and controlling harmful emissions from our fleet through exhaust after-treatments.

For example, we’ve been working hard for Oxford’s environment for many years and from an already low level we’ve cut particulates by two thirds in just the last three years.

One third of our fleet is to the latest Euro 5 standard: in fact we have the greenest bus fleet in the country.

One of our vehicles is far better for the environment than all the private cars that would be needed to replace the buses. Half the people in the centre of Oxford, whether at work or recreation got there by bus. We are literally transporting economic success to the centre of Oxford; an important consideration as the economy faces difficult times.

Philip Kirk, Managing director, Oxford Bus Company