A number of studies have been undertaken to assess the total costs and benefits of air quality controls. The most recent comprehensive assessment was the Evaluation of the Air Quality Strategy, a report presented to DEFRA in 2004.
This evaluated a range of air quality policies covering both industrial and transport measures. It estimated the total cost of the measures at £4 to £6 billion and the benefits at £14 to £69 billion, yielding a benefit cost ratio of between 2.3:1 and 17.2:1. It is important to note that it is not currently possible to quantify all the public health or environmental benefits of improved air quality.