2.3. Payment vehicle
The manner, in which the payment of the WTP amount is made, including the timing and duration of the payment, is known as the payment vehicle. This study applied an out-of-pocket voluntary payment vehicle. We asked respondents their annual contribution for the rest of their lives. For example: “A 50% decrease in air pollution emissions by 2030 will increase life expectancy by 6 months. What is the maximum amount of money you would be willing to pay (annually, for the rest of your life) to gain 6 months of life expectancy? The maximum amount of money I am willing to pay is..... € or £ | per year”. The conversion from Pounds to Euros was based on 2010 exchange rate. Respondents were reminded to take their annual household net income into account prior to answering the WTP questions what they as a person would be willing to pay.