Exploring the public's willingness to reduce air pollution and greenhouse gas emissions from private road transport in Catalonia.

Internalizing environmental externalities is a market-driven approach to correcting people's private costs and benefits. One way of quantifying these externalities is estimating the willingness to pay (WTP) of people to reduce them. To better understand the determinants of this WTP, we use the Theory of Planned Behavior (TPB), which is a commonly used approach for predicting behavioral intentions. Our study focuses on air pollution and greenhouse gas (GHG) emissions from private road transport. We gathered survey data from 406 residents of Catalonia to explore the relationships among the psychological factors determining willingness to pay to quantify the mentioned externalities. We expanded the TPB by adding as antecedent Environmental Concern (EC) prior to the theory's three main factors (Attitude, Subjective Norms and Perceived Behavioral Control). Next, we used Structural Equation Modeling (SEM) to calculate an estimate of these externalities. The results of our study show that environmental concern is positively related to the three main factors of TPB. Our model accounts for most of the variation of WTP (R-squared is 94.7%). Our results also reveal that a majority of the respondents in Catalonia are willing to pay to reduce air pollution and GHG emissions from private road transport.