Title: Willingness to pay to reduce health risks of air pollution – the effect from survey mode and current air quality
Abstract: We examine whether willingness to pay (WTP) for reducing long-term health risks associated with air pollution depends on the stated preference survey mode and the prevailing air quality conditions. We conduct web-based and face-to-face (f2f) surveys in Beijing, China, during the winter between 2016 and 2017. The results indicate that the web-based survey mode yields a higher proportion of responses on days with higher pollution levels compared to the f2f mode. Using matching to generate two comparable web and f2f subsamples, we observe that WTP estimates are generally lower in the f2f subsample compared to the web subsample, especially for the mortality and timeliness elements in health risks. We also find evidence that current air pollution levels affect the extensive margin in the web survey mode by increasing willingness to participate in the survey, and the intensive margin in both survey modes by shifting marginal WTP. Several demographics-specific survey mode effects are also observed for WTP and scale heterogeneity.
